Chao Li <[email protected]> writes:
> I tested DEFAULT_IO_BUFFER_SIZE with 4K, 32K, 64K, 128K and 256K. Looks like
> increasing the buffer size doesn’t improve the performance significantly.
> Actually, with the buffer size 64K, 128K and 256K, the test results are very
> close. I tested both with lz4 and none compression. I am not suggesting
> tuning the buffer size. These data are only for your reference.
Yeah, I would not expect straight pg_dump/pg_restore performance
to vary very much once the buffer size gets above not-too-many KB.
The thing we are really interested in here is how fast pg_restore
can skip over unwanted table data in a large archive file, and that
I believe should be pretty sensitive to block size.
You could measure that without getting into the complexities of
parallel restore if you make a custom-format dump of a few large
tables that does not have offset data in it, and then seeing how
fast is selective restore of just the last table.
regards, tom lane
