Thank you very much, your explanation helped a lot. This is the tool I needed the solution for http://code.google.com/p/pc-tools/ if you are interested.
On 4 August 2011 01:10, Pavan Deolasee <pavan.deola...@gmail.com> wrote: > On Wed, Aug 3, 2011 at 12:33 PM, Pavan Deolasee > <pavan.deola...@gmail.com> wrote: >> >> >> The only problem, other than a surprising behavior that you noted, >> that I see with this approach is that we might repeatedly try to >> truncate a relation which in fact does not have anything to truncate. >> The worst thing is we might unnecessarily take an exclusive lock on >> the table. >> > > So it seems we tried to fix this issue sometime back > http://archives.postgresql.org/pgsql-hackers/2008-12/msg01994.php > > But I don't quite understand how the fix would really work. > nonempty_pages would most likely be set at a value lower than relpages > if the last page in the relation is all-visible according to the > visibility map. Did we mean to test (nonempty_pages > 0) there ? But > even that may not work except for the case when there are no dead > tuples in the relation. > > Thanks, > Pavan > > -- > Pavan Deolasee > EnterpriseDB http://www.enterprisedb.com > -- Sergey Konoplev Blog: http://gray-hemp.blogspot.com / Linkedin: http://ru.linkedin.com/in/grayhemp / JID/GTalk: gray...@gmail.com / Skype: gray-hemp -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers