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Re: InstantDB: Table with binary objects keep growing and growing


Pete,

I'm using fixed size blobs (16 KB) in the tests. In real life, I expect
the data to vary in size in a range of 2 to 4 KB.

I'm sorry I cannot provide you with a sample code at this stage
because the test I'm using is full of application objects.

Do you have an advice on how I could temporarily fix this problem?
Is it possible to write an export / import script that works with blobs?

Or should I rather write my own Java utility to compact the database?

Thanks for your help.
--Pitch

> I think InstantDB is maybe having problems re-using deleted blob space

> efficiently. When a blob gets deleted/updated the space released is
> placed on a list of free blobs. These should get re-used. If they're
> not getting reused then that's definitely a bug.

> Also, InstantDB doesn't concatenate free adjacent blobs (there's
> nothing to stop it doing that - the code just hasn't been added yet).
> If you're blobs get progressively bigger then InstantDB won't find any

> free blobs large enough and it will end up creating new ones. Is that
> the case here? Do the your objects grow in size?

> Pete

                      ----- Original Message -----
                      From: "Chevalier, Pierre-Yves"
<Pierre-Yves.Chevalier@mkms.xerox.com>
                      Date: Monday, March 12, 2001 10:45 am
                      Subject: InstantDB: Table with binary objects keep
growing and growing

                      > Hi,
                      >
                      > I have three tables holding serialized objects.
Every time
                      > I store a new version of an object, the new
content gets
                      > appended to the .blb file while the new version
stays forever.
                      >
                      > So for example: storing 10 objects of size 16
KB, 400 times
                      > creates a blob file that is 66MB large! The
optimal value
                      > would be near 160KB.
                      >
                      > This seems related to a problem posted last
month:
                      >

http://instantdb.enhydra.org/project/mailingLists/instantdb/msg01167.htm

                      l
                      >
                      > Instead of doing an UPDATE, I tried first
removing the tuple
                      > and then to do a fresh INSERT. Same result.
                      > Am I missing something here?
                      >
                      > I would appreciate your dilligent help on this
subject.
                      >
                      > Regards
                      > --Pitch.
                      >
----------------------------------------------------------------
                      > Pierre-Yves Chevalier - Project Leader askOnce
                      > Xerox Internet Business Group (IBG)
                      > 6 ch. de Maupertuis, F-38240 Meylan
                      > Tel: +33 (0)4.76.61.50.93 - Fax: +33
(0)4.76.61.51.89
                      > mailto:Pierre-Yves.Chevalier@mkms.xerox.com
                      >
----------------------------------------------------------------
                      > perso: http://www.xrce.xerox.com/people/pitch/
                      > public: http://www.xerox.co
                      >
-------------------------------------------------------------------

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