*** a/src/backend/storage/lmgr/predicate.c
--- b/src/backend/storage/lmgr/predicate.c
***************
*** 1436,1443 **** GetSafeSnapshot(Snapshot origSnapshot)
  		 * them marked us as conflicted.
  		 */
  		MySerializableXact->flags |= SXACT_FLAG_DEFERRABLE_WAITING;
! 		while (!(SHMQueueEmpty((SHM_QUEUE *)
! 							 &MySerializableXact->possibleUnsafeConflicts) ||
  				 SxactIsROUnsafe(MySerializableXact)))
  		{
  			LWLockRelease(SerializableXactHashLock);
--- 1436,1442 ----
  		 * them marked us as conflicted.
  		 */
  		MySerializableXact->flags |= SXACT_FLAG_DEFERRABLE_WAITING;
! 		while (!(SHMQueueEmpty(&MySerializableXact->possibleUnsafeConflicts) ||
  				 SxactIsROUnsafe(MySerializableXact)))
  		{
  			LWLockRelease(SerializableXactHashLock);
***************
*** 3120,3132 **** ReleasePredicateLocks(const bool isCommit)
  		 * opposed to 'outLink' for the r/w xacts.
  		 */
  		possibleUnsafeConflict = (RWConflict)
! 			SHMQueueNext((SHM_QUEUE *) &MySerializableXact->possibleUnsafeConflicts,
! 				  (SHM_QUEUE *) &MySerializableXact->possibleUnsafeConflicts,
  						 offsetof(RWConflictData, inLink));
  		while (possibleUnsafeConflict)
  		{
  			nextConflict = (RWConflict)
! 				SHMQueueNext((SHM_QUEUE *) &MySerializableXact->possibleUnsafeConflicts,
  							 &possibleUnsafeConflict->inLink,
  							 offsetof(RWConflictData, inLink));
  
--- 3119,3131 ----
  		 * opposed to 'outLink' for the r/w xacts.
  		 */
  		possibleUnsafeConflict = (RWConflict)
! 			SHMQueueNext(&MySerializableXact->possibleUnsafeConflicts,
! 						 &MySerializableXact->possibleUnsafeConflicts,
  						 offsetof(RWConflictData, inLink));
  		while (possibleUnsafeConflict)
  		{
  			nextConflict = (RWConflict)
! 				SHMQueueNext(&MySerializableXact->possibleUnsafeConflicts,
  							 &possibleUnsafeConflict->inLink,
  							 offsetof(RWConflictData, inLink));
  
***************
*** 3159,3171 **** ReleasePredicateLocks(const bool isCommit)
  	 * previously committed transactions.
  	 */
  	conflict = (RWConflict)
! 		SHMQueueNext((SHM_QUEUE *) &MySerializableXact->outConflicts,
! 					 (SHM_QUEUE *) &MySerializableXact->outConflicts,
  					 offsetof(RWConflictData, outLink));
  	while (conflict)
  	{
  		nextConflict = (RWConflict)
! 			SHMQueueNext((SHM_QUEUE *) &MySerializableXact->outConflicts,
  						 &conflict->outLink,
  						 offsetof(RWConflictData, outLink));
  
--- 3158,3170 ----
  	 * previously committed transactions.
  	 */
  	conflict = (RWConflict)
! 		SHMQueueNext(&MySerializableXact->outConflicts,
! 					 &MySerializableXact->outConflicts,
  					 offsetof(RWConflictData, outLink));
  	while (conflict)
  	{
  		nextConflict = (RWConflict)
! 			SHMQueueNext(&MySerializableXact->outConflicts,
  						 &conflict->outLink,
  						 offsetof(RWConflictData, outLink));
  
***************
*** 3192,3204 **** ReleasePredicateLocks(const bool isCommit)
  	 * we're rolling back, clear them all.
  	 */
  	conflict = (RWConflict)
! 		SHMQueueNext((SHM_QUEUE *) &MySerializableXact->inConflicts,
! 					 (SHM_QUEUE *) &MySerializableXact->inConflicts,
  					 offsetof(RWConflictData, inLink));
  	while (conflict)
  	{
  		nextConflict = (RWConflict)
! 			SHMQueueNext((SHM_QUEUE *) &MySerializableXact->inConflicts,
  						 &conflict->inLink,
  						 offsetof(RWConflictData, inLink));
  
--- 3191,3203 ----
  	 * we're rolling back, clear them all.
  	 */
  	conflict = (RWConflict)
! 		SHMQueueNext(&MySerializableXact->inConflicts,
! 					 &MySerializableXact->inConflicts,
  					 offsetof(RWConflictData, inLink));
  	while (conflict)
  	{
  		nextConflict = (RWConflict)
! 			SHMQueueNext(&MySerializableXact->inConflicts,
  						 &conflict->inLink,
  						 offsetof(RWConflictData, inLink));
  
***************
*** 3219,3231 **** ReleasePredicateLocks(const bool isCommit)
  		 * up if they are known safe or known unsafe.
  		 */
  		possibleUnsafeConflict = (RWConflict)
! 			SHMQueueNext((SHM_QUEUE *) &MySerializableXact->possibleUnsafeConflicts,
! 				  (SHM_QUEUE *) &MySerializableXact->possibleUnsafeConflicts,
  						 offsetof(RWConflictData, outLink));
  		while (possibleUnsafeConflict)
  		{
  			nextConflict = (RWConflict)
! 				SHMQueueNext((SHM_QUEUE *) &MySerializableXact->possibleUnsafeConflicts,
  							 &possibleUnsafeConflict->outLink,
  							 offsetof(RWConflictData, outLink));
  
--- 3218,3230 ----
  		 * up if they are known safe or known unsafe.
  		 */
  		possibleUnsafeConflict = (RWConflict)
! 			SHMQueueNext(&MySerializableXact->possibleUnsafeConflicts,
! 						 &MySerializableXact->possibleUnsafeConflicts,
  						 offsetof(RWConflictData, outLink));
  		while (possibleUnsafeConflict)
  		{
  			nextConflict = (RWConflict)
! 				SHMQueueNext(&MySerializableXact->possibleUnsafeConflicts,
  							 &possibleUnsafeConflict->outLink,
  							 offsetof(RWConflictData, outLink));
  
***************
*** 3296,3302 **** ReleasePredicateLocks(const bool isCommit)
  	/* Add this to the list of transactions to check for later cleanup. */
  	if (isCommit)
  		SHMQueueInsertBefore(FinishedSerializableTransactions,
! 						  (SHM_QUEUE *) &(MySerializableXact->finishedLink));
  
  	if (!isCommit)
  		ReleaseOneSerializableXact(MySerializableXact, false, false);
--- 3295,3301 ----
  	/* Add this to the list of transactions to check for later cleanup. */
  	if (isCommit)
  		SHMQueueInsertBefore(FinishedSerializableTransactions,
! 							 &MySerializableXact->finishedLink);
  
  	if (!isCommit)
  		ReleaseOneSerializableXact(MySerializableXact, false, false);
***************
*** 3796,3802 **** CheckForSerializableConflictOut(const bool visible, const Relation relation,
  					  errhint("The transaction might succeed if retried.")));
  
  			if (SxactHasSummaryConflictIn(MySerializableXact)
! 			|| !SHMQueueEmpty((SHM_QUEUE *) &MySerializableXact->inConflicts))
  				ereport(ERROR,
  						(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  						 errmsg("could not serialize access due to read/write dependencies among transactions"),
--- 3795,3801 ----
  					  errhint("The transaction might succeed if retried.")));
  
  			if (SxactHasSummaryConflictIn(MySerializableXact)
! 				|| !SHMQueueEmpty(&MySerializableXact->inConflicts))
  				ereport(ERROR,
  						(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  						 errmsg("could not serialize access due to read/write dependencies among transactions"),
***************
*** 4469,4476 **** PreCommit_CheckForSerializationFailure(void)
  	}
  
  	nearConflict = (RWConflict)
! 		SHMQueueNext((SHM_QUEUE *) &MySerializableXact->inConflicts,
! 					 (SHM_QUEUE *) &MySerializableXact->inConflicts,
  					 offsetof(RWConflictData, inLink));
  	while (nearConflict)
  	{
--- 4468,4475 ----
  	}
  
  	nearConflict = (RWConflict)
! 		SHMQueueNext(&MySerializableXact->inConflicts,
! 					 &MySerializableXact->inConflicts,
  					 offsetof(RWConflictData, inLink));
  	while (nearConflict)
  	{
***************
*** 4503,4509 **** PreCommit_CheckForSerializationFailure(void)
  		}
  
  		nearConflict = (RWConflict)
! 			SHMQueueNext((SHM_QUEUE *) &MySerializableXact->inConflicts,
  						 &nearConflict->inLink,
  						 offsetof(RWConflictData, inLink));
  	}
--- 4502,4508 ----
  		}
  
  		nearConflict = (RWConflict)
! 			SHMQueueNext(&MySerializableXact->inConflicts,
  						 &nearConflict->inLink,
  						 offsetof(RWConflictData, inLink));
  	}
***************
*** 4550,4558 **** AtPrepare_PredicateLocks(void)
  	 * outConflicts lists, if they're non-empty we'll represent that by
  	 * setting the appropriate summary conflict flags.
  	 */
! 	if (!SHMQueueEmpty((SHM_QUEUE *) &MySerializableXact->inConflicts))
  		xactRecord->flags |= SXACT_FLAG_SUMMARY_CONFLICT_IN;
! 	if (!SHMQueueEmpty((SHM_QUEUE *) &MySerializableXact->outConflicts))
  		xactRecord->flags |= SXACT_FLAG_SUMMARY_CONFLICT_OUT;
  
  	RegisterTwoPhaseRecord(TWOPHASE_RM_PREDICATELOCK_ID, 0,
--- 4549,4557 ----
  	 * outConflicts lists, if they're non-empty we'll represent that by
  	 * setting the appropriate summary conflict flags.
  	 */
! 	if (!SHMQueueEmpty(&MySerializableXact->inConflicts))
  		xactRecord->flags |= SXACT_FLAG_SUMMARY_CONFLICT_IN;
! 	if (!SHMQueueEmpty(&MySerializableXact->outConflicts))
  		xactRecord->flags |= SXACT_FLAG_SUMMARY_CONFLICT_OUT;
  
  	RegisterTwoPhaseRecord(TWOPHASE_RM_PREDICATELOCK_ID, 0,