I don't know if this would work, but if you just want to restructure your rows, your could do this:
UPDATE table SET id = id WHERE id BETWEEN 0 AND 20000;
VACUUM table;
UPDATE table SET id = id WHERE id BETWEEN 20001 AND 40000;
VACUUM table;wash, rinse, repeat.
The idea is that an update rewrites the rows (in your new format) and that VACUUM (not FULL) is quite fast when you just modified a part of the table, and non-locking.
Would this work ?
"Iain" <[EMAIL PROTECTED]> writes:another way to speed up full vacuum?
Hmmm... a full vacuum may help to re-organize the structure of modified tables, but whether this is significant or not is another matter.
Actually, VACUUM FULL is designed to work nicely for the situation where a table has say 10% wasted space and you want the wasted space all compressed out. When there is a lot of wasted space, so that nearly all the rows have to be moved to complete the compaction operation, VACUUM FULL is not a very good choice. And it simply moves rows around, it doesn't modify the rows internally; so it does nothing at all to reclaim space that would have been freed up by DROP COLUMN operations.
CLUSTER is actually a better bet if you want to repack a table that's suffered a lot of updates or deletions. In PG 8.0 you might also consider one of the rewriting variants of ALTER TABLE.
regards, tom lane
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