Bug with sequence ?

Started by Christian Meunierabout 24 years ago4 messageshackers
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#1Christian Meunier
vchris@club-internet.fr

First just let you know i solved my past issue, i used IPCHAINS to redirect port 80 to a non root port, look like there is some ressource system leaking in IPCHAINS, i moved from it to IPTABLE and all works fine now.

Back to postgres :)

let's say i have one table with the following schema:

Table test(num int not null primary key,.........);
i have a sequence to handle the num: create sequence test_num_seq;

When i insert a new tuple i use: insert into test values(nextval('test_num_seq'),......);

When i look at my postgres log, time to time i see:
2002-02-04 08:11:47 ERROR: Cannot insert a duplicate key into unique index test_pkey

It's really rare (considering the traffic i handle) but it shouldnt happen at all.

Ha using 7.2RC2 btw
Best regards

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Christian Meunier (#1)
Re: Bug with sequence ?

"Christian Meunier" <vchris@club-internet.fr> writes:

When i insert a new tuple i use: insert into test values(nextval('test_num_=
seq'),......);
When i look at my postgres log, time to time i see:
2002-02-04 08:11:47 ERROR: Cannot insert a duplicate key into unique index=
test_pkey

You sure that's the *only* way that the num column gets inserted or
updated?

regards, tom lane

#3Tom Lane
tgl@sss.pgh.pa.us
In reply to: Tom Lane (#2)
Re: Bug with sequence ?

"Dave Cramer" <davec@fastcrypt.com> writes:

Mine manifests with the sequence being updated, and then another process
comes along and tries to do the same operation and somehow gets the same
sequence.

All I can say is I've been over the sequence code with a flinty eye,
and I'm darned if I can see anything wrong with it. I don't think
we are going to make much progress on this without being able to
investigate a failure with a debugger.

A self-contained example that shows a failure (even if only rarely)
would be really useful. Anything less really isn't useful.

regards, tom lane

#4Christian Meunier
vchris@club-internet.fr
In reply to: Christian Meunier (#1)
Re: Bug with sequence ?

Well correcting the report:

by the past, i was used to have this trouble ( using 7.2b5 or prior and
ipchains)

the only 2 occurences i have now in my log are not linked to sequence so it
must occur sometime somehow but it has nothing to do with postgres.

However by the past, i had this trouble with sequence, i dont know if i get
rid off this issue updating to 7.2RC2 or moving to IPTABLE instead of
ipchains.

----- Original Message -----
From: "Tom Lane" <tgl@sss.pgh.pa.us>
To: "Christian Meunier" <vchris@club-internet.fr>
Cc: <pgsql-hackers@postgresql.org>
Sent: Monday, February 04, 2002 5:21 PM
Subject: Re: [HACKERS] Bug with sequence ?

"Christian Meunier" <vchris@club-internet.fr> writes:

When i insert a new tuple i use: insert into test

values(nextval('test_num_=

seq'),......);
When i look at my postgres log, time to time i see:
2002-02-04 08:11:47 ERROR: Cannot insert a duplicate key into unique

index=

Show quoted text

test_pkey

You sure that's the *only* way that the num column gets inserted or
updated?

regards, tom lane