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https://issues.apache.org/jira/browse/TRAFODION-2478?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15864191#comment-15864191
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ASF GitHub Bot commented on TRAFODION-2478:
-------------------------------------------
Github user zellerh commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/953#discussion_r100865729
--- Diff: core/sql/cli/Globals.cpp ---
@@ -322,6 +310,18 @@ void CliGlobals::init( NABoolean espProcess,
capacities_.setHeap(defaultContext_->exCollHeap());
freespaces_.setHeap(defaultContext_->exCollHeap());
largestFragments_.setHeap(defaultContext_->exCollHeap());
+ if (statsGlobals_ != NULL)
+ memMonitor_ = statsGlobals_->getMemoryMonitor();
--- End diff --
Now that the memory monitor resides in another process, I think we need to
make any of its methods that shouldn't be called by the executor thread
private, like update() and updatePageFaultRate(). It would also be good to
update the comments in memorymonitor.h to indicate which calls are meant for
consumers and which ones are potentially in a separate thread.
> Reduce the number of memory monitoring threads in Trafodion SQL processes
> ---------------------------------------------------------------------------
>
> Key: TRAFODION-2478
> URL: https://issues.apache.org/jira/browse/TRAFODION-2478
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: sql-exe
> Affects Versions: any
> Reporter: Selvaganesan Govindarajan
> Assignee: Selvaganesan Govindarajan
>
> A memory monitor thread is created in every SQL process to handle the memory
> pressure in BMO (Big memory operators). This has following drawbacks:
> 1) No consistent view of the memory pressure in the node
> 2) Overhead of calculating the memory pressure in every trafodion SQL process.
> Proposal is to move this thread to RMS SSCP process. All SQL processes have
> access to RMS shared segment. Hence SQL processes can get the view of the
> memory pressure readily and easily from the shared segment.
> It is also possible to increase the frequency of the memory pressure
> calculation to get near real tiime picture of the memory pressure.
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