Re: generic copy options

On Thu, Sep 17, 2009 at 07:45:45PM -0400, Andrew Dunstan wrote:
>
>
> Dan Colish wrote:
>> CREATE TABLE
>> INSERT 0 100000
>> Timing is on.
>> COPY 100000
>> Time: 83.273 ms
>> BEGIN
>> Time: 0.412 ms
>> TRUNCATE TABLE
>> Time: 0.357 ms
>> COPY 100000
>> Time: 140.911 ms
>> COMMIT
>> Time: 4.909 ms
>>
>>
>>
>
> Anything that doesn't have times that are orders of magnitude greater
> than this is pretty much useless as a measurement of COPY performance,
> IMNSHO.
>
> In this particular test, to check for paring times, I'd be inclined to
> do copy repeatedly (i.e. probably quite a few thousand times) from an
> empty file to test the speed. Something like:
>
> select current_timestamp;
> begin;
> truncate;
> copy;copy;copy; ...
> commit;
> select current_timestamp;
>
>
> (tests like this are really a good case for DO ' something'; - we could
> put a loop in the DO.)
>
> cheers
>
> andrew
>

Ok, so I ran something like you suggested and did a simple copy from an
empty file to just test the parsing. I have the COPY statement run 3733
times in the transaction block and did the select timestamps, but I
still only was a few milliseconds difference between the two versions.
Maybe a more complex copy statment could be a better test of the parser,
but I do not see a significant difference of parsing speed here.

--
--Dan