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Add EXPLAIN documentation example.
gabrielle <gorthx@gmail.com>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/explain.sgml,v 1.50 2010/04/03 07:23:01 petere Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/explain.sgml,v 1.51 2010/08/03 17:14:19 momjian Exp $
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PostgreSQL documentation
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-->
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@ -247,6 +247,29 @@ EXPLAIN SELECT * FROM foo;
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</programlisting>
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</para>
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<para>
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Here is the same query, with JSON formatting:
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<programlisting>
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EXPLAIN (FORMAT JSON) SELECT * FROM foo;
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QUERY PLAN
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--------------------------------
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[ +
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{ +
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"Plan": { +
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"Node Type": "Seq Scan",+
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"Relation Name": "foo", +
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"Alias": "foo", +
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"Startup Cost": 0.00, +
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"Total Cost": 155.00, +
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"Plan Rows": 10000, +
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"Plan Width": 4 +
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} +
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} +
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]
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(1 row)
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</programlisting>
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</para>
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<para>
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If there is an index and we use a query with an indexable
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<literal>WHERE</literal> condition, <command>EXPLAIN</command>
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@ -263,6 +286,28 @@ EXPLAIN SELECT * FROM foo WHERE i = 4;
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</programlisting>
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</para>
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<para>
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Here is the same query, but in YAML output:
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<programlisting>
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EXPLAIN (FORMAT YAML) SELECT * FROM foo WHERE i='4';
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QUERY PLAN
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-------------------------------
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- Plan: +
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Node Type: "Index Scan" +
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Scan Direction: "Forward"+
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Index Name: "fi" +
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Relation Name: "foo" +
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Alias: "foo" +
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Startup Cost: 0.00 +
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Total Cost: 5.98 +
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Plan Rows: 1 +
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Plan Width: 4 +
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Index Cond: "(i = 4)"
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(1 row)
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</programlisting>
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XML output is left as an exercise to the reader.
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</para>
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<para>
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Here is the same plan with costs suppressed:
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