| From: | Bruno Wolff III <bruno(at)wolff(dot)to> |
|---|---|
| To: | Jerry III <jerryiii(at)hotmail(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Can this be indexed? |
| Date: | 2004-11-09 02:18:15 |
| Message-ID: | 20041109021815.GB14080@wolff.to |
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| Lists: | pgsql-general |
On Sun, Nov 07, 2004 at 09:29:30 +0000,
Jerry III <jerryiii(at)hotmail(dot)com> wrote:
> But if you do build an index over "id" then pgsql would only have to do a
> sequential scan on that index, which might be a lot faster if your table
> contains a lot of other data, won't it?
A full table index scan will be slower than a sequential scan; typically by
a lot. In the old days a sort step would have been needed and that would have
slowed things down. Now a method using hashing is available that will
work unless there is an extremely large number of unique values for "id".
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