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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2005-05-19 21:35:48 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2005-05-19 21:35:48 +0000 |
| commit | ee3b71f6bce929b07636f76d1654832cb6b5a489 (patch) | |
| tree | ce95108d3c0e832555b78e96afb173458991b19e /src/backend/access/transam/varsup.c | |
| parent | 6910032a56dd3841be137b4bef7c57ef32a60ac8 (diff) | |
| download | postgresql-ee3b71f6bce929b07636f76d1654832cb6b5a489.tar.gz postgresql-ee3b71f6bce929b07636f76d1654832cb6b5a489.zip | |
Split the shared-memory array of PGPROC pointers out of the sinval
communication structure, and make it its own module with its own lock.
This should reduce contention at least a little, and it definitely makes
the code seem cleaner. Per my recent proposal.
Diffstat (limited to 'src/backend/access/transam/varsup.c')
| -rw-r--r-- | src/backend/access/transam/varsup.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c index cb532d8df34..5c51e69253e 100644 --- a/src/backend/access/transam/varsup.c +++ b/src/backend/access/transam/varsup.c @@ -6,7 +6,7 @@ * Copyright (c) 2000-2005, PostgreSQL Global Development Group * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/transam/varsup.c,v 1.63 2005/04/13 18:54:56 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/varsup.c,v 1.64 2005/05/19 21:35:45 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -107,7 +107,7 @@ GetNewTransactionId(bool isSubXact) * nextXid are already present in PGPROC. Else we have a race * condition. * - * XXX by storing xid into MyProc without acquiring SInvalLock, we are + * XXX by storing xid into MyProc without acquiring ProcArrayLock, we are * relying on fetch/store of an xid to be atomic, else other backends * might see a partially-set xid here. But holding both locks at once * would be a nasty concurrency hit (and in fact could cause a @@ -120,8 +120,7 @@ GetNewTransactionId(bool isSubXact) * * A solution to the atomic-store problem would be to give each PGPROC * its own spinlock used only for fetching/storing that PGPROC's xid - * and related fields. (SInvalLock would then mean primarily that - * PGPROCs couldn't be added/removed while holding the lock.) + * and related fields. * * If there's no room to fit a subtransaction XID into PGPROC, set the * cache-overflowed flag instead. This forces readers to look in |