Horton

Re: Running update in chunks?

Tim Uckun <timuckun@gmail.com>

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From: Tim Uckun <timuckun@gmail.com>
To: Kevin Grittner <kgrittn@mail.com>
Cc: Richard Huxton <dev@archonet.com>, pgsql-general@postgresql.org
Date: 2013-01-21T23:36:10Z
Lists: pgsql-general 
> First off, what does it say for rows affected? (Hint, if you really
> are using a default configuration and it doesn't say 0 rows
> affected, please show us the actual query used.)

update imports set make_id = null

Query returned successfully: 98834 rows affected, 49673 ms execution time.


vacuum analyze imports

Query returned successfully with no result in 4138 ms.

VACUUM FULL imports;

Query returned successfully with no result in 38106 ms.

VACUUM FREEZE ANALYZE;

Query returned successfully with no result in 184635 ms

update imports set make_id = 0

Query returned successfully: 98834 rows affected, 45860 ms execution time.


So all the vacuuming saved about four seconds of execution time.

here is the postgresql.conf completely untouched from the default
install https://gist.github.com/4590590