>>>>> "Joshua" == Joshua D Drake <j...@commandprompt.com> writes:

 Joshua> The database dumps fine as long as we don't dump large
 Joshua> objects. However, if we try to dump the large objects, FreeBSD
 Joshua> will kill pg_dump as it will consume all free memory and
 Joshua> swap. With Andrew's help we were able to determine the
 Joshua> following:

 Joshua> There is a memory cost of about 160 bytes per largeobject.

I may have the exact number here wrong, it was just a quick eyeball of
the data structures (and depends on malloc overheads anyway).

The relevant code is getBlobs in pg_dump.c, which queries the whole of
pg_largeobject_metadata without using a cursor (so the PGresult is
already huge thanks to having >100 million rows), and then mallocs a
BlobInfo array and populates it from the PGresult, also using pg_strdup
for the oid string, owner name, and ACL if any.

-- 
Andrew (irc:RhodiumToad)


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

Reply via email to