On Wed, Sep 20, 2017 at 4:56 PM, Robert Haas <robertmh...@gmail.com> wrote: > On Wed, Sep 20, 2017 at 7:19 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: >>> Page-at-a-time index vacuum as in _hash_vacuum_one_page doesn't matter >>> because such an operation doesn't allow TIDs to be reused. >> >> Page-at-a-time index vacuum also allows TIDs to be reused but this is >> done only for already marked dead items whereas vacuum can make the >> non-dead entries to be removed. We don't have a problem with >> page-at-a-time vacuum as it won't remove any items which the scan is >> going to mark as dead. > > I don't think page-at-a-time index vacuum allows heap TIDs to be > reused. >
Right, I was thinking from the perspective of the index entry. Before marking index entry as dead, we do check for heaptid. So, as heaptid can't be reused via Page-at-a-time index vacuum, scan won't mark index entry as dead. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
