Log Message:
Changes 8.1.5:
* Disallow aggregate functions in "UPDATE" commands, except within
  sub-SELECTs (Tom)
  The behavior of such an aggregate was unpredictable, and in 8.1.X
  could cause a crash, so it has been disabled. The SQL standard does
  not allow this either.
* Fix core dump when an untyped literal is taken as ANYARRAY
* Fix core dump in duration logging for extended query protocol when
  a "COMMIT" or "ROLLBACK" is executed
* Fix mishandling of AFTER triggers when query contains a SQL
  function returning multiple rows (Tom)
* Fix "ALTER TABLE ... TYPE" to recheck NOT NULL for USING clause
  (Tom)
* Fix string_to_array() to handle overlapping matches for the
  separator string
  For example, string_to_array('123xx456xxx789', 'xx').
* Fix to_timestamp() for AM/PM formats (Bruce)
* Fix autovacuum's calculation that decides whether "ANALYZE" is
  needed (Alvaro)
* Fix corner cases in pattern matching for psql's \d commands
* Fix index-corrupting bugs in /contrib/ltree (Teodor)
* Numerous robustness fixes in ecpg (Joachim Wieland)
* Fix backslash escaping in /contrib/dbmirror
* Minor fixes in /contrib/dblink and /contrib/tsearch2
* Efficiency improvements in hash tables and bitmap index scans (Tom)
* Fix instability of statistics collection on Win32 (Tom, Andrew)
* Fix statement_timeout to use the proper units on Win32 (Bruce)
  In previous Win32 8.1.X versions, the delay was off by a factor of
  100.
* Fixes for MSVC and Borland C++ compilers (Hiroshi Saito)
* Fixes for AIX and Intel compilers (Tom)