https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=32719 Bug ID: 32719 Summary: db_revs 210600001 can take a long time Change sponsored?: --- Product: Koha Version: master Hardware: All OS: All Status: NEW Severity: enhancement Priority: P5 - low Component: Database Assignee: koha-bugs@lists.koha-community.org Reporter: magnus@libriotech.no QA Contact: testopia@bugs.koha-community.org I did an upgrade from 20.11.06 to 22.05.08 last night, and db_rev 210600001 (bug 28489) took something like an hour. The problem was probably that the sessions table was huge, and should have been cleaned regularly. But it wasn't. Here is what the update does: $dbh->do('DELETE FROM sessions'); $dbh->do('ALTER TABLE sessions MODIFY a_session LONGBLOB NOT NULL'); I expected the delete to be quick and altering an empty table should also be quick. But it wasn't. "show processlist" showed this for a long time: copy to tmp table | ALTER TABLE sessions MODIFY a_session LONGBLOB NOT NULL I wonder if the problem is that the DELETE and the ALTER is in the same transaction? Which means the "deleted" data needs to be kept track of, while the "alter" is running? Maybe this could be made more efficient for others with a large sessions table? -- You are receiving this mail because: You are the assignee for the bug. You are watching all bug changes.