"Tom Burke" <lists@spamex.com> writes:
> I have experienced problems with indexes on varchar columns causing
> updates to be very slow. You might also try doing a REINDEX TABLE
> command on the relevant tables. I have found this to give a
> performance increase for queries/updates, but generally still find
> character indexes to drag down insert/update performance.
Coupla questions: did you build with --enable-locale? How about
--enable-multibyte? If yes to either, which locale and encoding
settings are you using exactly?
Also, what platforms are involved here? The known problems with
strcoll() in early 2.2.* glibc releases are in the back of my mind
here, though the symptoms we have seen from that bug ran in the
"backend dumps core" line rather than "backend is slow" line.
Finally, do your indexed varchar columns tend to have lots and
lots of repeated values?
regards, tom lane