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Re: Problems with long checkpoints

Posted in 2011

Art Kagel — — source: Usenet: comp.databases.informix

Here's the cause, in your onstat header during the checkpoint: IBM Informix Dynamic Server Version 11.50.FC6 -- On-Line (CKPT INP) -- Up 02:48:10 -- 6638456 Kbytes Blocked:DBS_DROP The checkpoint is blocked while a dbspace is being dropped. Probably very slow IO response. You should not be using NFS mounted volumes for chunks. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Tue, Sep 27, 2011 at 4:15 PM, Sean Baker <SBaker@moneymailer.com> wrote: > > -----Original Message----- > > From: informix-list-bounces@iiug.org [mailto:informix-list- > > bounces@iiug.org] On Behalf Of jrenaut > > Sent: Tuesday, September 27, 2011 1:06 PM > > To: informix-list@iiug.org > > Subject: Re: Problems with long checkpoints > > > > On Sep 27, 2:48 pm, Sean Baker <SBa...@moneymailer.com> wrote: > > > > -----Original Message----- > > > > From: informix-list-boun...@iiug.org [mailto:informix-list- > > > > boun...@iiug.org] On Behalf Of jrenaut > > > > Sent: Tuesday, September 27, 2011 12:41 PM > > > > To: informix-l...@iiug.org > > > > Subject: Re: Problems with long checkpoints > > > > > > > On Sep 27, 2:05 pm, Sean Baker <SBa...@moneymailer.com> wrote: > > > > > Hello, > > > > > > > > We're stuck without a dba after some massive layoffs. I know a > > > > little, but I'm no dba. > > > > > > > > IDS 11.50.FC6 on RHEL 5.3 > > > > > > > > We have a development instance that is suddenly going into long > > > > checkpoints (43 minutes, 61 minutes, 90 minutes!). We've rebooted > > the > > > > server and restarted the instance, and even did a restore from our > > > > production server to the dev server. It lasts for a while (maybe > > 30 > > > > minutes) then goes into long checkpoints. > > > > > > > > One of our developers has been creating new dbspaces, and it > > seems > > > > that might be the cause. Although he's added a few over the past > > > > several months without any problems. After the restore today, he > > added > > > > a dbspace, and we're stuck in long checkpoints again: > > > > > > > > IBM Informix Dynamic Server Version 11.50.FC6 -- On-Line > > (CKPT > > > > INP) -- Up 01:39:05 -- 6638456 Kbytes> > > > > > > > I've listed the last few log entries from today below. Can > > anyone > > > > give me some obvious things to check? Or some better data to > > provide > > > > to the list for some help? > > > > > > > > Thanks, > > > > > > > > Sean > > > > > > > > Log: > > > > > > > > 11:31:41 Checkpoint Completed: duration was 0 seconds. > > > > > 11:31:41 Tue Sep 27 - loguniq 15415, logpos 0x33f1018, > > timestamp:> > > > 0x4f4c8892 Interval: 209340 > > > > > > > > 11:31:41 Maximum server connections 12 > > > > > 11:31:41 Checkpoint Statistics - Avg. Txn Block Time 0.000, #> > Txns > > > > blocked 0, Plog used 0, Llog used 2 > > > > > > > > 11:35:02 Space 'sm_dbs0' added. > > > > > 11:35:02 Checkpoint Completed: duration was 0 seconds. > > > > > 11:35:02 Tue Sep 27 - loguniq 15415, logpos 0x33fb2e4, > > timestamp:> > > > 0x4f4c8a3d Interval: 209341 > > > > > > > > 11:35:02 Maximum server connections 12 > > > > > 11:35:02 Checkpoint Statistics - Avg. Txn Block Time 0.000, #> > Txns > > > > blocked 0, Plog used 16, Llog used 10 > > > > > > > > 11:35:13 Checkpoint Completed: duration was 0 seconds. > > > > > 11:35:13 Tue Sep 27 - loguniq 15415, logpos 0x33fe018, > > timestamp:> > > > 0x4f4c8b0c Interval: 209342 > > > > > > > > 11:35:13 Maximum server connections 12 > > > > > 11:35:13 Checkpoint Statistics - Avg. Txn Block Time 0.000, #> > Txns > > > > blocked 0, Plog used 0, Llog used 3 > > > > > > > > 11:40:40 Checkpoint Completed: duration was 1 seconds. > > > > > 11:40:40 Tue Sep 27 - loguniq 15415, logpos 0x3867018, > > timestamp:> > > > 0x4f4cdac8 Interval: 209343 > > > > > > > > 11:40:40 Maximum server connections 12 > > > > > 11:40:40 Checkpoint Statistics - Avg. Txn Block Time 0.000, #> > Txns > > > > blocked 0, Plog used 134, Llog used 1129 > > > > > > > > 11:44:58 Adjusting LRU for bufferpool - id 0 size 2k > > > > > 11:44:58 Old max 60.0 min 50.0 New max 59.4 min 49.5 > > > > > 11:46:07 Adjusting LRU for bufferpool - id 0 size 2k > > > > > 11:46:07 Old max 59.4 min 49.5 New max 58.8 min 49.0> > > > > > > Well, we can't really get much from what you've posted as the > > > > checkpoint duration's listed in that snipped of MSGPATH file are 0 > > > > seconds. How about you post onstat -g ckp output after a long > > > > checkpoint happens? Perhaps that will be more helpful. > > > > > > Will do. Although we're going on an hour since the last > > checkpoint... > > > > Well, if it's happening right now, how about you post and onstat -g > > ath and then find the thread id for the main_loop() thread and post an > > onstat -g stk <thread id of main_loop() thread> to see what main_loop> > is doing, or what it might be waiting for. > > > > Jacques Renaut > > IBM Informix Advanced Support > > APD Team > > The developer tried dropping the dbspace he created, so now we're blocked > with "DBS_DROP". Here's the onstat -g ath for the main_loop(): > > IBM Informix Dynamic Server Version 11.50.FC6 -- On-Line (CKPT INP) -- > Up 02:48:10 -- 6638456 Kbytes > Blocked:DBS_DROP > > Threads:> tid tcb rstcb prty status > vp-class name > 18 15f37a548 15e56f028 3 sleeping secs: 1 > 5cpu main_loop() > > And here's onstat -g stk 18: > > IBM Informix Dynamic Server Version 11.50.FC6 -- On-Line (CKPT INP) -- > Up 02:49:56 -- 6638456 Kbytes > Blocked:DBS_DROP> > Stack for thread: 18 main_loop() > base: 0x000000015f3c6000 > len: 69632 > pc: 0x0000000001073d0e > tos: 0x000000015f3d5a40> state: sleeping > vp: 4 > > 0x0000000001073d0e (/opt/IBM/informix/bin/oninit) yield_processor_mvp > 0x000000000107556b (/opt/IBM/informix/bin/oninit) mt_yield > 0x0000000000bb951a (/opt/IBM/informix/bin/oninit) dskflush_bfpool > 0x0000000000bb98c2 (/opt/IBM/informix/bin/oninit) dskflush > 0x0000000000b56165 (/opt/IBM/informix/bin/oninit) checkpoint > 0x00000000005336e9 (/opt/IBM/informix/bin/oninit) main_loop > 0x000000000108560f (/opt/IBM/informix/bin/oninit) startup > > Thanks, > > Sean. > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list >

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