src/include/access/multixact.h

   1 /*
   2  * multixact.h
   3  *
   4  * PostgreSQL multi-transaction-log manager
   5  *
   6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  * src/include/access/multixact.h
  10  */
  11 #ifndef MULTIXACT_H
  12 #define MULTIXACT_H
  13
  14 #include "access/xlogreader.h"
  15 #include "lib/stringinfo.h"
  16 #include "storage/sync.h"
  17
  18
  19 /*
  20  * The first two MultiXactId values are reserved to store the truncation Xid
  21  * and epoch of the first segment, so we start assigning multixact values from
  22  * 2.
  23  */
  24 #define InvalidMultiXactId      ((MultiXactId) 0)
  25 #define FirstMultiXactId        ((MultiXactId) 1)
  26 #define MaxMultiXactId          ((MultiXactId) 0xFFFFFFFF)
  27
  28 #define MultiXactIdIsValid(multi) ((multi) != InvalidMultiXactId)
  29
  30 #define MaxMultiXactOffset      ((MultiXactOffset) 0xFFFFFFFF)
  31
  32 /*
  33  * Possible multixact lock modes ("status").  The first four modes are for
  34  * tuple locks (FOR KEY SHARE, FOR SHARE, FOR NO KEY UPDATE, FOR UPDATE); the
  35  * next two are used for update and delete modes.
  36  */
  37 typedef enum
  38 {
  39         MultiXactStatusForKeyShare = 0x00,
  40         MultiXactStatusForShare = 0x01,
  41         MultiXactStatusForNoKeyUpdate = 0x02,
  42         MultiXactStatusForUpdate = 0x03,
  43         /* an update that doesn't touch "key" columns */
  44         MultiXactStatusNoKeyUpdate = 0x04,
  45         /* other updates, and delete */
  46         MultiXactStatusUpdate = 0x05,
  47 } MultiXactStatus;
  48
  49 #define MaxMultiXactStatus MultiXactStatusUpdate
  50
  51 /* does a status value correspond to a tuple update? */
  52 #define ISUPDATE_from_mxstatus(status) \
  53                         ((status) > MultiXactStatusForUpdate)
  54
  55
  56 typedef struct MultiXactMember
  57 {
  58         TransactionId xid;
  59         MultiXactStatus status;
  60 } MultiXactMember;
  61
  62
  63 /* ----------------
  64  *              multixact-related XLOG entries
  65  * ----------------
  66  */
  67
  68 #define XLOG_MULTIXACT_ZERO_OFF_PAGE    0x00
  69 #define XLOG_MULTIXACT_ZERO_MEM_PAGE    0x10
  70 #define XLOG_MULTIXACT_CREATE_ID                0x20
  71 #define XLOG_MULTIXACT_TRUNCATE_ID              0x30
  72
  73 typedef struct xl_multixact_create
  74 {
  75         MultiXactId mid;                        /* new MultiXact's ID */
  76         MultiXactOffset moff;           /* its starting offset in members file */
  77         int32           nmembers;               /* number of member XIDs */
  78         MultiXactMember members[FLEXIBLE_ARRAY_MEMBER];
  79 } xl_multixact_create;
  80
  81 #define SizeOfMultiXactCreate (offsetof(xl_multixact_create, members))
  82
  83 typedef struct xl_multixact_truncate
  84 {
  85         Oid                     oldestMultiDB;
  86
  87         /* to-be-truncated range of multixact offsets */
  88         MultiXactId startTruncOff;      /* just for completeness' sake */
  89         MultiXactId endTruncOff;
  90
  91         /* to-be-truncated range of multixact members */
  92         MultiXactOffset startTruncMemb;
  93         MultiXactOffset endTruncMemb;
  94 } xl_multixact_truncate;
  95
  96 #define SizeOfMultiXactTruncate (sizeof(xl_multixact_truncate))
  97
  98
  99 extern MultiXactId MultiXactIdCreate(TransactionId xid1,
 100                                                                          MultiXactStatus status1, TransactionId xid2,
 101                                                                          MultiXactStatus status2);
 102 extern MultiXactId MultiXactIdExpand(MultiXactId multi, TransactionId xid,
 103                                                                          MultiXactStatus status);
 104 extern MultiXactId MultiXactIdCreateFromMembers(int nmembers,
 105                                                                                                 MultiXactMember *members);
 106
 107 extern MultiXactId ReadNextMultiXactId(void);
 108 extern void ReadMultiXactIdRange(MultiXactId *oldest, MultiXactId *next);
 109 extern bool MultiXactIdIsRunning(MultiXactId multi, bool isLockOnly);
 110 extern void MultiXactIdSetOldestMember(void);
 111 extern int      GetMultiXactIdMembers(MultiXactId multi, MultiXactMember **members,
 112                                                                   bool from_pgupgrade, bool isLockOnly);
 113 extern bool MultiXactIdPrecedes(MultiXactId multi1, MultiXactId multi2);
 114 extern bool MultiXactIdPrecedesOrEquals(MultiXactId multi1,
 115                                                                                 MultiXactId multi2);
 116
 117 extern int      multixactoffsetssyncfiletag(const FileTag *ftag, char *path);
 118 extern int      multixactmemberssyncfiletag(const FileTag *ftag, char *path);
 119
 120 extern void AtEOXact_MultiXact(void);
 121 extern void AtPrepare_MultiXact(void);
 122 extern void PostPrepare_MultiXact(TransactionId xid);
 123
 124 extern Size MultiXactShmemSize(void);
 125 extern void MultiXactShmemInit(void);
 126 extern void BootStrapMultiXact(void);
 127 extern void StartupMultiXact(void);
 128 extern void TrimMultiXact(void);
 129 extern void SetMultiXactIdLimit(MultiXactId oldest_datminmxid,
 130                                                                 Oid oldest_datoid,
 131                                                                 bool is_startup);
 132 extern void MultiXactGetCheckptMulti(bool is_shutdown,
 133                                                                          MultiXactId *nextMulti,
 134                                                                          MultiXactOffset *nextMultiOffset,
 135                                                                          MultiXactId *oldestMulti,
 136                                                                          Oid *oldestMultiDB);
 137 extern void CheckPointMultiXact(void);
 138 extern MultiXactId GetOldestMultiXactId(void);
 139 extern void TruncateMultiXact(MultiXactId newOldestMulti,
 140                                                           Oid newOldestMultiDB);
 141 extern void MultiXactSetNextMXact(MultiXactId nextMulti,
 142                                                                   MultiXactOffset nextMultiOffset);
 143 extern void MultiXactAdvanceNextMXact(MultiXactId minMulti,
 144                                                                           MultiXactOffset minMultiOffset);
 145 extern void MultiXactAdvanceOldest(MultiXactId oldestMulti, Oid oldestMultiDB);
 146 extern int      MultiXactMemberFreezeThreshold(void);
 147
 148 extern void multixact_twophase_recover(TransactionId xid, uint16 info,
 149                                                                            void *recdata, uint32 len);
 150 extern void multixact_twophase_postcommit(TransactionId xid, uint16 info,
 151                                                                                   void *recdata, uint32 len);
 152 extern void multixact_twophase_postabort(TransactionId xid, uint16 info,
 153                                                                                  void *recdata, uint32 len);
 154
 155 extern void multixact_redo(XLogReaderState *record);
 156 extern void multixact_desc(StringInfo buf, XLogReaderState *record);
 157 extern const char *multixact_identify(uint8 info);
 158 extern char *mxid_to_string(MultiXactId multi, int nmembers,
 159                                                         MultiXactMember *members);
 160
 161 #endif                                                  /* MULTIXACT_H */