public inbox for [email protected]help / color / mirror / Atom feed
Bogus duplicate-message complaints from PG mail lists 3+ messages / 3 participants [nested] [flat]
* Bogus duplicate-message complaints from PG mail lists @ 2013-01-15 20:45 Tom Lane <[email protected]> 0 siblings, 2 replies; 3+ messages in thread From: Tom Lane @ 2013-01-15 20:45 UTC (permalink / raw) To: pgsql-www Several times over the past couple of days, I have gotten complaints like the one attached about duplicate message IDs. I can see from my sendmail daemon's log that I sent only one copy of this, and the complaint is dated about twenty minutes after the fact, so I'm pretty sure the duplicate is not of my making. Usually when I get this type of thing I can tell from the Received: lines that it's the fault of some list subscriber's MUA re-submitting a message to the lists. But the Received: lines in this example and the last couple don't show that the message has gone anywhere outside postgresql.org. So I'm thinking it's a recently-introduced glitch in the mail list server arrangements. regards, tom lane ------- Forwarded Message Received: from malur.postgresql.org (malur.postgresql.org [217.196.149.56]) by sss.pgh.pa.us (8.14.5/8.14.5) with ESMTP id r0FKV40w002187 for <[email protected]>; Tue, 15 Jan 2013 15:31:04 -0500 (EST) Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from <[email protected]>) id 1TvD9z-00056W-US for [email protected]; Tue, 15 Jan 2013 20:31:03 +0000 MIME-Version: 1.0 X-Mailer: MIME-tools 5.428 (Entity 5.428) Date: Tue, 15 Jan 2013 20:31:03 +0000 From: [email protected] To: Tom Lane <[email protected]> Subject: Denied post to pgsql-hackers Content-Type: multipart/mixed; boundary="----------=_1358281863-9659-3" Message-ID: <[email protected]> This is a multi-part message in MIME format... ------------=_1358281863-9659-3 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Content-Transfer-Encoding: 7bit Content-Language: en Your message to the pgsql-hackers list has been denied for the following reason(s): A message was previous posted with this Message-ID Duplicate Message-ID - <[email protected]> (Tue Jan 15 20:11:10 2013) Duplicate Message Checksum (Tue Jan 15 20:11:10 2013) Duplicate Partial Message Checksum (Tue Jan 15 20:11:10 2013) ------------=_1358281863-9659-3 Content-Type: message/rfc822 Content-Disposition: inline Content-Transfer-Encoding: 8bit Content-Description: Original message Received: from makus.postgresql.org ([98.129.198.125]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from <[email protected]>) id 1TvD9z-00056R-Hi for [email protected]; Tue, 15 Jan 2013 20:31:03 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from <[email protected]>) id 1TvCqf-0005ve-W6 for [email protected]; Tue, 15 Jan 2013 20:11:09 +0000 Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.5/8.14.5) with ESMTP id r0FKB2UL001724; Tue, 15 Jan 2013 15:11:03 -0500 (EST) From: Tom Lane <[email protected]> To: Bruce Momjian <[email protected]> cc: Robert Haas <[email protected]>, Simon Riggs <[email protected]>, Jeff Janes <[email protected]>, pgsql-hackers <[email protected]> Subject: Re: [HACKERS] [PERFORM] Slow query: bitmap scan troubles In-reply-to: <[email protected]> References: <CA+U5nMLjf2-kTa4-AR-0XLKKwbc+=_fb4237i_UAWYzowW+-1Q@mail.gmail.com> <[email protected]> <[email protected]> <CA+U5nMKbOGVfQXfJi5_vOUPEatF_V_+e_HX4P5R=tb9JSo2ceA@mail.gmail.com> <[email protected]> <[email protected]> <CA+TgmoYQ6Nq-tpHiDPCUH3CkH2N9D67=oDKJtLxuRRC=dRteSQ@mail.gmail.com> <[email protected]> <CA+Tg!moa+wzu9RBUK75veRn6UTWjSZZJa2aOjfvn0LD1_mx+rRg@mail.gmail.com> <[email protected]> <[email protected]> Comments: In-reply-to Bruce Momjian <[email protected]> message dated "Tue, 15 Jan 2013 14:46:39 -0500" Date: Tue, 15 Jan 2013 15:11:02 -0500 Message-ID: <[email protected]> X-Pg-Spam-Score: -1.9 (-) Bruce Momjian <[email protected]> writes: > On Mon, Jan 14, 2013 at 12:56:37PM -0500, Tom Lane wrote: >> Remember also that "enable_seqscan=off" merely adds 1e10 to the >> estimated cost of seqscans. For sufficiently large tables this is not >> exactly a hard disable, just a thumb on the scales. But I don't know >> what your definition of "extremely large indexes" is. > Wow, do we need to bump up that value based on larger modern hardware? I'm disinclined to bump it up very much. If it's more than about 1e16, ordinary cost contributions would disappear into float8 roundoff error, causing the planner to be making choices that are utterly random except for minimizing the number of seqscans. Even at 1e14 or so you'd be losing a lot of finer-grain distinctions. What we want is for the behavior to be "minimize the number of seqscans but plan normally otherwise", so those other cost contributions are still important. Anyway, at this point we're merely speculating about what's behind Robert's report --- I'd want to see some concrete real-world examples before changing anything. regards, tom lane ------------=_1358281863-9659-3-- ------- End of Forwarded Message -- Sent via pgsql-www mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-www ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Bogus duplicate-message complaints from PG mail lists @ 2013-01-15 20:48 Magnus Hagander <[email protected]> parent: Tom Lane <[email protected]> 1 sibling, 0 replies; 3+ messages in thread From: Magnus Hagander @ 2013-01-15 20:48 UTC (permalink / raw) To: Tom Lane <[email protected]>; +Cc: pgsql-www On Tue, Jan 15, 2013 at 9:45 PM, Tom Lane <[email protected]> wrote: > Several times over the past couple of days, I have gotten complaints > like the one attached about duplicate message IDs. I can see from my > sendmail daemon's log that I sent only one copy of this, and the > complaint is dated about twenty minutes after the fact, so I'm pretty > sure the duplicate is not of my making. > > Usually when I get this type of thing I can tell from the Received: > lines that it's the fault of some list subscriber's MUA re-submitting > a message to the lists. But the Received: lines in this example and > the last couple don't show that the message has gone anywhere outside > postgresql.org. So I'm thinking it's a recently-introduced glitch in > the mail list server arrangements. Hi! Stefan and Alvaro were looking into this earlier, and it looks like a weird networking issue that we've had for a couple of days into one of our hosting boxes. Exactly what it's coming from is unknown at this point, but it seems to soimetimes cause a connection drop - which yet more sometimes happens in a position where the sending box never gets the acknowledgement that tht email was sent - and thus retries. Hopefully the ycan add some more details to the discussion, but I wanted to throw out a quick "yeah, confirmed, we've seen something is afoot" message. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-www mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-www ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Bogus duplicate-message complaints from PG mail lists @ 2013-01-15 20:56 Stefan Kaltenbrunner <[email protected]> parent: Tom Lane <[email protected]> 1 sibling, 0 replies; 3+ messages in thread From: Stefan Kaltenbrunner @ 2013-01-15 20:56 UTC (permalink / raw) To: Tom Lane <[email protected]>; +Cc: pgsql-www On 01/15/2013 09:45 PM, Tom Lane wrote: > Several times over the past couple of days, I have gotten complaints > like the one attached about duplicate message IDs. I can see from my > sendmail daemon's log that I sent only one copy of this, and the > complaint is dated about twenty minutes after the fact, so I'm pretty > sure the duplicate is not of my making. > > Usually when I get this type of thing I can tell from the Received: > lines that it's the fault of some list subscriber's MUA re-submitting > a message to the lists. But the Received: lines in this example and > the last couple don't show that the message has gone anywhere outside > postgresql.org. So I'm thinking it's a recently-introduced glitch in > the mail list server arrangements. those are caused by a network issue between one of the .eu server locations and the .eu location the listserver itself is in. The problem is that TCP sessions will get cut off in-transmission and both ends of the communication end up seeing different states of the session. In the particular cases of the "mail duplication" it is basically the sender (makus.postgresql.org - inbound MX) getting a TCP-session timeout after the the end of DATA in the SMTP session and the receiving side(malur.postgresql.org - the listserver) actually got the full mail AND acknowledged it but the sender never got the reply back. The sender (having no ack from the receiver) retries, generating a dup... We are working on fully diagnosing what is causing this (other parts of the infrastructure are impacted as well just not as visible) but the intermediate nature and the complexity(and number) of networks involved are not helping. Stefan -- Sent via pgsql-www mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-www ^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2013-01-15 20:56 UTC | newest] Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2013-01-15 20:45 Bogus duplicate-message complaints from PG mail lists Tom Lane <[email protected]> 2013-01-15 20:48 ` Magnus Hagander <[email protected]> 2013-01-15 20:56 ` Stefan Kaltenbrunner <[email protected]>
This inbox is served by agora; see mirroring instructions for how to clone and mirror all data and code used for this inbox