GitHub user zellerh opened a pull request:
https://github.com/apache/incubator-trafodion/pull/944
Improve concurrency of drop constraint, log memory pressure
Two minor changes found as result of some experiments:
Add a cardinality hint to a join query used during drop constraint.
This should cause us to use a nested join, reducing the chances of
a write conflict during commit processing.
Also added debugging support for memory pressure, setting an environment
variable allows to log the parameters to a file. It's best to use
this with a single sqlci tool, like this:
export SQL_MEMMONITOR_LOGFILE=mylogfile
sqlci
Sample output:
Fri Feb 3 01:33:42 2017: pctFree=0.274771, pageFaultRate=24.115740,
(free*normpagefault*commitratio) = (-0.099085 * 0.246121 * 0.535585), pressure=0
Fri Feb 3 01:33:48 2017: pctFree=0.274772, pageFaultRate=25.187914,
(free*normpagefault*commitratio) = (-0.099086 * 0.257064 * 0.535585), pressure=0
Fri Feb 3 01:33:54 2017: pctFree=0.274771, pageFaultRate=25.458275,
(free*normpagefault*commitratio) = (-0.099085 * 0.259823 * 0.535587), pressure=0
Fri Feb 3 01:34:00 2017: pctFree=0.274785, pageFaultRate=20.749832,
(free*normpagefault*commitratio) = (-0.099139 * 0.211769 * 0.535575), pressure=0
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/zellerh/incubator-trafodion bug/cses_jan-17
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-trafodion/pull/944.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #944
----
commit 01fcd3cc8b1eee5cb2fc608fc30475e943a3dc60
Author: Hans Zeller <[email protected]>
Date: 2017-02-03T01:39:29Z
Improve concurrency of drop constraint, log memory pressure
Two minor changes found as result of some experiments:
Add a cardinality hint to a join query used during drop constraint.
This should cause us to use a nested join, reducing the chances of
a write conflict during commit processing.
Also added debugging support for memory pressure, setting an environment
variable allows to log the parameters to a file. It's best to use
this with a single sqlci tool, like this:
export SQL_MEMMONITOR_LOGFILE=mylogfile
sqlci
Sample output:
Fri Feb 3 01:33:42 2017: pctFree=0.274771, pageFaultRate=24.115740,
(free*normpagefault*commitratio) = (-0.099085 * 0.246121 * 0.535585), pressure=0
Fri Feb 3 01:33:48 2017: pctFree=0.274772, pageFaultRate=25.187914,
(free*normpagefault*commitratio) = (-0.099086 * 0.257064 * 0.535585), pressure=0
Fri Feb 3 01:33:54 2017: pctFree=0.274771, pageFaultRate=25.458275,
(free*normpagefault*commitratio) = (-0.099085 * 0.259823 * 0.535587), pressure=0
Fri Feb 3 01:34:00 2017: pctFree=0.274785, pageFaultRate=20.749832,
(free*normpagefault*commitratio) = (-0.099139 * 0.211769 * 0.535575), pressure=0
----
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