xiong duan created CALCITE-7053: ----------------------------------- Summary: In HepPlanner, move down the collectGarbage to topological order for better optimizer performance Key: CALCITE-7053 URL: https://issues.apache.org/jira/browse/CALCITE-7053 Project: Calcite Issue Type: Bug Reporter: xiong duan
According to the java comment in HepPlanner#getGraphIterator: {code:java} // Make sure there's no garbage, because topological sort // doesn't start from a specific root, and rules can't // deal with firing on garbage. // FIXME jvs 25-Sept-2006: I had to move this earlier because // of FRG-215, which is still under investigation. Once we // figure that one out, move down to location below for // better optimizer performance. {code} Based on the current implementation, I haven't found the reason why the depth-first order requires garbage collection every time. Since it always starts the search from a specific Vertex, the issue mentioned the FRG-215 - I haven't found any description or information about this problem. Therefore, this PR attempts to delegate the collectGarbage operation to the topological order. -- This message was sent by Atlassian Jira (v8.20.10#820010)