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From Sameer Thakur
Subject pg_stat_statements query normalization
Date
Msg-id CABzZFEuc0ww6jHtLKPp44y8mXwr_tXjorXXJdc9E-ArfFU53XQ@mail.gmail.com
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Responses Re: pg_stat_statements query normalization  (Peter Geoghegan <peter.geoghegan86@gmail.com>)
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Hello,
Reading code documentation of pg_stat_statements it says 

* As of Postgres 9.2, this module normalizes query entries.  Normalization
 * is a process whereby similar queries, typically differing only in their
 * constants (though the exact rules are somewhat more subtle than that) are
 * recognized as equivalent, and are tracked as a single entry.  This is
 * particularly useful for non-prepared queries.

Consider query
SELECT * FROM pgbench_branches LEFT JOIN pgbench_tellers ON pgbench_tellers.bid= pgbench_branches.bid WHERE pgbench_branches.bID=5

Does this mean that all queries with just the constant changing are normalized 

pgbench_branches.bID=10,pgbench_branches.bID=15

Or are queries where conditions changed included as well?

pgbench_branches.bID <10,pgbench_branches.bID>15

regards

Sameer




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