Ron Mayer <[EMAIL PROTECTED]> writes:
> Does running a query only twice really insure that a result is cached?
> It seems not to be the case for seq-scans on Linux.
Should work for tables small enough to fit into the shared_buffers
arena. I wouldn't necessarily assume it for large tables.
Note that what I was really doing was taking the timing measurement
again on data cached by the *first* run, so that I would have something
that could fairly be compared to the following EXPLAIN ANALYZE --- which
of course would likewise be operating on cached data.
regards, tom lane
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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
