Github user robertamarton commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/766#discussion_r84122119
--- Diff: core/sql/optimizer/NATable.cpp ---
@@ -275,75 +282,28 @@ void HistogramCache::getHistograms(NATable& table)
// look up the cache and get a reference to statistics for this table
cachedHistograms = lookUp(table);
- // first thing to check is, if the table to which the histograms are
cached
- // has been updated
+ // (Possibly useless) sanity tests
+
+ // Check to see if the redefinition timestamp has changed. This seems
+ // to be always stubbed to zero today on Trafodion, so this check
+ // seems to never fail.
if (cachedHistograms && (cachedHistograms->getRedefTime() !=
redefTime))
{
deCache(&cachedHistograms);
}
--- End diff --
I actually changed DDL code to use the non-zero redeftime in descriptors as
part of my role invalidation change, but it caused some interesting regression
failures. So I removed the change before delivering the code; hopefully, I can
get back to it sometime.
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