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| author | Simon Riggs <simon@2ndQuadrant.com> | 2010-07-28 05:22:24 +0000 |
|---|---|---|
| committer | Simon Riggs <simon@2ndQuadrant.com> | 2010-07-28 05:22:24 +0000 |
| commit | 2dbbda02e7e688311e161a912a0ce00cde9bb6fc (patch) | |
| tree | adf4f2ca8c477550f19bd6362d0b6fa4ae19f68b /src/backend/rewrite/rewriteDefine.c | |
| parent | 133924e13e004db8979424bf5436e21b0a09a069 (diff) | |
| download | postgresql-2dbbda02e7e688311e161a912a0ce00cde9bb6fc.tar.gz postgresql-2dbbda02e7e688311e161a912a0ce00cde9bb6fc.zip | |
Reduce lock levels of CREATE TRIGGER and some ALTER TABLE, CREATE RULE actions.
Avoid hard-coding lockmode used for many altering DDL commands, allowing easier
future changes of lock levels. Implementation of initial analysis on DDL
sub-commands, so that many lock levels are now at ShareUpdateExclusiveLock or
ShareRowExclusiveLock, allowing certain DDL not to block reads/writes.
First of number of planned changes in this area; additional docs required
when full project complete.
Diffstat (limited to 'src/backend/rewrite/rewriteDefine.c')
| -rw-r--r-- | src/backend/rewrite/rewriteDefine.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c index 06469b31cf0..8e32aed13ec 100644 --- a/src/backend/rewrite/rewriteDefine.c +++ b/src/backend/rewrite/rewriteDefine.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/rewrite/rewriteDefine.c,v 1.141 2010/02/14 18:42:15 rhaas Exp $ + * $PostgreSQL: pgsql/src/backend/rewrite/rewriteDefine.c,v 1.142 2010/07/28 05:22:24 sriggs Exp $ * *------------------------------------------------------------------------- */ @@ -236,11 +236,14 @@ DefineQueryRewrite(char *rulename, /* * If we are installing an ON SELECT rule, we had better grab * AccessExclusiveLock to ensure no SELECTs are currently running on the - * event relation. For other types of rules, it might be sufficient to - * grab ShareLock to lock out insert/update/delete actions. But for now, - * let's just grab AccessExclusiveLock all the time. + * event relation. For other types of rules, it is sufficient to + * grab ShareRowExclusiveLock to lock out insert/update/delete actions + * and to ensure that we lock out current CREATE RULE statements. */ - event_relation = heap_open(event_relid, AccessExclusiveLock); + if (event_type == CMD_SELECT) + event_relation = heap_open(event_relid, AccessExclusiveLock); + else + event_relation = heap_open(event_relid, ShareRowExclusiveLock); /* * Verify relation is of a type that rules can sensibly be applied to. |