On 09/01/2014 05:52 PM, Andres Freund wrote: > On 2014-08-29 20:12:16 +0200, Hannu Krosing wrote: >> It would need to replace plain tid (pagenr, tupnr) with triple of (partid, >> pagenr, tupnr). >> >> Cross-partition indexes are especially needed if we want to allow putting >> UNIQUE constraints on non-partition-key columns. > I actually don't think this is necessary. I'm pretty sure that you can > build an efficient and correct version of unique constraints with > several underlying indexes in different partitions each. The way > exclusion constraints are implemented imo is a good guide. > > I personally think that implementing cross partition indexes has a low > enough cost/benefit ratio that I doubt it's wise to tackle it anytime > soon. Also it has the downside of (possibly) making DROP PARTITION either slow or wasting space until next VACUUM.
So if building composite unique indexes over multiple per-partition indexes is doable, I would much prefer this. Cheers -- Hannu Krosing PostgreSQL Consultant Performance, Scalability and High Availability 2ndQuadrant Nordic OÜ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
