Determining if you are using a forest of trees index

You can determine whether an index is a forest of trees index by viewing SET EXPLAIN output. A forest of trees index has FOT in the Index Name field of the output.

In the following example of partial SET EXPLAIN output, informix.fot_idx is the name of a forest of trees index.

Estimated Cost: 1
Estimated # of Rows Returned: 1

  1) informix.t: INDEX PATH

    (1) Index Name: informix.fot_idx (FOT)
        Index Keys: c1 c2   (Serial, fragments: ALL)
        Lower Index Filter: informix.t.c1 = 1