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https://issues.apache.org/jira/browse/TRAFODION-2478?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15864261#comment-15864261
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ASF GitHub Bot commented on TRAFODION-2478:
-------------------------------------------

Github user selvaganesang commented on a diff in the pull request:

    https://github.com/apache/incubator-trafodion/pull/953#discussion_r100874924
  
    --- Diff: core/sql/cli/memorymonitor.cpp ---
    @@ -102,12 +102,18 @@ MemoryMonitor::MemoryMonitor(Lng32 windowSize,
     {
       // if the windowSize is 0, we do not need memory monitor.
       assert(windowSize);
    -  char buffer[1024];
    +  char buffer[2048];
       char *currPtr;
       size_t bytesRead;
       fd_meminfo_ = fopen("/proc/meminfo", "r");
       if (fd_meminfo_) {
    -    bytesRead = fread(buffer, 1, 1024, fd_meminfo_);
    +    bytesRead = fread(buffer, 1, 2048, fd_meminfo_);
    +    if (ferror(fd_meminfo_))
    +       assert(false); 
    --- End diff --
    
    And possibly 10 core dumps of mxsscp process because mxsscp process is 
retried 10 times before giving up


> 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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