pgsql: Fix order of arguments to SubTransSetParent().

Fix order of arguments to SubTransSetParent().

ProcessTwoPhaseBuffer (formerly StandbyRecoverPreparedTransactions)
mixed up the parent and child XIDs when calling SubTransSetParent to
record the transactions' relationship in pg_subtrans.

Remarkably, analysis by Simon Riggs suggests that this doesn't lead to
visible problems (at least, not in non-Assert builds). That might
explain why we'd not noticed it before. Nonetheless, it's surely wrong.

This code was born broken, so back-patch to all supported branches.

Discussion: https://postgr.es/m/20110.1492905318@sss.pgh.pa.us

Branch
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REL9_5_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/a66e01bbcc8808674ade41d38cfba711a36b8b15

Modified Files
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src/backend/access/transam/twophase.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)