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Add new function planstate_tree_walker.

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ExplainPreScanNode knows how to iterate over a generic tree of plan
states; factor that logic out into a separate walker function so that
other code, such as upcoming patches for parallel query, can also use
it.

Patch by me, reviewed by Tom Lane.
This commit is contained in:
Robert Haas
2015-09-17 11:24:49 -04:00
parent 293fd7c77e
commit 8dd401aa07
3 changed files with 132 additions and 90 deletions
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93
src/backend/commands/explain.c
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@ -55,10 +55,7 @@ static void ExplainOneQuery(Query *query, IntoClause *into, ExplainState *es,
static void report_triggers(ResultRelInfo *rInfo, bool show_relname,
ExplainState *es);
static double elapsed_time(instr_time *starttime);
static void ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used);
static void ExplainPreScanMemberNodes(List *plans, PlanState **planstates,
Bitmapset **rels_used);
static void ExplainPreScanSubPlans(List *plans, Bitmapset **rels_used);
static bool ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used);
static void ExplainNode(PlanState *planstate, List *ancestors,
const char *relationship, const char *plan_name,
ExplainState *es);
@ -724,7 +721,7 @@ elapsed_time(instr_time *starttime)
* This ensures that we don't confusingly assign un-suffixed aliases to RTEs
* that never appear in the EXPLAIN output (such as inheritance parents).
*/
static void
static bool
ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used)
{
Plan *plan = planstate->plan;
@ -764,91 +761,7 @@ ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used)
break;
}
/* initPlan-s */
if (planstate->initPlan)
ExplainPreScanSubPlans(planstate->initPlan, rels_used);
/* lefttree */
if (outerPlanState(planstate))
ExplainPreScanNode(outerPlanState(planstate), rels_used);
/* righttree */
if (innerPlanState(planstate))
ExplainPreScanNode(innerPlanState(planstate), rels_used);
/* special child plans */
switch (nodeTag(plan))
{
case T_ModifyTable:
ExplainPreScanMemberNodes(((ModifyTable *) plan)->plans,
((ModifyTableState *) planstate)->mt_plans,
rels_used);
break;
case T_Append:
ExplainPreScanMemberNodes(((Append *) plan)->appendplans,
((AppendState *) planstate)->appendplans,
rels_used);
break;
case T_MergeAppend:
ExplainPreScanMemberNodes(((MergeAppend *) plan)->mergeplans,
((MergeAppendState *) planstate)->mergeplans,
rels_used);
break;
case T_BitmapAnd:
ExplainPreScanMemberNodes(((BitmapAnd *) plan)->bitmapplans,
((BitmapAndState *) planstate)->bitmapplans,
rels_used);
break;
case T_BitmapOr:
ExplainPreScanMemberNodes(((BitmapOr *) plan)->bitmapplans,
((BitmapOrState *) planstate)->bitmapplans,
rels_used);
break;
case T_SubqueryScan:
ExplainPreScanNode(((SubqueryScanState *) planstate)->subplan,
rels_used);
break;
default:
break;
}
/* subPlan-s */
if (planstate->subPlan)
ExplainPreScanSubPlans(planstate->subPlan, rels_used);
}
/*
* Prescan the constituent plans of a ModifyTable, Append, MergeAppend,
* BitmapAnd, or BitmapOr node.
*
* Note: we don't actually need to examine the Plan list members, but
* we need the list in order to determine the length of the PlanState array.
*/
static void
ExplainPreScanMemberNodes(List *plans, PlanState **planstates,
Bitmapset **rels_used)
{
int nplans = list_length(plans);
int j;
for (j = 0; j < nplans; j++)
ExplainPreScanNode(planstates[j], rels_used);
}
/*
* Prescan a list of SubPlans (or initPlans, which also use SubPlan nodes).
*/
static void
ExplainPreScanSubPlans(List *plans, Bitmapset **rels_used)
{
ListCell *lst;
foreach(lst, plans)
{
SubPlanState *sps = (SubPlanState *) lfirst(lst);
ExplainPreScanNode(sps->planstate, rels_used);
}
return planstate_tree_walker(planstate, ExplainPreScanNode, rels_used);
}
/*