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| author | Thomas Munro <tmunro@postgresql.org> | 2020-09-25 18:49:43 +1200 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2020-09-25 19:00:15 +1200 |
| commit | dee663f7843902535a15ae366cede8b4089f1144 (patch) | |
| tree | 24858a312bb174c78ad7047ab52656a673f3de4e /src/backend/storage/lmgr/predicate.c | |
| parent | ca7f8e2b86e5f15a40b67e6199d714f45a467ff1 (diff) | |
| download | postgresql-dee663f7843902535a15ae366cede8b4089f1144.tar.gz | |
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
Diffstat (limited to 'src/backend/storage/lmgr/predicate.c')
| -rw-r--r-- | src/backend/storage/lmgr/predicate.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c index a2f8e7524b..8a365b400c 100644 --- a/src/backend/storage/lmgr/predicate.c +++ b/src/backend/storage/lmgr/predicate.c @@ -821,9 +821,7 @@ SerialInit(void) SerialSlruCtl->PagePrecedes = SerialPagePrecedesLogically; SimpleLruInit(SerialSlruCtl, "Serial", NUM_SERIAL_BUFFERS, 0, SerialSLRULock, "pg_serial", - LWTRANCHE_SERIAL_BUFFER); - /* Override default assumption that writes should be fsync'd */ - SerialSlruCtl->do_fsync = false; + LWTRANCHE_SERIAL_BUFFER, SYNC_HANDLER_NONE); /* * Create or attach to the SerialControl structure. @@ -1052,7 +1050,7 @@ CheckPointPredicate(void) SimpleLruTruncate(SerialSlruCtl, tailPage); /* - * Flush dirty SLRU pages to disk + * Write dirty SLRU pages to disk * * This is not actually necessary from a correctness point of view. We do * it merely as a debugging aid. @@ -1061,7 +1059,7 @@ CheckPointPredicate(void) * before deleting the file in which they sit, which would be completely * pointless. */ - SimpleLruFlush(SerialSlruCtl, true); + SimpleLruWriteAll(SerialSlruCtl, true); } /*------------------------------------------------------------------------*/ |