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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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50
src/backend/executor/execMain.c
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@ -26,7 +26,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.287 2007/02/20 17:32:14 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.288 2007/02/22 22:00:22 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -92,9 +92,9 @@ static void ExecProcessReturning(ProjectionInfo *projectReturning,
DestReceiver *dest);
static TupleTableSlot *EvalPlanQualNext(EState *estate);
static void EndEvalPlanQual(EState *estate);
static void ExecCheckRTPerms(List *rangeTable);
static void ExecCheckRTEPerms(RangeTblEntry *rte);
static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt);
static void ExecCheckRangeTblReadOnly(List *rtable);
static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
evalPlanQual *priorepq);
static void EvalPlanQualStop(evalPlanQual *epq);
@ -348,16 +348,14 @@ ExecutorRewind(QueryDesc *queryDesc)
* ExecCheckRTPerms
* Check access permissions for all relations listed in a range table.
*/
void
static void
ExecCheckRTPerms(List *rangeTable)
{
ListCell *l;
foreach(l, rangeTable)
{
RangeTblEntry *rte = lfirst(l);
ExecCheckRTEPerms(rte);
ExecCheckRTEPerms((RangeTblEntry *) lfirst(l));
}
}
@ -373,12 +371,9 @@ ExecCheckRTEPerms(RangeTblEntry *rte)
Oid userid;
/*
* Only plain-relation RTEs need to be checked here. Subquery RTEs are
* checked by ExecInitSubqueryScan if the subquery is still a separate
* subquery --- if it's been pulled up into our query level then the RTEs
* are in our rangetable and will be checked here. Function RTEs are
* Only plain-relation RTEs need to be checked here. Function RTEs are
* checked by init_fcache when the function is prepared for execution.
* Join and special RTEs need no checks.
* Join, subquery, and special RTEs need no checks.
*/
if (rte->rtekind != RTE_RELATION)
return;
@ -417,6 +412,8 @@ ExecCheckRTEPerms(RangeTblEntry *rte)
static void
ExecCheckXactReadOnly(PlannedStmt *plannedstmt)
{
ListCell *l;
/*
* CREATE TABLE AS or SELECT INTO?
*
@ -426,32 +423,9 @@ ExecCheckXactReadOnly(PlannedStmt *plannedstmt)
goto fail;
/* Fail if write permissions are requested on any non-temp table */
ExecCheckRangeTblReadOnly(plannedstmt->rtable);
return;
fail:
ereport(ERROR,
(errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
errmsg("transaction is read-only")));
}
static void
ExecCheckRangeTblReadOnly(List *rtable)
{
ListCell *l;
/* Fail if write permissions are requested on any non-temp table */
foreach(l, rtable)
foreach(l, plannedstmt->rtable)
{
RangeTblEntry *rte = lfirst(l);
if (rte->rtekind == RTE_SUBQUERY)
{
Assert(!rte->subquery->into);
ExecCheckRangeTblReadOnly(rte->subquery->rtable);
continue;
}
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
if (rte->rtekind != RTE_RELATION)
continue;
@ -494,9 +468,7 @@ InitPlan(QueryDesc *queryDesc, int eflags)
ListCell *l;
/*
* Do permissions checks. It's sufficient to examine the query's top
* rangetable here --- subplan RTEs will be checked during
* ExecInitSubPlan().
* Do permissions checks
*/
ExecCheckRTPerms(rangeTable);