Re: BUG #7853: Incorrect statistics in table with many dead rows.

From: jimbob <skaggs(dot)james(at)gmail(dot)com>
To: pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #7853: Incorrect statistics in table with many dead rows.
Date: 2013-02-25 19:00:10
Message-ID: 1361818810310-5746602.post@n5.nabble.com
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So, I have some observations. Is this what you are seeing as well?

So when we CLUSTER a table heavily-updated table:

CLUSTER does appear to reset *n_dead_tup*, *n_tup_ins*, *n_tup_del*,
*n_tup_hot_upd*, but NOT *n_live_tup*

pg_stat_reset() truly clears out all the statistics counters. I tried this
because *n_live_tup* is not correct.

A subsequent ANALYZE will update *n_dead_tup* and *n_live_tup* to some
values that could not possibly be based on the newly CLUSTERed table

So, how to get correct statistics for a heavily updated table? In my
experience, we only need to get the exponent correct, but we're not even
getting that.

BTW, I've upgraded to 8.4.15.

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