Re: Slow catchup of 2PC (twophase) transactions on replica in LR

Hi Kuroda-san,

Thanks for addressing most of my v6-0001 review comments.

Below are some minor follow-up comments for v7-0001.

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src/backend/access/transam/twophase.c

1. IsTwoPhaseTransactionGidForSubid

+/*
+ * IsTwoPhaseTransactionGidForSubid
+ * Check whether the given GID is formed by TwoPhaseTransactionGid.
+ */
+static bool
+IsTwoPhaseTransactionGidForSubid(Oid subid, char *gid)

I think the function comment should mention something about 'subid'.

SUGGESTION
Check whether the given GID (as formed by TwoPhaseTransactionGid) is
for the specified 'subid'.

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src/backend/commands/subscriptioncmds.c

2. AlterSubscription

+ if (!opts.twophase &&
+ form->subtwophasestate == LOGICALREP_TWOPHASE_STATE_ENABLED &&
+ LookupGXactBySubid(subid))
+ /* Add error message */
+ ereport(ERROR,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("cannot disable two_phase when uncommitted prepared
transactions present"),
+ errhint("Resolve these transactions and try again")));

The comment "/* Add error message */" seems unnecessary.

======
Kind Regards,
Peter Smith.
Fujitsu Australia