Heikki Linnakangas <hlinnakan...@vmware.com> writes: > 2. Instead of storing the new compressed posting list in the WAL record, > store only the new item pointers added to the page. WAL replay would > then have to duplicate the work done in the main insertion code path: > find the right posting lists to insert to, decode them, add the new > items, and re-encode.
That sounds fairly dangerous ... is any user-defined code involved in those decisions? > This record format would be higher-level, in the sense that we would not > store the physical copy of the compressed posting list as it was formed > originally. The same work would be done at WAL replay. As the code > stands, it will produce exactly the same result, but that's not > guaranteed if we make bugfixes to the code later, and a master and > standby are running different minor version. There's not necessarily > anything wrong with that, but it's something to keep in mind. Version skew would be a hazard too, all right. I think it's important that WAL replay be a pretty mechanical, predictable process. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers