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Diffstat (limited to 'src/include/access/xlogutils.h')
| -rw-r--r-- | src/include/access/xlogutils.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h new file mode 100644 index 0000000..c9d0b75 --- /dev/null +++ b/src/include/access/xlogutils.h @@ -0,0 +1,118 @@ +/* + * xlogutils.h + * + * Utilities for replaying WAL records. + * + * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/access/xlogutils.h + */ +#ifndef XLOG_UTILS_H +#define XLOG_UTILS_H + +#include "access/xlogreader.h" +#include "storage/bufmgr.h" + +/* + * Prior to 8.4, all activity during recovery was carried out by the startup + * process. This local variable continues to be used in many parts of the + * code to indicate actions taken by RecoveryManagers. Other processes that + * potentially perform work during recovery should check RecoveryInProgress(). + * See XLogCtl notes in xlog.c. + */ +extern PGDLLIMPORT bool InRecovery; + +/* + * Like InRecovery, standbyState is only valid in the startup process. + * In all other processes it will have the value STANDBY_DISABLED (so + * InHotStandby will read as false). + * + * In DISABLED state, we're performing crash recovery or hot standby was + * disabled in postgresql.conf. + * + * In INITIALIZED state, we've run InitRecoveryTransactionEnvironment, but + * we haven't yet processed a RUNNING_XACTS or shutdown-checkpoint WAL record + * to initialize our primary-transaction tracking system. + * + * When the transaction tracking is initialized, we enter the SNAPSHOT_PENDING + * state. The tracked information might still be incomplete, so we can't allow + * connections yet, but redo functions must update the in-memory state when + * appropriate. + * + * In SNAPSHOT_READY mode, we have full knowledge of transactions that are + * (or were) running on the primary at the current WAL location. Snapshots + * can be taken, and read-only queries can be run. + */ +typedef enum +{ + STANDBY_DISABLED, + STANDBY_INITIALIZED, + STANDBY_SNAPSHOT_PENDING, + STANDBY_SNAPSHOT_READY +} HotStandbyState; + +extern PGDLLIMPORT HotStandbyState standbyState; + +#define InHotStandby (standbyState >= STANDBY_SNAPSHOT_PENDING) + + +extern bool XLogHaveInvalidPages(void); +extern void XLogCheckInvalidPages(void); + +extern void XLogDropRelation(RelFileNode rnode, ForkNumber forknum); +extern void XLogDropDatabase(Oid dbid); +extern void XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, + BlockNumber nblocks); + +/* Result codes for XLogReadBufferForRedo[Extended] */ +typedef enum +{ + BLK_NEEDS_REDO, /* changes from WAL record need to be applied */ + BLK_DONE, /* block is already up-to-date */ + BLK_RESTORED, /* block was restored from a full-page image */ + BLK_NOTFOUND /* block was not found (and hence does not + * need to be replayed) */ +} XLogRedoAction; + +/* Private data of the read_local_xlog_page_no_wait callback. */ +typedef struct ReadLocalXLogPageNoWaitPrivate +{ + bool end_of_wal; /* true, when end of WAL is reached */ +} ReadLocalXLogPageNoWaitPrivate; + +extern XLogRedoAction XLogReadBufferForRedo(XLogReaderState *record, + uint8 buffer_id, Buffer *buf); +extern Buffer XLogInitBufferForRedo(XLogReaderState *record, uint8 block_id); +extern XLogRedoAction XLogReadBufferForRedoExtended(XLogReaderState *record, + uint8 buffer_id, + ReadBufferMode mode, bool get_cleanup_lock, + Buffer *buf); + +extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, + BlockNumber blkno, ReadBufferMode mode, + Buffer recent_buffer); + +extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); +extern void FreeFakeRelcacheEntry(Relation fakerel); + +extern int read_local_xlog_page(XLogReaderState *state, + XLogRecPtr targetPagePtr, int reqLen, + XLogRecPtr targetRecPtr, char *cur_page); +extern int read_local_xlog_page_no_wait(XLogReaderState *state, + XLogRecPtr targetPagePtr, int reqLen, + XLogRecPtr targetRecPtr, + char *cur_page); +extern void wal_segment_open(XLogReaderState *state, + XLogSegNo nextSegNo, + TimeLineID *tli_p); +extern void wal_segment_close(XLogReaderState *state); + +extern void XLogReadDetermineTimeline(XLogReaderState *state, + XLogRecPtr wantPage, + uint32 wantLength, + TimeLineID currTLI); + +extern void WALReadRaiseError(WALReadError *errinfo); + +#endif |