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Not using index from 'possible_keys'
Posted by: Maciej Nadolski
Date: May 08, 2008 05:52AM

Hi,

I'd like to ask you about opinion.
I have complicated query with explain like that:

<snip>
id: 1
select_type: PRIMARY
table: tbl
type: ALL
possible_keys: idx
key: NULL
key_len: NULL
ref: NULL
rows: 278309
Extra:
</snip>

tbl uses MyISAM storage. Db version is 5.0.22-log. It has probably never been ANALYZEd nor OPTIMIZEd.
I'm wondering why "idx" index isn't used (BTREE index). My guess: idx is useless beacouse of lack of updating index statistics and optimized chooses to do full scan.
What do you think about it?

Thanks in advance.

--
Best regards,
Maciej Nadolski

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