Thread: RE: [HACKERS] "CANNOT EXTEND" -

Is this from vacuum or pg_dump?

I'm just wondering if vacuum cannot cope with a table that is >1Gb
(hence in two segments), and when cleaned down, is <1Gb (one segment).

Saying that, why is it saying the tuple is too big? What is creating
that tuple?

-----Original Message-----
From: Bruce Momjian [mailto:maillist@candle.pha.pa.us]
Sent: Tuesday, March 23, 1999 2:55 PM
To: tim@perdue.net
Cc: hackers@postgreSQL.org
Subject: Re: [HACKERS] "CANNOT EXTEND" -


> 
> Bruce, for the most part, I have worked around the problems with
> pg_dump.
> 
> But I am getting this error now, and it is worrisome:
> 
> NOTICE:  Can't truncate multi-segments relation tbl_mail_archive
> ERROR:  Tuple is too big: size 10024
> 

Can someone comment on this?  It is coming from
./backend/storage/smgr/md.c in mdtruncate().  Is this table very large?

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania
19026

> Is this from vacuum or pg_dump?

I'm not sure about the original message. In my case, I got 
NOTICE:  Can't truncate multi-segments relation tbl_mail_archive

while doing vacuum on a multi-segment relation.

However I didn't get:

ERROR:  Tuple is too big: size 10024

I'm not sure if I was just lucky.

> I'm just wondering if vacuum cannot cope with a table that is >1Gb
> (hence in two segments), and when cleaned down, is <1Gb (one segment).

I don't think vacuum is currently usable for a segmented relation.

> Saying that, why is it saying the tuple is too big? What is creating
> that tuple?

Seems that comes from RelationPutHeapTupleAtEnd(). It's saying
requested tuple length is too big to fit into a page.  (10024 is
apparently bigger than 8192) Someting very weird is going on...
---
Tatsuo Ishii