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class B segments

Posted in 2014

Summary

User asked what "class B" segments mean in Informix 12.10 onstat output. Multiple experts confirmed that B represents dynamic buffer pool segments—in v12.10, buffer pools were moved to their own shared memory segments. With multiple buffer pool page sizes, each gets its own B segment. User's follow-up question about why B segments showed high allocation on fresh boot went unanswered in the thread.

Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.

Topics: Server Administration, Platform-Specific Issues, Versions, Editions & End-of-Life

BillHatVerizon — — source: IIUG Forums & Mailing Lists

I have a question on the below “onstat –g seg” output. What does the class B represent? I never saw the B class until I went to TC2. IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 --740672 Kbytes Segment Summary: id key addr size ovhd class blkused blkfree 1381386241 52564801 c000000 4980736 255904 R* 1213 3 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 1381386243 52564803 23280000 171180032 1 B* 41792 0 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 Total: - - 758448128 - - 96031 89137 (* segment locked in memory) No reserve memory is allocated This is on 64bit Windows server 2008R2 sp1. My onconfig has this: RESIDENT 1 SHMBASE 0xc000000L SHMVIRTSIZE 374528 SHMADD 8192 EXTSHMADD 8192 SHMTOTAL 2097152 SHMVIRT_ALLOCSEG 0,3 BUFFERPOOL default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 BUFFERPOOL size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 BUFFERPOOL size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 The Working Set in task manager shows only 401mb for oninit.

↪ replying to BillHatVerizon
John Miller iii — — source: IIUG Forums & Mailing Lists

Each bufferpool can have one or more segments now. B indicates a bufferpool segment. John F. Miller III STSM, Lead Architect miller3@us.ibm.com 503-747-1366 IBM Informix Dynamic Server (IDS) ids-bounces@iiug.org wrote on 02/05/2014 08:19:03 AM: > From: "BillHatVerizon" <garage_dba@verizon.net> > To: ids@iiug.org, > Date: 02/05/2014 08:19 AM > Subject: class B segments [32408] > Sent by: ids-bounces@iiug.org > > I have a question on the below “onstat –g seg” output. What does the > class B represent? > I never saw the B class until I went to TC2. > > IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 --> 740672 Kbytes > > Segment Summary: > id key addr size ovhd class blkused blkfree > 1381386241 52564801 c000000 4980736 255904 R* 1213 3 > 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 > 1381386243 52564803 23280000 171180032 1 B* 41792 0 > 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 > Total: - - 758448128 - - 96031 89137 > > (* segment locked in memory) > No reserve memory is allocated > > This is on 64bit Windows server 2008R2 sp1. > My onconfig has this: > RESIDENT 1 > SHMBASE 0xc000000L > SHMVIRTSIZE 374528 > SHMADD 8192 > EXTSHMADD 8192 > SHMTOTAL 2097152 > SHMVIRT_ALLOCSEG 0,3 > > BUFFERPOOL > default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 > BUFFERPOOL > size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 > BUFFERPOOL > size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00> > The Working Set in task manager shows only 401mb for oninit. > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. >

↪ replying to BillHatVerizon
Art Kagel — — source: IIUG Forums & Mailing Lists

B is a dynamic buffer segment. V12 can expand the buffer pools on the fly if needed. Art Art S. Kagel Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on the IIUG or any other organization with which I sm associated either explicitely or implicitely not on individuals affiliated with those organizations. On Feb 5, 2014 11:19 AM, "BillHatVerizon" <garage_dba@verizon.net> wrote: > I have a question on the below "onstat -g seg" output. What does the > class B represent? > I never saw the B class until I went to TC2. > > IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 > --> 740672 Kbytes > > Segment Summary: > id key addr size ovhd class blkused blkfree > 1381386241 52564801 c000000 4980736 255904 R* 1213 3 > 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 > 1381386243 52564803 23280000 171180032 1 B* 41792 0 > 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 > Total: - - 758448128 - - 96031 89137 > > (* segment locked in memory) > No reserve memory is allocated > > This is on 64bit Windows server 2008R2 sp1. > My onconfig has this: > RESIDENT 1 > SHMBASE 0xc000000L > SHMVIRTSIZE 374528 > SHMADD 8192 > EXTSHMADD 8192 > SHMTOTAL 2097152 > SHMVIRT_ALLOCSEG 0,3 > > BUFFERPOOL > default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 > BUFFERPOOL > size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 > BUFFERPOOL > size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00> > The Working Set in task manager shows only 401mb for oninit. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --089e0158b832d1235004f1abc157

↪ replying to BillHatVerizon
JACQUES RENAUT — — source: IIUG Forums & Mailing Lists

original post: I have a question on the below “onstat –g seg” output. What does the class B represent? I never saw the B class until I went to TC2. IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 --740672 Kbytes Segment Summary: id key addr size ovhd class blkused blkfree 1381386241 52564801 c000000 4980736 255904 R* 1213 3 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 1381386243 52564803 23280000 171180032 1 B* 41792 0 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 Total: - - 758448128 - - 96031 89137 (* segment locked in memory) No reserve memory is allocated This is on 64bit Windows server 2008R2 sp1. My onconfig has this: RESIDENT 1 SHMBASE 0xc000000L SHMVIRTSIZE 374528 SHMADD 8192 EXTSHMADD 8192 SHMTOTAL 2097152 SHMVIRT_ALLOCSEG 0,3 BUFFERPOOL default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 BUFFERPOOL size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 BUFFERPOOL size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 The Working Set in task manager shows only 401mb for oninit. response: In 12.10.xC2 the buffer pools for the server were moved to their own shared memory segments, which as reported by onstat -g seg would be of type 'B'. Since you have two different buffer pool page sizes, you have 2 different segments of type 'B' (1 for each page size). Jacques Renaut IBM Informix Advanced Support APD Team

↪ replying to Art Kagel
BillHatVerizon — — source: IIUG Forums & Mailing Lists

My problem is that it was a fresh boot. Nobody is running anything on this box at this time There is still a ton of allocated memory to class B. Why would this happen? IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 03:42:44 --740672 Kbytes Segment Summary: id key addr size ovhd class blkused blkfree 1381386241 52564801 c000000 4980736 255904 R* 1213 3 1381386242 52564802 c4c0000 383516672 2248360 V 4281 89351 1381386243 52564803 23280000 171180032 1 B* 41792 0 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 Total: - - 758448128 - - 95814 89354 (* segment locked in memory) No reserve memory is allocated -----Original Message----- From: Art Kagel Sent: Wednesday, February 05, 2014 11:05 AM To: ids@iiug.org Subject: Re: class B segments [32410] B is a dynamic buffer segment. V12 can expand the buffer pools on the fly if needed. Art Art S. Kagel Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on the IIUG or any other organization with which I sm associated either explicitely or implicitely not on individuals affiliated with those organizations. On Feb 5, 2014 11:19 AM, "BillHatVerizon" <garage_dba@verizon.net> wrote: > I have a question on the below "onstat -g seg" output. What does the > class B represent? > I never saw the B class until I went to TC2. > > IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 > --> 740672 Kbytes > > Segment Summary: > id key addr size ovhd class blkused blkfree > 1381386241 52564801 c000000 4980736 255904 R* 1213 3 > 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 > 1381386243 52564803 23280000 171180032 1 B* 41792 0 > 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 > Total: - - 758448128 - - 96031 89137 > > (* segment locked in memory) > No reserve memory is allocated > > This is on 64bit Windows server 2008R2 sp1. > My onconfig has this: > RESIDENT 1 > SHMBASE 0xc000000L > SHMVIRTSIZE 374528 > SHMADD 8192 > EXTSHMADD 8192 > SHMTOTAL 2097152 > SHMVIRT_ALLOCSEG 0,3 > > BUFFERPOOL > default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 > BUFFERPOOL > size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 > BUFFERPOOL > size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00> > The Working Set in task manager shows only 401mb for oninit. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --089e0158b832d1235004f1abc157 ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.

↪ replying to John Miller iii
BillHatVerizon — — source: IIUG Forums & Mailing Lists

No Arabic spoken here. -----Original Message----- From: John Miller iii Sent: Wednesday, February 05, 2014 10:28 AM To: ids@iiug.org Subject: Re: class B segments [32409] Each bufferpool can have one or more segments now. B indicates a bufferpool segment. John F. Miller III STSM, Lead Architect miller3@us.ibm.com 503-747-1366 IBM Informix Dynamic Server (IDS) ids-bounces@iiug.org wrote on 02/05/2014 08:19:03 AM: > From: "BillHatVerizon" <garage_dba@verizon.net> > To: ids@iiug.org, > Date: 02/05/2014 08:19 AM > Subject: class B segments [32408] > Sent by: ids-bounces@iiug.org > > I have a question on the below “onstat –g seg” output. What does the > class B represent? > I never saw the B class until I went to TC2. > > IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 --> 740672 Kbytes > > Segment Summary: > id key addr size ovhd class blkused blkfree > 1381386241 52564801 c000000 4980736 255904 R* 1213 3 > 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 > 1381386243 52564803 23280000 171180032 1 B* 41792 0 > 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 > Total: - - 758448128 - - 96031 89137 > > (* segment locked in memory) > No reserve memory is allocated > > This is on 64bit Windows server 2008R2 sp1. > My onconfig has this: > RESIDENT 1 > SHMBASE 0xc000000L > SHMVIRTSIZE 374528 > SHMADD 8192 > EXTSHMADD 8192 > SHMTOTAL 2097152 > SHMVIRT_ALLOCSEG 0,3 > > BUFFERPOOL > default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 > BUFFERPOOL > size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 > BUFFERPOOL > size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00> > The Working Set in task manager shows only 401mb for oninit. > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.

↪ replying to JACQUES RENAUT
BillHatVerizon — — source: IIUG Forums & Mailing Lists

Thanks! Makes more sense now. -----Original Message----- From: JACQUES RENAUT Sent: Wednesday, February 05, 2014 2:29 PM To: ids@iiug.org Subject: Re: class B segments [32411] original post: I have a question on the below âonstat âg seg❠output. What does the class B represent? I never saw the B class until I went to TC2. IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 --740672 Kbytes Segment Summary: id key addr size ovhd class blkused blkfree 1381386241 52564801 c000000 4980736 255904 R* 1213 3 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 1381386243 52564803 23280000 171180032 1 B* 41792 0 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 Total: - - 758448128 - - 96031 89137 (* segment locked in memory) No reserve memory is allocated This is on 64bit Windows server 2008R2 sp1. My onconfig has this: RESIDENT 1 SHMBASE 0xc000000L SHMVIRTSIZE 374528 SHMADD 8192 EXTSHMADD 8192 SHMTOTAL 2097152 SHMVIRT_ALLOCSEG 0,3 BUFFERPOOL default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 BUFFERPOOL size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 BUFFERPOOL size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 The Working Set in task manager shows only 401mb for oninit. response: In 12.10.xC2 the buffer pools for the server were moved to their own shared memory segments, which as reported by onstat -g seg would be of type 'B'. Since you have two different buffer pool page sizes, you have 2 different segments of type 'B' (1 for each page size). Jacques Renaut IBM Informix Advanced Support APD Team ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.

↪ replying to Art Kagel
Fernando Nunes — — source: IIUG Forums & Mailing Lists

Not yet ;) On Wed, Feb 5, 2014 at 5:05 PM, Art Kagel <art.kagel@gmail.com> wrote: > B is a dynamic buffer segment. V12 can expand the buffer pools on the fly > if needed. > > Art > > Art S. Kagel > > Disclaimer: Please keep in mind that my own opinions are my own opinions > and do not reflect on the IIUG or any other organization with which I sm > associated either explicitely or implicitely not on individuals affiliated > with those organizations. > > On Feb 5, 2014 11:19 AM, "BillHatVerizon" <garage_dba@verizon.net> wrote: > > > I have a question on the below "onstat -g seg" output. What does the > > class B represent? > > I never saw the B class until I went to TC2. > > > > IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 > > --> > 740672 Kbytes > > > > Segment Summary: > > id key addr size ovhd class blkused blkfree > > 1381386241 52564801 c000000 4980736 255904 R* 1213 3 > > 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 > > 1381386243 52564803 23280000 171180032 1 B* 41792 0 > > 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 > > Total: - - 758448128 - - 96031 89137 > > > > (* segment locked in memory) > > No reserve memory is allocated > > > > This is on 64bit Windows server 2008R2 sp1. > > My onconfig has this: > > RESIDENT 1 > > SHMBASE 0xc000000L > > SHMVIRTSIZE 374528 > > SHMADD 8192 > > EXTSHMADD 8192 > > SHMTOTAL 2097152 > > SHMVIRT_ALLOCSEG 0,3 > > > > BUFFERPOOL > > default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 > > BUFFERPOOL > > size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 > > BUFFERPOOL > > size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00> > > > The Working Set in task manager shows only 401mb for oninit. > > > > > > > > > > ******************************************************************************* > > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > > > --089e0158b832d1235004f1abc157 > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > -- Fernando Nunes Portugal http://informix-technology.blogspot.com My email works... but I don't check it frequently... --bcaec548a15b3ed41d04f1bbcb4c

↪ replying to BillHatVerizon
Art Kagel — — source: IIUG Forums & Mailing Lists

Buffers are reallocated at startup. Art Art S. Kagel Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on the IIUG or any other organization with which I sm associated either explicitely or implicitely not on individuals affiliated with those organizations. On Feb 5, 2014 5:32 PM, "BillHatVerizon" <garage_dba@verizon.net> wrote: > My problem is that it was a fresh boot. > Nobody is running anything on this box at this time > There is still a ton of allocated memory to class B. > Why would this happen? > > IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 03:42:44 > --> 740672 Kbytes > Segment Summary: > id key addr size ovhd class blkused blkfree > 1381386241 52564801 c000000 4980736 255904 R* 1213 3 > 1381386242 52564802 c4c0000 383516672 2248360 V 4281 89351 > 1381386243 52564803 23280000 171180032 1 B* 41792 0 > 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 > Total: - - 758448128 - - 95814 89354 > > (* segment locked in memory) > No reserve memory is allocated > > -----Original Message----- > From: Art Kagel > Sent: Wednesday, February 05, 2014 11:05 AM > To: ids@iiug.org > Subject: Re: class B segments [32410] > > B is a dynamic buffer segment. V12 can expand the buffer pools on the fly > if needed. > > Art > > Art S. Kagel > > Disclaimer: Please keep in mind that my own opinions are my own opinions > and do not reflect on the IIUG or any other organization with which I sm > associated either explicitely or implicitely not on individuals affiliated > with those organizations. > > On Feb 5, 2014 11:19 AM, "BillHatVerizon" <garage_dba@verizon.net> wrote: > > > I have a question on the below "onstat -g seg" output. What does the > > class B represent? > > I never saw the B class until I went to TC2. > > > > IBM Informix Dynamic Server Version 12.10.TC2IE -- On-Line -- Up 01:46:25 > > --> > 740672 Kbytes > > > > Segment Summary: > > id key addr size ovhd class blkused blkfree > > 1381386241 52564801 c000000 4980736 255904 R* 1213 3 > > 1381386242 52564802 c4c0000 383516672 2248360 V 4498 89134 > > 1381386243 52564803 23280000 171180032 1 B* 41792 0 > > 1381386244 52564804 2d5c0000 198770688 1 B* 48528 0 > > Total: - - 758448128 - - 96031 89137 > > > > (* segment locked in memory) > > No reserve memory is allocated > > > > This is on 64bit Windows server 2008R2 sp1. > > My onconfig has this: > > RESIDENT 1 > > SHMBASE 0xc000000L > > SHMVIRTSIZE 374528 > > SHMADD 8192 > > EXTSHMADD 8192 > > SHMTOTAL 2097152 > > SHMVIRT_ALLOCSEG 0,3 > > > > BUFFERPOOL > > default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50 > > BUFFERPOOL > > size=4K,buffers=40000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00 > > BUFFERPOOL > > size=16K,buffers=12000,lrus=8,lru_min_dirty=20.00,lru_max_dirty=30.00> > > > The Working Set in task manager shows only 401mb for oninit. > > > > > > > > > > > ******************************************************************************* > > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > > > --089e0158b832d1235004f1abc157 > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --089e0149433240952604f1bddfd9

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