| From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
|---|---|
| To: | Kenneth Marshall <ktm(at)rice(dot)edu> |
| Cc: | Mark Mielke <mark(at)mark(dot)mielke(dot)cc>, Hannu Krosing <hannu(at)skype(dot)net>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Gregory Stark <stark(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Hash index todo list item |
| Date: | 2007-09-07 06:20:38 |
| Message-ID: | 20070907062038.GA23630@svana.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Thu, Sep 06, 2007 at 01:08:59PM -0500, Kenneth Marshall wrote:
> Since we already have to check the actual tuple values for any index
> lookup in postgresql, we could only store the full hash value and the
> corresponding TIDs in the bucket. Then when we lookup an item by
> calculating its hash, if the exact hash is not present in the bucket,
> then we know that the item is not in the index.
Sounds like you'd be returning a bitmap for use with a bitmap scan.
That's a different take on other suggestions I've heard and would allow
a hash index to have an almost unlimited key size yet flexible
matching... (combined with other index, or even just the same index).
Neat.
Have a nice day,
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Phil | 2007-09-07 06:44:26 | Installation problem and a question |
| Previous Message | Florian G. Pflug | 2007-09-07 04:36:01 | Re: Low hanging fruit in lazy-XID-assignment patch? |