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| author | Richard Guo <rguo@postgresql.org> | 2025-05-08 18:21:32 +0900 |
|---|---|---|
| committer | Richard Guo <rguo@postgresql.org> | 2025-05-08 18:21:32 +0900 |
| commit | c06e909c26f070dee78f73c35565d6f4a4ffdcda (patch) | |
| tree | 9f69470d8ba03027f37796542b8c0e7bafb2f44e /src/include/nodes/pathnodes.h | |
| parent | 773db22269d474fab46d25e9e15b1e55252cf92c (diff) | |
Track the number of presorted outer pathkeys in MergePath
When creating an explicit Sort node for the outer path of a mergejoin,
we need to determine the number of presorted keys of the outer path to
decide whether explicit incremental sort can be applied. Currently,
this is done by repeatedly calling pathkeys_count_contained_in.
This patch caches the number of presorted outer pathkeys in MergePath,
allowing us to save several calls to pathkeys_count_contained_in. It
can be considered a complement to the changes in commit 828e94c9d.
Reported-by: David Rowley <dgrowleyml@gmail.com>
Author: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Tender Wang <tndrwang@gmail.com>
Discussion: https://postgr.es/m/CAApHDvqvBireB_w6x8BN5txdvBEHxVgZBt=rUnpf5ww5P_E_ww@mail.gmail.com
Diffstat (limited to 'src/include/nodes/pathnodes.h')
| -rw-r--r-- | src/include/nodes/pathnodes.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h index 011e5a811c3..1dd2d1560cb 100644 --- a/src/include/nodes/pathnodes.h +++ b/src/include/nodes/pathnodes.h @@ -2253,6 +2253,12 @@ typedef struct NestPath * mergejoin. If it is not NIL then it is a PathKeys list describing * the ordering that must be created by an explicit Sort node. * + * outer_presorted_keys is the number of presorted keys of the outer + * path that match outersortkeys. It is used to determine whether + * explicit incremental sort can be applied when outersortkeys is not + * NIL. We do not track the number of presorted keys of the inner + * path, as incremental sort currently does not support mark/restore. + * * skip_mark_restore is true if the executor need not do mark/restore calls. * Mark/restore overhead is usually required, but can be skipped if we know * that the executor need find only one match per outer tuple, and that the @@ -2270,6 +2276,8 @@ typedef struct MergePath List *path_mergeclauses; /* join clauses to be used for merge */ List *outersortkeys; /* keys for explicit sort, if any */ List *innersortkeys; /* keys for explicit sort, if any */ + int outer_presorted_keys; /* number of presorted keys of the + * outer path */ bool skip_mark_restore; /* can executor skip mark/restore? */ bool materialize_inner; /* add Materialize to inner? */ } MergePath; |