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Commit947eb97

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author
Neil Conway
committed
Update some comments to use SQL examples rather than QUEL. From Simon
Riggs.
1 parenta7f2a78 commit947eb97

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2 files changed

+9
-10
lines changed

2 files changed

+9
-10
lines changed

‎src/backend/executor/nodeAppend.c

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@@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/executor/nodeAppend.c,v 1.62 2004/12/31 21:59:45 pgsql Exp $
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* $PostgreSQL: pgsql/src/backend/executor/nodeAppend.c,v 1.63 2005/04/24 11:46:20 neilc Exp $
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*
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*-------------------------------------------------------------------------
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*/
@@ -43,7 +43,7 @@
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*and student-emp inherits from student and employee, the
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*query:
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*
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*retrieve (e.name) frome inperson*
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*selectname from person
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*
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*generates the plan:
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*

‎src/backend/executor/nodeResult.c

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@@ -8,33 +8,32 @@
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*Result nodes are used in queries where no relations are scanned.
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*Examples of such queries are:
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*
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*retrieve (x = 1)
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*and
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*append emp (name = "mike", salary = 15000)
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*select 1 * 2
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*
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*Result nodes are also used to optimise queries with constant
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*qualifications (ie, quals that do not depend on the scanned data),
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*such as:
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*
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*retrieve (emp.all) where 2 > 1
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*select * fromemp where 2 > 1
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*
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*In this case, the plan generated is
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*
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*Result(with 2 > 1 qual)
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*/
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* SeqScan (emp.all)
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*
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*At runtime, the Result node evaluates the constant qual once.
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*If it's false, we can return an empty result set without running
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*the controlled plan at all. If it's true, we run the controlled
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*At runtime, the Result node evaluates the constant qual once,
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*which is shown by EXPLAIN as a One-Time Filter. If it's
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*false, we can return an empty result set without running the
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*controlled plan at all. If it's true, we run the controlled
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*plan normally and pass back the results.
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*
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*
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.29 2004/12/31 21:59:45 pgsql Exp $
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* $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.30 2005/04/24 11:46:21 neilc Exp $
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*
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*-------------------------------------------------------------------------
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*/

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