Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
> On 12.01.2011 17:15, David Fetter wrote:
>> On Wed, Jan 12, 2011 at 10:26:05AM +0100, marcin mank wrote:
>>> Considering that parallell base backups would be io-bound (or
>>> network-bound), there is little need to actually run them in parallell
>>
>> That's not actually true. Backups at the moment are CPU-bound, and
>> running them in parallel is one way to make them closer to I/O-bound,
>> which is what they *should* be.
> That's a different kind of "parallel". We're talking about taking
> multiple backups in parallel, each using one process, and you're talking
> about taking one backup using multiple parallel processes or threads.
Even more to the point, you're confusing pg_dump with a base backup.
The reason pg_dump eats a lot of CPU is primarily COPY's data conversion
and formatting requirements, none of which will happen in a base backup
(streaming or otherwise).
regards, tom lane