[postgis-users] [GENERAL] How to improve this query?

[Mark Cave-Ayland]

On 08/02/11 11:05, Jorge Arévalo wrote:

> 2011/2/8 Stefan Keller<sfkeller at gmail.com>:
>> "  Hash Cond: (TABLE_C.STR_FIELD = TABLE_B.STR_FIELD)"
>> tells me that these two longish strings are compared first.
>> Did you already try to index TABLE_C.STR_FIELD and TABLE_B.STR_FIELD
>> as hash instead btree?
>
> I thought hash indexes were discouraged over btree. Anyway, I'll test it.

Absolutely. You do not want to be using Hash Indexes these days - stick 
with B-Tree. The hash refers to the method by which the executor matches 
the two column fields and is not related to the underlying index type.


ATB,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
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