src/include/access/multixact.h

   1 /*
   2  * multixact.h
   3  *
   4  * PostgreSQL multi-transaction-log manager
   5  *
   6  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  * $PostgreSQL$
  10  */
  11 #ifndef MULTIXACT_H
  12 #define MULTIXACT_H
  13
  14 #include "access/xlog.h"
  15
  16 #define InvalidMultiXactId      ((MultiXactId) 0)
  17 #define FirstMultiXactId        ((MultiXactId) 1)
  18
  19 #define MultiXactIdIsValid(multi) ((multi) != InvalidMultiXactId)
  20
  21 /* Number of SLRU buffers to use for multixact */
  22 #define NUM_MXACTOFFSET_BUFFERS         8
  23 #define NUM_MXACTMEMBER_BUFFERS         16
  24
  25 /* ----------------
  26  *              multixact-related XLOG entries
  27  * ----------------
  28  */
  29
  30 #define XLOG_MULTIXACT_ZERO_OFF_PAGE    0x00
  31 #define XLOG_MULTIXACT_ZERO_MEM_PAGE    0x10
  32 #define XLOG_MULTIXACT_CREATE_ID                0x20
  33
  34 typedef struct xl_multixact_create
  35 {
  36         MultiXactId mid;                        /* new MultiXact's ID */
  37         MultiXactOffset moff;           /* its starting offset in members file */
  38         int32           nxids;                  /* number of member XIDs */
  39         TransactionId xids[1];          /* VARIABLE LENGTH ARRAY */
  40 } xl_multixact_create;
  41
  42 #define MinSizeOfMultiXactCreate offsetof(xl_multixact_create, xids)
  43
  44
  45 extern MultiXactId MultiXactIdCreate(TransactionId xid1, TransactionId xid2);
  46 extern MultiXactId MultiXactIdExpand(MultiXactId multi, TransactionId xid);
  47 extern bool MultiXactIdIsRunning(MultiXactId multi);
  48 extern bool MultiXactIdIsCurrent(MultiXactId multi);
  49 extern void MultiXactIdWait(MultiXactId multi);
  50 extern bool ConditionalMultiXactIdWait(MultiXactId multi);
  51 extern void MultiXactIdSetOldestMember(void);
  52 extern int      GetMultiXactIdMembers(MultiXactId multi, TransactionId **xids);
  53
  54 extern void AtEOXact_MultiXact(void);
  55
  56 extern Size MultiXactShmemSize(void);
  57 extern void MultiXactShmemInit(void);
  58 extern void BootStrapMultiXact(void);
  59 extern void StartupMultiXact(void);
  60 extern void ShutdownMultiXact(void);
  61 extern void MultiXactGetCheckptMulti(bool is_shutdown,
  62                                                  MultiXactId *nextMulti,
  63                                                  MultiXactOffset *nextMultiOffset);
  64 extern void CheckPointMultiXact(void);
  65 extern void MultiXactSetNextMXact(MultiXactId nextMulti,
  66                                           MultiXactOffset nextMultiOffset);
  67 extern void MultiXactAdvanceNextMXact(MultiXactId minMulti,
  68                                                   MultiXactOffset minMultiOffset);
  69
  70 extern void multixact_redo(XLogRecPtr lsn, XLogRecord *record);
  71 extern void multixact_desc(StringInfo buf, uint8 xl_info, char *rec);
  72
  73 #endif   /* MULTIXACT_H */