X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id C8A8F9FB1F0 for ; Tue, 2 May 2006 17:50:58 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 84856-02 for ; Tue, 2 May 2006 17:50:45 -0300 (ADT) X-Greylist: domain auto-whitelisted by SQLgrey- Received: from py-out-1112.google.com (pproxy.gmail.com [64.233.166.176]) by postgresql.org (Postfix) with ESMTP id 5D1FB9FB1D5 for ; Tue, 2 May 2006 17:50:44 -0300 (ADT) Received: by py-out-1112.google.com with SMTP id b29so7623pya for ; Tue, 02 May 2006 13:50:44 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=bVm0l//suBo9qYjHrIo1u3xaMEwUxKl4pPmKT7tCrabhFVhlxIfElc5ys9J8M+3RXJ4XLtJrsey9XcV/xtuWy6L+lfLXpDHGx1Hsd82m83jUgqKrirn1SiXnwpvccxUQXHyVyfDjUEqxKKcBeri8+BEMHzzGLeDY8zjJnz1FQFw= Received: by 10.35.88.17 with SMTP id q17mr1128379pyl; Tue, 02 May 2006 13:50:43 -0700 (PDT) Received: by 10.35.49.6 with HTTP; Tue, 2 May 2006 13:50:43 -0700 (PDT) Message-ID: <6d8daee30605021350p4172bbc5w7ecf87573099abd9@mail.gmail.com> Date: Tue, 2 May 2006 13:50:43 -0700 From: "Tony Wasson" To: "Bruno Wolff III" , "Tony Wasson" , "Vivek Khera" , "Pgsql performance" Subject: Re: postgresql transaction id monitoring with nagios In-Reply-To: <20060502201928.GB14674@wolff.to> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <6d8daee30605021126o7b44e255q552dcdc676c565bf@mail.gmail.com> <628A837A-9718-46BB-85D7-8A63BBB1CA32@khera.org> <6d8daee30605021206h8170a48w94670b5d23633a72@mail.gmail.com> <20060502201928.GB14674@wolff.to> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/47 X-Sequence-Number: 18834 On 5/2/06, Bruno Wolff III wrote: > On Tue, May 02, 2006 at 12:06:30 -0700, > Tony Wasson wrote: > > > > Ah thanks, it's a bug in my understanding of the thresholds. > > > > "With the standard freezing policy, the age column will start at one > > billion for a freshly-vacuumed database." > > > > So essentially, 1B is normal, 2B is the max. The logic is now.. > > > > The script detects a wrap at 2 billion. It starts warning once one or > > more databases show an age over 1.5 billion transactions. It reports > > critical at 1.75B transactions. > > > > If anyone else understands differently, hit me with a clue bat. > > Isn't this obsolete now anyway? I am pretty sure 8.1 has safeguards again= st > wrap around. My motivation was primarily to monitor some existing PostgreSQL 8.0 servers. I'm not convinced it is "safe" to stop worrying about transaction ids even on an 8.1 box. It is comforting that 8.1 does safeguard against wraparound in at least 2 ways. First, it emits a warnings during the last 10 million transactions. If you manage to ignore all those, posgresql will shut down before a wraparound. I think PostgreSQL does everything correctly there, but I suspect someone will run into the shut down daemon problem.