Log Message:
-----------
Some small tuptoaster improvements from Greg Stark. Avoid unnecessary
decompression of an already-compressed external value when we have to copy
it; save a few cycles when a value is too short for compression; and
annotate various lines that are currently unreachable.
Modified Files:
--------------
pgsql/src/backend/access/heap:
tuptoaster.c (r1.74 -> r1.75)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/heap/tuptoaster.c?r1=1.74&r2=1.75)