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Problem IT27616
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Status: Closed |
QUERIES PERFORMING INDEX SELF JOIN MAY NOT YIELD FREQUENTLY ENOUGH LEADING TO BLOCKED CHECKPOINT REQUESTS
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| product: |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 |
| Problem description: |
Certain types of SQL query that use an index self join on large
tables where the index pages are held in the buffer pool may not
yield frequently enough during their execution. This could
result in a blocked checkpoint request if another thread is in
critical section and waiting on the result of an I/O request and
that result needs to be processed by the kaio thread running on
the same CPU VP as the non-yielding query.
A stack of the running thread may be similar to:
btfind
btsearch
kposition
rsstart
fmstart
nextlkeyrg
startsubq
scan_next
getrow
fetchrow
exfetch
sql_nfetch
sq_nfetch
sqmain
As the thread is in a running state the top few functions may or
may not be present. The key indicator for this problem is the
function nextlkeyrg which may perform a loop operation. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Users of IDS prior to 12.10.xC13. *
****************************************************************
* PROBLEM DESCRIPTION: *
* Queries performing index self join may not yield frequently *
* enough leading to blocked checkpoint requests. *
****************************************************************
* RECOMMENDATION: *
**************************************************************** |
| Local Fix: |
|
| Solution |
|
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 27.12.2018
03.10.2019
03.10.2019 |
| Problem solved at the following versions (IBM BugInfos) |
12.10.xC13
|
| Problem solved according to the fixlist(s) of the following version(s) |
