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Add display of sort keys to the default EXPLAIN output.

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This commit is contained in:
Tom Lane
2002-05-18 21:38:41 +00:00
parent a5b370943e
commit dd9af92c41
3 changed files with 87 additions and 4 deletions
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65
src/backend/commands/explain.c
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@ -5,7 +5,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.77 2002/05/12 20:10:02 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.78 2002/05/18 21:38:40 tgl Exp $
*
*/
@ -56,6 +56,8 @@ static void show_upper_qual(List *qual, const char *qlabel,
const char *outer_name, int outer_varno, Plan *outer_plan,
const char *inner_name, int inner_varno, Plan *inner_plan,
StringInfo str, int indent, ExplainState *es);
static void show_sort_keys(List *tlist, int nkeys, const char *qlabel,
StringInfo str, int indent, ExplainState *es);
static Node *make_ors_ands_explicit(List *orclauses);
static TextOutputState *begin_text_output(CommandDest dest, char *title);
static void do_text_output(TextOutputState *tstate, char *aline);
@ -410,7 +412,7 @@ explain_outNode(StringInfo str, Plan *plan, Plan *outer_plan,
}
appendStringInfo(str, "\n");
/* quals */
/* quals, sort keys, etc */
switch (nodeTag(plan))
{
case T_IndexScan:
@ -495,6 +497,11 @@ explain_outNode(StringInfo str, Plan *plan, Plan *outer_plan,
"", 0, NULL,
str, indent, es);
break;
case T_Sort:
show_sort_keys(plan->targetlist, ((Sort *) plan)->keycount,
"Sort Key",
str, indent, es);
break;
case T_Result:
show_upper_qual((List *) ((Result *) plan)->resconstantqual,
"One-Time Filter",
@ -731,6 +738,60 @@ show_upper_qual(List *qual, const char *qlabel,
appendStringInfo(str, " %s: %s\n", qlabel, exprstr);
}
/*
* Show the sort keys for a Sort node.
*/
static void
show_sort_keys(List *tlist, int nkeys, const char *qlabel,
StringInfo str, int indent, ExplainState *es)
{
List *context;
bool useprefix;
int keyno;
List *tl;
char *exprstr;
int i;
if (nkeys <= 0)
return;
for (i = 0; i < indent; i++)
appendStringInfo(str, " ");
appendStringInfo(str, " %s: ", qlabel);
/*
* In this routine we expect that the plan node's tlist has not been
* processed by set_plan_references(), so any Vars will contain valid
* varnos referencing the actual rtable.
*/
context = deparse_context_from_rtable(es->rtable);
useprefix = length(es->rtable) > 1;
for (keyno = 1; keyno <= nkeys; keyno++)
{
/* find key expression in tlist */
foreach(tl, tlist)
{
TargetEntry *target = (TargetEntry *) lfirst(tl);
if (target->resdom->reskey == keyno)
{
/* Deparse the expression */
exprstr = deparse_expression(target->expr, context, useprefix);
/* And add to str */
if (keyno > 1)
appendStringInfo(str, ", ");
appendStringInfo(str, "%s", exprstr);
break;
}
}
if (tl == NIL)
elog(ERROR, "show_sort_keys: no tlist entry for key %d", keyno);
}
appendStringInfo(str, "\n");
}
/*
* Indexscan qual lists have an implicit OR-of-ANDs structure. Make it
* explicit so deparsing works properly.