The confancestors table should have an index for lookups by ancestorid

Problem

Currently queries like:

select DESCENDENTID from CONFANCESTORS where ANCESTORID = 589828;

require a full table scan, because no index exists on the ancestorid column. On instances with a large number of confancestor entries, this can make various actions such as editing pages very slow.

Workaround

Performance can be improved by doing the following:

1. Rebuild the ancestor table
2. Run VACUUM CONFANCESTORS; (or equivalent command if not using PostgreSQL)
3. Create the index on the ancestorid column by using the following query (for PostgreSQL, should be similar for other databases):

   CREATE INDEX confanc_ancestors ON CONFANCESTORS USING btree(ANCESTORID);