On Feb 16, 2009, at 9:07 AM, Craig Ringer wrote:
CREATE INDEX uidx_product_partno_producer_id
ON product
USING btree
(partno, producer_id);
CREATE INDEX idx_product_partno
ON product
USING btree
(partno);
Can I safely delete the second one?
You can safely delete BOTH in that it won't hurt your data, only
potentially hurt performance.
Deleting the index on (partno) should somewhat improve insert
performance and performance on updates that can't be done via HOT.
However, the index on (partno, producer_id) is requires more
storage and
memory than the index on just (partno). AFAIK it's considerably slower
to scan.
Actually, that's not necessarily true. If both partno and procuder_id
are ints and you're on a 64bit platform, there won't be any change in
index size, due to alignment issues.
--
Decibel!, aka Jim C. Nasby, Database Architect decibel@xxxxxxxxxxx
Give your computer some brain candy! www.distributed.net Team #1828
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