Paul Rogers created DRILL-5070: ---------------------------------- Summary: Code cache compares sources, but method order varies Key: DRILL-5070 URL: https://issues.apache.org/jira/browse/DRILL-5070 Project: Apache Drill Issue Type: Bug Affects Versions: 1.8.0 Reporter: Paul Rogers Priority: Minor
The Drill generated code cache compares the sources from two different generation events to detect duplicate code. Unfortunately, the code generator emits methods in the order returned by {{Class.getDeclaredMethods}}, but this method makes no guarantee about the order of the methods. This issue appeared when attempting to modify tests to capture generated code for comparison to future results. Even a simple generated case from {{ExpressionTest.testBasicExpression()}} that generates {{if(true) then 1 else 0 end}} (all constants) produced methods in different orders on each test run. The fix is simple, in the {{SignatureHolder}} constructor, sort methods by name after retrieving them from the class. The sort ensures that method order is deterministic. Fortunately, the number of methods is small, so the sort step adds little cost. Without this fix, it is likely that the code cache holds many "copies" of the same code: equivalent code but with different method orders. After this fix, the cache should hold only one copy of each bit of equivalent code. -- This message was sent by Atlassian JIRA (v6.3.4#6332)