|
Problem IC84529
|
Status: Closed |
A prefetch request at a high offset into a large tablespace may lead to a hang situation. |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
Under certain conditions tablespace I/O will be done by db2
prefetcher edus.
When very large tablespaces exist and an I/O request is
submitted to a db2 prefetcher
that is at an offset higher than 2^31 x <the DB2 I/O size>,
then the request submitting edu may hang and the I/O request
never completes.
This can cause the application or eventually even the database
to hang.
A typical stack trace would show :
sqloCSemP
sqlbpfParallelDirectIO
sqlbpfParallelDirectRead
...
Note that this stacks trace is typical for any edu waiting for
an I/O to be done by the prefetchers,
but the stack should not remain the same indefinitely.
This problem is more likely to occur on LOB I/O, when the I/O
size is only 1k.
So any I/O request above 2^31 x 1k = 2TB could cause a hang in
this case. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade toV10 FP1 or disable the parallel IO *
**************************************************************** |
| Local Fix: |
Disable the parallel I/O for the tablespace where your object is
located.
For example, if the object is in tablespace 3 use the following
registery:
db2set DB2_PARALLEL_IO=3:1 |
| available fix packs: |
DB2 Version 10.1 Fix Pack 1 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 2 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
|
| Solution |
First fixed in V10 FP1 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 14.06.2012
21.11.2012
21.11.2012 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.1
|
 |
| 10.5.0.1
|
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