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From Paul Davern <pdav...@4c.ucc.ie>
Subject Execution tree metadata
Date Tue, 05 Nov 2013 14:44:48 GMT

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!

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.

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?


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