From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | umut orhan <umut_angelfire(at)yahoo(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: postgresql scalability issue |
Date: | 2010-11-08 15:55:15 |
Message-ID: | 25416.1289231715@sss.pgh.pa.us |
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Lists: | pgsql-hackers |
umut orhan <umut_angelfire(at)yahoo(dot)com> writes:
> When I pin a single query to an individual core, its execution time is observed
> as 111 seconds. This result is my base case. Then, I fire two instances of the
> same query concurrently and pin them to two different cores separately. However,
> each execution time becomes 132 seconds in this case.
If the queries are fetching the exact same data, this seems unsurprising
--- you will have a lot of contention for page-level locks. A more
realistic case would involve concurrent queries looking at different
data. Perhaps overlapping sets of data, but not exactly the same data.
regards, tom lane
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