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https://issues.apache.org/jira/browse/TRAFODION-2478?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15864669#comment-15864669
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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_r100925922
--- 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 --
I am not sure. This should never happen and hence I am thinking it should
be ok to leave it as assert
> 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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