Hmm that's a range, that should do a table scan in 4.0.18, since a memory table type is just a hash table. In 4.1 I believe it supports ranges since the table is more of a myISAM type.
Is there an index on TIMESTAMP? Does the range cover more then 30% of the table? > -----Original Message----- > From: Kevin A. Burton [mailto:[EMAIL PROTECTED] > Sent: Thursday, January 13, 2005 4:01 PM > To: mysql@lists.mysql.com > Subject: Memory tables much slower in 4.1.7 ? > > Under 4.0.18 we were loading about 800M of data into a memory > table to get better performance from some of our main queries. > > Via crontab we would DELETE older links in the memory table > and then INSERT links from a myisam table. > > This process under 4.1.7 is MUCH slower. Specifically the > DELETE is taking forever. > > We would run: > > DELETE FROM FOO_MEMORY WHERE FOO_MEMORY.TIMESTAMP < 1105055409729; > > But now this takes forever... > > I realize that no index is used on this query but due to the > fact that its a memory table it should sitll be FAST as heck. > > Hash anything changed with rehashing that could effect the > performance here? > > I could install a 4.0.18 node to benchmark but this would > take a while as they are all upgraded....... > > Kevin > > -- > > Use Rojo (RSS/Atom aggregator). Visit http://rojo.com. Ask > me for an invite! Also see irc.freenode.net #rojo if you > want to chat. > > Rojo is Hiring! - http://www.rojonetworks.com/JobsAtRojo.html > > If you're interested in RSS, Weblogs, Social Networking, > etc... then you should work for Rojo! If you recommend > someone and we hire them you'll get a free iPod! > > Kevin A. Burton, Location - San Francisco, CA > AIM/YIM - sfburtonator, Web - http://peerfear.org/ > GPG fingerprint: 5FB2 F3E2 760E 70A8 6174 D393 E84D 8D04 99F1 4412 > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
