What does "ERROR: failed to find parent tuple for heap-only tuple at (1192248,5) in table "fruits"" mean?
This error message is new in postgres and is indeed related to the replication bug fixed in 9.3.3

As mentioned in the git commit from Mon, 17 Mar 2014:


  The recently-fixed bug in WAL replay could result in not finding a
  parent tuple for a heap-only tuple. The existing code would either
  Assert or generate an invalid index entry, neither of which is
  desirable.  Throw a regular error instead.


Since the parent tuple is an internal notion of postgres, the implication would be that the data structure for this relation is in a corrupted state, beyond troubleshooting at the SQL level.

The safest way out of this mess would be, if at all possible, to pg_dump the affected databases, then drop and reload them, and then recreate the constraints on this clean state.