Large Object table data file does not have expected size

Started by u15074almost 23 years ago2 messagesgeneral
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#1u15074
u15074@hs-harz.de

I am a little bit confused by the following effect.
For test reasons I insert about 100000 large objects into the database. Each has
a size of 10240 Bytes (10K). So the expected size of the large object datafile
should be at least 1024000000 Bytes (about 976MB) just to hold the large objects.
But the according data file is much smaller than that. If I query the large
objetcs from psql all data seems to be there (i just randomly picked out some
large objects). I first thought there was a bug in my test program (not all
large objetcs are inserted), but I couldn't find one. Also this was unlikely,
since I always insert the same binary data (for the large objetc) in a simple loop.

Has anyone an idea why the datafiles are much smaller than I expect them to be?

Thanks, Andreas.

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#2Martijn van Oosterhout
kleptog@svana.org
In reply to: u15074 (#1)
Re: Large Object table data file does not have expected size

Compression? Postgres tends to compress large fields.

On Fri, Jun 27, 2003 at 10:08:34AM +0200, u15074 wrote:

I am a little bit confused by the following effect.
For test reasons I insert about 100000 large objects into the database. Each has
a size of 10240 Bytes (10K). So the expected size of the large object datafile
should be at least 1024000000 Bytes (about 976MB) just to hold the large objects.
But the according data file is much smaller than that. If I query the large
objetcs from psql all data seems to be there (i just randomly picked out some
large objects). I first thought there was a bug in my test program (not all
large objetcs are inserted), but I couldn't find one. Also this was unlikely,
since I always insert the same binary data (for the large objetc) in a simple loop.

Has anyone an idea why the datafiles are much smaller than I expect them to be?

Thanks, Andreas.

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