Обсуждение: pgsql: Don't assume rd_smgr stays open across all of a rewriteheap

Log Message:
-----------
Don't assume rd_smgr stays open across all of a rewriteheap operation;
doing so can result in crash if an sinval reset occurs meanwhile.
I believe this explains intermittent buildfarm failures in cluster test.

Modified Files:
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    pgsql/src/backend/access/heap:
        rewriteheap.c (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/heap/rewriteheap.c.diff?r1=1.1&r2=1.2)