tableam: Perform CheckXidAlive check once per scan Previously, the CheckXidAlive check was performed within the table_scan*next* functions. This caused the check to be executed for every fetched tuple, an unnecessary overhead.
To fix, move the check to table_beginscan* so it is performed once per scan rather than once per row. Note: table_tuple_fetch_row_version() does not use a scan descriptor; therefore, the CheckXidAlive check is retained in that function. The overhead is unlikely to be relevant for the existing callers. Reported-by: Andres Freund <[email protected]> Author: Dilip Kumar <[email protected]> Suggested-by: Andres Freund <[email protected]> Suggested-by: Amit Kapila <[email protected]> Reviewed-by: Andres Freund <[email protected]> Discussion: https://www.postgresql.org/message-id/tlpltqm5jjwj7mp66dtebwwhppe4ri36vdypux2zoczrc2i3mp%40dhv4v4nikyfg Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/87f7b824f20c1c06884ef0711b4d32dbf4461436 Modified Files -------------- src/backend/access/heap/heapam.c | 10 ----- src/backend/access/index/genam.c | 30 +++++++------- src/backend/access/table/tableam.c | 20 +++------- src/include/access/tableam.h | 82 +++++++++++++++++--------------------- 4 files changed, 57 insertions(+), 85 deletions(-)
