Re: Importing large object (with lo_import) to table in separate tablespaces takes up lots of space in $PGDATA

På torsdag 09. oktober 2014 kl. 07:29:30, skrev Guillaume Lelarge <
guillaume(at)lelarge(dot)info <mailto:guillaume(at)lelarge(dot)info>>: Hi,

Le 9 oct. 2014 01:31, "Andreas Joseph Krogh" <andreas(at)visena(dot)com
<mailto:andreas(at)visena(dot)com>> a écrit :
>
> Hi all.
>  
> I'm having a database, called "apeland", which at first (when created) was
in the default-tablespace (in $PGDATA), then I moved it with the commands:
>  
> # create tablespace apeland location
'/home/andreak/programs/postgresql/9.3.5/tablespaces/apeland';
> CREATE TABLESPACE
>  
> Check space-usage before moving:
> $ du -hs data/ tablespaces/
> 59M     data/
> 27M     tablespaces/
>  
> Move the database to new tablespace
> # alter database apeland set tablespace apeland;
> ALTER DATABASE
>  
> Check space-usage after moving:
> $ du -hs data/ tablespaces/
> 52M     data/
> 34M     tablespaces/
>  
>  
> Then I created this table:
> # create table files(data oid);
> CREATE TABLE
>  
> Insert this file:
> $ du -hs origo-war-01-14-01.20.war
> 130M    origo-war-01-14-01.20.war
>  
> # insert into files(data)
values(lo_import('/home/andreak/data/origo-war-01-14-01.20.war'));
> INSERT 0 1
>  
> Check space-usage:
> $ du -hs data/ tablespaces/
> 164M    data/
> 208M    tablespaces/
>  
> Now - why is so much extra space used in $PGDATA? Is there a way to reclame
it? Was the "apeland"-db moved completely or is there lots dangeling left in
PGDATA?
>  

Everything is moved if you used ALTER DATABASE.

I'd guess what you have in the data folder are mostly WAL files. You should
use du on data/base to get size from relations' files, and not everything else
including configuration files.

Thanks. After inserting lots of more LOs I see that $PGDATA doesn't grow at
that rate anymore.   -- Andreas Joseph Krogh CTO / Partner - Visena AS Mobile:
+47 909 56 963 andreas(at)visena(dot)com <mailto:andreas(at)visena(dot)com> www.visena.com
<https://www.visena.com> <https://www.visena.com>