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From Rick Hillegas <Richard.Hille...@Sun.COM>
Subject Re: bulk import issue
Date Tue, 01 Dec 2009 13:39:27 GMT
Hi Mike,

I would expect the single import to take a little less time than the 
two-phase import, the difference being the tiny cost of compiling the 
second import statement. What you report sounds like a bug. It would 
help if you could script the problem and attach your repro to a JIRA.


Mike Andrews wrote:
> dear derby developers,
> if i bulk import data into a table, i get much better performance if i
> do it in a single SYSCS_UTIL.SYSCS_IMPORT_TABLE statement rather than
> in multiple shots.
> for example, if there are three large files "a.txt", "b.txt", and
> "c.txt", where "c.txt" is just the concatenation of "a.txt" and
> "b.txt", then
> CALL SYSCS_UTIL.SYSCS_IMPORT_TABLE (null, 'mytable', 'c.txt', ' ', null,null, 1)
> takes much less time than the sum of:
> CALL SYSCS_UTIL.SYSCS_IMPORT_TABLE (null, 'mytable', 'a.txt', ' ', null,null, 1)
> CALL SYSCS_UTIL.SYSCS_IMPORT_TABLE (null, 'mytable', 'b.txt', ' ', null,null, 0)
> even though they result in exactly the same set of data in the table.
> any ideas why? is there a way to get better performance doing it in
> multiple shots? currently my data is in several text files, and so i
> concatenate them all and run a single SYSCS_UTIL.SYSCS_IMPORT_TABLE
> for best performance.
> best regards,
> mike

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