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Re: dump/load time

From: Jan Hendrik <list.jan.hendrik_at_gmail.com>
Date: Tue, 9 Sep 2008 20:22:14 +0200

Concerning Re: dump/load time
Troy Curtis Jr wrote on 28 Aug 2008, 22:23, at least in part:

> I know this is really late, but I was going through my email tonight
> and saw you never got an answer. I'm not sure whether the --deltas
> option would have made much difference one way or the other in your
> timing, it would make the resulting dump file smaller, but that isn't
> want you want.
>
> Actually, as you are using the BDB back-end you long load time are
> probably related to the automatic removal of bdb log files and/or log
> file fsyncs. The next time you do a load enable the 'DB_TXN_NOSYNC'
> option in <repo>/db/DB_CONFIG and also disable 'DB_LOG_AUTOREMOVE'.
> After you are done you should flip both of these back though because
> they are useful, but really slow things down when you are iterating
> through a ton of revisions.

Troy,

many thanks for your suggestions. For the sake of knowledge I
tried them for a regular dump of revs. 0-1000:

regular loading into fresh 1.5 repository takes 3' 20"

changing both options as suggested time shrinks to 1' 10"

enabling just DB_TXN_NOSYNC likewise takes 1' 10"

likewise loading from a dumpfile with --deltas on 1' 5"

Regular dumping of revs 1-1000 took 6 minutes, with the --deltas
switch 18", with dump filesizes of 660 MB vs. 117 MB.

After resetting the options, svnadmin recover & removal of unused
logs the first three repositories are of exactly the same size (278
MB) while the last one loaded from the --deltas dumpfile is only
261.5 MB. I have not tried loading from --deltas dumpfile without
fiddling options in DB_CONFIG as there was no point in it.
Dumping with --deltas has some time penalty in creation, though
neglectible compared with loading, but practically no gain in load
time. Its only advantage is the significantly smaller size of the
dumpfile.

The system is a 1.6GHz Centrino with 2GB RAM, running WinXP
SP2, with several apps open in the background, but none actively
used nor in a state of doing autosaving or similar things on their
own during all the operations above.

Maybe a hint for the savvy to enable DB_TXN_NOSYNC during a
load could be added to the manual. I certainly will take a note!

Jan Hendrik
---------------------------------------
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Received on 2008-09-09 20:50:22 CEST

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