Github user dyozie commented on a diff in the pull request:
https://github.com/apache/incubator-hawq-docs/pull/69#discussion_r91634985
--- Diff: pxf/TroubleshootingPXF.html.md.erb ---
@@ -200,4 +200,107 @@ Examine/collect the log messages from `stdout`.
``` sql
gpadmin=# SET client_min_messages=NOTICE
-```
\ No newline at end of file
+```
+
+
+## <a id="pxf-memcfg"></a>Mitigating PXF Memory Issues
+
+The Java heap size can be a limiting factor in PXFâs ability to serve
many concurrent requests or to run queries against large tables.
+
+You may run into situations where a query will hang or fail with an Out of
Memory exception (OOM). This typically occurs when many threads are reading
different data fragments from an external table and insufficient heap space
exists to open all fragments at the same time. To avert or remedy this
situation, Pivotal recommends either increasing the Java maximum heap size or
decreasing the Tomcat maximum number of threads.
+
--- End diff --
There should be some mention of why to modify one vs the other. Is it
simply a question of, if you have enough memory you should increase heap size,
and only reduce threads if you're out of memory?
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