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dee663f784
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
68 lines
2.0 KiB
C
68 lines
2.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* sync.h
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* File synchronization management code.
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*
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* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/sync.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef SYNC_H
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#define SYNC_H
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#include "storage/relfilenode.h"
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/*
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* Type of sync request. These are used to manage the set of pending
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* requests to call a sync handler's sync or unlink functions at the next
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* checkpoint.
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*/
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typedef enum SyncRequestType
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{
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SYNC_REQUEST, /* schedule a call of sync function */
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SYNC_UNLINK_REQUEST, /* schedule a call of unlink function */
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SYNC_FORGET_REQUEST, /* forget all calls for a tag */
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SYNC_FILTER_REQUEST /* forget all calls satisfying match fn */
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} SyncRequestType;
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/*
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* Which set of functions to use to handle a given request. The values of
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* the enumerators must match the indexes of the function table in sync.c.
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*/
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typedef enum SyncRequestHandler
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{
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SYNC_HANDLER_MD = 0,
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SYNC_HANDLER_CLOG,
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SYNC_HANDLER_COMMIT_TS,
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SYNC_HANDLER_MULTIXACT_OFFSET,
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SYNC_HANDLER_MULTIXACT_MEMBER,
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SYNC_HANDLER_NONE
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} SyncRequestHandler;
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/*
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* A tag identifying a file. Currently it has the members required for md.c's
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* usage, but sync.c has no knowledge of the internal structure, and it is
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* liable to change as required by future handlers.
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*/
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typedef struct FileTag
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{
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int16 handler; /* SyncRequestHandler value, saving space */
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int16 forknum; /* ForkNumber, saving space */
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RelFileNode rnode;
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uint32 segno;
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} FileTag;
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extern void InitSync(void);
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extern void SyncPreCheckpoint(void);
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extern void SyncPostCheckpoint(void);
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extern void ProcessSyncRequests(void);
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extern void RememberSyncRequest(const FileTag *ftag, SyncRequestType type);
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extern void EnableSyncRequestForwarding(void);
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extern bool RegisterSyncRequest(const FileTag *ftag, SyncRequestType type,
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bool retryOnError);
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#endif /* SYNC_H */
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