Andrew Dunstan <andrew@dunslane.net> wrote:
> OK, here is a patch that I think incorporates all the ideas discussed
> (including part of Mark Mielke's suggestion about optimising %_). There
> is now no special treatment of UTF8 other than its use of a faster
> NextChar macro.
This is a benchmark result of 1000 loops of
SELECT count(*) INTO cnt FROM item WHERE i_title LIKE '%BABABABABARIBA%'
on the table with 10000 rows.
| SQL_ASCII | LATIN1 | UTF8 | EUC_JP
---------+-----------+--------+-------+---------
HEAD | 8017 | 8029 | 16928 | 18213
Patched | 7899 | 7887 | 9985 | 10370 [ms]
It improved the performance not only for UTF8, but also for other
multi-byte encodings and a bit for single-byte encodings.
Thanks for the good work ;)
---
ITAGAKI Takahiro
NTT Open Source Software Center
