Re: like/ilike improvements - Mailing list pgsql-hackers

From ITAGAKI Takahiro
Subject Re: like/ilike improvements
Date
Msg-id 20070921180728.68E4.ITAGAKI.TAKAHIRO@oss.ntt.co.jp
Whole thread Raw
In response to Re: like/ilike improvements  ("Guillaume Smet" <guillaume.smet@gmail.com>)
Responses Re: like/ilike improvements
List pgsql-hackers
"Guillaume Smet" <guillaume.smet@gmail.com> wrote:

> It's better but still slower than 8.2.

It probablly comes from 'var-varlena' feature in 8.3. Now we store
text fields in a compact format on disks and extract them on access.
It consumes some CPU cycles. If all of data are in buffer cache
and the encoding of database is single-byte encodings, the performance
of LIKE in 8.3 was 10-20% slower than 8.2 on my tests.

Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center




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