From c5e4e91a96aa27f7dee05a763122ad66c5c69282 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 17 Apr 2008 18:30:18 +0000
Subject: [PATCH] Add some code to EXPLAIN to show the targetlist (ie, output
columns) of each plan node. For the moment this is debug support only and is
not enabled unless EXPLAIN_PRINT_TLISTS is defined at build time. Later I'll
see about the idea of letting EXPLAIN VERBOSE do it.
---
src/backend/commands/explain.c | 59 ++++++++++++++++++++++++++++++++--
1 file changed, 57 insertions(+), 2 deletions(-)
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index d1511b2fe8c..768ae7797ef 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.171 2008/03/26 18:48:59 alvherre Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.172 2008/04/17 18:30:18 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -61,6 +61,8 @@ static void explain_outNode(StringInfo str,
Plan *plan, PlanState *planstate,
Plan *outer_plan,
int indent, ExplainState *es);
+static void show_plan_tlist(Plan *plan,
+ StringInfo str, int indent, ExplainState *es);
static void show_scan_qual(List *qual, const char *qlabel,
int scanrelid, Plan *outer_plan, Plan *inner_plan,
StringInfo str, int indent, ExplainState *es);
@@ -443,7 +445,7 @@ explain_outNode(StringInfo str,
Plan *outer_plan,
int indent, ExplainState *es)
{
- char *pname;
+ const char *pname;
int i;
if (plan == NULL)
@@ -744,6 +746,9 @@ explain_outNode(StringInfo str,
appendStringInfo(str, " (never executed)");
appendStringInfoChar(str, '\n');
+ /* target list */
+ show_plan_tlist(plan, str, indent, es);
+
/* quals, sort keys, etc */
switch (nodeTag(plan))
{
@@ -1043,6 +1048,56 @@ explain_outNode(StringInfo str,
}
}
+/*
+ * Show the targetlist of a plan node
+ */
+static void
+show_plan_tlist(Plan *plan,
+ StringInfo str, int indent, ExplainState *es)
+{
+#ifdef EXPLAIN_PRINT_TLISTS
+ List *context;
+ bool useprefix;
+ ListCell *lc;
+ int i;
+
+ /* No work if empty tlist (this occurs eg in bitmap indexscans) */
+ if (plan->targetlist == NIL)
+ return;
+ /* The tlist of an Append isn't real helpful, so suppress it */
+ if (IsA(plan, Append))
+ return;
+
+ /* Set up deparsing context */
+ context = deparse_context_for_plan((Node *) outerPlan(plan),
+ (Node *) innerPlan(plan),
+ es->rtable);
+ useprefix = list_length(es->rtable) > 1;
+
+ /* Emit line prefix */
+ for (i = 0; i < indent; i++)
+ appendStringInfo(str, " ");
+ appendStringInfo(str, " Output: ");
+
+ /* Deparse each non-junk result column */
+ i = 0;
+ foreach(lc, plan->targetlist)
+ {
+ TargetEntry *tle = (TargetEntry *) lfirst(lc);
+
+ if (tle->resjunk)
+ continue;
+ if (i++ > 0)
+ appendStringInfo(str, ", ");
+ appendStringInfoString(str,
+ deparse_expression((Node *) tle->expr, context,
+ useprefix, false));
+ }
+
+ appendStringInfoChar(str, '\n');
+#endif /* EXPLAIN_PRINT_TLISTS */
+}
+
/*
* Show a qualifier expression for a scan plan node
*
--
GitLab