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1 /*------------------------------------------------------------------------
2 * PostgreSQL manual configuration settings
3 *
4 * This file contains various configuration symbols and limits. In
5 * all cases, changing them is only useful in very rare situations or
6 * for developers. If you edit any of these, be sure to do a *full*
7 * rebuild (and an initdb if noted).
8 *
9 * $PostgreSQL$
10 *------------------------------------------------------------------------
11 */
13 /*
14 * Maximum length for identifiers (e.g. table names, column names,
15 * function names). Names actually are limited to one less byte than this,
16 * because the length must include a trailing zero byte.
17 *
18 * Changing this requires an initdb.
19 */
20 #define NAMEDATALEN 64
22 /*
23 * Maximum number of arguments to a function.
24 *
25 * The minimum value is 8 (index cost estimation uses 8-argument functions).
26 * The maximum possible value is around 600 (limited by index tuple size in
27 * pg_proc's index; BLCKSZ larger than 8K would allow more). Values larger
28 * than needed will waste memory and processing time, but do not directly
29 * cost disk space.
30 *
31 * Changing this does not require an initdb, but it does require a full
32 * backend recompile (including any user-defined C functions).
33 */
34 #define FUNC_MAX_ARGS 100
36 /*
37 * Maximum number of columns in an index. There is little point in making
38 * this anything but a multiple of 32, because the main cost is associated
39 * with index tuple header size (see access/itup.h).
40 *
41 * Changing this requires an initdb.
42 */
43 #define INDEX_MAX_KEYS 32
45 /*
46 * Set the upper and lower bounds of sequence values.
47 */
48 #ifndef INT64_IS_BUSTED
49 #define SEQ_MAXVALUE INT64CONST(0x7FFFFFFFFFFFFFFF)
51 #define SEQ_MAXVALUE ((int64) 0x7FFFFFFF)
54 #define SEQ_MINVALUE (-SEQ_MAXVALUE)
56 /*
57 * Number of spare LWLocks to allocate for user-defined add-on code.
58 */
59 #define NUM_USER_DEFINED_LWLOCKS 4
61 /*
62 * Define this if you want to allow the lo_import and lo_export SQL
63 * functions to be executed by ordinary users. By default these
64 * functions are only available to the Postgres superuser. CAUTION:
65 * These functions are SECURITY HOLES since they can read and write
66 * any file that the PostgreSQL server has permission to access. If
67 * you turn this on, don't say we didn't warn you.
68 */
69 /* #define ALLOW_DANGEROUS_LO_FUNCTIONS */
71 /*
72 * MAXPGPATH: standard size of a pathname buffer in PostgreSQL (hence,
73 * maximum usable pathname length is one less).
74 *
75 * We'd use a standard system header symbol for this, if there weren't
76 * so many to choose from: MAXPATHLEN, MAX_PATH, PATH_MAX are all
77 * defined by different "standards", and often have different values
78 * on the same platform! So we just punt and use a reasonably
79 * generous setting here.
80 */
81 #define MAXPGPATH 1024
83 /*
84 * PG_SOMAXCONN: maximum accept-queue length limit passed to
85 * listen(2). You'd think we should use SOMAXCONN from
86 * <sys/socket.h>, but on many systems that symbol is much smaller
87 * than the kernel's actual limit. In any case, this symbol need be
88 * twiddled only if you have a kernel that refuses large limit values,
89 * rather than silently reducing the value to what it can handle
90 * (which is what most if not all Unixen do).
91 */
92 #define PG_SOMAXCONN 10000
94 /*
95 * You can try changing this if you have a machine with bytes of
96 * another size, but no guarantee...
97 */
98 #define BITS_PER_BYTE 8
100 /*
101 * Preferred alignment for disk I/O buffers. On some CPUs, copies between
102 * user space and kernel space are significantly faster if the user buffer
103 * is aligned on a larger-than-MAXALIGN boundary. Ideally this should be
104 * a platform-dependent value, but for now we just hard-wire it.
105 */
106 #define ALIGNOF_BUFFER 32
108 /*
109 * Disable UNIX sockets for certain operating systems.
110 */
111 #if defined(WIN32)
112 #undef HAVE_UNIX_SOCKETS
113 #endif
115 /*
116 * Define this if your operating system supports link()
117 */
118 #if !defined(WIN32) && !defined(__CYGWIN__)
119 #define HAVE_WORKING_LINK 1
120 #endif
122 /*
123 * USE_POSIX_FADVISE controls whether Postgres will attempt to use the
124 * posix_fadvise() kernel call. Usually the automatic configure tests are
125 * sufficient, but some older Linux distributions had broken versions of
126 * posix_fadvise(). If necessary you can remove the #define here.
127 */
128 #if HAVE_DECL_POSIX_FADVISE && defined(HAVE_POSIX_FADVISE)
129 #define USE_POSIX_FADVISE
130 #endif
132 /*
133 * USE_PREFETCH code should be compiled only if we have a way to implement
134 * prefetching. (This is decoupled from USE_POSIX_FADVISE because there
135 * might in future be support for alternative low-level prefetch APIs.)
136 */
137 #ifdef USE_POSIX_FADVISE
138 #define USE_PREFETCH
139 #endif
141 /*
142 * This is the default directory in which AF_UNIX socket files are
143 * placed. Caution: changing this risks breaking your existing client
144 * applications, which are likely to continue to look in the old
145 * directory. But if you just hate the idea of sockets in /tmp,
146 * here's where to twiddle it. You can also override this at runtime
147 * with the postmaster's -k switch.
148 */
151 /*
152 * The random() function is expected to yield values between 0 and
153 * MAX_RANDOM_VALUE. Currently, all known implementations yield
154 * 0..2^31-1, so we just hardwire this constant. We could do a
155 * configure test if it proves to be necessary. CAUTION: Think not to
156 * replace this with RAND_MAX. RAND_MAX defines the maximum value of
157 * the older rand() function, which is often different from --- and
158 * considerably inferior to --- random().
159 */
160 #define MAX_RANDOM_VALUE (0x7FFFFFFF)
163 /*
164 *------------------------------------------------------------------------
165 * The following symbols are for enabling debugging code, not for
166 * controlling user-visible features or resource limits.
167 *------------------------------------------------------------------------
168 */
170 /*
171 * Define this to cause pfree()'d memory to be cleared immediately, to
172 * facilitate catching bugs that refer to already-freed values.
173 * Right now, this gets defined automatically if --enable-cassert.
174 */
175 #ifdef USE_ASSERT_CHECKING
176 #define CLOBBER_FREED_MEMORY
177 #endif
179 /*
180 * Define this to check memory allocation errors (scribbling on more
181 * bytes than were allocated). Right now, this gets defined
182 * automatically if --enable-cassert.
183 */
184 #ifdef USE_ASSERT_CHECKING
185 #define MEMORY_CONTEXT_CHECKING
186 #endif
188 /*
189 * Define this to cause palloc()'d memory to be filled with random data, to
190 * facilitate catching code that depends on the contents of uninitialized
191 * memory. Caution: this is horrendously expensive.
192 */
193 /* #define RANDOMIZE_ALLOCATED_MEMORY */
195 /*
196 * Define this to force all parse and plan trees to be passed through
197 * copyObject(), to facilitate catching errors and omissions in
198 * copyObject().
199 */
200 /* #define COPY_PARSE_PLAN_TREES */
202 /*
203 * Enable debugging print statements for lock-related operations.
204 */
205 /* #define LOCK_DEBUG */
207 /*
208 * Enable debugging print statements for WAL-related operations; see
209 * also the wal_debug GUC var.
210 */
211 /* #define WAL_DEBUG */
213 /*
214 * Enable tracing of resource consumption during sort operations;
215 * see also the trace_sort GUC var. For 8.1 this is enabled by default.
216 */
217 #define TRACE_SORT 1
219 /*
220 * Enable tracing of syncscan operations (see also the trace_syncscan GUC var).
221 */
222 /* #define TRACE_SYNCSCAN */
224 /*
225 * Other debug #defines (documentation, anyone?)
226 */
227 /* #define HEAPDEBUGALL */
228 /* #define ACLDEBUG */
229 /* #define RTDEBUG */