Based on discussion with Jan, I have a patch for this...

- It comes in as a stored function: addPartialLogIndices()
- If it knows that one of the tables is unused (as happens, for
instance, after the log switch does a TRUNCATE), then it'll add a
partial index for each known origin, and drop any partial indices for
"ex-origins."
- It is invoked in several places:
 - After the TRUNCATE in log switching
 - After MOVE SET, CREATE SET, DROP SET, FAILOVER

That should resolve the XXID index concerns...