Re: Compressed Backup too big - Mailing list pgsql-general

From Magnus Hagander
Subject Re: Compressed Backup too big
Date
Msg-id 1195492440.7785.12.camel@mha-laptop.clients.sollentuna.se
Whole thread Raw
In response to Compressed Backup too big  ("Andrus" <kobruleht2@hot.ee>)
List pgsql-general
On Thu, 2007-11-15 at 20:35 +0200, Andrus wrote:
> "PostgreSQL 8.2.3 on i686-pc-mingw32, compiled by GCC gcc.exe (GCC) 3.4.2
> (mingw-special)"
> Database size in disk returned by  pg_database_size() is 210 MB
>
> Database compressesed  backup file size is now 125 MB.
> This seems too much. I expect compression to decrease size 10 times, also
> indexes are not backed up. A year ago compressed backup size was 9 MB only.
>
> I created query returning biggest tables with and without indexes and found:
>
>       1  pg_toast_22185                      95 MB           96 MB
>       2  rid                                 21 MB           27 MB
>       3  klient                              13 MB           19 MB
>       4  mailbox                             10 MB           11 MB
>       5  dok                                 7640 kB         12 MB
>       6  desktop                             8080 kB         8200 kB
>       7  strings                             5536 kB         6584 kB
>       8  pg_toast_22338                      5232 kB         5368 kB
>
> ...
>
> Questions:
>
> 1. Tables are relatively small and thus cannot create 125 MB compressed
> backup file.
> Why backup file sis so big ?

Is this a pg_dump backup or a PITR style backup?
If it's a pg_dump backup, you can open it up in an editor to find out
what's taking so much space.

> 2. How to determine what data is containing in  pg_toast_22185  ?
> Why this is so big ?

Could it be that you haven't been VACUUMing properly? Possibly you need
to run a VACUUM FULL if you haven't kept up. If it's a PITR style backup
on 1, that could be the same reason.


To find what table has pg_toast_22185, try:
SELECT relname FROM pg_class WHERE oid=22185


//Magnus


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