On 2014-12-08 14:09:19 -0500, Robert Haas wrote: > > records, just fpis. There is no evidence that we even want to compress > > other record types, nor that our compression mechanism is effective at > > doing so. Simple => keep name as compress_full_page_writes > > Quite right.
I don't really agree with this. There's lots of records which can be quite big where compression could help a fair bit. Most prominently HEAP2_MULTI_INSERT + INIT_PAGE. During initial COPY that's the biggest chunk of WAL. And these are big and repetitive enough that compression is very likely to be beneficial. I still think that just compressing the whole record if it's above a certain size is going to be better than compressing individual parts. Michael argued thta that'd be complicated because of the varying size of the required 'scratch space'. I don't buy that argument though. It's easy enough to simply compress all the data in some fixed chunk size. I.e. always compress 64kb in one go. If there's more compress that independently. 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