|
10 | 10 | * |
11 | 11 | *select 1 * 2 |
12 | 12 | * |
| 13 | + *insert into emp values ('mike', 15000) |
| 14 | + * |
| 15 | + *(Remember that in an INSERT or UPDATE, we need a plan tree that |
| 16 | + *generates the new rows.) |
| 17 | + * |
13 | 18 | *Result nodes are also used to optimise queries with constant |
14 | 19 | *qualifications (ie, quals that do not depend on the scanned data), |
15 | 20 | *such as: |
|
20 | 25 | * |
21 | 26 | *Result(with 2 > 1 qual) |
22 | 27 | */ |
23 | | - * SeqScan (emp.all) |
| 28 | + * SeqScan (emp.*) |
24 | 29 | * |
25 | 30 | *At runtime, the Result node evaluates the constant qual once, |
26 | 31 | *which is shown by EXPLAIN as a One-Time Filter. If it's |
|
33 | 38 | * Portions Copyright (c) 1994, Regents of the University of California |
34 | 39 | * |
35 | 40 | * IDENTIFICATION |
36 | | - * $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.30 2005/04/2411:46:21 neilc Exp $ |
| 41 | + * $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.31 2005/04/2415:32:07 tgl Exp $ |
37 | 42 | * |
38 | 43 | *------------------------------------------------------------------------- |
39 | 44 | */ |
|