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Problem IT40336
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Status: Closed |
PERFORMANCE PROBLEM FOR PDQ QUERY USING A SUBQUERY
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| product: |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 |
| Problem description: |
The fix for IT39149 "Select with PDQ and subquery can produce
wrong results" resolves a number of issues relating to queries
containing subqueries that run with PDQ enabled. However, this
fix also introduces a significant performance problem such that
the query running with PDQ may take longer than the same query
without it.
Observations of the stacks for the scan threads whilst the query
is running show that they spend much of the time waiting on the
"cb_anyall" mutex introduced with the fix for IT39149:
yield_processor_mvp
mt_lock_wait
mt_lock_helper
mt_lock
ev_anyall
new_eval
gettupl
scan_next
producer_thread
startup |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Users of Informix Server prior to 12.10.xC16 and 14.10.xC8. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Informix Server 12.10.xC16 or 14.10.xC8. *
**************************************************************** |
| Local Fix: |
|
| Solution |
|
| Workaround |
****************************************************************
* USERS AFFECTED: *
* Users of Informix Server prior to 12.10.xC16 and 14.10.xC8. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Informix Server 12.10.xC16 or 14.10.xC8. *
**************************************************************** |
| Comment |
Fixed in Informix Server 12.10.xC16 and 14.10.xC8. |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 19.03.2022
08.05.2023
08.05.2023 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
