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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/include | |
| parent | e1042a348421bc16f4d4307228a9951e38a984f1 (diff) | |
| download | postgresql-d573e239f03506920938bf0be56c868d9c3416da.tar.gz postgresql-d573e239f03506920938bf0be56c868d9c3416da.zip | |
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/include')
| -rw-r--r-- | src/include/tcop/pquery.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/include/tcop/pquery.h b/src/include/tcop/pquery.h index 2a5e871c92a..ce37af3be10 100644 --- a/src/include/tcop/pquery.h +++ b/src/include/tcop/pquery.h @@ -28,7 +28,7 @@ extern List *FetchPortalTargetList(Portal portal); extern List *FetchStatementTargetList(Node *stmt); extern void PortalStart(Portal portal, ParamListInfo params, - Snapshot snapshot); + bool use_active_snapshot); extern void PortalSetResultFormat(Portal portal, int nFormats, int16 *formats); |