doc/src/sgml/release-8.3.sgml

   1 <!-- $PostgreSQL$ -->
   2 <!-- See header comment in release.sgml about typical markup -->
   3
   4  <sect1 id="release-8-3-7">
   5   <title>Release 8.3.7</title>
   6
   7   <note>
   8   <title>Release date</title>
   9   <simpara>2009-03-16</simpara>
  10   </note>
  11
  12   <para>
  13    This release contains a variety of fixes from 8.3.6.
  14    For information about new features in the 8.3 major release, see
  15    <xref linkend="release-8-3">.
  16   </para>
  17
  18   <sect2>
  19    <title>Migration to Version 8.3.7</title>
  20
  21    <para>
  22     A dump/restore is not required for those running 8.3.X.
  23     However, if you are upgrading from a version earlier than 8.3.5,
  24     see the release notes for 8.3.5.
  25    </para>
  26
  27   </sect2>
  28
  29   <sect2>
  30    <title>Changes</title>
  31
  32    <itemizedlist>
  33
  34     <listitem>
  35      <para>
  36       Prevent error recursion crashes when encoding conversion fails (Tom)
  37      </para>
  38
  39      <para>
  40       This change extends fixes made in the last two minor releases for
  41       related failure scenarios.  The previous fixes were narrowly tailored
  42       for the original problem reports, but we have now recognized that
  43       <emphasis>any</> error thrown by an encoding conversion function could
  44       potentially lead to infinite recursion while trying to report the
  45       error.  The solution therefore is to disable translation and encoding
  46       conversion and report the plain-ASCII form of any error message,
  47       if we find we have gotten into a recursive error reporting situation.
  48       (CVE-2009-0922)
  49      </para>
  50     </listitem>
  51
  52     <listitem>
  53      <para>
  54       Disallow <command>CREATE CONVERSION</> with the wrong encodings
  55       for the specified conversion function (Heikki)
  56      </para>
  57
  58      <para>
  59       This prevents one possible scenario for encoding conversion failure.
  60       The previous change is a backstop to guard against other kinds of
  61       failures in the same area.
  62      </para>
  63     </listitem>
  64
  65     <listitem>
  66      <para>
  67       Fix <function>xpath()</> to not modify the path expression unless
  68       necessary, and to make a saner attempt at it when necessary (Andrew)
  69      </para>
  70
  71      <para>
  72       The SQL standard suggests that <function>xpath</> should work on data
  73       that is a document fragment, but <application>libxml</> doesn't support
  74       that, and indeed it's not clear that this is sensible according to the
  75       XPath standard.  <function>xpath</> attempted to work around this
  76       mismatch by modifying both the data and the path expression, but the
  77       modification was buggy and could cause valid searches to fail.  Now,
  78       <function>xpath</> checks whether the data is in fact a well-formed
  79       document, and if so invokes <application>libxml</> with no change to the
  80       data or path expression.  Otherwise, a different modification method
  81       that is somewhat less likely to fail is used.
  82      </para>
  83
  84      <note>
  85       <para>
  86        The new modification method is still not 100% satisfactory, and it
  87        seems likely that no real solution is possible.  This patch should
  88        therefore be viewed as a band-aid to keep from breaking existing
  89        applications unnecessarily.  It is likely that
  90        <productname>PostgreSQL</> 8.4 will simply reject use of
  91        <function>xpath</> on data that is not a well-formed document.
  92       </para>
  93      </note>
  94     </listitem>
  95
  96     <listitem>
  97      <para>
  98       Fix core dump when <function>to_char()</> is given format codes that
  99       are inappropriate for the type of the data argument (Tom)
 100      </para>
 101     </listitem>
 102
 103     <listitem>
 104      <para>
 105       Fix possible failure in text search when C locale is used with
 106       a multi-byte encoding (Teodor)
 107      </para>
 108
 109      <para>
 110       Crashes were possible on platforms where <type>wchar_t</> is narrower
 111       than <type>int</>; Windows in particular.
 112      </para>
 113     </listitem>
 114
 115     <listitem>
 116      <para>
 117       Fix extreme inefficiency in text search parser's handling of an
 118       email-like string containing multiple <literal>@</> characters (Heikki)
 119      </para>
 120     </listitem>
 121
 122     <listitem>
 123      <para>
 124       Fix planner problem with sub-<command>SELECT</> in the output list
 125       of a larger subquery (Tom)
 126      </para>
 127
 128      <para>
 129       The known symptom of this bug is a <quote>failed to locate grouping
 130       columns</> error that is dependent on the datatype involved;
 131       but there could be other issues as well.
 132      </para>
 133     </listitem>
 134
 135     <listitem>
 136      <para>
 137       Fix decompilation of <literal>CASE WHEN</> with an implicit coercion
 138       (Tom)
 139      </para>
 140
 141      <para>
 142       This mistake could lead to Assert failures in an Assert-enabled build,
 143       or an <quote>unexpected CASE WHEN clause</> error message in other
 144       cases, when trying to examine or dump a view.
 145      </para>
 146     </listitem>
 147
 148     <listitem>
 149      <para>
 150       Fix possible misassignment of the owner of a TOAST table's rowtype (Tom)
 151      </para>
 152
 153      <para>
 154       If <command>CLUSTER</> or a rewriting variant of <command>ALTER TABLE</>
 155       were executed by someone other than the table owner, the
 156       <structname>pg_type</> entry for the table's TOAST table would end up
 157       marked as owned by that someone.  This caused no immediate problems,
 158       since the permissions on the TOAST rowtype aren't examined by any
 159       ordinary database operation.  However, it could lead to unexpected
 160       failures if one later tried to drop the role that issued the command
 161       (in 8.1 or 8.2), or <quote>owner of data type appears to be invalid</>
 162       warnings from <application>pg_dump</> after having done so (in 8.3).
 163      </para>
 164     </listitem>
 165
 166     <listitem>
 167      <para>
 168       Change <command>UNLISTEN</> to exit quickly if the current session has
 169       never executed any <command>LISTEN</> command (Tom)
 170      </para>
 171
 172      <para>
 173       Most of the time this is not a particularly useful optimization, but
 174       since <command>DISCARD ALL</> invokes <command>UNLISTEN</>, the previous
 175       coding caused a substantial performance problem for applications that
 176       made heavy use of <command>DISCARD ALL</>.
 177      </para>
 178     </listitem>
 179
 180     <listitem>
 181      <para>
 182       Fix PL/pgSQL to not treat <literal>INTO</> after <command>INSERT</> as
 183       an INTO-variables clause anywhere in the string, not only at the start;
 184       in particular, don't fail for <command>INSERT INTO</> within
 185       <command>CREATE RULE</> (Tom)
 186      </para>
 187     </listitem>
 188
 189     <listitem>
 190      <para>
 191       Clean up PL/pgSQL error status variables fully at block exit
 192       (Ashesh Vashi and Dave Page)
 193      </para>
 194
 195      <para>
 196       This is not a problem for PL/pgSQL itself, but the omission could cause
 197       the PL/pgSQL Debugger to crash while examining the state of a function.
 198      </para>
 199     </listitem>
 200
 201     <listitem>
 202      <para>
 203       Retry failed calls to <function>CallNamedPipe()</> on Windows
 204       (Steve Marshall, Magnus)
 205      </para>
 206
 207      <para>
 208       It appears that this function can sometimes fail transiently;
 209       we previously treated any failure as a hard error, which could
 210       confuse <command>LISTEN</>/<command>NOTIFY</> as well as other
 211       operations.
 212      </para>
 213     </listitem>
 214
 215     <listitem>
 216      <para>
 217       Add <literal>MUST</> (Mauritius Island Summer Time) to the default list
 218       of known timezone abbreviations (Xavier Bugaud)
 219      </para>
 220     </listitem>
 221
 222    </itemizedlist>
 223
 224   </sect2>
 225  </sect1>
 226
 227  <sect1 id="release-8-3-6">
 228   <title>Release 8.3.6</title>
 229
 230   <note>
 231   <title>Release date</title>
 232   <simpara>2009-02-02</simpara>
 233   </note>
 234
 235   <para>
 236    This release contains a variety of fixes from 8.3.5.
 237    For information about new features in the 8.3 major release, see
 238    <xref linkend="release-8-3">.
 239   </para>
 240
 241   <sect2>
 242    <title>Migration to Version 8.3.6</title>
 243
 244    <para>
 245     A dump/restore is not required for those running 8.3.X.
 246     However, if you are upgrading from a version earlier than 8.3.5,
 247     see the release notes for 8.3.5.
 248    </para>
 249
 250   </sect2>
 251
 252   <sect2>
 253    <title>Changes</title>
 254
 255    <itemizedlist>
 256
 257     <listitem>
 258      <para>
 259       Make <command>DISCARD ALL</> release advisory locks, in addition
 260       to everything it already did (Tom)
 261      </para>
 262
 263      <para>
 264       This was decided to be the most appropriate behavior.  This could
 265       affect existing applications, however.
 266      </para>
 267     </listitem>
 268
 269     <listitem>
 270      <para>
 271       Fix whole-index GiST scans to work correctly (Teodor)
 272      </para>
 273
 274      <para>
 275       This error could cause rows to be lost if a table is clustered
 276       on a GiST index.
 277      </para>
 278     </listitem>
 279
 280     <listitem>
 281      <para>
 282       Fix crash of <literal>xmlconcat(NULL)</> (Peter)
 283      </para>
 284     </listitem>
 285
 286     <listitem>
 287      <para>
 288       Fix possible crash in <literal>ispell</> dictionary if high-bit-set
 289       characters are used as flags (Teodor)
 290      </para>
 291
 292      <para>
 293       This is known to be done by one widely available Norwegian dictionary,
 294       and the same condition may exist in others.
 295      </para>
 296     </listitem>
 297
 298     <listitem>
 299      <para>
 300       Fix misordering of <application>pg_dump</> output for composite types
 301       (Tom)
 302      </para>
 303
 304      <para>
 305       The most likely problem was for user-defined operator classes to
 306       be dumped after indexes or views that needed them.
 307      </para>
 308     </listitem>
 309
 310     <listitem>
 311      <para>
 312       Improve handling of URLs in <function>headline()</> function (Teodor)
 313      </para>
 314     </listitem>
 315
 316     <listitem>
 317      <para>
 318       Improve handling of overlength headlines in <function>headline()</>
 319       function (Teodor)
 320      </para>
 321     </listitem>
 322
 323     <listitem>
 324      <para>
 325       Prevent possible Assert failure or misconversion if an encoding
 326       conversion is created with the wrong conversion function for the
 327       specified pair of encodings (Tom, Heikki)
 328      </para>
 329     </listitem>
 330
 331     <listitem>
 332      <para>
 333       Fix possible Assert failure if a statement executed in PL/pgSQL is
 334       rewritten into another kind of statement, for example if an
 335       <command>INSERT</> is rewritten into an <command>UPDATE</> (Heikki)
 336      </para>
 337     </listitem>
 338
 339     <listitem>
 340      <para>
 341       Ensure that a snapshot is available to datatype input functions (Tom)
 342      </para>
 343
 344      <para>
 345       This primarily affects domains that are declared with <literal>CHECK</>
 346       constraints involving user-defined stable or immutable functions.  Such
 347       functions typically fail if no snapshot has been set.
 348      </para>
 349     </listitem>
 350
 351     <listitem>
 352      <para>
 353       Make it safer for SPI-using functions to be used within datatype I/O;
 354       in particular, to be used in domain check constraints (Tom)
 355      </para>
 356     </listitem>
 357
 358     <listitem>
 359      <para>
 360       Avoid unnecessary locking of small tables in <command>VACUUM</>
 361       (Heikki)
 362      </para>
 363     </listitem>
 364
 365     <listitem>
 366      <para>
 367       Fix a problem that sometimes kept <command>ALTER TABLE ENABLE/DISABLE
 368       RULE</> from being recognized by active sessions (Tom)
 369      </para>
 370     </listitem>
 371
 372     <listitem>
 373      <para>
 374       Fix a problem that made <literal>UPDATE RETURNING tableoid</>
 375       return zero instead of the correct OID (Tom)
 376      </para>
 377     </listitem>
 378
 379     <listitem>
 380      <para>
 381       Allow functions declared as taking <type>ANYARRAY</> to work on
 382       the <structname>pg_statistic</> columns of that type (Tom)
 383      </para>
 384
 385      <para>
 386       This used to work, but was unintentionally broken in 8.3.
 387      </para>
 388     </listitem>
 389
 390     <listitem>
 391      <para>
 392       Fix planner misestimation of selectivity when transitive equality
 393       is applied to an outer-join clause (Tom)
 394      </para>
 395
 396      <para>
 397       This could result in bad plans for queries like
 398       <literal>... from a left join b on a.a1 = b.b1 where a.a1 = 42 ...</>
 399      </para>
 400     </listitem>
 401
 402     <listitem>
 403      <para>
 404       Improve optimizer's handling of long <literal>IN</> lists (Tom)
 405      </para>
 406
 407      <para>
 408       This change avoids wasting large amounts of time on such lists
 409       when constraint exclusion is enabled.
 410      </para>
 411     </listitem>
 412
 413     <listitem>
 414      <para>
 415       Prevent synchronous scan during GIN index build (Tom)
 416      </para>
 417
 418      <para>
 419       Because GIN is optimized for inserting tuples in increasing TID order,
 420       choosing to use a synchronous scan could slow the build by a factor of
 421       three or more.
 422      </para>
 423     </listitem>
 424
 425     <listitem>
 426      <para>
 427       Ensure that the contents of a holdable cursor don't depend on the
 428       contents of TOAST tables (Tom)
 429      </para>
 430
 431      <para>
 432       Previously, large field values in a cursor result might be represented
 433       as TOAST pointers, which would fail if the referenced table got dropped
 434       before the cursor is read, or if the large value is deleted and then
 435       vacuumed away.  This cannot happen with an ordinary cursor,
 436       but it could with a cursor that is held past its creating transaction.
 437      </para>
 438     </listitem>
 439
 440     <listitem>
 441      <para>
 442       Fix memory leak when a set-returning function is terminated without
 443       reading its whole result (Tom)
 444      </para>
 445     </listitem>
 446
 447     <listitem>
 448      <para>
 449       Fix encoding conversion problems in XML functions when the database
 450       encoding isn't UTF-8 (Tom)
 451      </para>
 452     </listitem>
 453
 454     <listitem>
 455      <para>
 456       Fix <filename>contrib/dblink</>'s
 457       <function>dblink_get_result(text,bool)</> function (Joe)
 458      </para>
 459     </listitem>
 460
 461     <listitem>
 462      <para>
 463       Fix possible garbage output from <filename>contrib/sslinfo</> functions
 464       (Tom)
 465      </para>
 466     </listitem>
 467
 468     <listitem>
 469      <para>
 470       Fix incorrect behavior of <filename>contrib/tsearch2</> compatibility
 471       trigger when it's fired more than once in a command (Teodor)
 472      </para>
 473     </listitem>
 474
 475     <listitem>
 476      <para>
 477       Fix possible mis-signaling in autovacuum (Heikki)
 478      </para>
 479     </listitem>
 480
 481     <listitem>
 482      <para>
 483       Support running as a service on Windows 7 beta (Dave and Magnus)
 484      </para>
 485     </listitem>
 486
 487     <listitem>
 488      <para>
 489       Fix <application>ecpg</>'s handling of varchar structs (Michael)
 490      </para>
 491     </listitem>
 492
 493     <listitem>
 494      <para>
 495       Fix <application>configure</> script to properly report failure when
 496       unable to obtain linkage information for PL/Perl (Andrew)
 497      </para>
 498     </listitem>
 499
 500     <listitem>
 501      <para>
 502       Make all documentation reference <literal>pgsql-bugs</> and/or
 503       <literal>pgsql-hackers</> as appropriate, instead of the
 504       now-decommissioned <literal>pgsql-ports</> and <literal>pgsql-patches</>
 505       mailing lists (Tom)
 506      </para>
 507     </listitem>
 508
 509     <listitem>
 510      <para>
 511       Update time zone data files to <application>tzdata</> release 2009a (for
 512       Kathmandu and historical DST corrections in Switzerland, Cuba)
 513      </para>
 514     </listitem>
 515
 516    </itemizedlist>
 517
 518   </sect2>
 519  </sect1>
 520
 521  <sect1 id="release-8-3-5">
 522   <title>Release 8.3.5</title>
 523
 524   <note>
 525   <title>Release date</title>
 526   <simpara>2008-11-03</simpara>
 527   </note>
 528
 529   <para>
 530    This release contains a variety of fixes from 8.3.4.
 531    For information about new features in the 8.3 major release, see
 532    <xref linkend="release-8-3">.
 533   </para>
 534
 535   <sect2>
 536    <title>Migration to Version 8.3.5</title>
 537
 538    <para>
 539     A dump/restore is not required for those running 8.3.X.
 540     However, if you are upgrading from a version earlier than 8.3.1,
 541     see the release notes for 8.3.1.  Also, if you were running a previous
 542     8.3.X release, it is recommended to <command>REINDEX</> all GiST
 543     indexes after the upgrade.
 544    </para>
 545
 546   </sect2>
 547
 548   <sect2>
 549    <title>Changes</title>
 550
 551    <itemizedlist>
 552
 553     <listitem>
 554      <para>
 555       Fix GiST index corruption due to marking the wrong index entry
 556       <quote>dead</> after a deletion (Teodor)
 557      </para>
 558
 559      <para>
 560       This would result in index searches failing to find rows they
 561       should have found.  Corrupted indexes can be fixed with
 562       <command>REINDEX</>.
 563      </para>
 564     </listitem>
 565
 566     <listitem>
 567      <para>
 568       Fix backend crash when the client encoding cannot represent a localized
 569       error message (Tom)
 570      </para>
 571
 572      <para>
 573       We have addressed similar issues before, but it would still fail if
 574       the <quote>character has no equivalent</> message itself couldn't
 575       be converted.  The fix is to disable localization and send the plain
 576       ASCII error message when we detect such a situation.
 577      </para>
 578     </listitem>
 579
 580     <listitem>
 581      <para>
 582       Fix possible crash in <type>bytea</>-to-XML mapping (Michael McMaster)
 583      </para>
 584     </listitem>
 585
 586     <listitem>
 587      <para>
 588       Fix possible crash when deeply nested functions are invoked from
 589       a trigger (Tom)
 590      </para>
 591     </listitem>
 592
 593     <listitem>
 594      <para>
 595       Improve optimization of <replaceable>expression</> <literal>IN</>
 596       (<replaceable>expression-list</>) queries (Tom, per an idea from Robert
 597       Haas)
 598      </para>
 599
 600      <para>
 601       Cases in which there are query variables on the right-hand side had been
 602       handled less efficiently in 8.2.x and 8.3.x than in prior versions.
 603       The fix restores 8.1 behavior for such cases.
 604      </para>
 605     </listitem>
 606
 607     <listitem>
 608      <para>
 609       Fix mis-expansion of rule queries when a sub-<literal>SELECT</> appears
 610       in a function call in <literal>FROM</>,  a multi-row <literal>VALUES</>
 611       list, or a <literal>RETURNING</> list (Tom)
 612      </para>
 613
 614      <para>
 615       The usual symptom of this problem is an <quote>unrecognized node type</>
 616       error.
 617      </para>
 618     </listitem>
 619
 620     <listitem>
 621      <para>
 622       Fix Assert failure during rescan of an <literal>IS NULL</>
 623       search of a GiST index (Teodor)
 624      </para>
 625     </listitem>
 626
 627     <listitem>
 628      <para>
 629       Fix memory leak during rescan of a hashed aggregation plan (Neil)
 630      </para>
 631     </listitem>
 632
 633     <listitem>
 634      <para>
 635       Ensure an error is reported when a newly-defined PL/pgSQL trigger
 636       function is invoked as a normal function (Tom)
 637      </para>
 638     </listitem>
 639
 640     <listitem>
 641      <para>
 642       Force a checkpoint before <command>CREATE DATABASE</> starts to copy
 643       files (Heikki)
 644      </para>
 645
 646      <para>
 647       This prevents a possible failure if files had recently been deleted
 648       in the source database.
 649      </para>
 650     </listitem>
 651
 652     <listitem>
 653      <para>
 654       Prevent possible collision of <structfield>relfilenode</> numbers
 655       when moving a table to another tablespace with <command>ALTER SET
 656       TABLESPACE</> (Heikki)
 657      </para>
 658
 659      <para>
 660       The command tried to re-use the existing filename, instead of
 661       picking one that is known unused in the destination directory.
 662      </para>
 663     </listitem>
 664
 665     <listitem>
 666      <para>
 667       Fix incorrect text search headline generation when single query
 668       item matches first word of text (Sushant Sinha)
 669      </para>
 670     </listitem>
 671
 672     <listitem>
 673      <para>
 674       Fix improper display of fractional seconds in interval values when
 675       using a non-ISO datestyle in an <option>--enable-integer-datetimes</>
 676       build (Ron Mayer)
 677      </para>
 678     </listitem>
 679
 680     <listitem>
 681      <para>
 682       Make <literal>ILIKE</> compare characters case-insensitively
 683       even when they're escaped (Andrew)
 684      </para>
 685     </listitem>
 686
 687     <listitem>
 688      <para>
 689       Ensure <command>DISCARD</> is handled properly by statement logging (Tom)
 690      </para>
 691     </listitem>
 692
 693     <listitem>
 694      <para>
 695       Fix incorrect logging of last-completed-transaction time during
 696       PITR recovery (Tom)
 697      </para>
 698     </listitem>
 699
 700     <listitem>
 701      <para>
 702       Ensure <function>SPI_getvalue</> and <function>SPI_getbinval</>
 703       behave correctly when the passed tuple and tuple descriptor have
 704       different numbers of columns (Tom)
 705      </para>
 706
 707      <para>
 708       This situation is normal when a table has had columns added or removed,
 709       but these two functions didn't handle it properly.
 710       The only likely consequence is an incorrect error indication.
 711      </para>
 712     </listitem>
 713
 714     <listitem>
 715      <para>
 716       Mark <varname>SessionReplicationRole</> as <literal>PGDLLIMPORT</>
 717       so it can be used by <application>Slony</> on Windows (Magnus)
 718      </para>
 719     </listitem>
 720
 721     <listitem>
 722      <para>
 723       Fix small memory leak when using <application>libpq</>'s
 724       <literal>gsslib</> parameter (Magnus)
 725      </para>
 726
 727      <para>
 728       The space used by the parameter string was not freed at connection
 729       close.
 730      </para>
 731     </listitem>
 732
 733     <listitem>
 734      <para>
 735       Ensure <application>libgssapi</> is linked into <application>libpq</>
 736       if needed (Markus Schaaf)
 737      </para>
 738     </listitem>
 739
 740     <listitem>
 741      <para>
 742       Fix <application>ecpg</>'s parsing of <command>CREATE ROLE</> (Michael)
 743      </para>
 744     </listitem>
 745
 746     <listitem>
 747      <para>
 748       Fix recent breakage of <literal>pg_ctl restart</> (Tom)
 749      </para>
 750     </listitem>
 751
 752     <listitem>
 753      <para>
 754       Ensure <filename>pg_control</> is opened in binary mode
 755       (Itagaki Takahiro)
 756      </para>
 757
 758      <para>
 759       <application>pg_controldata</> and <application>pg_resetxlog</>
 760       did this incorrectly, and so could fail on Windows.
 761      </para>
 762     </listitem>
 763
 764     <listitem>
 765      <para>
 766       Update time zone data files to <application>tzdata</> release 2008i (for
 767       DST law changes in Argentina, Brazil, Mauritius, Syria)
 768      </para>
 769     </listitem>
 770
 771    </itemizedlist>
 772
 773   </sect2>
 774  </sect1>
 775
 776  <sect1 id="release-8-3-4">
 777   <title>Release 8.3.4</title>
 778
 779   <note>
 780   <title>Release date</title>
 781   <simpara>2008-09-22</simpara>
 782   </note>
 783
 784   <para>
 785    This release contains a variety of fixes from 8.3.3.
 786    For information about new features in the 8.3 major release, see
 787    <xref linkend="release-8-3">.
 788   </para>
 789
 790   <sect2>
 791    <title>Migration to Version 8.3.4</title>
 792
 793    <para>
 794     A dump/restore is not required for those running 8.3.X.
 795     However, if you are upgrading from a version earlier than 8.3.1,
 796     see the release notes for 8.3.1.
 797    </para>
 798
 799   </sect2>
 800
 801   <sect2>
 802    <title>Changes</title>
 803
 804    <itemizedlist>
 805
 806     <listitem>
 807      <para>
 808       Fix bug in btree WAL recovery code (Heikki)
 809      </para>
 810
 811      <para>
 812       Recovery failed if the WAL ended partway through a page split operation.
 813      </para>
 814     </listitem>
 815
 816     <listitem>
 817      <para>
 818       Fix potential use of wrong cutoff XID for HOT page pruning (Alvaro)
 819      </para>
 820
 821      <para>
 822       This error created a risk of corruption in system
 823       catalogs that are consulted by <command>VACUUM</>: dead tuple versions
 824       might be removed too soon.  The impact of this on actual database
 825       operations would be minimal, since the system doesn't follow MVCC
 826       rules while examining catalogs, but it might result in transiently
 827       wrong output from <application>pg_dump</> or other client programs.
 828      </para>
 829     </listitem>
 830
 831     <listitem>
 832      <para>
 833       Fix potential miscalculation of <structfield>datfrozenxid</> (Alvaro)
 834      </para>
 835
 836      <para>
 837       This error may explain some recent reports of failure to remove old
 838       <structname>pg_clog</> data.
 839      </para>
 840     </listitem>
 841
 842     <listitem>
 843      <para>
 844       Fix incorrect HOT updates after <structname>pg_class</> is reindexed
 845       (Tom)
 846      </para>
 847
 848      <para>
 849       Corruption of <structname>pg_class</> could occur if <literal>REINDEX
 850       TABLE pg_class</> was followed in the same session by an <literal>ALTER
 851       TABLE RENAME</> or <literal>ALTER TABLE SET SCHEMA</> command.
 852      </para>
 853     </listitem>
 854
 855     <listitem>
 856      <para>
 857       Fix missed <quote>combo cid</> case (Karl Schnaitter)
 858      </para>
 859
 860      <para>
 861       This error made rows incorrectly invisible to a transaction in which they
 862       had been deleted by multiple subtransactions that all aborted.
 863      </para>
 864     </listitem>
 865
 866     <listitem>
 867      <para>
 868       Prevent autovacuum from crashing if the table it's currently
 869       checking is deleted at just the wrong time (Alvaro)
 870      </para>
 871     </listitem>
 872
 873     <listitem>
 874      <para>
 875       Widen local lock counters from 32 to 64 bits (Tom)
 876      </para>
 877
 878      <para>
 879       This responds to reports that the counters could overflow in
 880       sufficiently long transactions, leading to unexpected <quote>lock is
 881       already held</> errors.
 882      </para>
 883     </listitem>
 884
 885     <listitem>
 886      <para>
 887       Fix possible duplicate output of tuples during a GiST index scan (Teodor)
 888      </para>
 889     </listitem>
 890
 891     <listitem>
 892      <para>
 893       Regenerate foreign key checking queries from scratch when either
 894       table is modified (Tom)
 895      </para>
 896
 897      <para>
 898       Previously, 8.3 would attempt to replan the query, but would work from
 899       previously generated query text.  This led to failures if a
 900       table or column was renamed.
 901      </para>
 902     </listitem>
 903
 904     <listitem>
 905      <para>
 906       Fix missed permissions checks when a view contains a simple
 907       <literal>UNION ALL</> construct (Heikki)
 908      </para>
 909
 910      <para>
 911       Permissions for the referenced tables were checked properly, but not
 912       permissions for the view itself.
 913      </para>
 914     </listitem>
 915
 916     <listitem>
 917      <para>
 918       Add checks in executor startup to ensure that the tuples produced by an
 919       <command>INSERT</> or <command>UPDATE</> will match the target table's
 920       current rowtype (Tom)
 921      </para>
 922
 923      <para>
 924       This situation is believed to be impossible in 8.3, but it can happen in
 925       prior releases, so a check seems prudent.
 926      </para>
 927     </listitem>
 928
 929     <listitem>
 930      <para>
 931       Fix possible repeated drops during <command>DROP OWNED</> (Tom)
 932      </para>
 933
 934      <para>
 935       This would typically result in strange errors such as <quote>cache
 936       lookup failed for relation NNN</>.
 937      </para>
 938     </listitem>
 939
 940     <listitem>
 941      <para>
 942       Fix several memory leaks in XML operations (Kris Jurka, Tom)
 943      </para>
 944     </listitem>
 945
 946     <listitem>
 947      <para>
 948       Fix <function>xmlserialize()</> to raise error properly for
 949       unacceptable target data type (Tom)
 950      </para>
 951     </listitem>
 952
 953     <listitem>
 954      <para>
 955       Fix a couple of places that mis-handled multibyte characters in text
 956       search configuration file parsing (Tom)
 957      </para>
 958
 959      <para>
 960       Certain characters occurring in configuration files would always cause
 961       <quote>invalid byte sequence for encoding</> failures.
 962      </para>
 963     </listitem>
 964
 965     <listitem>
 966      <para>
 967       Provide file name and line number location for all errors reported
 968       in text search configuration files (Tom)
 969      </para>
 970     </listitem>
 971
 972     <listitem>
 973      <para>
 974       Fix <literal>AT TIME ZONE</> to first try to interpret its timezone
 975       argument as a timezone abbreviation, and only try it as a full timezone
 976       name if that fails, rather than the other way around as formerly (Tom)
 977      </para>
 978
 979      <para>
 980       The timestamp input functions have always resolved ambiguous zone names
 981       in this order.  Making <literal>AT TIME ZONE</> do so as well improves
 982       consistency, and fixes a compatibility bug introduced in 8.1:
 983       in ambiguous cases we now behave the same as 8.0 and before did,
 984       since in the older versions <literal>AT TIME ZONE</> accepted
 985       <emphasis>only</> abbreviations.
 986      </para>
 987     </listitem>
 988
 989     <listitem>
 990      <para>
 991       Fix datetime input functions to correctly detect integer overflow when
 992       running on a 64-bit platform (Tom)
 993      </para>
 994     </listitem>
 995
 996     <listitem>
 997      <para>
 998       Prevent integer overflows during units conversion when displaying a
 999       configuration parameter that has units (Tom)
1000      </para>
1001     </listitem>
1002
1003     <listitem>
1004      <para>
1005       Improve performance of writing very long log messages to syslog (Tom)
1006      </para>
1007     </listitem>
1008
1009     <listitem>
1010      <para>
1011       Allow spaces in the suffix part of an LDAP URL in
1012       <filename>pg_hba.conf</> (Tom)
1013      </para>
1014     </listitem>
1015
1016     <listitem>
1017      <para>
1018       Fix bug in backwards scanning of a cursor on a <literal>SELECT DISTINCT
1019       ON</> query (Tom)
1020      </para>
1021     </listitem>
1022
1023     <listitem>
1024      <para>
1025       Fix planner bug that could improperly push down <literal>IS NULL</>
1026       tests below an outer join (Tom)
1027      </para>
1028
1029      <para>
1030       This was triggered by occurrence of <literal>IS NULL</> tests for
1031       the same relation in all arms of an upper <literal>OR</> clause.
1032      </para>
1033     </listitem>
1034
1035     <listitem>
1036      <para>
1037       Fix planner bug with nested sub-select expressions (Tom)
1038      </para>
1039
1040      <para>
1041       If the outer sub-select has no direct dependency on the parent query,
1042       but the inner one does, the outer value might not get recalculated
1043       for new parent query rows.
1044      </para>
1045     </listitem>
1046
1047     <listitem>
1048      <para>
1049       Fix planner to estimate that <literal>GROUP BY</> expressions yielding
1050       boolean results always result in two groups, regardless of the
1051       expressions' contents (Tom)
1052      </para>
1053
1054      <para>
1055       This is very substantially more accurate than the regular <literal>GROUP
1056       BY</> estimate for certain boolean tests like <replaceable>col</>
1057       <literal>IS NULL</>.
1058      </para>
1059     </listitem>
1060
1061     <listitem>
1062      <para>
1063       Fix PL/PgSQL to not fail when a <literal>FOR</> loop's target variable
1064       is a record containing composite-type fields (Tom)
1065      </para>
1066     </listitem>
1067
1068     <listitem>
1069      <para>
1070       Fix PL/Tcl to behave correctly with Tcl 8.5, and to be more careful
1071       about the encoding of data sent to or from Tcl (Tom)
1072      </para>
1073     </listitem>
1074
1075     <listitem>
1076      <para>
1077       Improve performance of <function>PQescapeBytea()</> (Rudolf Leitgeb)
1078      </para>
1079     </listitem>
1080
1081     <listitem>
1082      <para>
1083       On Windows, work around a Microsoft bug by preventing
1084       <application>libpq</> from trying to send more than 64kB per system call
1085       (Magnus)
1086      </para>
1087     </listitem>
1088
1089     <listitem>
1090      <para>
1091       Fix <application>ecpg</> to handle variables properly in <command>SET</>
1092       commands (Michael)
1093      </para>
1094     </listitem>
1095
1096     <listitem>
1097      <para>
1098       Improve <application>pg_dump</> and <application>pg_restore</>'s
1099       error reporting after failure to send a SQL command (Tom)
1100      </para>
1101     </listitem>
1102
1103     <listitem>
1104      <para>
1105       Fix <application>pg_ctl</> to properly preserve postmaster
1106       command-line arguments across a <literal>restart</> (Bruce)
1107      </para>
1108     </listitem>
1109
1110     <listitem>
1111      <para>
1112       Fix erroneous WAL file cutoff point calculation in
1113       <application>pg_standby</> (Simon)
1114      </para>
1115     </listitem>
1116
1117     <listitem>
1118      <para>
1119       Update time zone data files to <application>tzdata</> release 2008f (for
1120       DST law changes in Argentina, Bahamas, Brazil, Mauritius, Morocco,
1121       Pakistan, Palestine, and Paraguay)
1122      </para>
1123     </listitem>
1124
1125    </itemizedlist>
1126
1127   </sect2>
1128  </sect1>
1129
1130  <sect1 id="release-8-3-3">
1131   <title>Release 8.3.3</title>
1132
1133   <note>
1134   <title>Release date</title>
1135   <simpara>2008-06-12</simpara>
1136   </note>
1137
1138   <para>
1139    This release contains one serious and one minor bug fix over 8.3.2.
1140    For information about new features in the 8.3 major release, see
1141    <xref linkend="release-8-3">.
1142   </para>
1143
1144   <sect2>
1145    <title>Migration to Version 8.3.3</title>
1146
1147    <para>
1148     A dump/restore is not required for those running 8.3.X.
1149     However, if you are upgrading from a version earlier than 8.3.1,
1150     see the release notes for 8.3.1.
1151    </para>
1152
1153   </sect2>
1154
1155   <sect2>
1156    <title>Changes</title>
1157
1158    <itemizedlist>
1159
1160     <listitem>
1161      <para>
1162       Make <function>pg_get_ruledef()</> parenthesize negative constants (Tom)
1163      </para>
1164
1165      <para>
1166       Before this fix, a negative constant in a view or rule might be dumped
1167       as, say, <literal>-42::integer</>, which is subtly incorrect: it should
1168       be <literal>(-42)::integer</> due to operator precedence rules.
1169       Usually this would make little difference, but it could interact with
1170       another recent patch to cause
1171       <productname>PostgreSQL</> to reject what had been a valid
1172       <command>SELECT DISTINCT</> view query.  Since this could result in
1173       <application>pg_dump</> output failing to reload, it is being treated
1174       as a high-priority fix.  The only released versions in which dump
1175       output is actually incorrect are 8.3.1 and 8.2.7.
1176      </para>
1177     </listitem>
1178
1179     <listitem>
1180      <para>
1181       Make <command>ALTER AGGREGATE ... OWNER TO</> update
1182       <structname>pg_shdepend</> (Tom)
1183      </para>
1184
1185      <para>
1186       This oversight could lead to problems if the aggregate was later
1187       involved in a <command>DROP OWNED</> or <command>REASSIGN OWNED</>
1188       operation.
1189      </para>
1190     </listitem>
1191
1192    </itemizedlist>
1193
1194   </sect2>
1195  </sect1>
1196
1197  <sect1 id="release-8-3-2">
1198   <title>Release 8.3.2</title>
1199
1200   <note>
1201   <title>Release date</title>
1202   <simpara>never released</simpara>
1203   </note>
1204
1205   <para>
1206    This release contains a variety of fixes from 8.3.1.
1207    For information about new features in the 8.3 major release, see
1208    <xref linkend="release-8-3">.
1209   </para>
1210
1211   <sect2>
1212    <title>Migration to Version 8.3.2</title>
1213
1214    <para>
1215     A dump/restore is not required for those running 8.3.X.
1216     However, if you are upgrading from a version earlier than 8.3.1,
1217     see the release notes for 8.3.1.
1218    </para>
1219
1220   </sect2>
1221
1222   <sect2>
1223    <title>Changes</title>
1224
1225    <itemizedlist>
1226
1227     <listitem>
1228      <para>
1229       Fix <literal>ERRORDATA_STACK_SIZE exceeded</literal> crash that
1230       occurred on Windows when using UTF-8 database encoding and a different
1231       client encoding (Tom)
1232      </para>
1233     </listitem>
1234
1235     <listitem>
1236      <para>
1237       Fix incorrect archive truncation point calculation for the
1238       <literal>%r</> macro in <varname>recovery_command</> parameters
1239       (Simon)
1240      </para>
1241
1242      <para>
1243       This could lead to data loss if a warm-standby script relied on
1244       <literal>%r</> to decide when to throw away WAL segment files.
1245      </para>
1246     </listitem>
1247
1248     <listitem>
1249      <para>
1250       Fix <command>ALTER TABLE ADD COLUMN ... PRIMARY KEY</> so that the new
1251       column is correctly checked to see if it's been initialized to all
1252       non-nulls (Brendan Jurd)
1253      </para>
1254
1255      <para>
1256       Previous versions neglected to check this requirement at all.
1257      </para>
1258     </listitem>
1259
1260     <listitem>
1261      <para>
1262       Fix <command>REASSIGN OWNED</> so that it works on procedural
1263       languages too (Alvaro)
1264      </para>
1265     </listitem>
1266
1267     <listitem>
1268      <para>
1269       Fix problems with <command>SELECT FOR UPDATE/SHARE</> occurring as a
1270       subquery in a query with a non-<command>SELECT</> top-level operation
1271       (Tom)
1272      </para>
1273     </listitem>
1274
1275     <listitem>
1276      <para>
1277       Fix possible <command>CREATE TABLE</> failure when inheriting the
1278       <quote>same</> constraint from multiple parent relations that
1279       inherited that constraint from a common ancestor (Tom)
1280      </para>
1281     </listitem>
1282
1283     <listitem>
1284      <para>
1285       Fix <function>pg_get_ruledef()</> to show the alias, if any, attached
1286       to the target table of an <command>UPDATE</> or <command>DELETE</>
1287       (Tom)
1288      </para>
1289     </listitem>
1290
1291     <listitem>
1292      <para>
1293       Restore the pre-8.3 behavior that an out-of-range block number in a
1294       TID being used in a TidScan plan results in silently not matching any
1295       rows (Tom)
1296      </para>
1297
1298      <para>
1299       8.3.0 and 8.3.1 threw an error instead.
1300      </para>
1301     </listitem>
1302
1303     <listitem>
1304      <para>
1305       Fix GIN bug that could result in a <literal>too many LWLocks
1306       taken</literal> failure (Teodor)
1307      </para>
1308     </listitem>
1309
1310     <listitem>
1311      <para>
1312       Fix broken GiST comparison function for <type>tsquery</> (Teodor)
1313      </para>
1314     </listitem>
1315
1316     <listitem>
1317      <para>
1318       Fix <function>tsvector_update_trigger()</> and <function>ts_stat()</>
1319       to accept domains over the types they expect to work with (Tom)
1320      </para>
1321     </listitem>
1322
1323     <listitem>
1324      <para>
1325       Fix failure to support enum data types as foreign keys (Tom)
1326      </para>
1327     </listitem>
1328
1329     <listitem>
1330      <para>
1331       Avoid possible crash when decompressing corrupted data
1332       (Zdenek Kotala)
1333      </para>
1334     </listitem>
1335
1336     <listitem>
1337      <para>
1338       Fix race conditions between delayed unlinks and <command>DROP
1339       DATABASE</> (Heikki)
1340      </para>
1341
1342      <para>
1343       In the worst case this could result in deleting a newly created table
1344       in a new database that happened to get the same OID as the
1345       recently-dropped one; but of course that is an extremely
1346       low-probability scenario.
1347      </para>
1348     </listitem>
1349
1350     <listitem>
1351      <para>
1352       Repair two places where SIGTERM exit of a backend could leave corrupted
1353       state in shared memory (Tom)
1354      </para>
1355
1356      <para>
1357       Neither case is very important if SIGTERM is used to shut down the
1358       whole database cluster together, but there was a problem if someone
1359       tried to SIGTERM individual backends.
1360      </para>
1361     </listitem>
1362
1363     <listitem>
1364      <para>
1365       Fix possible crash due to incorrect plan generated for an
1366       <literal><replaceable>x</> IN (SELECT <replaceable>y</>
1367       FROM ...)</literal> clause when <replaceable>x</> and <replaceable>y</>
1368       have different data types; and make sure the behavior is semantically
1369       correct when the conversion from <replaceable>y</>'s type to
1370       <replaceable>x</>'s type is lossy (Tom)
1371      </para>
1372     </listitem>
1373
1374     <listitem>
1375      <para>
1376       Fix oversight that prevented the planner from substituting known Param
1377       values as if they were constants (Tom)
1378      </para>
1379
1380      <para>
1381       This mistake partially disabled optimization of unnamed
1382       extended-Query statements in 8.3.0 and 8.3.1: in particular the
1383       LIKE-to-indexscan optimization would never be applied if the LIKE
1384       pattern was passed as a parameter, and constraint exclusion
1385       depending on a parameter value didn't work either.
1386      </para>
1387     </listitem>
1388
1389     <listitem>
1390      <para>
1391       Fix planner failure when an indexable <function>MIN</> or
1392       <function>MAX</> aggregate is used with <literal>DISTINCT</> or
1393       <literal>ORDER BY</> (Tom)
1394      </para>
1395     </listitem>
1396
1397     <listitem>
1398      <para>
1399       Fix planner to ensure it never uses a <quote>physical tlist</> for a
1400       plan node that is feeding a Sort node (Tom)
1401      </para>
1402
1403      <para>
1404       This led to the sort having to push around more data than it really
1405       needed to, since unused column values were included in the sorted
1406       data.
1407      </para>
1408     </listitem>
1409
1410     <listitem>
1411      <para>
1412       Avoid unnecessary copying of query strings (Tom)
1413      </para>
1414
1415      <para>
1416       This fixes a performance problem introduced in 8.3.0 when a very large
1417       number of commands are submitted as a single query string.
1418      </para>
1419     </listitem>
1420
1421     <listitem>
1422      <para>
1423       Make <function>TransactionIdIsCurrentTransactionId()</> use binary
1424       search instead of linear search when checking child-transaction XIDs
1425       (Heikki)
1426      </para>
1427
1428      <para>
1429       This fixes some cases in which 8.3.0 was significantly
1430       slower than earlier releases.
1431      </para>
1432     </listitem>
1433
1434     <listitem>
1435      <para>
1436       Fix conversions between ISO-8859-5 and other encodings to handle
1437       Cyrillic <quote>Yo</> characters (<literal>e</> and <literal>E</> with
1438       two dots) (Sergey Burladyan)
1439      </para>
1440     </listitem>
1441
1442     <listitem>
1443      <para>
1444       Fix several datatype input functions, notably <function>array_in()</>,
1445       that were allowing unused bytes in their results to contain
1446       uninitialized, unpredictable values (Tom)
1447      </para>
1448
1449      <para>
1450       This could lead to failures in which two apparently identical literal
1451       values were not seen as equal, resulting in the parser complaining
1452       about unmatched <literal>ORDER BY</> and <literal>DISTINCT</>
1453       expressions.
1454      </para>
1455     </listitem>
1456
1457     <listitem>
1458      <para>
1459       Fix a corner case in regular-expression substring matching
1460       (<literal>substring(<replaceable>string</> from
1461       <replaceable>pattern</>)</literal>) (Tom)
1462      </para>
1463
1464      <para>
1465       The problem occurs when there is a match to the pattern overall but
1466       the user has specified a parenthesized subexpression and that
1467       subexpression hasn't got a match.  An example is
1468       <literal>substring('foo' from 'foo(bar)?')</>.
1469       This should return NULL, since <literal>(bar)</> isn't matched, but
1470       it was mistakenly returning the whole-pattern match instead (ie,
1471       <literal>foo</>).
1472      </para>
1473     </listitem>
1474
1475     <listitem>
1476      <para>
1477       Prevent cancellation of an auto-vacuum that was launched to prevent
1478       XID wraparound (Alvaro)
1479      </para>
1480     </listitem>
1481
1482     <listitem>
1483      <para>
1484       Improve <command>ANALYZE</>'s handling of in-doubt tuples (those
1485       inserted or deleted by a not-yet-committed transaction) so that the
1486       counts it reports to the stats collector are more likely to be correct
1487       (Pavan Deolasee)
1488      </para>
1489     </listitem>
1490
1491     <listitem>
1492      <para>
1493       Fix <application>initdb</> to reject a relative path for its
1494       <literal>--xlogdir</> (<literal>-X</>) option (Tom)
1495      </para>
1496     </listitem>
1497
1498     <listitem>
1499      <para>
1500       Make <application>psql</> print tab characters as an appropriate
1501       number of spaces, rather than <literal>\x09</literal> as was done in
1502       8.3.0 and 8.3.1 (Bruce)
1503      </para>
1504     </listitem>
1505
1506     <listitem>
1507      <para>
1508       Update time zone data files to <application>tzdata</> release 2008c (for
1509       DST law changes in Morocco, Iraq, Choibalsan, Pakistan, Syria, Cuba, and
1510       Argentina/San_Luis)
1511      </para>
1512     </listitem>
1513
1514     <listitem>
1515      <para>
1516       Add <function>ECPGget_PGconn()</> function to
1517       <application>ecpglib</> (Michael)
1518      </para>
1519     </listitem>
1520
1521     <listitem>
1522      <para>
1523       Fix incorrect result from <application>ecpg</>'s
1524       <function>PGTYPEStimestamp_sub()</> function (Michael)
1525      </para>
1526     </listitem>
1527
1528     <listitem>
1529      <para>
1530       Fix handling of continuation line markers in <application>ecpg</>
1531       (Michael)
1532      </para>
1533     </listitem>
1534
1535     <listitem>
1536      <para>
1537       Fix possible crashes in <filename>contrib/cube</> functions (Tom)
1538      </para>
1539     </listitem>
1540
1541     <listitem>
1542      <para>
1543       Fix core dump in <filename>contrib/xml2</>'s
1544       <function>xpath_table()</> function when the input query returns a
1545       NULL value (Tom)
1546      </para>
1547     </listitem>
1548
1549     <listitem>
1550      <para>
1551       Fix <filename>contrib/xml2</>'s makefile to not override
1552       <literal>CFLAGS</>, and make it auto-configure properly for
1553       <application>libxslt</> present or not (Tom)
1554      </para>
1555     </listitem>
1556
1557    </itemizedlist>
1558
1559   </sect2>
1560  </sect1>
1561
1562  <sect1 id="release-8-3-1">
1563   <title>Release 8.3.1</title>
1564
1565   <note>
1566   <title>Release date</title>
1567   <simpara>2008-03-17</simpara>
1568   </note>
1569
1570   <para>
1571    This release contains a variety of fixes from 8.3.0.
1572    For information about new features in the 8.3 major release, see
1573    <xref linkend="release-8-3">.
1574   </para>
1575
1576   <sect2>
1577    <title>Migration to Version 8.3.1</title>
1578
1579    <para>
1580     A dump/restore is not required for those running 8.3.X.
1581     However, you might need to <command>REINDEX</> indexes on textual
1582     columns after updating, if you are affected by the Windows locale
1583     issue described below.
1584    </para>
1585
1586   </sect2>
1587
1588   <sect2>
1589    <title>Changes</title>
1590
1591    <itemizedlist>
1592
1593     <listitem>
1594      <para>
1595       Fix character string comparison for Windows locales that consider
1596       different character combinations as equal (Tom)
1597      </para>
1598
1599      <para>
1600       This fix applies only on Windows and only when using UTF-8
1601       database encoding.  The same fix was made for all other cases
1602       over two years ago, but Windows with UTF-8 uses a separate code
1603       path that was not updated.  If you are using a locale that
1604       considers some non-identical strings as equal, you may need to
1605       <command>REINDEX</> to fix existing indexes on textual columns.
1606      </para>
1607     </listitem>
1608
1609     <listitem>
1610      <para>
1611       Repair corner-case bugs in <command>VACUUM FULL</> (Tom)
1612      </para>
1613
1614      <para>
1615       A potential deadlock between concurrent <command>VACUUM FULL</>
1616       operations on different system catalogs was introduced in 8.2.
1617       This has now been corrected.  8.3 made this worse because the
1618       deadlock could occur within a critical code section, making it
1619       a PANIC rather than just ERROR condition.
1620      </para>
1621
1622      <para>
1623       Also, a <command>VACUUM FULL</> that failed partway through
1624       vacuuming a system catalog could result in cache corruption in
1625       concurrent database sessions.
1626      </para>
1627
1628      <para>
1629       Another <command>VACUUM FULL</> bug introduced in 8.3 could
1630       result in a crash or out-of-memory report when dealing with
1631       pages containing no live tuples.
1632      </para>
1633     </listitem>
1634
1635     <listitem>
1636      <para>
1637       Fix misbehavior of foreign key checks involving <type>character</>
1638       or <type>bit</> columns (Tom)
1639      </para>
1640
1641      <para>
1642       If the referencing column were of a different but compatible type
1643       (for instance <type>varchar</>), the constraint was enforced incorrectly.
1644      </para>
1645     </listitem>
1646
1647     <listitem>
1648      <para>
1649       Avoid needless deadlock failures in no-op foreign-key checks (Stephan
1650       Szabo, Tom)
1651      </para>
1652     </listitem>
1653
1654     <listitem>
1655      <para>
1656       Fix possible core dump when re-planning a prepared query (Tom)
1657      </para>
1658
1659      <para>
1660       This bug affected only protocol-level prepare operations, not
1661       SQL <command>PREPARE</>, and so tended to be seen only with
1662       JDBC, DBI, and other client-side drivers that use prepared
1663       statements heavily.
1664      </para>
1665     </listitem>
1666
1667     <listitem>
1668      <para>
1669       Fix possible failure when re-planning a query that calls an SPI-using
1670       function (Tom)
1671      </para>
1672     </listitem>
1673
1674     <listitem>
1675      <para>
1676       Fix failure in row-wise comparisons involving columns of different
1677       datatypes (Tom)
1678      </para>
1679     </listitem>
1680
1681     <listitem>
1682      <para>
1683       Fix longstanding <command>LISTEN</>/<command>NOTIFY</>
1684       race condition (Tom)
1685      </para>
1686
1687      <para>
1688       In rare cases a session that had just executed a
1689       <command>LISTEN</> might not get a notification, even though
1690       one would be expected because the concurrent transaction executing
1691       <command>NOTIFY</> was observed to commit later.
1692      </para>
1693
1694      <para>
1695       A side effect of the fix is that a transaction that has executed
1696       a not-yet-committed <command>LISTEN</> command will not see any
1697       row in <structname>pg_listener</> for the <command>LISTEN</>,
1698       should it choose to look; formerly it would have.  This behavior
1699       was never documented one way or the other, but it is possible that
1700       some applications depend on the old behavior.
1701      </para>
1702     </listitem>
1703
1704     <listitem>
1705      <para>
1706       Disallow <command>LISTEN</> and <command>UNLISTEN</> within a
1707       prepared transaction (Tom)
1708      </para>
1709
1710      <para>
1711       This was formerly allowed but trying to do it had various unpleasant
1712       consequences, notably that the originating backend could not exit
1713       as long as an <command>UNLISTEN</> remained uncommitted.
1714      </para>
1715     </listitem>
1716
1717     <listitem>
1718      <para>
1719       Disallow dropping a temporary table within a
1720       prepared transaction (Heikki)
1721      </para>
1722
1723      <para>
1724       This was correctly disallowed by 8.1, but the check was inadvertently
1725       broken in 8.2 and 8.3.
1726      </para>
1727     </listitem>
1728
1729     <listitem>
1730      <para>
1731       Fix rare crash when an error occurs during a query using a hash index
1732       (Heikki)
1733      </para>
1734     </listitem>
1735
1736     <listitem>
1737      <para>
1738       Fix incorrect comparison of <type>tsquery</> values (Teodor)
1739      </para>
1740     </listitem>
1741
1742     <listitem>
1743      <para>
1744       Fix incorrect behavior of <literal>LIKE</> with non-ASCII characters
1745       in single-byte encodings (Rolf Jentsch)
1746      </para>
1747     </listitem>
1748
1749     <listitem>
1750      <para>
1751       Disable <function>xmlvalidate</> (Tom)
1752      </para>
1753
1754      <para>
1755       This function should have been removed before 8.3 release, but
1756       was inadvertently left in the source code.  It poses a small
1757       security risk since unprivileged users could use it to read the
1758       first few characters of any file accessible to the server.
1759      </para>
1760     </listitem>
1761
1762     <listitem>
1763      <para>
1764       Fix memory leaks in certain usages of set-returning functions (Neil)
1765      </para>
1766     </listitem>
1767
1768     <listitem>
1769      <para>
1770       Make <function>encode(<replaceable>bytea</>, 'escape')</> convert all
1771       high-bit-set byte values into <literal>\</><replaceable>nnn</> octal
1772       escape sequences (Tom)
1773      </para>
1774
1775      <para>
1776       This is necessary to avoid encoding problems when the database
1777       encoding is multi-byte.  This change could pose compatibility issues
1778       for applications that are expecting specific results from
1779       <function>encode</>.
1780      </para>
1781     </listitem>
1782
1783     <listitem>
1784      <para>
1785       Fix input of datetime values for February 29 in years BC (Tom)
1786      </para>
1787
1788      <para>
1789       The former coding was mistaken about which years were leap years.
1790      </para>
1791     </listitem>
1792
1793     <listitem>
1794      <para>
1795       Fix <quote>unrecognized node type</> error in some variants of
1796       <command>ALTER OWNER</> (Tom)
1797      </para>
1798     </listitem>
1799
1800     <listitem>
1801      <para>
1802       Avoid tablespace permissions errors in <command>CREATE TABLE LIKE
1803       INCLUDING INDEXES</> (Tom)
1804      </para>
1805     </listitem>
1806
1807     <listitem>
1808      <para>
1809       Ensure <structname>pg_stat_activity</>.<structfield>waiting</> flag
1810       is cleared when a lock wait is aborted (Tom)
1811      </para>
1812     </listitem>
1813
1814     <listitem>
1815      <para>
1816       Fix handling of process permissions on Windows Vista (Dave, Magnus)
1817      </para>
1818
1819      <para>
1820       In particular, this fix allows starting the server as the Administrator
1821       user.
1822      </para>
1823     </listitem>
1824
1825     <listitem>
1826      <para>
1827       Update time zone data files to <application>tzdata</> release 2008a
1828       (in particular, recent Chile changes); adjust timezone abbreviation
1829       <literal>VET</> (Venezuela) to mean UTC-4:30, not UTC-4:00 (Tom)
1830      </para>
1831     </listitem>
1832
1833     <listitem>
1834      <para>
1835       Fix <application>ecpg</> problems with arrays (Michael)
1836      </para>
1837     </listitem>
1838
1839     <listitem>
1840      <para>
1841       Fix <application>pg_ctl</> to correctly extract the postmaster's port
1842       number from command-line options (Itagaki Takahiro, Tom)
1843      </para>
1844
1845      <para>
1846       Previously, <literal>pg_ctl start -w</> could try to contact the
1847       postmaster on the wrong port, leading to bogus reports of startup
1848       failure.
1849      </para>
1850     </listitem>
1851
1852     <listitem>
1853      <para>
1854       Use <option>-fwrapv</> to defend against possible misoptimization
1855       in recent <application>gcc</> versions (Tom)
1856      </para>
1857
1858      <para>
1859       This is known to be necessary when building <productname>PostgreSQL</>
1860       with <application>gcc</> 4.3 or later.
1861      </para>
1862     </listitem>
1863
1864     <listitem>
1865      <para>
1866       Enable building <filename>contrib/uuid-ossp</> with MSVC (Hiroshi Saito)
1867      </para>
1868     </listitem>
1869
1870    </itemizedlist>
1871
1872   </sect2>
1873  </sect1>
1874
1875  <sect1 id="release-8-3">
1876   <title>Release 8.3</title>
1877
1878   <note>
1879    <title>Release date</title>
1880    <simpara>2008-02-04</simpara>
1881   </note>
1882
1883   <sect2>
1884    <title>Overview</title>
1885
1886    <para>
1887     With significant new functionality and performance enhancements,
1888     this release represents a major leap forward for
1889     <productname>PostgreSQL</>. This was made possible by a growing
1890     community that has dramatically accelerated the pace of
1891     development. This release adds the following major features:
1892    </para>
1893
1894    <itemizedlist>
1895
1896     <listitem>
1897      <para>
1898       Full text search is integrated into the core database system
1899      </para>
1900     </listitem>
1901
1902     <listitem>
1903      <para>
1904       Support for the SQL/XML standard, including new operators and an
1905       <type>XML</type> data type
1906      </para>
1907     </listitem>
1908
1909     <listitem>
1910      <para>
1911       Enumerated data types (<type>ENUM</type>)
1912      </para>
1913     </listitem>
1914
1915     <listitem>
1916      <para>
1917       Arrays of composite types
1918      </para>
1919     </listitem>
1920
1921     <listitem>
1922      <para>
1923       Universally Unique Identifier (<type>UUID</>) data type
1924      </para>
1925     </listitem>
1926
1927     <listitem>
1928      <para>
1929       Add control over whether <literal>NULL</>s sort first or last
1930      </para>
1931     </listitem>
1932
1933     <listitem>
1934      <para>
1935       Updatable cursors
1936      </para>
1937     </listitem>
1938
1939     <listitem>
1940      <para>
1941       Server configuration parameters can now be set on a per-function
1942       basis
1943      </para>
1944     </listitem>
1945
1946     <listitem>
1947      <para>
1948       User-defined types can now have type modifiers
1949      </para>
1950     </listitem>
1951
1952     <listitem>
1953      <para>
1954       Automatically re-plan cached queries when table
1955       definitions change or statistics are updated
1956      </para>
1957     </listitem>
1958
1959     <listitem>
1960      <para>
1961       Numerous improvements in logging and statistics collection
1962      </para>
1963     </listitem>
1964
1965     <listitem>
1966      <para>
1967       Support Security Service Provider Interface (<acronym>SSPI</>) for
1968       authentication on Windows
1969      </para>
1970     </listitem>
1971
1972     <listitem>
1973      <para>
1974       Support multiple concurrent autovacuum processes, and other
1975       autovacuum improvements
1976      </para>
1977     </listitem>
1978
1979     <listitem>
1980      <para>
1981       Allow the whole <productname>PostgreSQL</> distribution to be compiled
1982       with <productname>Microsoft Visual C++</>
1983      </para>
1984     </listitem>
1985
1986    </itemizedlist>
1987
1988    <para>
1989     Major performance improvements are listed below.  Most of
1990     these enhancements are automatic and do not require user changes or
1991     tuning:
1992    </para>
1993
1994   <itemizedlist>
1995
1996     <listitem>
1997      <para>
1998       Asynchronous commit delays writes to WAL during transaction commit
1999      </para>
2000     </listitem>
2001
2002     <listitem>
2003      <para>
2004       Checkpoint writes can be spread over a longer time period to smooth
2005       the I/O spike during each checkpoint
2006      </para>
2007     </listitem>
2008
2009     <listitem>
2010      <para>
2011       Heap-Only Tuples (<acronym>HOT</>) accelerate space reuse for
2012       most <command>UPDATE</>s and <command>DELETE</>s
2013      </para>
2014     </listitem>
2015
2016     <listitem>
2017      <para>
2018       Just-in-time background writer strategy improves disk write
2019       efficiency
2020      </para>
2021     </listitem>
2022
2023     <listitem>
2024      <para>
2025       Using non-persistent transaction IDs for read-only transactions
2026       reduces overhead and <command>VACUUM</> requirements
2027      </para>
2028     </listitem>
2029
2030     <listitem>
2031      <para>
2032       Per-field and per-row storage overhead has been reduced
2033      </para>
2034     </listitem>
2035
2036     <listitem>
2037      <para>
2038       Large sequential scans no longer force out frequently used
2039       cached pages
2040      </para>
2041     </listitem>
2042
2043     <listitem>
2044      <para>
2045       Concurrent large sequential scans can now share disk reads
2046      </para>
2047     </listitem>
2048
2049     <listitem>
2050      <para>
2051       <literal>ORDER BY ... LIMIT</> can be done without sorting
2052      </para>
2053     </listitem>
2054
2055    </itemizedlist>
2056
2057    <para>
2058     The above items are explained in more detail in the sections below.
2059    </para>
2060
2061   </sect2>
2062
2063   <sect2>
2064    <title>Migration to Version 8.3</title>
2065
2066    <para>
2067     A dump/restore using <application>pg_dump</application> is
2068     required for those wishing to migrate data from any previous
2069     release.
2070    </para>
2071
2072    <para>
2073     Observe the following incompatibilities:
2074    </para>
2075
2076    <sect3>
2077     <title>General</title>
2078     <itemizedlist>
2079
2080      <listitem>
2081       <para>
2082        Non-character data types are no longer automatically cast to
2083        <type>TEXT</> (Peter, Tom)
2084       </para>
2085
2086       <para>
2087        Previously, if a non-character value was supplied to an operator or
2088        function that requires <type>text</> input, it was automatically
2089        cast to <type>text</>, for most (though not all) built-in data types.
2090        This no longer happens: an explicit cast to <type>text</> is now
2091        required for all non-character-string types.  For example, these
2092        expressions formerly worked:
2093
2094 <programlisting>
2095 substr(current_date, 1, 4)
2096 23 LIKE '2%'
2097 </programlisting>
2098
2099        but will now draw <quote>function does not exist</> and <quote>operator
2100        does not exist</> errors respectively.  Use an explicit cast instead:
2101
2102 <programlisting>
2103 substr(current_date::text, 1, 4)
2104 23::text LIKE '2%'
2105 </programlisting>
2106
2107        (Of course, you can use the more verbose <literal>CAST()</> syntax too.)
2108        The reason for the change is that these automatic casts too often caused
2109        surprising behavior.  An example is that in previous releases, this
2110        expression was accepted but did not do what was expected:
2111
2112 <programlisting>
2113 current_date &lt; 2017-11-17
2114 </programlisting>
2115
2116        This is actually comparing a date to an integer, which should be
2117        (and now is) rejected &mdash; but in the presence of automatic
2118        casts both sides were cast to <type>text</> and a textual comparison
2119        was done, because the <literal>text &lt; text</> operator was able
2120        to match the expression when no other <literal>&lt;</> operator could.
2121       </para>
2122
2123       <para>
2124        Types <type>char(<replaceable>n</>)</type> and
2125        <type>varchar(<replaceable>n</>)</type> still cast to <type>text</>
2126        automatically.  Also, automatic casting to <type>text</> still works for
2127        inputs to the concatenation (<literal>||</>) operator, so long as least
2128        one input is a character-string type.
2129       </para>
2130      </listitem>
2131
2132      <listitem>
2133       <para>
2134         Full text search features from <filename>contrib/tsearch2</> have
2135         been moved into the core server, with some minor syntax changes
2136       </para>
2137
2138       <para>
2139        <filename>contrib/tsearch2</> now contains a compatibility
2140        interface.
2141       </para>
2142      </listitem>
2143
2144      <listitem>
2145       <para>
2146        <literal>ARRAY(SELECT ...)</literal>, where the <command>SELECT</>
2147        returns no rows, now returns an empty array, rather than NULL
2148        (Tom)
2149       </para>
2150      </listitem>
2151
2152      <listitem>
2153       <para>
2154        The array type name for a base data type is no longer always the base
2155        type's name with an underscore prefix
2156       </para>
2157
2158       <para>
2159        The old naming convention is still honored when possible, but
2160        application code should no longer depend on it. Instead
2161        use the new <literal>pg_type.typarray</literal> column to
2162        identify the array data type associated with a given type.
2163       </para>
2164      </listitem>
2165
2166      <listitem>
2167       <para>
2168        <literal>ORDER BY ... USING</> <replaceable>operator</> must now
2169        use a less-than or greater-than <replaceable>operator</> that is
2170        defined in a btree operator class
2171       </para>
2172
2173       <para>
2174        This restriction was added to prevent inconsistent results.
2175       </para>
2176      </listitem>
2177
2178      <listitem>
2179       <para>
2180        <command>SET LOCAL</command> changes now persist until
2181        the end of the outermost transaction, unless rolled back (Tom)
2182       </para>
2183
2184       <para>
2185        Previously <command>SET LOCAL</command>'s effects were lost
2186        after subtransaction commit (<command>RELEASE SAVEPOINT</>
2187        or exit from a PL/pgSQL exception block).
2188       </para>
2189      </listitem>
2190
2191      <listitem>
2192       <para>
2193        Commands rejected in transaction blocks are now also rejected in
2194        multiple-statement query strings (Tom)
2195       </para>
2196
2197       <para>
2198        For example, <literal>"BEGIN; DROP DATABASE; COMMIT"</> will now be
2199        rejected even if submitted as a single query message.
2200       </para>
2201      </listitem>
2202
2203      <listitem>
2204       <para>
2205        <command>ROLLBACK</> outside a transaction block now
2206        issues <literal>NOTICE</> instead of <literal>WARNING</> (Bruce)
2207       </para>
2208      </listitem>
2209
2210      <listitem>
2211       <para>
2212        Prevent <command>NOTIFY</command>/<command>LISTEN</command>/<command>UNLISTEN</command>
2213        from accepting schema-qualified names (Bruce)
2214       </para>
2215
2216       <para>
2217        Formerly, these commands accepted <literal>schema.relation</> but
2218        ignored the schema part, which was confusing.
2219       </para>
2220      </listitem>
2221
2222      <listitem>
2223       <para>
2224        <command>ALTER SEQUENCE</> no longer affects the sequence's
2225        <function>currval()</> state (Tom)
2226       </para>
2227      </listitem>
2228
2229      <listitem>
2230       <para>
2231        Foreign keys now must match indexable conditions for
2232        cross-data-type references (Tom)
2233       </para>
2234
2235       <para>
2236        This improves semantic consistency and helps avoid
2237        performance problems.
2238       </para>
2239      </listitem>
2240
2241      <listitem>
2242       <para>
2243        Restrict object size functions to users who have reasonable
2244        permissions to view such information (Tom)
2245       </para>
2246
2247       <para>
2248        For example, <function>pg_database_size()</function> now requires
2249        <literal>CONNECT</> permission, which is granted to everyone by
2250        default. <function>pg_tablespace_size()</function> requires
2251        <literal>CREATE</> permission in the tablespace, or is allowed if
2252        the tablespace is the default tablespace for the database.
2253       </para>
2254      </listitem>
2255
2256      <listitem>
2257       <para>
2258        Remove the undocumented <literal>!!=</> (not in) operator (Tom)
2259       </para>
2260
2261       <para>
2262        <literal>NOT IN (SELECT ...)</literal> is the proper way to
2263        perform this operation.
2264       </para>
2265      </listitem>
2266
2267      <listitem>
2268       <para>
2269        Internal hashing functions are now more uniformly-distributed (Tom)
2270       </para>
2271
2272       <para>
2273        If application code was computing and storing hash values using
2274        internal <productname>PostgreSQL</> hashing functions, the hash
2275        values must be regenerated.
2276       </para>
2277      </listitem>
2278
2279      <listitem>
2280       <para>
2281        C-code conventions for handling variable-length data values
2282        have changed (Greg Stark, Tom)
2283       </para>
2284
2285       <para>
2286        The new <function>SET_VARSIZE()</> macro <emphasis>must</> be used
2287        to set the length of generated <type>varlena</> values. Also, it
2288        might be necessary to expand (<quote>de-TOAST</quote>) input values
2289        in more cases.
2290       </para>
2291      </listitem>
2292
2293      <listitem>
2294       <para>
2295        Continuous archiving no longer reports each successful archive
2296        operation to the server logs unless <literal>DEBUG</> level is used
2297        (Simon)
2298       </para>
2299      </listitem>
2300
2301     </itemizedlist>
2302
2303     </sect3>
2304
2305     <sect3>
2306      <title>Configuration Parameters</title>
2307
2308     <itemizedlist>
2309
2310      <listitem>
2311       <para>
2312        Numerous changes in administrative server parameters
2313       </para>
2314
2315       <para>
2316        <varname>bgwriter_lru_percent</>,
2317        <varname>bgwriter_all_percent</>,
2318        <varname>bgwriter_all_maxpages</>,
2319        <varname>stats_start_collector</>, and
2320        <varname>stats_reset_on_server_start</> are removed.
2321        <varname>redirect_stderr</> is renamed to
2322        <varname>logging_collector</>.
2323        <varname>stats_command_string</> is renamed to
2324        <varname>track_activities</>.
2325        <varname>stats_block_level</> and <varname>stats_row_level</>
2326        are merged into <varname>track_counts</>.
2327        A new boolean configuration parameter, <varname>archive_mode</>,
2328        controls archiving. Autovacuum's default settings have changed.
2329       </para>
2330      </listitem>
2331
2332      <listitem>
2333       <para>
2334        Remove <varname>stats_start_collector</varname> parameter (Tom)
2335       </para>
2336
2337       <para>
2338        We now always start the collector process, unless <acronym>UDP</>
2339        socket creation fails.
2340       </para>
2341      </listitem>
2342
2343      <listitem>
2344       <para>
2345        Remove <varname>stats_reset_on_server_start</varname> parameter (Tom)
2346       </para>
2347
2348       <para>
2349        This was removed because <function>pg_stat_reset()</function>
2350        can be used for this purpose.
2351       </para>
2352      </listitem>
2353
2354      <listitem>
2355       <para>
2356        Commenting out a parameter in <filename>postgresql.conf</> now
2357        causes it to revert to its default value (Joachim Wieland)
2358       </para>
2359
2360       <para>
2361        Previously, commenting out an entry left the parameter's value unchanged
2362        until the next server restart.
2363       </para>
2364      </listitem>
2365
2366     </itemizedlist>
2367
2368     </sect3>
2369
2370
2371     <sect3>
2372      <title>Character Encodings</title>
2373
2374     <itemizedlist>
2375
2376      <listitem>
2377       <para>
2378        Add more checks for invalidly-encoded data (Andrew)
2379       </para>
2380
2381       <para>
2382        This change plugs some holes that existed in literal backslash
2383        escape string processing and <command>COPY</command> escape
2384        processing. Now the de-escaped string is rechecked to see if the
2385        result created an invalid multi-byte character.
2386       </para>
2387      </listitem>
2388
2389      <listitem>
2390       <para>
2391        Disallow database encodings that are inconsistent with the server's
2392        locale setting (Tom)
2393       </para>
2394
2395       <para>
2396        On most platforms, <literal>C</> locale is the only locale that
2397        will work with any database encoding.  Other locale settings imply
2398        a specific encoding and will misbehave if the database encoding
2399        is something different.  (Typical symptoms include bogus textual
2400        sort order and wrong results from <function>upper()</> or
2401        <function>lower()</>.)  The server now rejects attempts to create
2402        databases that have an incompatible encoding.
2403       </para>
2404      </listitem>
2405
2406      <listitem>
2407       <para>
2408        Ensure that <function>chr()</function> cannot create
2409        invalidly-encoded values (Andrew)
2410       </para>
2411
2412       <para>
2413        In UTF8-encoded databases the argument of <function>chr()</function> is
2414        now treated as a Unicode code point. In other multi-byte encodings
2415        <function>chr()</function>'s argument must designate a 7-bit ASCII
2416        character.  Zero is no longer accepted.
2417        <function>ascii()</function> has been adjusted to match.
2418       </para>
2419      </listitem>
2420
2421      <listitem>
2422       <para>
2423        Adjust <function>convert()</function> behavior to ensure encoding
2424        validity (Andrew)
2425       </para>
2426
2427       <para>
2428        The two argument form of <function>convert()</function> has been
2429        removed. The three argument form now takes a <type>bytea</type>
2430        first argument and returns a <type>bytea</type>. To cover the
2431        loss of functionality, three new functions have been added:
2432       </para>
2433
2434       <itemizedlist>
2435        <listitem>
2436         <para>
2437          <function>convert_from(bytea, name)</function> returns
2438          <type>text</> &mdash; converts the first argument from the named
2439          encoding to the database encoding
2440         </para>
2441        </listitem>
2442
2443        <listitem>
2444         <para>
2445          <function>convert_to(text, name)</function> returns
2446          <type>bytea</> &mdash; converts the first argument from the
2447          database encoding to the named encoding
2448         </para>
2449        </listitem>
2450
2451        <listitem>
2452         <para>
2453          <function>length(bytea, name)</function> returns
2454          <type>integer</> &mdash; gives the length of the first
2455          argument in characters in the named encoding
2456         </para>
2457        </listitem>
2458       </itemizedlist>
2459      </listitem>
2460
2461      <listitem>
2462       <para>
2463        Remove <literal>convert(argument USING conversion_name)</literal>
2464        (Andrew)
2465       </para>
2466
2467       <para>
2468        Its behavior did not match the SQL standard.
2469       </para>
2470      </listitem>
2471
2472      <listitem>
2473       <para>
2474        Make JOHAB encoding client-only (Tatsuo)
2475       </para>
2476
2477       <para>
2478        JOHAB is not safe as a server-side encoding.
2479       </para>
2480      </listitem>
2481
2482     </itemizedlist>
2483
2484    </sect3>
2485
2486   </sect2>
2487
2488   <sect2>
2489    <title>Changes</title>
2490
2491    <para>
2492     Below you will find a detailed account of the
2493     changes between <productname>PostgreSQL</productname> 8.3 and
2494     the previous major release.
2495    </para>
2496
2497    <sect3>
2498     <title>Performance</title>
2499     <itemizedlist>
2500
2501      <listitem>
2502       <para>
2503        Asynchronous commit delays writes to WAL during transaction commit
2504        (Simon)
2505       </para>
2506
2507       <para>
2508        This feature dramatically increases performance for short data-modifying
2509        transactions.  The disadvantage is that because disk writes are delayed,
2510        if the database or operating system crashes before data is written to
2511        the disk, committed data will be lost.  This feature is useful for
2512        applications that can accept some data loss.  Unlike turning off
2513        <varname>fsync</varname>, using asynchronous commit does not put
2514        database consistency at risk; the worst case is that after a crash the
2515        last few reportedly-committed transactions might not be committed after
2516        all.
2517        This feature is enabled by turning off <varname>synchronous_commit</>
2518        (which can be done per-session or per-transaction, if some transactions
2519        are critical and others are not).
2520        <varname>wal_writer_delay</> can be adjusted to control the maximum
2521        delay before transactions actually reach disk.
2522       </para>
2523      </listitem>
2524
2525      <listitem>
2526       <para>
2527        Checkpoint writes can be spread over a longer time period to smooth
2528        the I/O spike during each checkpoint (Itagaki Takahiro and Heikki
2529        Linnakangas)
2530       </para>
2531
2532       <para>
2533        Previously all modified buffers were forced to disk as quickly as
2534        possible during a
2535        checkpoint, causing an I/O spike that decreased server performance.
2536        This new approach spreads out disk writes during checkpoints,
2537        reducing peak I/O usage. (User-requested and shutdown checkpoints
2538        are still written as quickly as possible.)
2539       </para>
2540      </listitem>
2541
2542      <listitem>
2543       <para>
2544        Heap-Only Tuples (<acronym>HOT</>) accelerate space reuse for most
2545        <command>UPDATE</>s and <command>DELETE</>s (Pavan Deolasee, with
2546        ideas from many others)
2547       </para>
2548
2549       <para>
2550        <command>UPDATE</>s and <command>DELETE</>s leave dead tuples
2551        behind, as do failed <command>INSERT</>s.  Previously only
2552        <command>VACUUM</> could reclaim space taken by dead tuples. With
2553        <acronym>HOT</> dead tuple space can be automatically reclaimed at
2554        the time of <command>INSERT</> or <command>UPDATE</> if no changes
2555        are made to indexed columns.  This allows for more consistent
2556        performance.  Also, <acronym>HOT</> avoids adding duplicate index
2557        entries.
2558       </para>
2559      </listitem>
2560
2561      <listitem>
2562       <para>
2563        Just-in-time background writer strategy improves disk write
2564        efficiency (Greg Smith, Itagaki Takahiro)
2565       </para>
2566
2567       <para>
2568        This greatly reduces the need for manual tuning of the background
2569        writer.
2570       </para>
2571      </listitem>
2572
2573      <listitem>
2574       <para>
2575        Per-field and per-row storage overhead have been reduced
2576        (Greg Stark, Heikki Linnakangas)
2577       </para>
2578
2579       <para>
2580        Variable-length data types with data values less than 128 bytes long
2581        will see a storage decrease of 3 to 6 bytes. For example, two adjacent
2582        <type>char(1)</type> fields now use 4 bytes instead of 16. Row headers
2583        are also 4 bytes shorter than before.
2584       </para>
2585      </listitem>
2586
2587      <listitem>
2588       <para>
2589        Using non-persistent transaction IDs for read-only transactions
2590        reduces overhead and <command>VACUUM</> requirements (Florian Pflug)
2591       </para>
2592
2593       <para>
2594        Non-persistent transaction IDs do not increment the global
2595        transaction counter. Therefore, they reduce the load on
2596        <structname>pg_clog</> and increase the time between forced
2597        vacuums to prevent transaction ID wraparound.
2598        Other performance
2599        improvements were also made that should improve concurrency.
2600       </para>
2601      </listitem>
2602
2603      <listitem>
2604       <para>
2605        Avoid incrementing the command counter after a read-only command (Tom)
2606       </para>
2607
2608       <para>
2609        There was formerly a hard limit of 2<superscript>32</>
2610        (4 billion) commands per transaction.  Now only commands that
2611        actually changed the database count, so while this limit still
2612        exists, it should be significantly less annoying.
2613       </para>
2614      </listitem>
2615
2616      <listitem>
2617       <para>
2618        Create a dedicated <acronym>WAL</> writer process to off-load
2619        work from backends (Simon)
2620       </para>
2621      </listitem>
2622
2623      <listitem>
2624       <para>
2625        Skip unnecessary WAL writes for <command>CLUSTER</command> and
2626        <command>COPY</command> (Simon)
2627       </para>
2628
2629       <para>
2630        Unless WAL archiving is enabled, the system now avoids WAL writes
2631        for <command>CLUSTER</command> and just <function>fsync()</>s the
2632        table at the end of the command.  It also does the same for
2633        <command>COPY</command> if the table was created in the same
2634        transaction.
2635       </para>
2636      </listitem>
2637
2638      <listitem>
2639       <para>
2640        Large sequential scans no longer force out frequently used
2641        cached pages (Simon, Heikki, Tom)
2642       </para>
2643      </listitem>
2644
2645      <listitem>
2646       <para>
2647        Concurrent large sequential scans can now share disk reads (Jeff Davis)
2648       </para>
2649
2650       <para>
2651        This is accomplished by starting the new sequential scan in the
2652        middle of the table (where another sequential scan is already
2653        in-progress) and wrapping around to the beginning to finish.  This
2654        can affect the order of returned rows in a query that does not
2655        specify <literal>ORDER BY</>.  The <varname>synchronize_seqscans</>
2656        configuration parameter can be used to disable this if necessary.
2657       </para>
2658      </listitem>
2659
2660      <listitem>
2661       <para>
2662        <literal>ORDER BY ... LIMIT</> can be done without sorting
2663        (Greg Stark)
2664       </para>
2665
2666       <para>
2667        This is done by sequentially scanning the table and tracking just
2668        the <quote>top N</> candidate rows, rather than performing a
2669        full sort of the entire table.  This is useful when there is no
2670        matching index and the <literal>LIMIT</> is not large.
2671       </para>
2672      </listitem>
2673
2674      <listitem>
2675       <para>
2676        Put a rate limit on messages sent to the statistics
2677        collector by backends
2678        (Tom)
2679       </para>
2680
2681       <para>
2682        This reduces overhead for short transactions, but might sometimes
2683        increase the delay before statistics are tallied.
2684       </para>
2685      </listitem>
2686
2687      <listitem>
2688       <para>
2689        Improve hash join performance for cases with many NULLs (Tom)
2690       </para>
2691      </listitem>
2692
2693      <listitem>
2694       <para>
2695        Speed up operator lookup for cases with non-exact datatype matches (Tom)
2696       </para>
2697      </listitem>
2698
2699     </itemizedlist>
2700
2701    </sect3>
2702
2703    <sect3>
2704     <title>Server</title>
2705     <itemizedlist>
2706
2707      <listitem>
2708       <para>
2709        Autovacuum is now enabled by default (Alvaro)
2710       </para>
2711
2712       <para>
2713        Several changes were made to eliminate disadvantages of having
2714        autovacuum enabled, thereby justifying the change in default.
2715        Several other autovacuum parameter defaults were also modified.
2716       </para>
2717      </listitem>
2718
2719      <listitem>
2720       <para>
2721        Support multiple concurrent autovacuum processes (Alvaro, Itagaki
2722        Takahiro)
2723       </para>
2724
2725       <para>
2726        This allows multiple vacuums to run concurrently.  This prevents
2727        vacuuming of a large table from delaying vacuuming of smaller tables.
2728       </para>
2729      </listitem>
2730
2731      <listitem>
2732       <para>
2733        Automatically re-plan cached queries when table
2734        definitions change or statistics are updated (Tom)
2735       </para>
2736
2737       <para>
2738        Previously PL/PgSQL functions that referenced temporary tables
2739        would fail if the temporary table was dropped and recreated
2740        between function invocations, unless <literal>EXECUTE</> was
2741        used.  This improvement fixes that problem and many related issues.
2742       </para>
2743      </listitem>
2744
2745      <listitem>
2746       <para>
2747        Add a <varname>temp_tablespaces</varname> parameter to control
2748        the tablespaces for temporary tables and files (Jaime Casanova,
2749        Albert Cervera, Bernd Helmle)
2750       </para>
2751
2752       <para>
2753        This parameter defines a list of tablespaces to be used.  This
2754        enables spreading the I/O load across multiple tablespaces. A random
2755        tablespace is chosen each time a temporary object is created.
2756        Temporary files are no longer stored in per-database
2757        <filename>pgsql_tmp/</filename> directories but in per-tablespace
2758        directories.
2759       </para>
2760      </listitem>
2761
2762      <listitem>
2763       <para>
2764        Place temporary tables' TOAST tables in special schemas named
2765        <literal>pg_toast_temp_<replaceable>nnn</></literal> (Tom)
2766       </para>
2767
2768       <para>
2769        This allows low-level code to recognize these tables as temporary,
2770        which enables various optimizations such as not WAL-logging changes
2771        and using local rather than shared buffers for access. This also
2772        fixes a bug wherein backends unexpectedly held open file references
2773        to temporary TOAST tables.
2774       </para>
2775      </listitem>
2776
2777      <listitem>
2778       <para>
2779        Fix problem that a constant flow of new connection requests could
2780        indefinitely delay the postmaster from completing a shutdown or
2781        a crash restart (Tom)
2782       </para>
2783      </listitem>
2784
2785      <listitem>
2786       <para>
2787        Guard against a very-low-probability data loss scenario by preventing
2788        re-use of a deleted table's relfilenode until after the next
2789        checkpoint (Heikki)
2790       </para>
2791      </listitem>
2792
2793      <listitem>
2794       <para>
2795        Fix <command>CREATE CONSTRAINT TRIGGER</>
2796        to convert old-style foreign key trigger definitions into regular
2797        foreign key constraints (Tom)
2798       </para>
2799
2800       <para>
2801        This will ease porting of foreign key constraints carried forward from
2802        pre-7.3 databases, if they were never converted using
2803        <filename>contrib/adddepend</>.
2804       </para>
2805      </listitem>
2806
2807      <listitem>
2808       <para>
2809        Fix <literal>DEFAULT NULL</> to override inherited defaults (Tom)
2810       </para>
2811
2812       <para>
2813        <literal>DEFAULT NULL</> was formerly considered a noise phrase, but it
2814        should (and now does) override non-null defaults that would otherwise
2815        be inherited from a parent table or domain.
2816       </para>
2817      </listitem>
2818
2819      <listitem>
2820       <para>
2821        Add new encodings EUC_JIS_2004 and SHIFT_JIS_2004 (Tatsuo)
2822       </para>
2823
2824       <para>
2825        These new encodings can be converted to and from UTF-8.
2826       </para>
2827      </listitem>
2828
2829      <listitem>
2830       <para>
2831        Change server startup log message from <quote>database system is
2832        ready</quote> to <quote>database system is ready to accept
2833        connections</quote>, and adjust its timing
2834       </para>
2835
2836       <para>
2837        The message now appears only when the postmaster is really ready
2838        to accept connections.
2839       </para>
2840      </listitem>
2841
2842     </itemizedlist>
2843
2844    </sect3>
2845
2846    <sect3>
2847     <title>Monitoring</title>
2848     <itemizedlist>
2849
2850      <listitem>
2851       <para>
2852        Add <varname>log_autovacuum_min_duration</varname> parameter to
2853        support configurable logging of autovacuum activity (Simon, Alvaro)
2854       </para>
2855      </listitem>
2856
2857      <listitem>
2858       <para>
2859        Add <varname>log_lock_waits</varname> parameter to log lock waiting
2860        (Simon)
2861       </para>
2862      </listitem>
2863
2864      <listitem>
2865       <para>
2866        Add <varname>log_temp_files</varname> parameter to log temporary
2867        file usage (Bill Moran)
2868       </para>
2869      </listitem>
2870
2871      <listitem>
2872       <para>
2873        Add <varname>log_checkpoints</varname> parameter to improve logging
2874        of checkpoints (Greg Smith, Heikki)
2875       </para>
2876      </listitem>
2877
2878      <listitem>
2879       <para>
2880        <varname>log_line_prefix</varname> now supports
2881        <literal>%s</literal> and <literal>%c</literal> escapes in all
2882        processes (Andrew)
2883       </para>
2884
2885       <para>
2886        Previously these escapes worked only for user sessions, not for
2887        background database processes.
2888       </para>
2889      </listitem>
2890
2891      <listitem>
2892       <para>
2893        Add <varname>log_restartpoints</varname> to control logging of
2894        point-in-time recovery restart points (Simon)
2895       </para>
2896      </listitem>
2897
2898      <listitem>
2899       <para>
2900        Last transaction end time is now logged at end of recovery and at
2901        each logged restart point (Simon)
2902       </para>
2903      </listitem>
2904
2905      <listitem>
2906       <para>
2907        Autovacuum now reports its activity start time in
2908        <literal>pg_stat_activity</literal> (Tom)
2909       </para>
2910      </listitem>
2911
2912      <listitem>
2913       <para>
2914        Allow server log output in comma-separated value (CSV) format (Arul
2915        Shaji, Greg Smith, Andrew Dunstan)
2916       </para>
2917
2918       <para>
2919        CSV-format log files can easily be loaded into a database table for
2920        subsequent analysis.
2921       </para>
2922      </listitem>
2923
2924      <listitem>
2925       <para>
2926        Use PostgreSQL-supplied timezone support for formatting timestamps
2927        displayed in the server log (Tom)
2928       </para>
2929
2930       <para>
2931        This avoids Windows-specific problems with localized time zone
2932        names that are in the wrong encoding. There is a new
2933        <varname>log_timezone</> parameter that controls the timezone
2934        used in log messages, independently of the client-visible
2935        <varname>timezone</> parameter.
2936       </para>
2937      </listitem>
2938
2939      <listitem>
2940       <para>
2941        New system view <literal>pg_stat_bgwriter</literal> displays
2942        statistics about background writer activity (Magnus)
2943       </para>
2944      </listitem>
2945
2946      <listitem>
2947       <para>
2948        Add new columns for database-wide tuple statistics to
2949        <literal>pg_stat_database</literal> (Magnus)
2950       </para>
2951      </listitem>
2952
2953      <listitem>
2954       <para>
2955        Add an <literal>xact_start</literal> (transaction start time) column to
2956        <literal>pg_stat_activity</literal> (Neil)
2957       </para>
2958
2959       <para>
2960        This makes it easier to identify long-running transactions.
2961       </para>
2962      </listitem>
2963
2964      <listitem>
2965       <para>
2966        Add <literal>n_live_tuples</> and <literal>n_dead_tuples</> columns
2967        to <literal>pg_stat_all_tables</literal> and related views (Glen
2968        Parker)
2969       </para>
2970      </listitem>
2971
2972      <listitem>
2973       <para>
2974        Merge <varname>stats_block_level</> and <varname>stats_row_level</>
2975        parameters into a single parameter <varname>track_counts</>, which
2976        controls all messages sent to the statistics collector process
2977        (Tom)
2978       </para>
2979      </listitem>
2980
2981      <listitem>
2982       <para>
2983        Rename <varname>stats_command_string</varname> parameter to
2984        <varname>track_activities</varname> (Tom)
2985       </para>
2986      </listitem>
2987
2988      <listitem>
2989       <para>
2990        Fix statistical counting of live and dead tuples to recognize that
2991        committed and aborted transactions have different effects (Tom)
2992       </para>
2993      </listitem>
2994
2995     </itemizedlist>
2996
2997    </sect3>
2998
2999    <sect3>
3000     <title>Authentication</title>
3001     <itemizedlist>
3002
3003      <listitem>
3004       <para>
3005        Support Security Service Provider Interface (<acronym>SSPI</>) for
3006        authentication on Windows (Magnus)
3007       </para>
3008      </listitem>
3009
3010      <listitem>
3011       <para>
3012        Support GSSAPI authentication (Henry Hotz, Magnus)
3013       </para>
3014
3015       <para>
3016        This should be preferred to native Kerberos authentication because
3017        GSSAPI is an industry standard.
3018       </para>
3019      </listitem>
3020
3021      <listitem>
3022       <para>
3023        Support a global SSL configuration file (Victor Wagner)
3024       </para>
3025      </listitem>
3026
3027      <listitem>
3028       <para>
3029        Add <varname>ssl_ciphers</> parameter to control accepted SSL ciphers
3030        (Victor Wagner)
3031       </para>
3032      </listitem>
3033
3034      <listitem>
3035       <para>
3036        Add a Kerberos realm parameter, <varname>krb_realm</> (Magnus)
3037       </para>
3038      </listitem>
3039
3040     </itemizedlist>
3041
3042    </sect3>
3043
3044    <sect3>
3045     <title>Write-Ahead Log (<acronym>WAL</>) and Continuous Archiving</title>
3046     <itemizedlist>
3047
3048      <listitem>
3049       <para>
3050        Change the timestamps recorded in transaction WAL records from
3051        time_t to TimestampTz representation (Tom)
3052       </para>
3053
3054       <para>
3055        This provides sub-second resolution in WAL, which can be useful for
3056        point-in-time recovery.
3057       </para>
3058      </listitem>
3059
3060      <listitem>
3061       <para>
3062        Reduce WAL disk space needed by warm standby servers (Simon)
3063       </para>
3064
3065       <para>
3066        This change allows a warm standby server to pass the name of the earliest
3067        still-needed WAL file to the recovery script, allowing automatic removal
3068        of no-longer-needed WAL files.  This is done using <literal>%r</> in
3069        the <varname>restore_command</varname> parameter of
3070        <filename>recovery.conf</filename>.
3071       </para>
3072      </listitem>
3073
3074      <listitem>
3075       <para>
3076        New boolean configuration parameter, <varname>archive_mode</>,
3077        controls archiving (Simon)
3078       </para>
3079
3080       <para>
3081        Previously setting <varname>archive_command</> to an empty string
3082        turned off archiving. Now <varname>archive_mode</> turns archiving
3083        on and off, independently of <varname>archive_command</>. This is
3084        useful for stopping archiving temporarily.
3085       </para>
3086      </listitem>
3087
3088     </itemizedlist>
3089
3090    </sect3>
3091
3092    <sect3>
3093     <title>Queries</title>
3094     <itemizedlist>
3095
3096      <listitem>
3097       <para>
3098        Full text search is integrated into the core database
3099        system (Teodor, Oleg)
3100       </para>
3101
3102       <para>
3103        Text search has been improved, moved into the core code, and is now
3104        installed by default.  <filename>contrib/tsearch2</> now contains
3105        a compatibility interface.
3106       </para>
3107      </listitem>
3108
3109      <listitem>
3110       <para>
3111        Add control over whether <literal>NULL</>s sort first or last (Teodor, Tom)
3112       </para>
3113
3114       <para>
3115        The syntax is <literal>ORDER BY ... NULLS FIRST/LAST</>.
3116       </para>
3117      </listitem>
3118
3119      <listitem>
3120       <para>
3121        Allow per-column ascending/descending (<literal>ASC</>/<literal>DESC</>)
3122        ordering options for indexes (Teodor, Tom)
3123       </para>
3124
3125       <para>
3126        Previously a query using <literal>ORDER BY</> with mixed
3127        <literal>ASC</>/<literal>DESC</> specifiers could not fully use
3128        an index. Now an index can be fully used in such cases if the
3129        index was created with matching
3130        <literal>ASC</>/<literal>DESC</> specifications.
3131        <literal>NULL</> sort order within an index can be controlled, too.
3132       </para>
3133      </listitem>
3134
3135      <listitem>
3136       <para>
3137        Allow <literal>col IS NULL</> to use an index (Teodor)
3138       </para>
3139      </listitem>
3140
3141      <listitem>
3142       <para>
3143        Updatable cursors (Arul Shaji, Tom)
3144       </para>
3145
3146       <para>
3147        This eliminates the need to reference a primary key to
3148        <command>UPDATE</> or <command>DELETE</> rows returned by a cursor.
3149        The syntax is <literal>UPDATE/DELETE WHERE CURRENT OF</>.
3150       </para>
3151      </listitem>
3152
3153      <listitem>
3154       <para>
3155        Allow <literal>FOR UPDATE</literal> in cursors (Arul Shaji, Tom)
3156       </para>
3157      </listitem>
3158
3159      <listitem>
3160       <para>
3161        Create a general mechanism that supports casts to and from the
3162        standard string types (<type>TEXT</type>, <type>VARCHAR</type>,
3163        <type>CHAR</type>) for <emphasis>every</emphasis> datatype, by
3164        invoking the datatype's I/O functions (Tom)
3165       </para>
3166
3167       <para>
3168        Previously, such casts were available only for types that had
3169        specialized function(s) for the purpose.
3170        These new casts are assignment-only in the to-string direction,
3171        explicit-only in the other direction, and therefore should create no
3172        surprising behavior.
3173       </para>
3174      </listitem>
3175
3176      <listitem>
3177       <para>
3178        Allow <literal>UNION</> and related constructs to return a domain
3179        type, when all inputs are of that domain type (Tom)
3180       </para>
3181
3182       <para>
3183        Formerly, the output would be considered to be of the domain's base
3184        type.
3185       </para>
3186      </listitem>
3187
3188      <listitem>
3189       <para>
3190        Allow limited hashing when using two different data types (Tom)
3191       </para>
3192
3193       <para>
3194        This allows hash joins, hash indexes, hashed subplans, and hash
3195        aggregation to be used in situations involving cross-data-type
3196        comparisons, if the data types have compatible hash functions.
3197        Currently, cross-data-type hashing support exists for
3198        <type>smallint</type>/<type>integer</type>/<type>bigint</type>,
3199        and for <type>float4</type>/<type>float8</type>.
3200       </para>
3201      </listitem>
3202
3203      <listitem>
3204       <para>
3205        Improve optimizer logic for detecting when variables are equal
3206        in a <literal>WHERE</> clause (Tom)
3207       </para>
3208
3209       <para>
3210        This allows mergejoins to work with descending sort orders, and
3211        improves recognition of redundant sort columns.
3212       </para>
3213      </listitem>
3214
3215      <listitem>
3216       <para>
3217        Improve performance when planning large inheritance trees in
3218        cases where most tables are excluded by constraints (Tom)
3219       </para>
3220      </listitem>
3221
3222     </itemizedlist>
3223
3224    </sect3>
3225
3226    <sect3>
3227     <title>Object Manipulation</title>
3228     <itemizedlist>
3229
3230      <listitem>
3231
3232       <para>
3233        Arrays of composite types (David Fetter, Andrew, Tom)
3234       </para>
3235
3236       <para>
3237        In addition to arrays of explicitly-declared composite types,
3238        arrays of the rowtypes of regular tables and views are now
3239        supported, except for rowtypes of system catalogs, sequences, and TOAST
3240        tables.
3241       </para>
3242
3243      </listitem>
3244
3245      <listitem>
3246       <para>
3247        Server configuration parameters can now be set on a per-function
3248        basis (Tom)
3249       </para>
3250
3251       <para>
3252        For example, functions can now set their own
3253        <varname>search_path</> to prevent unexpected behavior if a
3254        different <varname>search_path</> exists at run-time.  Security
3255        definer functions should set <varname>search_path</varname> to
3256        avoid security loopholes.
3257       </para>
3258      </listitem>
3259
3260      <listitem>
3261       <para>
3262        <command>CREATE/ALTER FUNCTION</command> now supports
3263        <literal>COST</literal> and <literal>ROWS</literal> options (Tom)
3264       </para>
3265
3266       <para>
3267        <literal>COST</literal> allows specification of the cost of a
3268        function call.  <literal>ROWS</literal> allows specification of
3269        the average number or rows returned by a set-returning function.
3270        These values are used by the optimizer in choosing the best plan.
3271       </para>
3272      </listitem>
3273
3274      <listitem>
3275       <para>
3276        Implement <command>CREATE TABLE LIKE ...  INCLUDING
3277        INDEXES</command> (Trevor Hardcastle, Nikhil Sontakke, Neil)
3278       </para>
3279      </listitem>
3280
3281      <listitem>
3282       <para>
3283        Allow <command>CREATE INDEX CONCURRENTLY</command> to ignore
3284        transactions in other databases (Simon)
3285       </para>
3286      </listitem>
3287
3288      <listitem>
3289       <para>
3290        Add <command>ALTER VIEW ... RENAME TO</command> and <command>ALTER
3291        SEQUENCE ... RENAME TO</command> (David Fetter, Neil)
3292       </para>
3293
3294       <para>
3295        Previously this could only be done via <command>ALTER TABLE ...
3296        RENAME TO</command>.
3297       </para>
3298      </listitem>
3299
3300      <listitem>
3301       <para>
3302        Make <command>CREATE/DROP/RENAME DATABASE</> wait briefly for
3303        conflicting backends to exit before failing (Tom)
3304       </para>
3305
3306       <para>
3307        This increases the likelihood that these commands will succeed.
3308       </para>
3309      </listitem>
3310
3311      <listitem>
3312       <para>
3313        Allow triggers and rules to be deactivated in groups using a
3314        configuration parameter, for replication purposes (Jan)
3315       </para>
3316
3317       <para>
3318        This allows replication systems to disable triggers and rewrite
3319        rules as a group without modifying the system catalogs directly.
3320        The behavior is controlled by <command>ALTER TABLE</> and a new
3321        parameter <varname>session_replication_role</varname>.
3322       </para>
3323      </listitem>
3324
3325      <listitem>
3326       <para>
3327        User-defined types can now have type modifiers (Teodor, Tom)
3328       </para>
3329
3330       <para>
3331        This allows a user-defined type to take a modifier, like
3332        <type>ssnum(7)</>.  Previously only built-in
3333        data types could have modifiers.
3334       </para>
3335      </listitem>
3336
3337     </itemizedlist>
3338
3339    </sect3>
3340
3341    <sect3>
3342     <title>Utility Commands</title>
3343     <itemizedlist>
3344
3345      <listitem>
3346       <para>
3347        Non-superuser database owners now are able to add trusted procedural
3348        languages to their databases by default (Jeremy Drake)
3349       </para>
3350
3351       <para>
3352        While this is reasonably safe, some administrators might wish to
3353        revoke the privilege. It is controlled by
3354        <structname>pg_pltemplate</>.<structfield>tmpldbacreate</>.
3355       </para>
3356      </listitem>
3357
3358      <listitem>
3359       <para>
3360        Allow a session's current parameter setting to be used as the
3361        default for future sessions (Tom)
3362       </para>
3363
3364       <para>
3365        This is done with <literal>SET ... FROM CURRENT</literal> in
3366        <command>CREATE/ALTER FUNCTION</command>, <command>ALTER
3367        DATABASE</command>, or <command>ALTER ROLE</command>.
3368       </para>
3369      </listitem>
3370
3371      <listitem>
3372       <para>
3373        Implement new commands <command>DISCARD ALL</command>,
3374        <command>DISCARD PLANS</command>, <command>DISCARD
3375        TEMPORARY</command>, <command>CLOSE ALL</command>, and
3376        <command>DEALLOCATE ALL</command> (Marko Kreen, Neil)
3377       </para>
3378
3379       <para>
3380        These commands simplify resetting a database session to its initial
3381        state, and are particularly useful for connection-pooling software.
3382       </para>
3383      </listitem>
3384
3385      <listitem>
3386       <para>
3387        Make <command>CLUSTER</command> MVCC-safe (Heikki Linnakangas)
3388       </para>
3389
3390       <para>
3391        Formerly, <command>CLUSTER</command> would discard all tuples
3392        that were committed dead, even if there were still transactions
3393        that should be able to see them under MVCC visibility rules.
3394       </para>
3395      </listitem>
3396
3397      <listitem>
3398       <para>
3399        Add new <command>CLUSTER</command> syntax: <literal>CLUSTER
3400        <replaceable>table</> USING <replaceable>index</></literal>
3401        (Holger Schurig)
3402      </para>
3403
3404       <para>
3405        The old <command>CLUSTER</command> syntax is still supported, but
3406        the new form is considered more logical.
3407       </para>
3408      </listitem>
3409
3410      <listitem>
3411       <para>
3412        Fix <command>EXPLAIN</command> so it can show complex plans
3413        more accurately (Tom)
3414       </para>
3415
3416       <para>
3417        References to subplan outputs are now always shown correctly,
3418        instead of using <literal>?column<replaceable>N</>?</literal>
3419        for complicated cases.
3420       </para>
3421      </listitem>
3422
3423      <listitem>
3424       <para>
3425        Limit the amount of information reported when a user is dropped
3426        (Alvaro)
3427       </para>
3428
3429       <para>
3430        Previously, dropping (or attempting to drop) a user who owned many
3431        objects could result in large <literal>NOTICE</literal> or
3432        <literal>ERROR</literal> messages listing all these objects; this
3433        caused problems for some client applications.  The length of the
3434        message is now limited, although a full list is still sent to the
3435        server log.
3436       </para>
3437      </listitem>
3438
3439     </itemizedlist>
3440
3441    </sect3>
3442
3443    <sect3>
3444     <title>Data Types</title>
3445     <itemizedlist>
3446
3447      <listitem>
3448       <para>
3449        Support for the SQL/XML standard, including new operators and an
3450        <type>XML</type> data type (Nikolay Samokhvalov, Pavel Stehule, Peter)
3451       </para>
3452      </listitem>
3453
3454      <listitem>
3455       <para>
3456        Enumerated data types (<type>ENUM</type>) (Tom Dunstan)
3457       </para>
3458
3459       <para>
3460        This feature provides convenient support for fields that have a
3461        small, fixed set of allowed values.  An example of creating an
3462        <literal>ENUM</> type is
3463        <literal>CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy')</>.
3464       </para>
3465      </listitem>
3466
3467      <listitem>
3468       <para>
3469        Universally Unique Identifier (<type>UUID</>) data type (Gevik
3470        Babakhani, Neil)
3471       </para>
3472
3473       <para>
3474        This closely matches <acronym>RFC</> 4122.
3475       </para>
3476      </listitem>
3477
3478      <listitem>
3479       <para>
3480        Widen the <type>MONEY</type> data type to 64 bits (D'Arcy Cain)
3481       </para>
3482
3483       <para>
3484        This greatly increases the range of supported <type>MONEY</>
3485        values.
3486       </para>
3487      </listitem>
3488
3489      <listitem>
3490       <para>
3491        Fix <type>float4</type>/<type>float8</type> to handle
3492        <literal>Infinity</> and <literal>NAN</> (Not A Number)
3493        consistently (Bruce)
3494       </para>
3495
3496       <para>
3497        The code formerly was not consistent about distinguishing
3498        <literal>Infinity</> from overflow conditions.
3499       </para>
3500      </listitem>
3501
3502      <listitem>
3503       <para>
3504        Allow leading and trailing whitespace during input of
3505        <type>boolean</type> values (Neil)
3506       </para>
3507      </listitem>
3508
3509      <listitem>
3510       <para>
3511        Prevent <command>COPY</> from using digits and lowercase letters as
3512        delimiters (Tom)
3513       </para>
3514      </listitem>
3515
3516     </itemizedlist>
3517
3518    </sect3>
3519
3520    <sect3>
3521     <title>Functions</title>
3522     <itemizedlist>
3523
3524      <listitem>
3525       <para>
3526        Add new regular expression functions
3527        <function>regexp_matches()</function>,
3528        <function>regexp_split_to_array()</function>, and
3529        <function>regexp_split_to_table()</function> (Jeremy Drake, Neil)
3530       </para>
3531
3532       <para>
3533        These functions provide extraction of regular expression
3534        subexpressions and allow splitting a string using a POSIX regular
3535        expression.
3536       </para>
3537      </listitem>
3538
3539      <listitem>
3540       <para>
3541        Add <function>lo_truncate()</function> for large object truncation
3542        (Kris Jurka)
3543       </para>
3544      </listitem>
3545
3546      <listitem>
3547       <para>
3548        Implement <function>width_bucket()</function> for the <type>float8</>
3549        data type (Neil)
3550       </para>
3551      </listitem>
3552
3553      <listitem>
3554       <para>
3555        Add <function>pg_stat_clear_snapshot()</function> to discard
3556        statistics snapshots collected during the current transaction
3557        (Tom)
3558       </para>
3559
3560       <para>
3561        The first request for statistics in a transaction takes a statistics
3562        snapshot that does not change during the transaction.  This function
3563        allows the snapshot to be discarded and a new snapshot loaded during
3564        the next statistics query. This is particularly useful for PL/PgSQL
3565        functions, which are confined to a single transaction.
3566       </para>
3567      </listitem>
3568
3569      <listitem>
3570       <para>
3571        Add <literal>isodow</> option to <function>EXTRACT()</> and
3572        <function>date_part()</> (Bruce)
3573       </para>
3574
3575       <para>
3576        This returns the day of the week, with Sunday as seven.
3577        (<literal>dow</> returns Sunday as zero.)
3578       </para>
3579      </listitem>
3580
3581      <listitem>
3582       <para>
3583        Add <literal>ID</> (ISO day of week) and <literal>IDDD</> (ISO
3584        day of year) format codes for <function>to_char()</>,
3585        <function>to_date()</>, and <function>to_timestamp()</> (Brendan
3586        Jurd)
3587       </para>
3588      </listitem>
3589
3590      <listitem>
3591       <para>
3592        Make <function>to_timestamp()</> and <function>to_date()</>
3593        assume <literal>TM</literal> (trim) option for potentially
3594        variable-width fields (Bruce)
3595       </para>
3596
3597       <para>
3598        This matches <productname>Oracle</>'s behavior.
3599       </para>
3600      </listitem>
3601
3602      <listitem>
3603       <para>
3604        Fix off-by-one conversion error in
3605        <function>to_date()</function>/<function>to_timestamp()</function>
3606        <literal>D</> (non-ISO day of week) fields (Bruce)
3607       </para>
3608      </listitem>
3609
3610      <listitem>
3611       <para>
3612        Make <function>setseed()</function> return void, rather than a
3613        useless integer value (Neil)
3614       </para>
3615      </listitem>
3616
3617      <listitem>
3618       <para>
3619        Add a hash function for <type>NUMERIC</type> (Neil)
3620       </para>
3621
3622       <para>
3623        This allows hash indexes and hash-based plans to be used with
3624        <type>NUMERIC</type> columns.
3625       </para>
3626      </listitem>
3627
3628      <listitem>
3629       <para>
3630        Improve efficiency of
3631        <literal>LIKE</literal>/<literal>ILIKE</literal>, especially for
3632        multi-byte character sets like UTF-8 (Andrew, Itagaki Takahiro)
3633       </para>
3634      </listitem>
3635
3636      <listitem>
3637       <para>
3638        Make <function>currtid()</function> functions require
3639        <literal>SELECT</literal> privileges on the target table (Tom)
3640       </para>
3641      </listitem>
3642
3643      <listitem>
3644       <para>
3645        Add several <function>txid_*()</function> functions to query
3646        active transaction IDs (Jan)
3647       </para>
3648
3649       <para>
3650        This is useful for various replication solutions.
3651       </para>
3652      </listitem>
3653
3654     </itemizedlist>
3655
3656    </sect3>
3657
3658    <sect3>
3659     <title>PL/PgSQL Server-Side Language</title>
3660     <itemizedlist>
3661
3662      <listitem>
3663       <para>
3664        Add scrollable cursor support, including directional control in
3665        <command>FETCH</command> (Pavel Stehule)
3666       </para>
3667      </listitem>
3668
3669      <listitem>
3670       <para>
3671        Allow <literal>IN</literal> as an alternative to
3672        <literal>FROM</literal> in PL/PgSQL's <command>FETCH</command>
3673        statement, for consistency with the backend's
3674        <command>FETCH</command> command (Pavel Stehule)
3675       </para>
3676      </listitem>
3677
3678      <listitem>
3679       <para>
3680        Add <command>MOVE</command> to PL/PgSQL (Magnus, Pavel Stehule,
3681        Neil)
3682       </para>
3683      </listitem>
3684
3685      <listitem>
3686       <para>
3687        Implement <command>RETURN QUERY</command> (Pavel Stehule, Neil)
3688       </para>
3689
3690       <para>
3691        This adds convenient syntax for PL/PgSQL set-returning functions
3692        that want to return the result of a query.  <command>RETURN QUERY</>
3693        is easier and more efficient than a loop
3694        around <command>RETURN NEXT</command>.
3695       </para>
3696      </listitem>
3697
3698      <listitem>
3699       <para>
3700        Allow function parameter names to be qualified with the
3701        function's name (Tom)
3702       </para>
3703
3704       <para>
3705        For example, <literal>myfunc.myvar</>. This is particularly
3706        useful for specifying variables in a query where the variable
3707        name might match a column name.
3708       </para>
3709      </listitem>
3710
3711      <listitem>
3712       <para>
3713        Make qualification of variables with block labels work properly (Tom)
3714       </para>
3715
3716       <para>
3717        Formerly, outer-level block labels could unexpectedly interfere with
3718        recognition of inner-level record or row references.
3719       </para>
3720      </listitem>
3721
3722      <listitem>
3723       <para>
3724        Tighten requirements for <literal>FOR</literal> loop
3725        <literal>STEP</> values (Tom)
3726       </para>
3727
3728       <para>
3729        Prevent non-positive <literal>STEP</> values, and handle
3730        loop overflows.
3731       </para>
3732      </listitem>
3733
3734      <listitem>
3735       <para>
3736        Improve accuracy when reporting syntax error locations (Tom)
3737       </para>
3738      </listitem>
3739
3740     </itemizedlist>
3741
3742    </sect3>
3743
3744    <sect3>
3745     <title>Other Server-Side Languages</title>
3746     <itemizedlist>
3747
3748      <listitem>
3749       <para>
3750        Allow type-name arguments to PL/Perl
3751        <function>spi_prepare()</function> to be data type aliases in
3752        addition to names found in <literal>pg_type</literal> (Andrew)
3753       </para>
3754      </listitem>
3755
3756      <listitem>
3757       <para>
3758        Allow type-name arguments to PL/Python
3759        <function>plpy.prepare()</function> to be data type aliases in
3760        addition to names found in <literal>pg_type</literal> (Andrew)
3761       </para>
3762      </listitem>
3763
3764      <listitem>
3765       <para>
3766        Allow type-name arguments to PL/Tcl <function>spi_prepare</> to
3767        be data type aliases in addition to names found in
3768        <literal>pg_type</literal> (Andrew)
3769       </para>
3770      </listitem>
3771
3772      <listitem>
3773       <para>
3774        Enable PL/PythonU to compile on Python 2.5 (Marko Kreen)
3775       </para>
3776      </listitem>
3777
3778      <listitem>
3779       <para>
3780        Support a true PL/Python boolean type in compatible Python versions
3781        (Python 2.3 and later) (Marko Kreen)
3782       </para>
3783      </listitem>
3784
3785      <listitem>
3786       <para>
3787        Fix PL/Tcl problems with thread-enabled <filename>libtcl</> spawning
3788        multiple threads within the backend (Steve Marshall, Paul Bayer,
3789        Doug Knight)
3790       </para>
3791
3792       <para>
3793        This caused all sorts of unpleasantness.
3794       </para>
3795      </listitem>
3796
3797     </itemizedlist>
3798
3799    </sect3>
3800
3801    <sect3>
3802     <title><link linkend="APP-PSQL"><application>psql</></link></title>
3803     <itemizedlist>
3804
3805      <listitem>
3806       <para>
3807        List disabled triggers separately in <literal>\d</literal> output
3808        (Brendan Jurd)
3809       </para>
3810      </listitem>
3811
3812      <listitem>
3813       <para>
3814        In <literal>\d</literal> patterns, always match <literal>$</literal>
3815        literally (Tom)
3816       </para>
3817      </listitem>
3818
3819      <listitem>
3820       <para>
3821        Show aggregate return types in <literal>\da</literal> output
3822        (Greg Sabino Mullane)
3823       </para>
3824      </listitem>
3825
3826      <listitem>
3827       <para>
3828        Add the function's volatility status to the output of
3829        <literal>\df+</literal> (Neil)
3830       </para>
3831      </listitem>
3832
3833      <listitem>
3834       <para>
3835        Add <literal>\prompt</literal> capability (Chad Wagner)
3836       </para>
3837      </listitem>
3838
3839      <listitem>
3840       <para>
3841        Allow <literal>\pset</literal>, <literal>\t</literal>, and
3842        <literal>\x</literal> to specify <literal>on</> or <literal>off</>,
3843        rather than just toggling (Chad Wagner)
3844       </para>
3845      </listitem>
3846
3847      <listitem>
3848       <para>
3849        Add <literal>\sleep</> capability (Jan)
3850       </para>
3851      </listitem>
3852
3853      <listitem>
3854       <para>
3855        Enable <literal>\timing</> output for <literal>\copy</> (Andrew)
3856       </para>
3857      </listitem>
3858
3859      <listitem>
3860       <para>
3861        Improve <literal>\timing</literal> resolution on Windows
3862        (Itagaki Takahiro)
3863       </para>
3864      </listitem>
3865
3866      <listitem>
3867       <para>
3868        Flush <literal>\o</> output after each backslash command (Tom)
3869       </para>
3870      </listitem>
3871
3872      <listitem>
3873       <para>
3874        Correctly detect and report errors while reading a <literal>-f</>
3875        input file (Peter)
3876       </para>
3877      </listitem>
3878
3879      <listitem>
3880       <para>
3881        Remove <literal>-u</> option (this option has long been deprecated)
3882        (Tom)
3883       </para>
3884      </listitem>
3885
3886     </itemizedlist>
3887
3888    </sect3>
3889
3890    <sect3>
3891     <title><link linkend="APP-PGDUMP"><application>pg_dump</></link></title>
3892     <itemizedlist>
3893
3894      <listitem>
3895       <para>
3896        Add <literal>--tablespaces-only</> and <literal>--roles-only</>
3897        options to <application>pg_dumpall</application> (Dave Page)
3898       </para>
3899      </listitem>
3900
3901      <listitem>
3902       <para>
3903        Add an output file option to
3904        <application>pg_dumpall</application> (Dave Page)
3905       </para>
3906
3907       <para>
3908        This is primarily useful on Windows, where output redirection of
3909        child <application>pg_dump</application> processes does not work.
3910       </para>
3911      </listitem>
3912
3913      <listitem>
3914       <para>
3915        Allow <application>pg_dumpall</> to accept an initial-connection
3916        database name rather than the default
3917        <literal>template1</literal> (Dave Page)
3918       </para>
3919      </listitem>
3920
3921      <listitem>
3922       <para>
3923        In <literal>-n</> and <literal>-t</> switches, always match
3924        <literal>$</literal> literally (Tom)
3925       </para>
3926      </listitem>
3927
3928      <listitem>
3929       <para>
3930        Improve performance when a database has thousands of objects (Tom)
3931       </para>
3932      </listitem>
3933
3934      <listitem>
3935       <para>
3936        Remove <literal>-u</> option (this option has long been deprecated)
3937        (Tom)
3938       </para>
3939      </listitem>
3940
3941     </itemizedlist>
3942
3943    </sect3>
3944
3945    <sect3>
3946     <title>Other Client Applications</title>
3947     <itemizedlist>
3948
3949      <listitem>
3950       <para>
3951        In <application>initdb</>, allow the location of the
3952        <filename>pg_xlog</filename> directory to be specified
3953        (Euler Taveira de Oliveira)
3954       </para>
3955      </listitem>
3956
3957      <listitem>
3958       <para>
3959        Enable server core dump generation in <application>pg_regress</>
3960        on supported operating systems (Andrew)
3961       </para>
3962      </listitem>
3963
3964      <listitem>
3965       <para>
3966        Add a <literal>-t</> (timeout) parameter to <application>pg_ctl</>
3967        (Bruce)
3968       </para>
3969
3970       <para>
3971        This controls how long <application>pg_ctl</> will wait when waiting
3972        for server startup or shutdown.  Formerly the timeout was hard-wired
3973        as 60 seconds.
3974       </para>
3975      </listitem>
3976
3977      <listitem>
3978       <para>
3979        Add a <application>pg_ctl</> option to control generation
3980        of server core dumps (Andrew)
3981       </para>
3982      </listitem>
3983
3984      <listitem>
3985       <para>
3986        Allow Control-C to cancel <application>clusterdb</>,
3987        <application>reindexdb</>, and <application>vacuumdb</> (Itagaki
3988        Takahiro, Magnus)
3989       </para>
3990      </listitem>
3991
3992      <listitem>
3993       <para>
3994        Suppress command tag output for <application>createdb</>,
3995        <application>createuser</>, <application>dropdb</>, and
3996        <application>dropuser</> (Peter)
3997       </para>
3998
3999       <para>
4000        The <literal>--quiet</> option is ignored and will be removed in 8.4.
4001        Progress messages when acting on all databases now go to stdout
4002        instead of stderr because they are not actually errors.
4003       </para>
4004      </listitem>
4005
4006     </itemizedlist>
4007
4008    </sect3>
4009
4010    <sect3>
4011     <title><link linkend="libpq"><application>libpq</></link></title>
4012     <itemizedlist>
4013
4014      <listitem>
4015       <para>
4016        Interpret the <literal>dbName</> parameter of
4017        <function>PQsetdbLogin()</> as a <literal>conninfo</> string if
4018        it contains an equals sign (Andrew)
4019       </para>
4020
4021       <para>
4022        This allows use of <literal>conninfo</> strings in client
4023        programs that still use <literal>PQsetdbLogin()</>.
4024       </para>
4025      </listitem>
4026
4027      <listitem>
4028       <para>
4029        Support a global <acronym>SSL</> configuration file (Victor
4030        Wagner)
4031       </para>
4032      </listitem>
4033
4034      <listitem>
4035       <para>
4036        Add environment variable <varname>PGSSLKEY</> to control
4037        <acronym>SSL</> hardware keys (Victor Wagner)
4038       </para>
4039      </listitem>
4040
4041      <listitem>
4042       <para>
4043        Add <function>lo_truncate()</function> for large object
4044        truncation (Kris Jurka)
4045       </para>
4046      </listitem>
4047
4048      <listitem>
4049       <para>
4050        Add <function>PQconnectionNeedsPassword()</function> that returns
4051        true if the server required a password but none was supplied
4052        (Joe Conway, Tom)
4053       </para>
4054
4055       <para>
4056        If this returns true after a failed connection attempt, a client
4057        application should prompt the user for a password.  In the past
4058        applications have had to check for a specific error message string to
4059        decide whether a password is needed; that approach is now
4060        deprecated.
4061       </para>
4062      </listitem>
4063
4064      <listitem>
4065       <para>
4066        Add <function>PQconnectionUsedPassword()</function> that returns
4067        true if the supplied password was actually used
4068        (Joe Conway, Tom)
4069       </para>
4070
4071       <para>
4072        This is useful in some security contexts where it is important
4073        to know whether a user-supplied password is actually valid.
4074       </para>
4075      </listitem>
4076
4077     </itemizedlist>
4078
4079    </sect3>
4080
4081    <sect3>
4082     <title><link linkend="ecpg"><application>ecpg</></link></title>
4083     <itemizedlist>
4084
4085      <listitem>
4086       <para>
4087        Use V3 frontend/backend protocol (Michael)
4088       </para>
4089
4090       <para>
4091        This adds support for server-side prepared statements.
4092       </para>
4093      </listitem>
4094
4095      <listitem>
4096       <para>
4097        Use native threads, instead of pthreads, on Windows (Magnus)
4098       </para>
4099      </listitem>
4100
4101      <listitem>
4102       <para>
4103        Improve thread-safety of ecpglib (Itagaki Takahiro)
4104       </para>
4105      </listitem>
4106
4107      <listitem>
4108       <para>
4109        Make the ecpg libraries export only necessary API symbols (Michael)
4110       </para>
4111      </listitem>
4112
4113     </itemizedlist>
4114
4115    </sect3>
4116
4117    <sect3>
4118     <title><application>Windows</> Port</title>
4119     <itemizedlist>
4120
4121      <listitem>
4122       <para>
4123        Allow the whole <productname>PostgreSQL</> distribution to be compiled
4124        with <productname>Microsoft Visual C++</> (Magnus and others)
4125       </para>
4126
4127       <para>
4128        This allows Windows-based developers to use familiar development
4129        and debugging tools.
4130        Windows executables made with Visual C++ might also have better
4131        stability and performance than those made with other tool sets.
4132        The client-only Visual C++ build scripts have been removed.
4133       </para>
4134      </listitem>
4135
4136      <listitem>
4137       <para>
4138        Drastically reduce postmaster's memory usage when it has many child
4139        processes (Magnus)
4140       </para>
4141      </listitem>
4142
4143      <listitem>
4144       <para>
4145        Allow regression tests to be started by an administrative
4146        user (Magnus)
4147       </para>
4148      </listitem>
4149
4150      <listitem>
4151       <para>
4152        Add native shared memory implementation (Magnus)
4153       </para>
4154      </listitem>
4155
4156     </itemizedlist>
4157
4158    </sect3>
4159
4160    <sect3>
4161     <title>Server Programming Interface (<acronym>SPI</>)</title>
4162     <itemizedlist>
4163
4164      <listitem>
4165       <para>
4166        Add cursor-related functionality in SPI (Pavel Stehule)
4167       </para>
4168
4169       <para>
4170        Allow access to the cursor-related planning options, and add
4171        <command>FETCH</>/<command>MOVE</> routines.
4172       </para>
4173      </listitem>
4174
4175      <listitem>
4176       <para>
4177        Allow execution of cursor commands through
4178        <function>SPI_execute</function> (Tom)
4179       </para>
4180
4181       <para>
4182        The macro <literal>SPI_ERROR_CURSOR</> still exists but will
4183        never be returned.
4184       </para>
4185      </listitem>
4186
4187      <listitem>
4188       <para>
4189        SPI plan pointers are now declared as <literal>SPIPlanPtr</> instead of
4190        <literal>void *</> (Tom)
4191       </para>
4192
4193       <para>
4194        This does not break application code, but switching is
4195        recommended to help catch simple programming mistakes.
4196       </para>
4197      </listitem>
4198
4199     </itemizedlist>
4200
4201    </sect3>
4202
4203    <sect3>
4204     <title>Build Options</title>
4205     <itemizedlist>
4206
4207      <listitem>
4208       <para>
4209        Add <application>configure</> option <literal>--enable-profiling</>
4210        to enable code profiling (works only with <application>gcc</>)
4211        (Korry Douglas and Nikhil Sontakke)
4212       </para>
4213      </listitem>
4214
4215      <listitem>
4216       <para>
4217        Add <application>configure</> option <literal>--with-system-tzdata</>
4218        to use the operating system's time zone database (Peter)
4219       </para>
4220      </listitem>
4221
4222      <listitem>
4223       <para>
4224        Fix <acronym>PGXS</> so extensions can be built against PostgreSQL
4225        installations whose <application>pg_config</> program does not
4226        appear first in the <varname>PATH</> (Tom)
4227       </para>
4228      </listitem>
4229
4230      <listitem>
4231       <para>
4232        Support <command>gmake draft</command> when building the
4233        <acronym>SGML</> documentation (Bruce)
4234       </para>
4235
4236       <para>
4237        Unless <literal>draft</> is used, the documentation build will
4238        now be repeated if necessary to ensure the index is up-to-date.
4239       </para>
4240      </listitem>
4241
4242     </itemizedlist>
4243
4244    </sect3>
4245
4246    <sect3>
4247     <title>Source Code</title>
4248     <itemizedlist>
4249
4250      <listitem>
4251       <para>
4252        Rename macro <literal>DLLIMPORT</> to <literal>PGDLLIMPORT</> to
4253        avoid conflicting with third party includes (like Tcl) that
4254        define <literal>DLLIMPORT</> (Magnus)
4255       </para>
4256      </listitem>
4257
4258      <listitem>
4259       <para>
4260        Create <quote>operator families</quote> to improve planning of
4261        queries involving cross-data-type comparisons (Tom)
4262       </para>
4263      </listitem>
4264
4265      <listitem>
4266       <para>
4267        Update GIN <function>extractQuery()</> API to allow signalling
4268        that nothing can satisfy the query (Teodor)
4269       </para>
4270      </listitem>
4271
4272      <listitem>
4273       <para>
4274        Move <literal>NAMEDATALEN</> definition from
4275        <filename>postgres_ext.h</> to <filename>pg_config_manual.h</>
4276        (Peter)
4277       </para>
4278      </listitem>
4279
4280      <listitem>
4281       <para>
4282        Provide <function>strlcpy()</function> and
4283        <function>strlcat()</function> on all platforms, and replace
4284        error-prone uses of <function>strncpy()</function>,
4285        <function>strncat()</function>, etc (Peter)
4286       </para>
4287      </listitem>
4288
4289      <listitem>
4290       <para>
4291        Create hooks to let an external plugin monitor (or even replace) the
4292        planner and create plans for hypothetical situations (Gurjeet
4293        Singh, Tom)
4294       </para>
4295      </listitem>
4296
4297      <listitem>
4298       <para>
4299        Create a function variable <literal>join_search_hook</> to let plugins
4300        override the join search order portion of the planner (Julius
4301        Stroffek)
4302       </para>
4303      </listitem>
4304
4305      <listitem>
4306       <para>
4307        Add <function>tas()</> support for Renesas' M32R processor
4308        (Kazuhiro Inaoka)
4309       </para>
4310      </listitem>
4311
4312      <listitem>
4313       <para>
4314        <function>quote_identifier()</function> and
4315        <application>pg_dump</application> no longer quote keywords that are
4316        unreserved according to the grammar (Tom)
4317       </para>
4318      </listitem>
4319
4320      <listitem>
4321       <para>
4322        Change the on-disk representation of the <type>NUMERIC</type>
4323        data type so that the <structfield>sign_dscale</> word comes
4324        before the weight (Tom)
4325       </para>
4326      </listitem>
4327
4328      <listitem>
4329       <para>
4330        Use <acronym>SYSV</> semaphores rather than POSIX on Darwin
4331        &gt;= 6.0, i.e., OS X 10.2 and up (Chris Marcellino)
4332       </para>
4333      </listitem>
4334
4335      <listitem>
4336       <para>
4337        Add <link linkend="acronyms">acronym</link> and <link
4338        linkend="creating-cluster-nfs">NFS</link> documentation
4339        sections (Bruce)
4340       </para>
4341      </listitem>
4342
4343      <listitem>
4344       <para>
4345        "Postgres" is now documented as an accepted alias for
4346        "PostgreSQL" (Peter)
4347       </para>
4348      </listitem>
4349
4350      <listitem>
4351       <para>
4352        Add documentation about preventing database server spoofing when
4353        the server is down (Bruce)
4354       </para>
4355      </listitem>
4356
4357     </itemizedlist>
4358
4359    </sect3>
4360
4361    <sect3>
4362     <title>Contrib</title>
4363     <itemizedlist>
4364
4365      <listitem>
4366       <para>
4367        Move <filename>contrib</> <filename>README</> content into the
4368        main <productname>PostgreSQL</> documentation (Albert Cervera i
4369        Areny)
4370       </para>
4371      </listitem>
4372
4373      <listitem>
4374       <para>
4375        Add <filename>contrib/pageinspect</filename> module for low-level
4376        page inspection (Simon, Heikki)
4377       </para>
4378      </listitem>
4379
4380      <listitem>
4381       <para>
4382        Add <filename>contrib/pg_standby</filename> module for controlling
4383        warm standby operation (Simon)
4384       </para>
4385      </listitem>
4386
4387      <listitem>
4388       <para>
4389        Add <filename>contrib/uuid-ossp</filename> module for generating
4390        <type>UUID</> values using the OSSP UUID library (Peter)
4391       </para>
4392
4393       <para>
4394        Use <application>configure</>
4395        <literal>--with-ossp-uuid</literal> to activate. This takes
4396        advantage of the new <type>UUID</type> builtin type.
4397       </para>
4398      </listitem>
4399
4400      <listitem>
4401       <para>
4402        Add <filename>contrib/dict_int</filename>,
4403        <filename>contrib/dict_xsyn</filename>, and
4404        <filename>contrib/test_parser</filename> modules to provide
4405        sample add-on text search dictionary templates and parsers
4406        (Sergey Karpov)
4407       </para>
4408      </listitem>
4409
4410      <listitem>
4411       <para>
4412        Allow <application>contrib/pgbench</> to set the fillfactor (Pavan
4413        Deolasee)
4414       </para>
4415      </listitem>
4416
4417      <listitem>
4418       <para>
4419        Add timestamps to <application>contrib/pgbench</> <literal>-l</>
4420        (Greg Smith)
4421       </para>
4422      </listitem>
4423
4424      <listitem>
4425       <para>
4426        Add usage count statistics to
4427        <filename>contrib/pgbuffercache</filename> (Greg Smith)
4428       </para>
4429      </listitem>
4430
4431      <listitem>
4432       <para>
4433        Add GIN support for <filename>contrib/hstore</> (Teodor)
4434       </para>
4435      </listitem>
4436
4437      <listitem>
4438       <para>
4439        Add GIN support for <filename>contrib/pg_trgm</> (Guillaume Smet, Teodor)
4440       </para>
4441      </listitem>
4442
4443      <listitem>
4444       <para>
4445        Update OS/X startup scripts in
4446        <filename>contrib/start-scripts</filename> (Mark Cotner, David
4447        Fetter)
4448       </para>
4449      </listitem>
4450
4451      <listitem>
4452       <para>
4453        Restrict <function>pgrowlocks()</function> and
4454        <function>dblink_get_pkey()</function> to users who have
4455        <literal>SELECT</literal> privilege on the target table (Tom)
4456       </para>
4457      </listitem>
4458
4459      <listitem>
4460       <para>
4461        Restrict <filename>contrib/pgstattuple</filename> functions to
4462        superusers (Tom)
4463       </para>
4464      </listitem>
4465
4466      <listitem>
4467       <para>
4468        <filename>contrib/xml2</filename> is deprecated and planned for
4469        removal in 8.4 (Peter)
4470       </para>
4471
4472       <para>
4473        The new XML support in core PostgreSQL supersedes this module.
4474       </para>
4475      </listitem>
4476
4477     </itemizedlist>
4478
4479    </sect3>
4480   </sect2>
4481  </sect1>