If you want MYSQL to process the SELECT, including information about how tables
are joined and in which order
usehttp://dev.mysql.com/doc/refman/5.0/en/using-explain.htmle.g. EXPLAIN
[EXTENDED] SELECT select_optionsIf you want MySQL uses the stored key
distribution to decide the order in which tables should be joined when you
perform a join on something other than a constant. In addition, key
distributions can be used when deciding which indexes to use for a specific
table within a query.
http://dev.mysql.com/doc/refman/5.0/en/analyze-table.htmlYou can also check
your stored key
distributionhttp://dev.mysql.com/doc/refman/5.0/en/show-index.htmlMartin
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> Date: Thu, 14 Aug 2008 17:35:00 +0530> From: [EMAIL PROTECTED]> To: [EMAIL
PROTECTED]> Subject: Re: SELECT in NULL state for a long time> CC:
mysql@lists.mysql.com> > Record the query, execute and see the result. Make
sure that you get the> result. To me its seems that lots of request are comming
and not full> filled. Check the query for optimization.> > On Thu, Aug 14, 2008
at 5:17 PM, Vlad Shalnev <[EMAIL PROTECTED]> wrote:> > > Hi,> >> > OS - Solaris
10, 32 Gb RAM, mysql 64-bit 4.1.22> >> > Every day I see in processlist many
SELECT queries that stay in NULL state> > for a long time. Something Like this>
>> > | 368966 | radius | fire-u1:35671 | srg_conf | Query | 106 |> > NULL
|SELECT id, deleted_id, status, name, LEFT( value, 1000 )> > FROM s> >> > |
368967 | radius | fire-u1-1:35672 | srg_conf | Query | 105 |> > NULL |SELECT
id, deleted_id, status, name, LEFT( value, 1000 )> > FROM s> >> > | 368968 |
radius | fire-u1-1:35673 | srg_conf | Query | 101 |> > NULL |SELECT id,
deleted_id, status, name, LEFT( value, 1000 )> > FROM s> >> > | 368969 | radius
| fire-u1:35674 | srg_conf | Query | 101 |> > NULL |SELECT id, deleted_id,
status, name, LEFT( value, 1000 )> > FROM s> >> > | 368970 | radius |
fire-u1:35675 | srg_conf | Query | 100 |> > NULL |SELECT id, deleted_id,
status, name, LEFT( value, 1000 )> > FROM s> >> > | 28 | mysql | fire-u1:58138
| hnt_cn | Query | 116 |> > NULL |SELECT id, deleted_id, status, name, LEFT(
value, 1000 )> > FROM h> >> > | 48 | radius | fire-u1:58166 | hnt_cn | Query |
114 |> > NULL |SELECT id, deleted_id, status, name, LEFT( value, 1000 )> > FROM
h> >> > | 49 | radius | fire-u1-1:58165 | srg_cn | Query | 127 |> > NULL
|SELECT id, deleted_id, status, name, LEFT( value, 1000 )> > FROM s> >> > | 50
| mysql | fire-u1-1:58163 | blr_cn | Query | 120 |> > NULL |SELECT id,
deleted_id, status, name, LEFT( value, 1000 )> > FROM b> >> > Connections grow
up during this time and after a couple minutes this> > problem gonna away.> >>
> Explain me please why it happens and how can I solve this problem> >> >
Thanks> >> > --> >> >
-------------------------------------------------------------------------------->
> Vlad A. Shalnev> > E-mail: [EMAIL PROTECTED]> >> > "Gravity can't be blamed>
> for someone> > falling in love"> >> > ( Albert Einstein )> >> > --> > MySQL
General Mailing List> > For list archives: http://lists.mysql.com/mysql> > To
unsubscribe:> > http://lists.mysql.com/[EMAIL PROTECTED]> >> >> > > -- >
Krishna Chandra Prajapati
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