ghalliday/HPCC-Platform — comment on commit 3dff10978d860f9d25587f7f772394f6641e1f7b
File: ecl/hql/hqlmeta.cpp line 653
By ghalliday:

Yes there is. However it will cause a LINK() on each child, and this is called sufficiently often for the time to be significant.

(The meta information is calculated whenever a dataset node is created - which includes whenever a new one is created when a tree is transformed.)