Обсуждение: PG_dump a large database fails

Hi

For migration purpose (from 8.2 to 8.4), i'm trying to make a dump of a 16 GB database.
(this is my dump command "pg_dump mydb | gzip > /var/dump/db.gz"

It fails whith this error message:
pg_dump: la commande SQL a échoué
pg_dump: Message d'erreur du serveur : ERREUR:  invalid memory alloc request size 1510382321
pg_dump: La commande était : COPY public.attach_data (id, thedata) TO stdout;

i executed this command to wich row exceed this size,
SELECT id, octet_length(thedata) as taille FROM attach_data WHERE octet_length(thedata)>1510382321 ORDER BY 2 DESC;
 id | taille
----+--------
(0 ligne)

Here we can see that there is no row greater than 1510382321

but i found rows exceeding 440 MB. i deleted them.

Now the dump stopped with the same error but with a different size

pg_dump: la commande SQL a échoué
pg_dump: Message d'erreur du serveur : ERREUR:  invalid memory alloc request size 1146242327
pg_dump: La commande était : COPY public.attach_data (id, thedata) TO stdout;

Can you give me some advices on how can i do the dump ?

Thanks a lot

fida aljounaidi <fida.aljounaidi@gmail.com> wrote:

> For migration purpose (from 8.2 to 8.4)

8.2.what? to 8.4.what?

> (this is my dump command "pg_dump mydb | gzip > /var/dump/db.gz"

Using pg_dump from which version?

> It fails whith this error message:
> pg_dump: la commande SQL a échoué
> pg_dump: Message d'erreur du serveur : ERREUR:  invalid memory
> alloc request size 1510382321
> pg_dump: La commande était : COPY public.attach_data (id, thedata)
> TO stdout;

Did you (or can you) get a core file and get a backtrace?

-Kevin