Kovalcik: The explains would be identical
Boehne: Are you saying my schema changed?
Brittman: Nope, i am saying that your index statistics may have
Brittman: Thus, you may see a different optimization strategy, different indexes used
Brittman: You might even see something done in 5.5 that wasnt possible in 5.1 and want to turn that off
Baell: How would they have changed?
Brittman: Scott0_: by restarting mysqld, or running “show table status” or lots of ways
Ikkela: I read through all the migration guide form 5.1 to 5.5 and didn’t find anything notable that I could turn off
Cante: I doubt that would have an impact
Brittman: Do you still have the old server to compare explain on it?
Clusky: I’ve restarted the previous server many times and the queries still run the same speed
Pilling: I could but the query is built with the application, not by hand
Brittman: Scott0_: turn on the general log for a minute, load the site, turn it off
Stegmann: I doubt this is an issue of just restarting the server and losing indexed data
Brittman: Scott0_: now you have the query instead of guesses
Robinsons: Im not guessing I know that its not from the indexing
Brittman: Run explain and the query a few times on old/new: select sql_no_cache .
Brittman: You might then say “hm, i see something called index merge is now being used but wasn’t before, maybe i can test with that off in my session or replace the indexes with compound index”
Brittman: Or that a different index is used, which you “fix” by running ****yze table, or dropping a silly index
Kuhr: Xgc: vegivamp: Willette: the only problem is, the data is 6.5+ million rows
Cockram: Wouldn’t that have been mentioned in the upgrade guide?
Cogill: As a new feature which could cause problems?
Brittman: Scott0_: this applies when you are not upgrading due to tranient statistics samples
Brittman: Scott0_: it also applies during upgrades.
Krewson: And idnex merge is an optimization, which shouldn’t be a default config
Warring: I have one index and its very strict
Brittman: Scott0_: no more help until you take steps to help your self
Commons: Which is why I doubt that’s what’s happening
Brittman: Scott0_: i am saying you know where to start now, so get to work
Makarewicz: I know well that its not the index
Pesta: I built the index and I use the index as I should
Brittman: Ok then it must be a problem with my.cnf, hopefully someone here can spot it for you
Pulos: That’s what I was asking
Yoxall: I could understand hunting the problem like you’ve mentioned if it’s a mess of indexes and different queries potentially spanning multiple indexes
Orea: But this is far simpler
Houben: Which is why I was focusing on the potential for multicore optimization because I read that 5.5 has benefits in ways 5.1 didn’t
Burghard: And that fresh install 5.5 may actually be slower than 5.1
Brittman: It is also much faster
Johansson: So my goal was maybe to chalk it up to that and then try to make use of the thread parameters
Braff: My server also has double the RAM now
Parfait: It should be a lot faster, but it seems to have gotten slower only on the mysql portion, other services are fast as expected
Kolp: Makes me wonder if I should have upgraded to 5.5
Baison: Brittman: so what would cause an index to behave differently across 5.1 and 5.5 keeping in mind the mysql binaries were moved over to the new server and the index should be the same.