Thread: Large Object table data file does not have expected size

Large Object table data file does not have expected size

From
u15074
Date:
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.



-------------------------------------------------
This mail sent through IMP: http://horde.org/imp/


Re: Large Object table data file does not have expected size

From
Martijn van Oosterhout
Date:
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.
>
>
>
> -------------------------------------------------
> This mail sent through IMP: http://horde.org/imp/
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings

--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> "the West won the world not by the superiority of its ideas or values or
> religion but rather by its superiority in applying organized violence.
> Westerners often forget this fact, non-Westerners never do."
>   - Samuel P. Huntington

Attachment