So this discussion died with no solution arising to the hint-bit-setting-invalidates-the-CRC problem.
Apparently the only solution in sight is to WAL-log hint bits. Simon opines it would be horrible from a performance standpoint to WAL-log every hint bit set, and I think we all agree with that. So we need to find an alternative mechanism to WAL log hint bits. I thought about causing a process that's about to write a page check a flag that says "this page has been dirtied by someone who didn't bother to generate WAL". If the flag is set, then the writer process is forced to write a WAL record containing all hint bits in the page, and only then it is allowed to write the page (and thus calculate the new CRC). -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
