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Problem IT37242
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Status: Closed |
WITH DBSPACES COMPRISED OF MANY CHUNKS, FREQUENT 'CHUNK DOWN' CHECKING CAN BE VERY EXPENSIVE
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| product: |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 |
| Problem description: |
On a secondary server system having multiple dbspaces with a
couple hundreds of chunks each, a significant log apply slowness
can be observed during heavy load on primary that, esp. with
HDR, can affect primary performance too.
Here's how this looks in 'onstat -g laq':
Log Apply Info:
Thread Queue Total Avg
Size Queued Depth
wreplay_1 0 189676 1.35
wreplay_2 0 153139 1.34
wreplay_3 0 260041 1.48
wreplay_4 0 161107 1.32
wreplay_5 0 164985 1.33
wreplay_6 0 115743 1.17
wreplay_7 0 246979 0.42
wreplay_8 0 172274 1.36
wreplay_9 0 125461 1.29
wreplay_10 0 116958 1.20
wreplay_11 0 211963 1.64
Secondary Apply Queue: Total Buffers:48 Size:2048K Free
Buffers:0
Log Recovery Queue: Total Buffers:48 Size:20480K Free
Buffers:0
Log Page Queue: Total Buffers:1024 Size:2K Free
Buffers:0
Log Record Queue: Total Buffers:1000 Size:16K Free
Buffers:981
So worker threads' queues empty or nearly empty most of the time
while Secondary Apply Queue, Log Recovery Queue and Log Page
Queue completely full, yet Log Record Queue again hardly used,
indicating a bottleneck at extracting log records from log pages
which is the bld_logrecs thread's business.
Looking at bld_logrecs thread under such conditions, that thread
would appear 'running' most of the time. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Users of Informix Server prior to 12.10.xC15 and 14.10.xC7. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Informix Server 12.10.xC15 or 14.10.xC7 (when *
* available). *
**************************************************************** |
| Local Fix: |
|
| Solution |
|
| Workaround |
****************************************************************
* USERS AFFECTED: *
* Users of Informix Server prior to 12.10.xC15 and 14.10.xC7. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Informix Server 12.10.xC15 or 14.10.xC7 (when *
* available). *
**************************************************************** |
| Comment |
Fixed in Informix Server 12.10.xC15 and 14.10.xC7. |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 14.06.2021
31.08.2021
31.08.2021 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
