On Thu, Jul 31, 2014 at 2:00 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: > On Wed, Jul 30, 2014 at 11:32 PM, Robert Haas <robertmh...@gmail.com> wrote: >> IMV, the way to eventually make this efficient is to have a background >> process that reads the WAL and figures out which data blocks have been >> modified, and tracks that someplace. > > Nice idea, however I think to make this happen we need to ensure > that WAL doesn't get deleted/overwritten before this process reads > it (may be by using some existing param or mechanism) and > wal_level has to be archive or more.
That should be a problem; logical decoding added a mechanism for retaining WAL until decoding is done with it, and if it needs to be extended a bit further, so be it. > One more thing, what will happen for unlogged tables with such a > mechanism? As Michael Paquier points out, it doesn't matter, because that data will be gone anyway. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
