On 13.9.12 16:42, Thomas Mueller wrote:
Hi,
To read a node, the query engine currently uses:
session.getCurrentRoot().getTree(path);
The query engine calls this whenever it has to evaluate a property. It
turns out internally the getCurrentRoot() method always calls
MicroKernel.getHeadRevision(). I wonder if this is required, and if yes,
why? The javadoc for this method is:
/**
* The current root as seen by this content session. Use
* {@link Root#commit(ConflictHandler)} to atomically apply the
changes made in that
* subtree the underlying Microkernel.
*
* @return the current root
*/
Should I cache the Root instance in the query engine for the duration of a
query? Or would it be possible to change the Root implementation so this
is not needed?
The root instance gives you a stable view of the tree at the time you
acquired the root. That's why acquiring a new root does a round trip to
the Microkernel. However evaluating a query I think its not only better
but also the correct thing to acquire the root once for the whole query
evaluation.
Michael
Regards,
Thomas
