On Wed, Jun 21, 2006 at 11:26:16AM -0700, David Wheeler wrote: > Howdy, > > Didn't see anything in the archives, so I thought I'd ask: has anyone > done any work to gauge the performance penalty of using DOMAINs? I'm > thinking of something like Elein's email DOMAIN: > > http://www.varlena.com/GeneralBits/ > > I figured that most simple domains that have a constraint check are > no faster or slower than tables with constraints that validate a > particular column. Is that the case? Probably. Only thing that might pose a difference is if you're doing a lot of manipulating of the domain that didn't involve table access; presumably PostgreSQL will perform the checks every time you cast something to a domain. > But I'm also interested in how Elein made the email domain case- > insensitive, since I'd like to have/create a truly case-insensitive > text type (ITEXT anyone?). The functions for the operator class there http://gborg.postgresql.org/project/citext/projdisplay.php > were mainly written in SQL, and if it adds a significant overhead, > I'm not sure it'd be a good idea to use that approach for a case- > insensitive text type, since I use it quite a lot in my apps, and > often do LIKE queries against text data. Thoughts? > > Many TIA, > > David > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match > -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
