diff options
| author | Richard Guo <rguo@postgresql.org> | 2025-07-22 11:19:17 +0900 |
|---|---|---|
| committer | Richard Guo <rguo@postgresql.org> | 2025-07-22 11:19:17 +0900 |
| commit | e0d05295268e3811e6743403cb779f21d1662426 (patch) | |
| tree | dec1e181c8c15a6a97d6a35e4b02e6092b545ca5 /src/backend/optimizer/prep | |
| parent | 0810fbb02dbe70b8a7a7bcc51580827b8bbddbdc (diff) | |
Expand virtual generated columns before sublink pull-up
Currently, we expand virtual generated columns after we have pulled up
any SubLinks within the query's quals. This ensures that the virtual
generated column references within SubLinks that should be transformed
into joins are correctly expanded. This approach works well and has
posed no issues.
In an upcoming patch, we plan to centralize the collection of catalog
information needed early in the planner. This will help avoid
repeated table_open/table_close calls for relations in the rangetable.
Since this information is required during sublink pull-up, we are
moving the expansion of virtual generated columns to occur beforehand.
To achieve this, if any EXISTS SubLinks can be pulled up, their
rangetables are processed just before pulling them up.
Author: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAMbWs4-bFJ1At4btk5wqbezdu8PLtQ3zv-aiaY3ry9Ymm=jgFQ@mail.gmail.com
Diffstat (limited to 'src/backend/optimizer/prep')
| -rw-r--r-- | src/backend/optimizer/prep/prepjointree.c | 20 |
1 files changed, 8 insertions, 12 deletions
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c index 87dc6f56b57..8140d22de70 100644 --- a/src/backend/optimizer/prep/prepjointree.c +++ b/src/backend/optimizer/prep/prepjointree.c @@ -4,10 +4,10 @@ * Planner preprocessing for subqueries and join tree manipulation. * * NOTE: the intended sequence for invoking these operations is + * expand_virtual_generated_columns * replace_empty_jointree * pull_up_sublinks * preprocess_function_rtes - * expand_virtual_generated_columns * pull_up_subqueries * flatten_simple_union_all * do expression preprocessing (including flattening JOIN alias vars) @@ -958,10 +958,6 @@ preprocess_function_rtes(PlannerInfo *root) * generation expressions. Note that we do not descend into subqueries; that * is taken care of when the subqueries are planned. * - * This has to be done after we have pulled up any SubLinks within the query's - * quals; otherwise any virtual generated column references within the SubLinks - * that should be transformed into joins wouldn't get expanded. - * * Returns a modified copy of the query tree, if any relations with virtual * generated columns are present. */ @@ -1334,6 +1330,13 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte, Assert(subquery->cteList == NIL); /* + * Scan the rangetable for relations with virtual generated columns, and + * replace all Var nodes in the subquery that reference these columns with + * the generation expressions. + */ + subquery = subroot->parse = expand_virtual_generated_columns(subroot); + + /* * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so * that we don't need so many special cases to deal with that situation. */ @@ -1353,13 +1356,6 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte, preprocess_function_rtes(subroot); /* - * Scan the rangetable for relations with virtual generated columns, and - * replace all Var nodes in the query that reference these columns with - * the generation expressions. - */ - subquery = subroot->parse = expand_virtual_generated_columns(subroot); - - /* * Recursively pull up the subquery's subqueries, so that * pull_up_subqueries' processing is complete for its jointree and * rangetable. |