I think we still have a serious problem with multicolumn indexes. As they
stand they're basically only indexes on the first column. The later columns
are not used to determine page splits.
It's not a fully truth, second keys can be used in split, if first columns has
non-unique values and second, the later columns uses in gistchoose method (wrap
for user-defined penalty methods).
But I am agreed, that split in multicolumn GiST indexes isn't very optimal, the
solution was suggested by Aoki, but it's require to change interface to user
function.
Look:
"Generalizing ''Search'' in Generalized Search Trees", 1997, Paul M. Aoki,
http://www.sai.msu.su/~megera/postgres/gist/papers/csd-97-950.pdf
--
Teodor Sigaev E-mail: [EMAIL PROTECTED]
WWW: http://www.sigaev.ru/
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