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| author | Robert Haas <rhaas@postgresql.org> | 2017-03-09 17:44:52 -0500 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2017-03-09 17:49:01 -0500 |
| commit | ccce90b398673d55b0387b3de66639b1b30d451b (patch) | |
| tree | a67a266ca479af316b636b09482426fcacf2e834 /src/include/storage/proc.h | |
| parent | f077e1b2e374fadc443b6aa9fa54ad9bb6f908c7 (diff) | |
Use group updates when setting transaction status in clog.
Commit 0e141c0fbb211bdd23783afa731e3eef95c9ad7a introduced a mechanism
to reduce contention on ProcArrayLock by having a single process clear
XIDs in the procArray on behalf of multiple processes, reducing the
need to hand the lock around. Use a similar mechanism to reduce
contention on CLogControlLock. Testing shows that this very
significantly reduces the amount of time waiting for CLogControlLock
on high-concurrency pgbench tests run on a large multi-socket
machines; whether that translates into a TPS improvement depends on
how much of that contention is simply shifted to some other lock,
particularly WALWriteLock.
Amit Kapila, with some cosmetic changes by me. Extensively reviewed,
tested, and benchmarked over a period of about 15 months by Simon
Riggs, Robert Haas, Andres Freund, Jesper Pedersen, and especially by
Tomas Vondra and Dilip Kumar.
Discussion: http://postgr.es/m/CAA4eK1L_snxM_JcrzEstNq9P66++F4kKFce=1r5+D1vzPofdtg@mail.gmail.com
Discussion: http://postgr.es/m/CAA4eK1LyR2A+m=RBSZ6rcPEwJ=rVi1ADPSndXHZdjn56yqO6Vg@mail.gmail.com
Discussion: http://postgr.es/m/91d57161-d3ea-0cc2-6066-80713e4f90d7@2ndquadrant.com
Diffstat (limited to 'src/include/storage/proc.h')
| -rw-r--r-- | src/include/storage/proc.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h index 5f38fa6b4f1..b3da73e8f4a 100644 --- a/src/include/storage/proc.h +++ b/src/include/storage/proc.h @@ -14,6 +14,7 @@ #ifndef _PROC_H_ #define _PROC_H_ +#include "access/clog.h" #include "access/xlogdefs.h" #include "lib/ilist.h" #include "storage/latch.h" @@ -161,6 +162,17 @@ struct PGPROC uint32 wait_event_info; /* proc's wait information */ + /* Support for group transaction status update. */ + bool clogGroupMember; /* true, if member of clog group */ + pg_atomic_uint32 clogGroupNext; /* next clog group member */ + TransactionId clogGroupMemberXid; /* transaction id of clog group member */ + XidStatus clogGroupMemberXidStatus; /* transaction status of clog + * group member */ + int clogGroupMemberPage; /* clog page corresponding to + * transaction id of clog group member */ + XLogRecPtr clogGroupMemberLsn; /* WAL location of commit record for + * clog group member */ + /* Per-backend LWLock. Protects fields below (but not group fields). */ LWLock backendLock; @@ -232,6 +244,8 @@ typedef struct PROC_HDR PGPROC *bgworkerFreeProcs; /* First pgproc waiting for group XID clear */ pg_atomic_uint32 procArrayGroupFirst; + /* First pgproc waiting for group transaction status update */ + pg_atomic_uint32 clogGroupFirst; /* WALWriter process's latch */ Latch *walwriterLatch; /* Checkpointer process's latch */ |