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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 <andres@anarazel.de> Author: Dilip Kumar <dilipbalaut@gmail.com> Suggested-by: Andres Freund <andres@anarazel.de> Suggested-by: Amit Kapila <akapila@postgresql.org> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://www.postgresql.org/message-id/tlpltqm5jjwj7mp66dtebwwhppe4ri36vdypux2zoczrc2i3mp%40dhv4v4nikyfg