Re: Disk I/O

Thanks! I will try this! In fact I was wondering if there was some way to restructure the query but I don't know enough about how things work behind the scenes to do more than guess. The original query has been running now for ten hours, and is still doing mostly disk writes, so I was about to give up. I'll let you know how it goes. Tim On 01/31/2015 12:47 AM, shamsul hassan wrote:

Hi,

I was going through your query and looks like that COUNT(DISTINCT source) is the killer.

I have rewritten the same query as below . Please try this and it should give you the same results.

select c.iso2 as country,count(c.source) as sources from (select iso2,source from sessions where timestamp>='2014-10-01' and timestamp<'2015-01-01' and ("action"='R' or "action"='T') and medium='E' group by iso2,source) c group by country order by sources desc;

Thanks

On Fri, Jan 30, 2015 at 11:00 AM, Tim Burress wrote:

...

On 01/30/2015 07:44 PM, Ying Zhang wrote:

...

You can try to run your query in, e.g., mclient, to see if that makes any difference.

Thanks! I will try your suggestion, and also see if the timing changes from query to query. The first instance of the query has been running now for about two hours, still writing to the disk. That's why I began to wonder if something was wrong.

Tim

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