On 04/02/2008 09:56 AM, Keulen, M. van (Maurice) wrote with possible deletions:
Hi Jan,
This one is likely to speed up my use of MXQ a lot! Does "references" also mean that a lot less elements will be constructed? One of the scalability bottlenecks that I frequently encounter in my experiments is not that it is slow, but that I create more than 2^32 elements (which doesn't fit in a bat with 32-bit oids). Avoiding subtree copies would probably improve the scalability of my experiments enormously. I must definitely push the move to the algebra backend :-)
Hi Maurice, you are completely correct :) As long as you do *not* query the constructed nodes but use them only for serialization the subtree copying will produce at most twice as many nodes (reference+original) as you construct. Note that this checkin does not improve the performance if you query the constructed nodes using a downward axis (e.g., if you use the constructed nodes as an intermediate 'tuple' representation). Jan -- Jan Rittinger Database Systems Technische Universität München (Germany) http://www-db.in.tum.de/~rittinge/