Re: day 2 results - Mailing list pgsql-hackers

From Thomas Lockhart
Subject Re: day 2 results
Date
Msg-id 3A410252.60AB9B52@alumni.caltech.edu
Whole thread Raw
In response to day 2 results  (Paul A Vixie <vixie@mfnx.net>)
List pgsql-hackers
> VACUUM ANALYZE after the INSERTs made no performance difference at all,
> which is good since no other modern database requires anything to be done
> to improve performance after a large number of INSERTs.  (i can understand
> why COPY would need it, but not INSERT.)

afaik every modern database requires something like this to update
optimizer stats, since on-the-fly stats accumulation can be expensive
and inaccurate. But most of my recent experience has been with
PostgreSQL and perhaps some other DBs have added some hacks to get
around this. Of course, some databases advertised as modern don't do
much optimization, so don't need the stats.

The biggest effect seen is when growing from an empty database, when the
stats would be changing the most. Once populated, the stats update
usually has little effect, but shouldn't be ignored forever.

Glad to see the tests are going well...
                    - Thomas

btw, I'll guess that "no other" and "every" could both be
overstatements, but it sure makes a better sentence, eh? ;)


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