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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2002-05-12 23:43:04 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2002-05-12 23:43:04 +0000 |
| commit | 3389a110d40a505951e7c7babdfb8681173bb2ca (patch) | |
| tree | 438acebac5cfd161cf920bcda6ad168affcb96a7 /src/backend/optimizer/README | |
| parent | f9e4f611a18f64fd9106a72ec9af9e2220075780 (diff) | |
| download | postgresql-3389a110d40a505951e7c7babdfb8681173bb2ca.tar.gz | |
Get rid of long-since-vestigial Iter node type, in favor of adding a
returns-set boolean field in Func and Oper nodes. This allows cleaner,
more reliable tests for expressions returning sets in the planner and
parser. For example, a WHERE clause returning a set is now detected
and complained of in the parser, not only at runtime.
Diffstat (limited to 'src/backend/optimizer/README')
| -rw-r--r-- | src/backend/optimizer/README | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/backend/optimizer/README b/src/backend/optimizer/README index 472efbcd9c..14e3990922 100644 --- a/src/backend/optimizer/README +++ b/src/backend/optimizer/README @@ -42,7 +42,8 @@ base rels of the query. Possible Paths for a primitive table relation include plain old sequential scan, plus index scans for any indexes that exist on the table. A subquery base relation just has one Path, a "SubqueryScan" path (which links to the -subplan that was built by a recursive invocation of the planner). +subplan that was built by a recursive invocation of the planner). Likewise +a function-RTE base relation has only one possible Path. Joins always occur using two RelOptInfos. One is outer, the other inner. Outers drive lookups of values in the inner. In a nested loop, lookups of |