Robert Haas 7aea8e4f2d Determine whether it's safe to attempt a parallel plan for a query. ... Commit 924bcf4f16 introduced a framework for parallel computation in PostgreSQL that makes most but not all built-in functions safe to execute in parallel mode. In order to have parallel query, we'll need to be able to determine whether that query contains functions (either built-in or user-defined) that cannot be safely executed in parallel mode. This requires those functions to be labeled, so this patch introduces an infrastructure for that. Some functions currently labeled as safe may need to be revised depending on how pending issues related to heavyweight locking under paralllelism are resolved. Parallel plans can't be used except for the case where the query will run to completion. If portal execution were suspended, the parallel mode restrictions would need to remain in effect during that time, but that might make other queries fail. Therefore, this patch introduces a framework that enables consideration of parallel plans only when it is known that the plan will be run to completion. This probably needs some refinement; for example, at bind time, we do not know whether a query run via the extended protocol will be execution to completion or run with a limited fetch count. Having the client indicate its intentions at bind time would constitute a wire protocol break. Some contexts in which parallel mode would be safe are not adjusted by this patch; the default is not to try parallel plans except from call sites that have been updated to say that such plans are OK. This commit doesn't introduce any parallel paths or plans; it just provides a way to determine whether they could potentially be used. I'm committing it on the theory that the remaining parallel sequential scan patches will also get committed to this release, hopefully in the not-too-distant future. Robert Haas and Amit Kapila. Reviewed (in earlier versions) by Noah Misch.		2015-09-16 15:38:47 -04:00
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clauses.c	Determine whether it's safe to attempt a parallel plan for a query.	2015-09-16 15:38:47 -04:00
joininfo.c	Update copyright for 2015	2015-01-06 11:43:47 -05:00
Makefile	Extract restriction OR clauses whether or not they are indexable.	2013-12-30 12:24:37 -05:00
orclauses.c	Improve planner's cost estimation in the presence of semijoins.	2015-03-11 21:21:00 -04:00
pathnode.c	Redesign tablesample method API, and do extensive code review.	2015-07-25 14:39:00 -04:00
placeholder.c	Update copyright for 2015	2015-01-06 11:43:47 -05:00
plancat.c	Check the relevant index element in ON CONFLICT unique index inference.	2015-07-26 18:20:41 +02:00
predtest.c	Teach predtest.c that "foo" implies "foo IS NOT NULL".	2015-08-01 14:31:46 -04:00
relnode.c	Remove an unsafe Assert, and explain join_clause_is_movable_into() better.	2015-07-28 13:20:39 -04:00
restrictinfo.c	Remove an unsafe Assert, and explain join_clause_is_movable_into() better.	2015-07-28 13:20:39 -04:00
tlist.c	Support GROUPING SETS, CUBE and ROLLUP.	2015-05-16 03:46:31 +02:00
var.c	pgindent run for 9.5	2015-05-23 21:35:49 -04:00