David Wayne Birdsall created TRAFODION-3326:
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Summary: Rewrite logsort utility
Key: TRAFODION-3326
URL: https://issues.apache.org/jira/browse/TRAFODION-3326
Project: Apache Trafodion
Issue Type: Improvement
Components: dev-environment
Affects Versions: 2.4
Reporter: David Wayne Birdsall
Assignee: David Wayne Birdsall
The logsort utility is used by the Trafodion development regression tests to
sort sqlci log output for SELECT statements that lack ORDER BY clauses. This is
done so that non-determinism in the order that rows are listed does not cause
false failures when comparing expected results with actual results.
This utility was written (by me as luck would have it) around 1990 or so in C.
It is object-oriented in design, and so could easily be rewritten using C++
classes. Too, it manually implements things such as linked lists that could be
replaced with C++ STL templates.
The most compelling reason to do a rewrite is that it uses the equivalent of a
bubble sort when sorting output. For most of our test results this is not an
issue; the number of rows listed in a typical test is usually in the tens or
less. But if there is a bug (either in the engine itself or in the testware),
we may get millions or rows or more. When this happens, logsort may run for
hours. So it would be good to replace the existing o(n^2) sort with a more
efficient one, perhaps using STL for this purpose.
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