From fc08814e00c04cddad512494bb52d9266928619e Mon Sep 17 00:00:00 2001 From: Bruce Momjian 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 5f4a8063f4..a1914c75ce 100644 --- a/doc/src/sgml/ref/explain.sgml +++ b/doc/src/sgml/ref/explain.sgml @@ -102,6 +102,8 @@ Description 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. @@ -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 diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index 0983097ace..6745b4f1f3 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 @@ -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 9bc0925bf2..04c87da9ee 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 -- 2.40.0