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Turn the rangetable used by the executor into a flat list, and avoid storing

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useless substructure for its RangeTblEntry nodes.  (I chose to keep using the
same struct node type and just zero out the link fields for unneeded info,
rather than making a separate ExecRangeTblEntry type --- it seemed too
fragile to have two different rangetable representations.)

Along the way, put subplans into a list in the toplevel PlannedStmt node,
and have SubPlan nodes refer to them by list index instead of direct pointers.
Vadim wanted to do that years ago, but I never understood what he was on about
until now.  It makes things a *whole* lot more robust, because we can stop
worrying about duplicate processing of subplans during expression tree
traversals.  That's been a constant source of bugs, and it's finally gone.

There are some consequent simplifications yet to be made, like not using
a separate EState for subplans in the executor, but I'll tackle that later.
This commit is contained in:
Tom Lane
2007-02-22 22:00:26 +00:00
parent 849000c782
commit eab6b8b27e
32 changed files with 841 additions and 1004 deletions
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17
src/backend/executor/nodeSubplan.c
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.85 2007/02/06 02:59:11 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.86 2007/02/22 22:00:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -637,13 +637,9 @@ void
ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
{
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
Plan *plan = exec_subplan_get_plan(estate->es_plannedstmt, subplan);
EState *sp_estate;
/*
* Do access checking on the rangetable entries in the subquery.
*/
ExecCheckRTPerms(subplan->rtable);
/*
* initialize my state
*/
@ -668,18 +664,21 @@ ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
* shares our Param ID space and es_query_cxt, however. XXX if rangetable
* access were done differently, the subquery could share our EState,
* which would eliminate some thrashing about in this module...
*
* XXX make that happen!
*/
sp_estate = CreateSubExecutorState(estate);
node->sub_estate = sp_estate;
sp_estate->es_range_table = subplan->rtable;
sp_estate->es_range_table = estate->es_range_table;
sp_estate->es_param_list_info = estate->es_param_list_info;
sp_estate->es_param_exec_vals = estate->es_param_exec_vals;
sp_estate->es_tupleTable =
ExecCreateTupleTable(ExecCountSlotsNode(subplan->plan) + 10);
ExecCreateTupleTable(ExecCountSlotsNode(plan) + 10);
sp_estate->es_snapshot = estate->es_snapshot;
sp_estate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
sp_estate->es_instrument = estate->es_instrument;
sp_estate->es_plannedstmt = estate->es_plannedstmt;
/*
* Start up the subplan (this is a very cut-down form of InitPlan())
@ -692,7 +691,7 @@ ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
if (subplan->parParam == NIL && subplan->setParam == NIL)
eflags |= EXEC_FLAG_REWIND;
node->planstate = ExecInitNode(subplan->plan, sp_estate, eflags);
node->planstate = ExecInitNode(plan, sp_estate, eflags);
node->needShutdown = true; /* now we need to shutdown the subplan */