Very different index usage on similar tables

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04-18-2008, 10:46 AM

Alvaro Nunes Melo

Posts: n/a

Very different index usage on similar tables

Hi,

I have two similar tables in a database, one stores persons and the
other stores telephones. They have a similar number of records (around
70.000), but a indexed search on the persons' table is way faster than
in the telephones' table. I'm sending the explains atacched, and I
believe that the problem can be in the fact the the explain extimates a
worng number of rows in the telefones' explain. I'm sending the explains
atacched, and the table and columns' names are in Portuguese, but if it
makes easier for you guys I can translate them in my next posts.

The in dex in the telephone table is multicolumn, I'd tried to drop it
and create a single-column index, but the results were quite the same.

Thanks,

--
+---------------------------------------------------+
| Alvaro Nunes Melo Atua Sistemas de Informacao |
| al_nunes@atua.com.br www.atua.com.br |
| UIN - 42722678 (54) 327-1044 |
+---------------------------------------------------+

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Very different index usage on similar tables