-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Robert Douglass schrieb:
For those of you who like reading performance tuning stuff: http://www.mysqlperformanceblog.com/2007/08/16/how-much-overhead-is-caused-b...
This could be particularly relevant to Drupal.org if we are still getting temp tables written to disk. It turns out that even when we specify MEMORY for temp tables, MySQL still has the option of writing to disk if other buffers aren't large enough.
You wouldn't believe the amazing mySQL bugs Narayan has discovered in that area. ;( "BLOB/TEXT columns are not supported with MEMORY storage engine so must use on disk MyISAM temporary table." There are a number of queries that could be improved to not use e.g. the teaser. I think it would be better if the query would first get the nids in the requested order and then in a second step get the needed teasers. Of course, the /tmp partition mySQL writes to is mapped to memory, so the difference between in memory and on disk shouldn't be that large. In other news: A new slow query log is available on the infra list. Cheers, Gerhard -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFGxr2Bfg6TFvELooQRAhrrAKCVMDYOGxeXqrdu4V/Mdl8vomHxzACdFizN 3uUicxEdax28Ri+1SDD4iE4= =4Xpl -----END PGP SIGNATURE-----