It would be perfectly reasonable to add an amisrecoverable like Simon described. It could automatically set indisvalid to false after a crash and treat the index as if indisvalid is false during recovery. That would be a lot smoother and safer than what we have now.

It might even be possible to do this with a new wal record type so it only happens if there was a write to the index. I imagine most users who read that warning and use hash indexes anyways are using them on read-only tables where they know it's safe.



--
Greg


On 18 Dec 2008, at 07:51, Heikki Linnakangas <heikki.linnakan...@enterprisedb.com > wrote:

Pavan Deolasee wrote:
BTW, if there is no proven case where hash index works significantly
better than btree (that's what the doc says), why not just completely
abandon it ?

That has been considered many times, see archives. I believe the changes done in 8.4 actually made it faster for some cases. And as Kenneth pointed out hash indexes can handle keys larger than 1/3 of page size, that b-tree can't.

--
 Heikki Linnakangas
 EnterpriseDB   http://www.enterprisedb.com

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