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Stamatis Zampetakis commented on CALCITE-2701: ---------------------------------------------- The main goal is to re-use instances and avoid memory-leaks due to the DataContext (and information stored in it). Of course, thread-safety is another important and desired benefit of immutability. > Ensure that the "Baz" classes generated by Janino are thread-safe > ----------------------------------------------------------------- > > Key: CALCITE-2701 > URL: https://issues.apache.org/jira/browse/CALCITE-2701 > Project: Calcite > Issue Type: Improvement > Components: core > Affects Versions: 1.17.0 > Reporter: Stamatis Zampetakis > Assignee: Julian Hyde > Priority: Major > Labels: pull-request-available > Fix For: 1.18.0 > > > Currently the Baz classes that are used to execute queries in the > EnumerableConvention are stateful since the code generated by > EnumerableRelImplementor#implementRoot method creates an instance variable > (i.e., DataContext root). Every call to the bind method changes the value of > the root variable making the object mutable. > I propose to remove the instance variable and in the body of the method use > the DataContext passed as a parameter. > It appears that the addition of the instance variable was a workaround for a > bug in Janino (JANINO-169). It seems that the bug is no longer present at the > current version of Janino used in Calcite (3.0.9) since the test > JdbcTest#testJanino169 (and the complete suite) pass successfully with the > proposed modification. > Unfortunately, I couldn't verify the fix in the release notes of Janino > neither in the commit history. The best, I could find is the following > commits in the Janino repository: > {code:none} > commit fe5edc1904278c1c189f3379e06417aaf4a26315 > Author: aunkrig <aunkrig@eb4544d6-894b-0410-9319-a9612837a279> > Date: Wed Jan 22 21:19:48 2014 +0000 > Partly fixed JANINO-169 - now you get "Compiler limitation: Initializers > cannot access local variables declared in an enclosing block". > commit 4d2bacf16229ac1278eafa0fb4d5a0377134d3f2 > Author: aunkrig <aunkrig@eb4544d6-894b-0410-9319-a9612837a279> > Date: Wed Jan 22 15:03:17 2014 +0000 > Added test case for JANINO-169. > {code} > > -- This message was sent by Atlassian JIRA (v7.6.3#76005)