On 2014-03-04 12:43:48 +0200, Heikki Linnakangas wrote: > >>This ought to be tested with the new logical decoding stuff as it modified > >>the WAL update record format which the logical decoding stuff also relies, > >>but I don't know anything about that. > > > >Hm, I think all it needs to do disable delta encoding if > >need_tuple_data (which is dependent on wal_level=logical). > > That's a pity, but we can live with it.
Agreed. This is hardly the first optimization that only works for some wal_levels. > If we did this at a higher level and > checked which columns have been modified, we could include just the modified > fields in the record, which should to be enough for logical decoding. It > might be even more useful for logical decoding too to know exactly which > fields were changed. Yea, I argued that way elsewhere in this thread. I do think we're going to need per column info for further features in the near future. It's a bit absurd that we're computing various sets of changed columns (HOT, key, identity) plus the pre/postfix with this patchset. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
