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From:dvd Date:February 7 2008 9:49pm
Subject:Re: very strange slow plain select
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Thanks very much. The default mysql behavior is a little
unusual. What is the parameter in my.cnf to control the cache
size before forcing a flush.  I waited for 2 mininutes second
before the output came out without the -q option. My server
is fast enough to read in more than 2 GB data during this time
so the cache would have been filled long before that. Kind
of puzzling. 

>In the last episode (Feb 07), dvd@stripped said:
>> I just stumbled on this hard to explain problem. Below
>> 
>> select * from BigTable      (BigTable has 5 million
> rows)
>> 
>> takes forever to even print out the first row. as you could see from
>> the sql, it is supposed to print out some rows right away regardless
>> of server config in my.cnf.   What is interesting is the following
>> sql
>> 
>> select * from BigTable limit 1000 
>> 
>> return the rows immediately as expected.
>
>You want the --quick option.  From the mysql manpage:
>
>       o  --quick, -q
>
>          Do not cache each query result, print each row as it is
>          received.  This may slow down the server if the output is
>          suspended. With this option, mysql does not use the history
>          file.
>
>-- 
>	Dan Nelson
>	dnelson@stripped
Thread
very strange slow plain selectdvd7 Feb
  • Re: very strange slow plain selectDan Nelson7 Feb
Re: very strange slow plain selectdvd7 Feb
  • Re: very strange slow plain selectmos8 Feb