diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2006-02-28 04:10:28 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2006-02-28 04:10:28 +0000 |
| commit | 2c0ef9777cce8f97dd01073d962e6aa31722b5ad (patch) | |
| tree | bcfa428f69e6013002a79ab29e053bd6c6cbcfa7 /src/backend/executor/nodeSubplan.c | |
| parent | 7f4f42fa100872507ca10d8e0f7d923acc266ee8 (diff) | |
| download | postgresql-2c0ef9777cce8f97dd01073d962e6aa31722b5ad.tar.gz postgresql-2c0ef9777cce8f97dd01073d962e6aa31722b5ad.zip | |
Extend the ExecInitNode API so that plan nodes receive a set of flag
bits indicating which optional capabilities can actually be exercised
at runtime. This will allow Sort and Material nodes, and perhaps later
other nodes, to avoid unnecessary overhead in common cases.
This commit just adds the infrastructure and arranges to pass the correct
flag values down to plan nodes; none of the actual optimizations are here
yet. I'm committing this separately in case anyone wants to measure the
added overhead. (It should be negligible.)
Simon Riggs and Tom Lane
Diffstat (limited to 'src/backend/executor/nodeSubplan.c')
| -rw-r--r-- | src/backend/executor/nodeSubplan.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c index 80679d9f63f..fd74cdc618b 100644 --- a/src/backend/executor/nodeSubplan.c +++ b/src/backend/executor/nodeSubplan.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.72 2005/12/28 01:29:59 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.73 2006/02/28 04:10:28 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -625,10 +625,14 @@ slotNoNulls(TupleTableSlot *slot) /* ---------------------------------------------------------------- * ExecInitSubPlan + * + * Note: the eflags are those passed to the parent plan node of this + * subplan; they don't directly describe the execution conditions the + * subplan will face. * ---------------------------------------------------------------- */ void -ExecInitSubPlan(SubPlanState *node, EState *estate) +ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags) { SubPlan *subplan = (SubPlan *) node->xprstate.expr; EState *sp_estate; @@ -678,8 +682,16 @@ ExecInitSubPlan(SubPlanState *node, EState *estate) /* * Start up the subplan (this is a very cut-down form of InitPlan()) + * + * The subplan will never need to do BACKWARD scan or MARK/RESTORE. + * If it is a parameterless subplan (not initplan), we suggest that it + * be prepared to handle REWIND efficiently; otherwise there is no need. */ - node->planstate = ExecInitNode(subplan->plan, sp_estate); + eflags &= EXEC_FLAG_EXPLAIN_ONLY; + if (subplan->parParam == NIL && subplan->setParam == NIL) + eflags |= EXEC_FLAG_REWIND; + + node->planstate = ExecInitNode(subplan->plan, sp_estate, eflags); node->needShutdown = true; /* now we need to shutdown the subplan */ |