From: alan <alan.miller3@gmail.com>
To: pgsql-sql@postgresql.org
Subject: how to use explain analyze
Date: Tue, 25 Oct 2011 07:12:17 -0700 (PDT)
Message-ID: <7be7d91b-c054-41c6-8a7c-08e77d29625e@v2g2000yqf.googlegroups.com> (raw)
I'm new to postgres and was wondering how to use EXPLAIN ANALYZE ....
Can I use the output from ANALYZE EXPLAIN to estimate or predict the
actual time
it would take for a given query to return?
I ask because I'm writing a typical web app that allows the user to
build and submit a query
to my DB. Since I don't know how "simple" or "complex" the user-
generated queries will be
I thought it might be possible to use the ANALYZE EXPLAIN output to
make a "guestimation"
about the expected return time of the query.
I'd like to use this in my web-app to determine whether to run the
query in real-time (user waits
for results) or queue up the query (and notify the user once the query
is finished). E.g.:
if (the Total runtime" reported by explain analyze is > n ms) {
tell the user that his request was submitted for processing, and
notify the user once resuilts are available
} else {
run the query and wait for the results in real time.
}
Thanks,
Alan
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To: pgsql-sql@postgresql.org
Cc: alan.miller3@gmail.com
Subject: Re: how to use explain analyze
In-Reply-To: <7be7d91b-c054-41c6-8a7c-08e77d29625e@v2g2000yqf.googlegroups.com>
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