postgresql/src/backend/tcop
Robert Haas d573e239f0 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.
2011-12-21 09:16:55 -05:00
..
Makefile Remove cvs keywords from all files. 2010-09-20 22:08:53 +02:00
dest.c Stamp copyrights for year 2011. 2011-01-01 13:18:15 -05:00
fastpath.c Pass collations to functions in FunctionCallInfoData, not FmgrInfo. 2011-04-12 19:19:24 -04:00
postgres.c Take fewer snapshots. 2011-12-21 09:16:55 -05:00
pquery.c Take fewer snapshots. 2011-12-21 09:16:55 -05:00
utility.c Improve table locking behavior in the face of current DDL. 2011-11-30 10:27:00 -05:00