Thanks Rick, I already looked at the ResultSet.getResultDescription(), but obviously not enough.
Paul. > Hi Paul, > > Some comments inline... > > On 11/5/13 6:44 AM, Paul Davern wrote: >> Hello >> >> I am looking at “monitoring/tracing” the resultset execution tree to >> observe the tuples/records as they propagate up the tree - specifically >> the calls to getNextRowCore() in BulkTableScanResultSet, >> NestedLoopJoinResultSet, etc. For aggregations I am looking at using >> the >> SortObserver type interface. >> >> There does not appear to be much in the way of metadata available (at >> least I have not found it) in the execution tree? I am traversing the >> AST >> tree after bind/generate to pick up some of the metadata. This is easy >> enough when a column is directly associated with a base table, but, is >> getting hacky otherwise. Is there a better solution? Putting something >> in >> during the generate phase looks like a daunting task! > Not sure what metadata you are looking for. But the following may be > useful: The execution plan is a tree of > org.apache.derby.iapi.sql.ResultSet nodes. The row signature of each > node can be obtained by calling ResultSet.getResultDescription(). >> I realise I can use the toXML/childrenToXML interface to walk the >> execution tree, but there does not appear to be much in the way of >> metadata here. > Thanks for raising this issue. It would be good to be able to plug > custom xml-formatters into those methods. I have logged an enhancement > request for this: https://issues.apache.org/jira/browse/DERBY-6404 > > In the meantime, if I were tackling this problem, I would hack the > toXML/childrenToXML methods to grab the metadata you need. For an > example of how to invoke toXML(), see > org.apache.derbyTesting.functionTests.tests.lang.NewOptimizerOverridesTest.getLastQueryPlan(). > > Hope this helps, > -Rick >> I suppose what I am asking is, is there a direct link from the >> org.apache.derby.impl.sql.execute.ResultSet hierarchy back to the >> org.apache.derby.impl.sql.compile.ResultSetNode hierarchy? >> >> >> Thanks, >> Paul. >> >> > > >
