At 08:34 AM 10/17/2006, you wrote:
> Hello,
>
> For the Radius server we're using MySQL cluster and the following query
> looks too slow:
>
>select ip from ipaddr
> where pool='INTERNET' and stype='S' and ls_id=3 and allocated is null
> limit 1;
>
> Table ipaddr is small (~6MB, 38000 records). Fields in WHERE clause have
> few values and no indexes:
> - pool: 2 distinct values;
> - stype: 6 distinct values;
> - ls_id: 5 distinct values;
> - allocated is null for ~30000 of records.
>
> Table type is NDB. If I change it to MEMORY everything starts to fly.
>
> Of course there are a lot of updates to ipaddr table too. For every
> select there are 3 updates. But updates are of type "update something
> where ip=ipaddr" and ipaddr is unique key.
>
> What can cause slowdown in NDB case? Table is small and is in memory
> (5.0 cluster). Maybe I can rewrite it in some better form for such case?
> MySQL setting are basically default. I did not find something in
> documentation about improving performance of NDB engine tables.
> Maybe increase read_buffer_size which is currently the default 128k?
> Server has 4GB of memory and runs x86_64 version of CentOS4 Linux.
>
> Thanks,
>
> Mindaugas
Mindaugas,
If your queries are always using those fields, why not create a
single compound index on those fields? This shouldn't slow down inserts
that much, and if they do, you could always use delayed inserts.
Mike
