"Steve Oualline" <[EMAIL PROTECTED]> writes:
> Question: I have a big table with 120,000,000 records.
> Let's assume that I DELETE 4,000,000 records, VACUUM FULL, and REINDEX.
> Now I have the same table, but with 240,000,000 records.
> I DELETE 8,000,000 records, VACUUM FULL, and REINDEX.
> Should the second operation with twice the data take twice the time as =
> the first?
At least. If you intend to reindex all the indexes, consider instead
doing
DROP INDEX(es)
VACUUM FULL
re-create indexes
as this avoids the very large amount of effort that VACUUM FULL puts
into index maintenance --- effort that's utterly wasted if you then
reindex.
CLUSTER and some forms of ALTER TABLE can accomplish a table rewrite
with less hassle than the above, although strictly speaking they violate
MVCC by discarding recently-dead tuples.
regards, tom lane
---------------------------(end of broadcast)---------------------------
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
