heap_prepare_freeze_tuple: Simplify coding
authorAlvaro Herrera <alvherre@alvh.no-ip.org>
Thu, 2 May 2019 20:13:48 +0000 (16:13 -0400)
committerAlvaro Herrera <alvherre@alvh.no-ip.org>
Thu, 2 May 2019 20:14:08 +0000 (16:14 -0400)
commit2bf372a4ae26337ee61cf7a82081cf4bed05182d
tree009e84014c009397e84e4069eb4de5863462fbb6
parent6dd86c269d5b9a176f6c9f67ea61cc17fef9d860
heap_prepare_freeze_tuple: Simplify coding

Commit d2599ecfcc74 introduced some contorted, confused code around:
readers would think that it's possible for HeapTupleHeaderGetXmin return
a non-frozen value for some frozen tuples, which would be disastrous.
There's no actual bug, but it seems better to make it clearer.

Per gripe from Tom Lane and Andres Freund.
Discussion: https://postgr.es/m/30116.1555430496@sss.pgh.pa.us
src/backend/access/heap/heapam.c