| From: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
|---|---|
| To: | Merlin Moncure <mmoncure(at)gmail(dot)com> |
| Cc: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Peter Geoghegan <peter(at)2ndquadrant(dot)com>, Stefan Keller <sfkeller(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Hash index use presently(?) discouraged since 2005: revive or bury it? |
| Date: | 2011-09-15 20:28:50 |
| Message-ID: | CAGTBQpbvMW55NPs2Oe_zpuYwcvRed=KQOG5-CnXHrCLqbwL-eQ@mail.gmail.com |
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| Lists: | pgsql-performance |
On Thu, Sep 15, 2011 at 5:00 PM, Merlin Moncure <mmoncure(at)gmail(dot)com> wrote:
>
> HM, what if you junked the current hash indexam, and just implemented
> a wrapper over btree so that the 'hash index' was just short hand for
> hashing the value into a standard index?
I'm doing this (only by hand, indexing on hash(blah)) on an
application, and it works wonders.
But... it's kinda not a hash table. It's still O(log N).
However, it would be a *very* useful feature if it can be made
transparent for applications.
And I would prefer it over a true hashtable, in the end. Hashes are,
in fact, O(N) worst case.
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