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From:Peter Grigor Date:November 7 2002 9:39pm
Subject:RE: Key/table cache size?
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> I've got a query that selects the count of distinct rows in a table; the 
> table has 453632 rows and 24 distinct class_id's.
> 
> mysql> SELECT count(DISTINCT(sig_class_id)) FROM acid_event;
> +-------------------------------+
> | count(DISTINCT(sig_class_id)) |
> +-------------------------------+
> |                            24 |
> +-------------------------------+
> 1 row in set (4.80 sec)
> 
> mysql> select count(*) FROM acid_event;
> +----------+
> | count(*) |
> +----------+
> |   453632 |
> +----------+
> 1 row in set (3.12 sec)
> 
> 
> Is there any way to speed up these queries (InnoDB tables), or just put
up?

If you are using a version of MySql that has the query cache you can turn it
on and those queries will run very fast after the initial query. The query
cache is cleared whenever the underlying table(s) are modified so you'll get
the initial time hit again after modification...but if your table contents
don't change much the query cache will make a BIG difference.

Peter
<^_^>
Thread
Key/table cache size?Michael T. Babcock7 Nov
  • Re: Key/table cache size?Dan Nelson7 Nov
  • Re: Key/table cache size?Michael T. Babcock7 Nov
  • Re: Key/table cache size?Jeremy Zawodny7 Nov
RE: Key/table cache size?Peter Grigor7 Nov
  • Re: Key/table cache size?Michael T. Babcock7 Nov