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src/include/access/xact.h
538 строк
18 KB
Etsuro Fujita
postgres_fdw: Inherit the local transaction's access/deferrable modes.
05 апр 2026, 12:55
05 апр 2026, 12:55
de28140
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/*------------------------------------------------------------------------- * * xact.h * postgres transaction system definitions * * * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * src/include/access/xact.h * *------------------------------------------------------------------------- */ #ifndef XACT_H #define XACT_H #include "access/transam.h" #include "access/xlogreader.h" #include "datatype/timestamp.h" #include "lib/stringinfo.h" #include "nodes/pg_list.h" #include "storage/relfilelocator.h" #include "storage/sinval.h" /* * Maximum size of Global Transaction ID (including '\0'). * * Note that the max value of GIDSIZE must fit in the uint16 gidlen, * specified in TwoPhaseFileHeader. */ #define GIDSIZE 200 /* * Xact isolation levels */ #define XACT_READ_UNCOMMITTED 0 #define XACT_READ_COMMITTED 1 #define XACT_REPEATABLE_READ 2 #define XACT_SERIALIZABLE 3 extern PGDLLIMPORT int DefaultXactIsoLevel; extern PGDLLIMPORT int XactIsoLevel; /* * We implement three isolation levels internally. * The weakest uses one snapshot per statement; * the two stronger levels use one snapshot per database transaction. * Serializable uses predicate locks in addition to the snapshot. * These macros can be used to determine which implementation to use * depending on the prevailing serialization level. */ #define IsolationUsesXactSnapshot() (XactIsoLevel >= XACT_REPEATABLE_READ) #define IsolationIsSerializable() (XactIsoLevel == XACT_SERIALIZABLE) /* Xact read-only state */ extern PGDLLIMPORT bool DefaultXactReadOnly; extern PGDLLIMPORT bool XactReadOnly; /* flag for logging statements in this transaction */ extern PGDLLIMPORT bool xact_is_sampled; /* * Xact is deferrable -- only meaningful (currently) for read only * SERIALIZABLE transactions */ extern PGDLLIMPORT bool DefaultXactDeferrable; extern PGDLLIMPORT bool XactDeferrable; typedef enum { SYNCHRONOUS_COMMIT_OFF, /* asynchronous commit */ SYNCHRONOUS_COMMIT_LOCAL_FLUSH, /* wait for local flush only */ SYNCHRONOUS_COMMIT_REMOTE_WRITE, /* wait for local flush and remote * write */ SYNCHRONOUS_COMMIT_REMOTE_FLUSH, /* wait for local and remote flush */ SYNCHRONOUS_COMMIT_REMOTE_APPLY, /* wait for local and remote flush and * remote apply */ } SyncCommitLevel; /* Define the default setting for synchronous_commit */ #define SYNCHRONOUS_COMMIT_ON SYNCHRONOUS_COMMIT_REMOTE_FLUSH /* Synchronous commit level */ extern PGDLLIMPORT int synchronous_commit; /* used during logical streaming of a transaction */ extern PGDLLIMPORT TransactionId CheckXidAlive; extern PGDLLIMPORT bool bsysscan; /* * Miscellaneous flag bits to record events which occur on the top level * transaction. These flags are only persisted in MyXactFlags and are intended * so we remember to do certain things later in the transaction. This is * globally accessible, so can be set from anywhere in the code which requires * recording flags. */ extern PGDLLIMPORT int MyXactFlags; /* * XACT_FLAGS_ACCESSEDTEMPNAMESPACE - set when a temporary object is accessed. * We don't allow PREPARE TRANSACTION in that case. */ #define XACT_FLAGS_ACCESSEDTEMPNAMESPACE (1U << 0) /* * XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK - records whether the top level xact * logged any Access Exclusive Locks. */ #define XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK (1U << 1) /* * XACT_FLAGS_NEEDIMMEDIATECOMMIT - records whether the top level statement * is one that requires immediate commit, such as CREATE DATABASE. */ #define XACT_FLAGS_NEEDIMMEDIATECOMMIT (1U << 2) /* * XACT_FLAGS_PIPELINING - set when we complete an extended-query-protocol * Execute message. This is useful for detecting that an implicit transaction * block has been created via pipelining. */ #define XACT_FLAGS_PIPELINING (1U << 3) /* * start- and end-of-transaction callbacks for dynamically loaded modules */ typedef enum { XACT_EVENT_COMMIT, XACT_EVENT_PARALLEL_COMMIT, XACT_EVENT_ABORT, XACT_EVENT_PARALLEL_ABORT, XACT_EVENT_PREPARE, XACT_EVENT_PRE_COMMIT, XACT_EVENT_PARALLEL_PRE_COMMIT, XACT_EVENT_PRE_PREPARE, } XactEvent; typedef void (*XactCallback) (XactEvent event, void *arg); typedef enum { SUBXACT_EVENT_START_SUB, SUBXACT_EVENT_COMMIT_SUB, SUBXACT_EVENT_ABORT_SUB, SUBXACT_EVENT_PRE_COMMIT_SUB, } SubXactEvent; typedef void (*SubXactCallback) (SubXactEvent event, SubTransactionId mySubid, SubTransactionId parentSubid, void *arg); /* Data structure for Save/RestoreTransactionCharacteristics */ typedef struct SavedTransactionCharacteristics { int save_XactIsoLevel; bool save_XactReadOnly; bool save_XactDeferrable; } SavedTransactionCharacteristics; /* ---------------- * transaction-related XLOG entries * ---------------- */ /* * XLOG allows to store some information in high 4 bits of log record xl_info * field. We use 3 for the opcode, and one about an optional flag variable. */ #define XLOG_XACT_COMMIT 0x00 #define XLOG_XACT_PREPARE 0x10 #define XLOG_XACT_ABORT 0x20 #define XLOG_XACT_COMMIT_PREPARED 0x30 #define XLOG_XACT_ABORT_PREPARED 0x40 #define XLOG_XACT_ASSIGNMENT 0x50 #define XLOG_XACT_INVALIDATIONS 0x60 /* free opcode 0x70 */ /* mask for filtering opcodes out of xl_info */ #define XLOG_XACT_OPMASK 0x70 /* does this record have a 'xinfo' field or not */ #define XLOG_XACT_HAS_INFO 0x80 /* * The following flags, stored in xinfo, determine which information is * contained in commit/abort records. */ #define XACT_XINFO_HAS_DBINFO (1U << 0) #define XACT_XINFO_HAS_SUBXACTS (1U << 1) #define XACT_XINFO_HAS_RELFILELOCATORS (1U << 2) #define XACT_XINFO_HAS_INVALS (1U << 3) #define XACT_XINFO_HAS_TWOPHASE (1U << 4) #define XACT_XINFO_HAS_ORIGIN (1U << 5) #define XACT_XINFO_HAS_AE_LOCKS (1U << 6) #define XACT_XINFO_HAS_GID (1U << 7) #define XACT_XINFO_HAS_DROPPED_STATS (1U << 8) /* * Also stored in xinfo, these indicating a variety of additional actions that * need to occur when emulating transaction effects during recovery. * * They are named XactCompletion... to differentiate them from * EOXact... routines which run at the end of the original transaction * completion. */ #define XACT_COMPLETION_APPLY_FEEDBACK (1U << 29) #define XACT_COMPLETION_UPDATE_RELCACHE_FILE (1U << 30) #define XACT_COMPLETION_FORCE_SYNC_COMMIT (1U << 31) /* Access macros for above flags */ #define XactCompletionApplyFeedback(xinfo) \ ((xinfo & XACT_COMPLETION_APPLY_FEEDBACK) != 0) #define XactCompletionRelcacheInitFileInval(xinfo) \ ((xinfo & XACT_COMPLETION_UPDATE_RELCACHE_FILE) != 0) #define XactCompletionForceSyncCommit(xinfo) \ ((xinfo & XACT_COMPLETION_FORCE_SYNC_COMMIT) != 0) typedef struct xl_xact_assignment { TransactionId xtop; /* assigned XID's top-level XID */ int nsubxacts; /* number of subtransaction XIDs */ TransactionId xsub[FLEXIBLE_ARRAY_MEMBER]; /* assigned subxids */ } xl_xact_assignment; #define MinSizeOfXactAssignment offsetof(xl_xact_assignment, xsub) /* * Commit and abort records can contain a lot of information. But a large * portion of the records won't need all possible pieces of information. So we * only include what's needed. * * A minimal commit/abort record only consists of a xl_xact_commit/abort * struct. The presence of additional information is indicated by bits set in * 'xl_xact_xinfo->xinfo'. The presence of the xinfo field itself is signaled * by a set XLOG_XACT_HAS_INFO bit in the xl_info field. * * NB: All the individual data chunks should be sized to multiples of * sizeof(int) and only require int32 alignment. If they require bigger * alignment, they need to be copied upon reading. */ /* sub-records for commit/abort */ typedef struct xl_xact_xinfo { /* * Even though we right now only require two bytes of space in xinfo we * use four so following records don't have to care about alignment. * Commit records can be large, so copying large portions isn't * attractive. */ uint32 xinfo; } xl_xact_xinfo; typedef struct xl_xact_dbinfo { Oid dbId; /* MyDatabaseId */ Oid tsId; /* MyDatabaseTableSpace */ } xl_xact_dbinfo; typedef struct xl_xact_subxacts { int nsubxacts; /* number of subtransaction XIDs */ TransactionId subxacts[FLEXIBLE_ARRAY_MEMBER]; } xl_xact_subxacts; #define MinSizeOfXactSubxacts offsetof(xl_xact_subxacts, subxacts) typedef struct xl_xact_relfilelocators { int nrels; /* number of relations */ RelFileLocator xlocators[FLEXIBLE_ARRAY_MEMBER]; } xl_xact_relfilelocators; #define MinSizeOfXactRelfileLocators offsetof(xl_xact_relfilelocators, xlocators) /* * A transactionally dropped statistics entry. * * Declared here rather than pgstat.h because pgstat.h can't be included from * frontend code, but the WAL format needs to be readable by frontend * programs. */ typedef struct xl_xact_stats_item { int kind; Oid dboid; /* * This stores the value of PgStat_HashKey.objid as two uint32 as all the * fields of xl_xact_xinfo should be multiples of size(int). */ uint32 objid_lo; uint32 objid_hi; } xl_xact_stats_item; typedef struct xl_xact_stats_items { int nitems; xl_xact_stats_item items[FLEXIBLE_ARRAY_MEMBER]; } xl_xact_stats_items; #define MinSizeOfXactStatsItems offsetof(xl_xact_stats_items, items) typedef struct xl_xact_invals { int nmsgs; /* number of shared inval msgs */ SharedInvalidationMessage msgs[FLEXIBLE_ARRAY_MEMBER]; } xl_xact_invals; #define MinSizeOfXactInvals offsetof(xl_xact_invals, msgs) typedef struct xl_xact_twophase { TransactionId xid; } xl_xact_twophase; typedef struct xl_xact_origin { XLogRecPtr origin_lsn; TimestampTz origin_timestamp; } xl_xact_origin; typedef struct xl_xact_commit { TimestampTz xact_time; /* time of commit */ /* xl_xact_xinfo follows if XLOG_XACT_HAS_INFO */ /* xl_xact_dbinfo follows if XINFO_HAS_DBINFO */ /* xl_xact_subxacts follows if XINFO_HAS_SUBXACT */ /* xl_xact_relfilelocators follows if XINFO_HAS_RELFILELOCATORS */ /* xl_xact_stats_items follows if XINFO_HAS_DROPPED_STATS */ /* xl_xact_invals follows if XINFO_HAS_INVALS */ /* xl_xact_twophase follows if XINFO_HAS_TWOPHASE */ /* twophase_gid follows if XINFO_HAS_GID. As a null-terminated string. */ /* xl_xact_origin follows if XINFO_HAS_ORIGIN, stored unaligned! */ } xl_xact_commit; #define MinSizeOfXactCommit (offsetof(xl_xact_commit, xact_time) + sizeof(TimestampTz)) typedef struct xl_xact_abort { TimestampTz xact_time; /* time of abort */ /* xl_xact_xinfo follows if XLOG_XACT_HAS_INFO */ /* xl_xact_dbinfo follows if XINFO_HAS_DBINFO */ /* xl_xact_subxacts follows if XINFO_HAS_SUBXACT */ /* xl_xact_relfilelocators follows if XINFO_HAS_RELFILELOCATORS */ /* xl_xact_stats_items follows if XINFO_HAS_DROPPED_STATS */ /* No invalidation messages needed. */ /* xl_xact_twophase follows if XINFO_HAS_TWOPHASE */ /* twophase_gid follows if XINFO_HAS_GID. As a null-terminated string. */ /* xl_xact_origin follows if XINFO_HAS_ORIGIN, stored unaligned! */ } xl_xact_abort; #define MinSizeOfXactAbort sizeof(xl_xact_abort) typedef struct xl_xact_prepare { uint32 magic; /* format identifier */ uint32 total_len; /* actual file length */ TransactionId xid; /* original transaction XID */ Oid database; /* OID of database it was in */ TimestampTz prepared_at; /* time of preparation */ Oid owner; /* user running the transaction */ int32 nsubxacts; /* number of following subxact XIDs */ int32 ncommitrels; /* number of delete-on-commit rels */ int32 nabortrels; /* number of delete-on-abort rels */ int32 ncommitstats; /* number of stats to drop on commit */ int32 nabortstats; /* number of stats to drop on abort */ int32 ninvalmsgs; /* number of cache invalidation messages */ bool initfileinval; /* does relcache init file need invalidation? */ uint16 gidlen; /* length of the GID - GID follows the header */ XLogRecPtr origin_lsn; /* lsn of this record at origin node */ TimestampTz origin_timestamp; /* time of prepare at origin node */ } xl_xact_prepare; /* * Commit/Abort records in the above form are a bit verbose to parse, so * there's a deconstructed versions generated by ParseCommit/AbortRecord() for * easier consumption. */ typedef struct xl_xact_parsed_commit { TimestampTz xact_time; uint32 xinfo; Oid dbId; /* MyDatabaseId */ Oid tsId; /* MyDatabaseTableSpace */ int nsubxacts; TransactionId *subxacts; int nrels; RelFileLocator *xlocators; int nstats; xl_xact_stats_item *stats; int nmsgs; SharedInvalidationMessage *msgs; TransactionId twophase_xid; /* only for 2PC */ char twophase_gid[GIDSIZE]; /* only for 2PC */ int nabortrels; /* only for 2PC */ RelFileLocator *abortlocators; /* only for 2PC */ int nabortstats; /* only for 2PC */ xl_xact_stats_item *abortstats; /* only for 2PC */ XLogRecPtr origin_lsn; TimestampTz origin_timestamp; } xl_xact_parsed_commit; typedef xl_xact_parsed_commit xl_xact_parsed_prepare; typedef struct xl_xact_parsed_abort { TimestampTz xact_time; uint32 xinfo; Oid dbId; /* MyDatabaseId */ Oid tsId; /* MyDatabaseTableSpace */ int nsubxacts; TransactionId *subxacts; int nrels; RelFileLocator *xlocators; int nstats; xl_xact_stats_item *stats; TransactionId twophase_xid; /* only for 2PC */ char twophase_gid[GIDSIZE]; /* only for 2PC */ XLogRecPtr origin_lsn; TimestampTz origin_timestamp; } xl_xact_parsed_abort; /* ---------------- * extern definitions * ---------------- */ extern bool IsTransactionState(void); extern bool IsAbortedTransactionBlockState(void); extern TransactionId GetTopTransactionId(void); extern TransactionId GetTopTransactionIdIfAny(void); extern TransactionId GetCurrentTransactionId(void); extern TransactionId GetCurrentTransactionIdIfAny(void); extern TransactionId GetStableLatestTransactionId(void); extern SubTransactionId GetCurrentSubTransactionId(void); extern FullTransactionId GetTopFullTransactionId(void); extern FullTransactionId GetTopFullTransactionIdIfAny(void); extern FullTransactionId GetCurrentFullTransactionId(void); extern FullTransactionId GetCurrentFullTransactionIdIfAny(void); extern void MarkCurrentTransactionIdLoggedIfAny(void); extern bool SubTransactionIsActive(SubTransactionId subxid); extern CommandId GetCurrentCommandId(bool used); extern void SetParallelStartTimestamps(TimestampTz xact_ts, TimestampTz stmt_ts); extern TimestampTz GetCurrentTransactionStartTimestamp(void); extern TimestampTz GetCurrentStatementStartTimestamp(void); extern TimestampTz GetCurrentTransactionStopTimestamp(void); extern void SetCurrentStatementStartTimestamp(void); extern int GetCurrentTransactionNestLevel(void); extern bool TransactionIdIsCurrentTransactionId(TransactionId xid); extern int GetTopReadOnlyTransactionNestLevel(void); extern void CommandCounterIncrement(void); extern void ForceSyncCommit(void); extern void StartTransactionCommand(void); extern void SaveTransactionCharacteristics(SavedTransactionCharacteristics *s); extern void RestoreTransactionCharacteristics(const SavedTransactionCharacteristics *s); extern void CommitTransactionCommand(void); extern void AbortCurrentTransaction(void); extern void BeginTransactionBlock(void); extern bool EndTransactionBlock(bool chain); extern bool PrepareTransactionBlock(const char *gid); extern void UserAbortTransactionBlock(bool chain); extern void BeginImplicitTransactionBlock(void); extern void EndImplicitTransactionBlock(void); extern void ReleaseSavepoint(const char *name); extern void DefineSavepoint(const char *name); extern void RollbackToSavepoint(const char *name); extern void BeginInternalSubTransaction(const char *name); extern void ReleaseCurrentSubTransaction(void); extern void RollbackAndReleaseCurrentSubTransaction(void); extern bool IsSubTransaction(void); extern Size EstimateTransactionStateSpace(void); extern void SerializeTransactionState(Size maxsize, char *start_address); extern void StartParallelWorkerTransaction(char *tstatespace); extern void EndParallelWorkerTransaction(void); extern bool IsTransactionBlock(void); extern bool IsTransactionOrTransactionBlock(void); extern char TransactionBlockStatusCode(void); extern void AbortOutOfAnyTransaction(void); extern void PreventInTransactionBlock(bool isTopLevel, const char *stmtType); extern void RequireTransactionBlock(bool isTopLevel, const char *stmtType); extern void WarnNoTransactionBlock(bool isTopLevel, const char *stmtType); extern bool IsInTransactionBlock(bool isTopLevel); extern void RegisterXactCallback(XactCallback callback, void *arg); extern void UnregisterXactCallback(XactCallback callback, void *arg); extern void RegisterSubXactCallback(SubXactCallback callback, void *arg); extern void UnregisterSubXactCallback(SubXactCallback callback, void *arg); extern bool IsSubxactTopXidLogPending(void); extern void MarkSubxactTopXidLogged(void); extern int xactGetCommittedChildren(TransactionId **ptr); extern XLogRecPtr XactLogCommitRecord(TimestampTz commit_time, int nsubxacts, TransactionId *subxacts, int nrels, RelFileLocator *rels, int ndroppedstats, xl_xact_stats_item *droppedstats, int nmsgs, SharedInvalidationMessage *msgs, bool relcacheInval, int xactflags, TransactionId twophase_xid, const char *twophase_gid); extern XLogRecPtr XactLogAbortRecord(TimestampTz abort_time, int nsubxacts, TransactionId *subxacts, int nrels, RelFileLocator *rels, int ndroppedstats, xl_xact_stats_item *droppedstats, int xactflags, TransactionId twophase_xid, const char *twophase_gid); extern void xact_redo(XLogReaderState *record); /* xactdesc.c */ extern void xact_desc(StringInfo buf, XLogReaderState *record); extern const char *xact_identify(uint8 info); /* also in xactdesc.c, so they can be shared between front/backend code */ extern void ParseCommitRecord(uint8 info, xl_xact_commit *xlrec, xl_xact_parsed_commit *parsed); extern void ParseAbortRecord(uint8 info, xl_xact_abort *xlrec, xl_xact_parsed_abort *parsed); extern void ParsePrepareRecord(uint8 info, xl_xact_prepare *xlrec, xl_xact_parsed_prepare *parsed); extern void EnterParallelMode(void); extern void ExitParallelMode(void); extern bool IsInParallelMode(void); #endif /* XACT_H */