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| author | Robert Haas <rhaas@postgresql.org> | 2011-12-21 09:16:55 -0500 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2011-12-21 09:16:55 -0500 |
| commit | d573e239f03506920938bf0be56c868d9c3416da (patch) | |
| tree | 204b429f7ae848e4413f7df75fc7f98dca0e084e /src/backend/commands/prepare.c | |
| parent | e1042a348421bc16f4d4307228a9951e38a984f1 (diff) | |
Take fewer snapshots.
When a PORTAL_ONE_SELECT query is executed, we can opportunistically
reuse the parse/plan shot for the execution phase. This cuts down the
number of snapshots per simple query from 2 to 1 for the simple
protocol, and 3 to 2 for the extended protocol. Since we are only
reusing a snapshot taken early in the processing of the same protocol
message, the change shouldn't be user-visible, except that the remote
possibility of the planning and execution snapshots being different is
eliminated.
Note that this change does not make it safe to assume that the parse/plan
snapshot will certainly be reused; that will currently only happen if
PortalStart() decides to use the PORTAL_ONE_SELECT strategy. It might
be worth trying to provide some stronger guarantees here in the future,
but for now we don't.
Patch by me; review by Dimitri Fontaine.
Diffstat (limited to 'src/backend/commands/prepare.c')
| -rw-r--r-- | src/backend/commands/prepare.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c index a94921574fa..dd0e837ebcc 100644 --- a/src/backend/commands/prepare.c +++ b/src/backend/commands/prepare.c @@ -278,7 +278,7 @@ ExecuteQuery(ExecuteStmt *stmt, const char *queryString, /* * Run the portal to completion. */ - PortalStart(portal, paramLI, GetActiveSnapshot()); + PortalStart(portal, paramLI, true); (void) PortalRun(portal, FETCH_ALL, false, dest, dest, completionTag); |