<html><body><span style="font-family:Verdana; color:#000000; font-size:10pt;"><div>Thanks Jaime for your feedback, I did add an index on SARS_ACTS_RUN.ALGORITHM column but it didn't improve the run time. The planner just changed the "Filter:" to an "Index Scan:" improving the cost of the Seq Scan on the <span style="font-family:Verdana; color:#000000; font-size:10pt;">sars_acts_run</span> table, but the overall run time remained the same. It seems like the bottleneck is in the Seq Scan on the sars_acts table.<br></div><div><br></div><div><span style="font-family:Verdana; color:#000000; font-size:10pt;"> -> Seq Scan on sars_acts_run tr1_ (cost=0.00..230565.81 rows=580 width=8)<br> Filter: ((algorithm)::text = 'SMAT'::text)</span></div><div><span style="font-family:Verdana; color:#000000; font-size:10pt;"><br></span></div><div><span style="font-family:Verdana; color:#000000; font-size:10pt;">I'll move this posting into the appropriate group</span></div><div><span style="font-family:Verdana; color:#000000; font-size:10pt;"><br></span></div><div><span style="font-family:Verdana; color:#000000; font-size:10pt;">thanks</span></div><div><span style="font-family:Verdana; color:#000000; font-size:10pt;"><br></span></div>
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-------- Original Message --------<br>
Subject: Re: [BUGS] Very slow inner join query unacceptable latency<br>
From: Jaime Casanova <<a href="mailto:jaime(at)2ndquadrant(dot)com">jaime(at)2ndquadrant(dot)com</a>><br>
Date: Tue, May 21, 2013 2:34 pm<br>
To: Freddie Burgess <<a href="mailto:fburgess(at)radiantblue(dot)com">fburgess(at)radiantblue(dot)com</a>><br>
Cc: pgsql-bugs <<a href="mailto:pgsql-bugs(at)postgresql(dot)org">pgsql-bugs(at)postgresql(dot)org</a>><br>
<br>
On Tue, May 21, 2013 at 3:54 PM, <<a href="mailto:fburgess(at)radiantblue(dot)com">fburgess(at)radiantblue(dot)com</a>> wrote:<br>
> The SARS_ACTS table currently has 37,115,515 rows<br>
><br>
> we have indexed: idx_sars_acts_acts_run_id ON SARS_ACTS USING btree<br>
> (sars_run_id)<br>
> we have pk constraint on the SARS_ACTS_RUN table; sars_acts_run_pkey PRIMARY<br>
> KEY (id )<br>
><br>
> serverdb=# explain select count(*) as y0_ from SARS_ACTS this_ inner join<br>
> SARS_ACTS_RUN tr1_ on this_.SARS_RUN_ID=<a href="http://tr1_.ID">tr1_.ID</a> where tr1_.ALGORITHM='SMAT';<br>
<br>
This is not a bug, you should write to the<br>
<a href="mailto:pgsql-general(at)postgresql(dot)org">pgsql-general(at)postgresql(dot)org</a> or <a href="mailto:pgsql-performance(at)postgresql(dot)org">pgsql-performance(at)postgresql(dot)org</a><br>
mailing lists.<br>
<br>
anyway, seems that you need an additional index on SARS_ACTS_RUN.ALGORITHM<br>
<br>
--<br>
Jaime Casanova <a href="http://www.2ndQuadrant.com">www.2ndQuadrant.com</a><br>
Professional PostgreSQL: Soporte 24x7 y capacitación<br>
Phone: +593 4 5107566 Cell: +593 987171157<br>
<br>
<br>
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