On Thu, Dec 1, 2016 at 1:33 AM, xu jian <jame...@outlook.com> wrote: > Hello, > > Please execute me if I am using the wrong mailing list, but I ask the > question in pgsql-admin, looks like no one know the answer. > > > we upgraded our pg db to 9.6, as we know, pg9.6 doesn't need full table scan > in vacuum freeze. > > http://rhaas.blogspot.com/2016/03/no-more-full-table-vacuums.html > > > so we think if we have run vacuum freeze on the table, and there is no > change on table which has been vacuum freeze before it should finish super > faster. > > > However, it doesn't look like we expect. the next run of vacuum freeze still > take long time. Then we run vacuum freeze with verbose. we notice it spends > long time on scanning index. > > it seems even all rows are frozen on the data page, vacuum freeze still > needs to scan all the index pages. if we drop the index, then vacuum freeze > finishes immediately. > > > Does anyone know if it is true?
Yeah that's true. The vacuum on each index is required in order to update index statistics even if no updating on table. > Btw, our table is large, and has about 40GB index files. is there anyway to > make the vacuum freeze faster in this case? I guess that there is no way. Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers