Re: Simple (hopefully) throughput question?
| От | Samuel Gendler |
|---|---|
| Тема | Re: Simple (hopefully) throughput question? |
| Дата | |
| Msg-id | AANLkTikL2=SydpMrUbDD6zLQ6DDTdqeCOWZzff7bbWNv@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Simple (hopefully) throughput question? (Vitalii Tymchyshyn <tivv00@gmail.com>) |
| Список | pgsql-performance |
On Thu, Nov 4, 2010 at 8:07 AM, Vitalii Tymchyshyn <tivv00@gmail.com> wrote:
04.11.10 16:31, Nick Matheson написав(ла):JDBC driver has some COPY support, but I don't remember details. You'd better ask in JDBC list.Heikki-Thanks for the suggestion. A preliminary test shows an improvement closer to our expected 35 MB/s.
Try COPY, ie. "COPY bulk_performance.counts TO STDOUT BINARY".
Are you familiar with any Java libraries for decoding the COPY format? The spec is clear and we could clearly write our own, but figured I would ask. ;)
The JDBC driver support works fine. You can pass a Reader or InputStream (if I recall correctly, the InputStream path is more efficient. Or maybe the Reader path was buggy. Regardless, I wound up using an InputStream in the driver which I then wrap in a Reader in order to get it line-by-line.
You can write a COPY statement to send standard CSV format - take a look at the postgres docs for the COPY statement to see the full syntax. I then have a subclass of BufferedReader which parses each line of CSV and does something interesting with it. I've had it working very reliably for many months now, processing about 500 million rows per day (I'm actually COPYing out, rather than in, but the concept is the same, rgardless - my outputstream is wrapper in a writer, which reformats data on the fly).
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