|
Problem IT08621
|
Status: Closed |
READAHEAD THREAD CAN RUN CONTINOUSLY BLOCKING A CPU VP HEREBY AND RESULTING IN HANG OF THE INSTANCE |
| product: |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 |
| Problem description: |
This has been observed during a migration from 11.70 to 12.10
with an instance that has about 3700 compressed tables.
During the migration to 12.10 an attached index on the
compression dictionary partition is created.
The instance message log is showing:
14:34:48 *** FromVersion=18 ToVersion=25 entity_ver=26
targetVersion=28 indexVersion=5 ***
14:34:48 *** FromVersion=25 ToVersion=26 entity_ver=26
targetVersion=28 indexVersion=6 ***
14:34:48 *** FromVersion=26 ToVersion=27 entity_ver=26
targetVersion=28 indexVersion=7 ***
14:34:48 *** RSAM 1 12.10.xC1 ***
The convert thread is in the state ready while the readahead
thread is continuously running on the CPU VP. There is only one
CPU VP configured.
The stack of the convert thread is showing:
...
kyadd
rsaddindex
rsam_1210_convert
do_each_version_work
generic_fw_main
convertSM
th_init_initgls
startup
So you are seeing in an onstat -g ath:
19 45b765f0 0 3 ready
1cpu* kaio
24 45e19028 44c2a928 3 running
1cpu readahead_0
21 45c5d808 44c28ee8 3 IO Wait
1cpu convert
and onstat -g glo shows that the CPU time used is increasing for
CPU VP 1. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* users migrating to 12.10 on a single CPU system with a *
* significant number of compressed tables *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Update to IBM Informix Server 12.10.xC6 *
**************************************************************** |
| Local Fix: |
As a temporary relief you can attempt the migration again.
- Stop current instance "kill -9 on PID of CPU VP 1".
- Use onrestorept to revert to previous instance state before
the migration or use a backup.
- Change onconfig parameter AUTO_READAHEAD to 0 and VPCLASS to
use more than one CPU VP.
- Disable KAIO (on Linux for example set environment variable
KAIOOFF before instance startup).
- Start migration again with oninit -v. |
| Solution |
Problem Fixed In IBM Informix Server 12.10.xC6 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 29.04.2015
30.12.2015
30.12.2015 |
| Problem solved at the following versions (IBM BugInfos) |
12.10.xC6
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 12.10.xC6
|
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