Preferred usage for 'copy to' for a subset of data
For recent postgres releases, is there any effective difference
(performance/memory/io) between:
create temp table foo as select * from bar where bar.date > '2007-01-01';
copy foo to '/tmp/bar.out';
drop table temp;
and this:
copy ( select * from bar where bar.date > '2007-01-01' ) to '/tmp/bar.out';
...that would lead me to use one method vs. the other on large data sets
(1M+ records)?
Just wondering,
Jason
"Jason L. Buberel" <jason@buberel.org> writes:
For recent postgres releases, is there any effective difference
(performance/memory/io) between:
create temp table foo as select * from bar where bar.date > '2007-01-01';
copy foo to '/tmp/bar.out';
drop table temp;
and this:
copy ( select * from bar where bar.date > '2007-01-01' ) to '/tmp/bar.out';
Surely the latter will be faster, since it doesn't bother to store all
the data in a server temp table.
regards, tom lane