My primary goal was not to improve performance. After all, currently the classic ACS does not work at all for Postgres, so you have to change (among other things) all "connect by" queries to something else.
If all hierarchical searches were implemented with db_dfs, then they would at least work by default, and only those searches that turn out to be too slow would have to be changed.
To quantify the difference: According to a series of tests I have run, the simulation of "connect by" by recursion in the Tcl layer is 4-5 times slower than the original Oracle feature.
I don't know how slow the emulation is in PL/SQL. Has somebody benchmarked it?
