Re: Should a DB vacuum use up a lot of space ?

Philippe Girolami <philippe.girolami@mosaik.com> writes:
> We’ve got a 16TB database that’s run up against the wrap-around tx id issue (despite running auto-vacuum):
>   ERROR:  database is not accepting commands to avoid wraparound data loss in database "public"
>   HINT:  Stop the postmaster and use a standalone backend to vacuum that database.
> The message says to VACUUM the whole database so we’ve dropped down to single user mode and issued a “vacuum verbose”
commandon the backend 

> 2)       File system usage is going steadily up (3TB over the past 9
> hours). Why is that ?

Probably because there's no background process to issue auto-checkpoints
and thereby recover WAL space.

I'd try doing a control-C on the VACUUM, then a CHECKPOINT, then start
over.  You might have to vacuum large tables individually and checkpoint
after each one.

            regards, tom lane