On Tue, Mar 23, 2010 at 8:15 AM, Jeremy Zawodny <jer...@zawodny.com> wrote: > Mark, >
Facebook changes are described in http://www.facebook.com/note.php?note_id=23844338919. Alas it doesn't use a generic memcache interface internally so it won't be useful to others. >> Are your slaves IO bound? If so, have you tried mk-slave-prefetch? I >> think it can fix the replication lag problems for IO bound slaves. It >> needs more people to test and use it. It can be used right now. > > I actually did use mk-slave-prefetch a year or so ago but ended up proving > to myself that we were not I/O bound in the worst case. We were then (and > still currently are, pending a few ALTER TABLEs) bound on index updates for > over-indexed tables in InnoDB. Is the bottleneck for those index updates CPU or IO? mk-slave-prefetch has recent changes to fetch in parallel and to fetch for all indexes on a table. For IO bound loads both of these are significant improvements over what it used to do. > > I'm still trying to fix the over-indexing nightmare that pre-dates me. I > should show slides at a conference sometime to illustrate the effects of > heavily indexed tables on replication (or general update) throughput. The > numbers shocked me at first. Off topic but do you use the Percona patch for SHOW INDEX_STATISTICS? -- Mark Callaghan mdcal...@gmail.com _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : drizzle-discuss@lists.launchpad.net Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
