On Wed, Apr 22, 2009 at 4:37 PM, Stephen Frost <sfrost@snowman.net> wrote:
> Thanks for doing the work. I had been intending to but hadn't gotten to
> it yet.
I'd done similar tests recently, for some batch import code, so it was
just a matter of recreating it.
>> separate inserts, no transaction: 21.21s
>> separate inserts, same transaction: 1.89s
>> 40 inserts, 100 rows/insert: 0.18s
>> one 40000-value insert: 0.16s
>> 40 prepared inserts, 100 rows/insert: 0.15s
>> COPY (text): 0.10s
>> COPY (binary): 0.10s
>
> What about 40000 individual prepared inserts? Just curious about it.
40000 inserts, one prepared statement each (constructing the prepared
statement only once), in a single transaction: 1.68s
I'm surprised that there's any win here at all.
> Also, kind of suprised about COPY text vs. binary. What was the data
> type in the table..? If text, that makes sense, if it was an integer or
> something else, I'm kind of suprised.
Each row had one integer column. I expect strings to be harder to
parse, since it's allocating buffers and parsing escapes, which is
usually more expensive than parsing an integer out of a string. I'd
expect the difference to be negligible either way, though, and I'd be
interested in hearing about use cases where binary copying is enough
of a win to be worth the development cost of maintaining the feature.
On Wed, Apr 22, 2009 at 4:49 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Also, just to be clear: were the "40 insert" cases 40 separate
> transactions or one transaction? I think the latter was meant but
> it's not 100% clear.
One transaction--the only case where I ran more than one transaction
was the first.
--
Glenn Maynard
