postgresql/src/include/access/commit_ts.h
Thomas Munro dee663f784 Defer flushing of SLRU files.
Previously, we called fsync() after writing out individual pg_xact,
pg_multixact and pg_commit_ts pages due to cache pressure, leading to
regular I/O stalls in user backends and recovery.  Collapse requests for
the same file into a single system call as part of the next checkpoint,
as we already did for relation files, using the infrastructure developed
by commit 3eb77eba.  This can cause a significant improvement to
recovery performance, especially when it's otherwise CPU-bound.

Hoist ProcessSyncRequests() up into CheckPointGuts() to make it clearer
that it applies to all the SLRU mini-buffer-pools as well as the main
buffer pool.  Rearrange things so that data collected in CheckpointStats
includes SLRU activity.

Also remove the Shutdown{CLOG,CommitTS,SUBTRANS,MultiXact}() functions,
because they were redundant after the shutdown checkpoint that
immediately precedes them.  (I'm not sure if they were ever needed, but
they aren't now.)

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (parts)
Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com>
Discussion: https://postgr.es/m/CA+hUKGLJ=84YT+NvhkEEDAuUtVHMfQ9i-N7k_o50JmQ6Rpj_OQ@mail.gmail.com
2020-09-25 19:00:15 +12:00

80 lines
2.4 KiB
C

/*
* commit_ts.h
*
* PostgreSQL commit timestamp manager
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/access/commit_ts.h
*/
#ifndef COMMIT_TS_H
#define COMMIT_TS_H
#include "access/xlog.h"
#include "datatype/timestamp.h"
#include "replication/origin.h"
#include "storage/sync.h"
#include "utils/guc.h"
extern PGDLLIMPORT bool track_commit_timestamp;
extern bool check_track_commit_timestamp(bool *newval, void **extra,
GucSource source);
extern void TransactionTreeSetCommitTsData(TransactionId xid, int nsubxids,
TransactionId *subxids, TimestampTz timestamp,
RepOriginId nodeid, bool write_xlog);
extern bool TransactionIdGetCommitTsData(TransactionId xid,
TimestampTz *ts, RepOriginId *nodeid);
extern TransactionId GetLatestCommitTsData(TimestampTz *ts,
RepOriginId *nodeid);
extern Size CommitTsShmemBuffers(void);
extern Size CommitTsShmemSize(void);
extern void CommitTsShmemInit(void);
extern void BootStrapCommitTs(void);
extern void StartupCommitTs(void);
extern void CommitTsParameterChange(bool newvalue, bool oldvalue);
extern void CompleteCommitTsInitialization(void);
extern void ShutdownCommitTs(void);
extern void CheckPointCommitTs(void);
extern void ExtendCommitTs(TransactionId newestXact);
extern void TruncateCommitTs(TransactionId oldestXact);
extern void SetCommitTsLimit(TransactionId oldestXact,
TransactionId newestXact);
extern void AdvanceOldestCommitTsXid(TransactionId oldestXact);
extern int committssyncfiletag(const FileTag *ftag, char *path);
/* XLOG stuff */
#define COMMIT_TS_ZEROPAGE 0x00
#define COMMIT_TS_TRUNCATE 0x10
#define COMMIT_TS_SETTS 0x20
typedef struct xl_commit_ts_set
{
TimestampTz timestamp;
RepOriginId nodeid;
TransactionId mainxid;
/* subxact Xids follow */
} xl_commit_ts_set;
#define SizeOfCommitTsSet (offsetof(xl_commit_ts_set, mainxid) + \
sizeof(TransactionId))
typedef struct xl_commit_ts_truncate
{
int pageno;
TransactionId oldestXid;
} xl_commit_ts_truncate;
#define SizeOfCommitTsTruncate (offsetof(xl_commit_ts_truncate, oldestXid) + \
sizeof(TransactionId))
extern void commit_ts_redo(XLogReaderState *record);
extern void commit_ts_desc(StringInfo buf, XLogReaderState *record);
extern const char *commit_ts_identify(uint8 info);
#endif /* COMMIT_TS_H */