On Fri, Sep 23, 2005 at 12:21:15PM +0200, Joost Kraaijeveld wrote:
On Fri, 2005-09-23 at 05:55 -0400, Michael Stone wrote:
It's not clear what your object id generator does. If it's just a
sequence, it's not clear that you need this program at all--just use a
SELECT INTO and make the object id a SERIAL.
It generates a GUID (and no, I do not want to turn this in a discussion
about GUIDs). As in the Java code comment: it is not the generation of
the GUID that is the problem (that is, I can generate millions of them
I didn't say it was, did I? If you use a SELECT INTO instead of
SELECTing each record and then reINSERTing it you avoid a round trip
latency for each row. There's a reason I said "if it's just a sequence".
If you do need to control the object id or do some other processing
before putting the data into the new table, rewrite to use a COPY
instead of an INSERT.
It is actually the shortest piece of code that gives me a poor
performance. The conversion problem is much, much larger and much much
Ok, that's great, but you didn't respond to the suggestion of using COPY
INTO instead of INSERT.
But I have no clue where to begin with determining the bottleneck (it
even may be a normal performance for all I know: I have no experience
with converting such (large) database).
Respond to the first suggestion?
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