| From: | Rod Taylor <rbt(at)rbt(dot)ca> |
|---|---|
| To: | PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | WHERE order |
| Date: | 2003-08-26 17:53:49 |
| Message-ID: | 1061920428.4370.25.camel@jester |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
It would appear that in 7.4 the order of clauses in WHERE affects the
execution time (not output if AND).
I would think that a simple optimization would be to push off evaluation
of a subplan whenever possible by re-arranging AND statements.
In the below example, it gives an order of magnitude speed increase on a
small dataset.
| Attachment | Content-Type | Size |
|---|---|---|
| long.query | text/plain | 513 bytes |
| long.explain | text/plain | 1.5 KB |
| short.explain | text/plain | 1.5 KB |
| short.query | text/plain | 513 bytes |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Alvaro Herrera Munoz | 2003-08-26 18:05:18 | Re: Date input changed in 7.4 ? |
| Previous Message | Jenny - | 2003-08-26 17:48:18 | Re: table-level and row-level locks. |