On Tue, Oct 13, 2009 at 06:30:31PM -0600, Shane Hathaway wrote: > Laurence Rowe wrote: > > Shane's earlier benchmarks show MySQL to be the fastest RelStorage backend: > > http://shane.willowrise.com/archives/relstorage-10-and-measurements/ > > Yep, despite my efforts to put PostgreSQL on top. :-) It seems that > PostgreSQL has more predictable performance and behavior, while MySQL > wins slightly in raw performance once every surprisingly slow query has > been optimized.
The usual wisdom on that is MySQL is faster at raw table reading, PostgreSQL at concurrency, esp. w/ any writing thrown in. Often, the performance curves 'cross' at some point. Could be > 16 in this case. For my druthers, I just _trust_ PostgreSQL a lot more: the one MySQL DB I have that I use on an on-going basis is my MythTV media-pc. Once a month or so I have to repair a table. I've used PostgreSQL in professional high load production for years and never had a corruption issue: even when running out of disk! (the main culprit in my experience w/ MySQL, since that's the default state for a PVR: full!) <snip caching discussion> > > This leads to an interesting question. Memcached or ZEO cache--which is > better? While memcached has a higher minimum performance penalty, it > also has a lower maximum penalty, since memcached hits never have to > wait for disk. Also, memcached can be shared among processes, there is > a large development community around memcached, and memcached creates > opportunities for developers to be creative with caching strategies. shared caches: this is the main reason I've been looking at relstore: we're running many Zope FEs against one ZOE right now, and due to the nature of the load-balancer, we're seeing little gain from the caches. I'm looking to fix that issue, to some extent, but sharing across all the FEs on one box would be a big win, I'm sure. > So I'm inclined to stick with memcached even though the ZEO cache > numbers look better. Ross -- Ross Reedstrom, Ph.D. reeds...@rice.edu Systems Engineer & Admin, Research Scientist phone: 713-348-6166 The Connexions Project http://cnx.org fax: 713-348-3665 Rice University MS-375, Houston, TX 77005 GPG Key fingerprint = F023 82C8 9B0E 2CC6 0D8E F888 D3AE 810E 88F0 BEDE _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev