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Diffstat (limited to 'src/include/access/xact.h')
| -rw-r--r-- | src/include/access/xact.h | 530 |
1 files changed, 530 insertions, 0 deletions
diff --git a/src/include/access/xact.h b/src/include/access/xact.h new file mode 100644 index 0000000..7d3b944 --- /dev/null +++ b/src/include/access/xact.h @@ -0,0 +1,530 @@ +/*------------------------------------------------------------------------- + * + * xact.h + * postgres transaction system definitions + * + * + * Portions Copyright (c) 1996-2023, 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 two stronger ones use one snapshot per database transaction; + * the others use one snapshot per statement. + * Serializable uses predicate locks in addition to snapshots. + * These macros should be used to check which isolation level is selected. + */ +#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; + Oid objoid; +} 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 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 */ |