diff options
Diffstat (limited to 'src/backend/executor/nodeResult.c')
| -rw-r--r-- | src/backend/executor/nodeResult.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/src/backend/executor/nodeResult.c b/src/backend/executor/nodeResult.c index abc94a2cf12..ee6c91cb9dc 100644 --- a/src/backend/executor/nodeResult.c +++ b/src/backend/executor/nodeResult.c @@ -8,15 +8,13 @@ * Result nodes are used in queries where no relations are scanned. * Examples of such queries are: * - * retrieve (x = 1) - * and - * append emp (name = "mike", salary = 15000) + * select 1 * 2 * * Result nodes are also used to optimise queries with constant * qualifications (ie, quals that do not depend on the scanned data), * such as: * - * retrieve (emp.all) where 2 > 1 + * select * from emp where 2 > 1 * * In this case, the plan generated is * @@ -24,9 +22,10 @@ * / * SeqScan (emp.all) * - * At runtime, the Result node evaluates the constant qual once. - * If it's false, we can return an empty result set without running - * the controlled plan at all. If it's true, we run the controlled + * At runtime, the Result node evaluates the constant qual once, + * which is shown by EXPLAIN as a One-Time Filter. If it's + * false, we can return an empty result set without running the + * controlled plan at all. If it's true, we run the controlled * plan normally and pass back the results. * * @@ -34,7 +33,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.29 2004/12/31 21:59:45 pgsql Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.30 2005/04/24 11:46:21 neilc Exp $ * *------------------------------------------------------------------------- */ |