Dear Steve,

  You are right, I saw these errors on the Slony master.  The master
was NOT quiesced for the Slony drop/recreate; data was rolling in.

  So does this mean 12,000 queries failed?  I don't see anything in
the database log like "query cancelled" or anything like that.

 Why does it say "cache lookup failed" as opposed to "insert failed"?
Cache lookup I can ignore (generally speaking, although it might be a
performance hit, lookup can still succeed, from the primary source, even
if it's not in the cache) but a failed query is more serious.

Best,
Aleksey