From fc08814e00c04cddad512494bb52d9266928619e Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Fri, 23 Apr 1999 21:23:49 +0000
Subject: [PATCH] Rename explain's "size" to "rows".
---
doc/src/sgml/ref/explain.sgml | 4 +++-
src/backend/commands/explain.c | 4 ++--
src/man/explain.l | 17 +++++++++--------
3 files changed, 14 insertions(+), 11 deletions(-)
diff --git a/doc/src/sgml/ref/explain.sgml b/doc/src/sgml/ref/explain.sgml
index 5f4a8063f43..a1914c75ce3 100644
--- a/doc/src/sgml/ref/explain.sgml
+++ b/doc/src/sgml/ref/explain.sgml
@@ -102,6 +102,8 @@ Description
<PARA>
This command outputs details about the supplied query.
The default output is the computed query cost.
+ The cost value is only meaningful to the optimizer in comparing
+ various query plans.
VERBOSE displays the full query plan and cost to your screen,
and pretty-prints the plan to the postmaster log file.
</para>
@@ -135,7 +137,7 @@ To show a query plan for a simple query:
postgres=> explain select * from foo;
NOTICE: QUERY PLAN:
-Seq Scan on foo (cost=0.00 size=0 width=4)
+Seq Scan on foo (cost=0.00 rows=0 width=4)
EXPLAIN
</ProgramListing>
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 0983097ace6..6745b4f1f38 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -4,7 +4,7 @@
*
* Copyright (c) 1994-5, Regents of the University of California
*
- * $Id: explain.c,v 1.33 1999/03/23 16:50:46 momjian Exp $
+ * $Id: explain.c,v 1.34 1999/04/23 21:23:48 momjian Exp $
*
*/
#include <stdio.h>
@@ -234,7 +234,7 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
}
if (es->printCost)
{
- appendStringInfo(str, " (cost=%.2f size=%d width=%d)",
+ appendStringInfo(str, " (cost=%.2f rows=%d width=%d)",
plan->cost, plan->plan_size, plan->plan_width);
}
appendStringInfo(str, "\n");
diff --git a/src/man/explain.l b/src/man/explain.l
index 9bc0925bf2d..04c87da9ee7 100644
--- a/src/man/explain.l
+++ b/src/man/explain.l
@@ -1,6 +1,6 @@
.\" This is -*-nroff-*-
.\" XXX standard disclaimer belongs here....
-.\" $Header: /cvsroot/pgsql/src/man/Attic/explain.l,v 1.10 1998/08/04 15:00:28 momjian Exp $
+.\" $Header: /cvsroot/pgsql/src/man/Attic/explain.l,v 1.11 1999/04/23 21:23:49 momjian Exp $
.TH EXPLAIN SQL 06/12/97 PostgreSQL PostgreSQL
.SH NAME
explain - explains statement execution details
@@ -10,21 +10,22 @@ explain - explains statement execution details
.fi
.SH DESCRIPTION
This command outputs details about the supplied query. The default
-output is the computed query cost. \f2verbose\f1 displays the full query
-plan and cost to your screen, and pretty-prints the plan to the postmaster
-log file.
+output is the computed query cost. The cost value is only meaningful to
+the optimizer in comparing various query plans. \f2verbose\f1 displays
+the full query plan and cost to your screen, and pretty-prints the plan
+to the postmaster log file.
.SH EXAMPLES
In the examples, the table has a single column of float4.
\fBcost\fR is the cost of scanning a base/join relation,
-\fBsize\fR is the expected number of tuples from a scan,
+\fBrows\fR is the expected number of rows from a scan,
\fBwidth\fR is the length of a tuple.
.nf
tgl=> explain select a from test\g
NOTICE:QUERY PLAN:
-Seq Scan on test (cost=0.00 size=0 width=4)
+Seq Scan on test (cost=0.00 rows=0 width=4)
EXPLAIN
tgl=> explain verbose select sum(a) from test;
@@ -41,8 +42,8 @@ NOTICE:QUERY PLAN:
:expr {VAR :varno 1 :varattno 1 :vartype 700 :varnoold 1 :varoattno 1}})
:qpqual <> :lefttree <> :righttree <> :scanrelid 1} :righttree <> :numagg 1 }
-Aggregate (cost=0.00 size=0 width=0)
- -> Seq Scan on test (cost=0.00 size=0 width=4)
+Aggregate (cost=0.00 rows=0 width=0)
+ -> Seq Scan on test (cost=0.00 rows=0 width=4)
.fi
The Postgres optimizer has chosen to use a sequential scan to retrieve rows from
--
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