diff --git a/src/backend/distributed/transaction/backend_data.c b/src/backend/distributed/transaction/backend_data.c
index b78e694d9..1f30878b9 100644
--- a/src/backend/distributed/transaction/backend_data.c
+++ b/src/backend/distributed/transaction/backend_data.c
@@ -541,9 +541,11 @@ BackendManagementShmemInit(void)
 
 		/*
 		 * We need to init per backend's spinlock before any backend
-		 * starts its execution.
+		 * starts its execution. Note that we initialize TotalProcs (e.g., not
+		 * MaxBackends) since some of the blocking processes could be prepared
+		 * transactions, which aren't covered by MaxBackends.
 		 */
-		for (backendIndex = 0; backendIndex < MaxBackends; ++backendIndex)
+		for (backendIndex = 0; backendIndex < TotalProcs; ++backendIndex)
 		{
 			SpinLockInit(&backendManagementShmemData->backends[backendIndex].mutex);
 		}
@@ -568,7 +570,7 @@ BackendManagementShmemSize(void)
 	Size size = 0;
 
 	size = add_size(size, sizeof(BackendManagementShmemData));
-	size = add_size(size, mul_size(sizeof(BackendData), MaxBackends));
+	size = add_size(size, mul_size(sizeof(BackendData), TotalProcs));
 
 	return size;
 }
diff --git a/src/backend/distributed/transaction/lock_graph.c b/src/backend/distributed/transaction/lock_graph.c
index d3b51b3e5..734b3acac 100644
--- a/src/backend/distributed/transaction/lock_graph.c
+++ b/src/backend/distributed/transaction/lock_graph.c
@@ -398,12 +398,12 @@ BuildLocalWaitGraph(void)
 	 */
 	waitGraph = (WaitGraph *) palloc0(sizeof(WaitGraph));
 	waitGraph->localNodeId = GetLocalGroupId();
-	waitGraph->allocatedSize = MaxBackends * 3;
+	waitGraph->allocatedSize = TotalProcs * 3;
 	waitGraph->edgeCount = 0;
 	waitGraph->edges = (WaitEdge *) palloc(waitGraph->allocatedSize * sizeof(WaitEdge));
 
-	remaining.procs = (PGPROC **) palloc(sizeof(PGPROC *) * MaxBackends);
-	remaining.procAdded = (bool *) palloc0(sizeof(bool *) * MaxBackends);
+	remaining.procs = (PGPROC **) palloc(sizeof(PGPROC *) * TotalProcs);
+	remaining.procAdded = (bool *) palloc0(sizeof(bool *) * TotalProcs);
 	remaining.procCount = 0;
 
 	LockLockData();
@@ -416,7 +416,7 @@ BuildLocalWaitGraph(void)
 	 */
 
 	/* build list of starting procs */
-	for (curBackend = 0; curBackend < MaxBackends; curBackend++)
+	for (curBackend = 0; curBackend < TotalProcs; curBackend++)
 	{
 		PGPROC *currentProc = &ProcGlobal->allProcs[curBackend];
 		BackendData currentBackendData;
@@ -762,7 +762,7 @@ AddProcToVisit(PROCStack *remaining, PGPROC *proc)
 		return;
 	}
 
-	Assert(remaining->procCount < MaxBackends);
+	Assert(remaining->procCount < TotalProcs);
 
 	remaining->procs[remaining->procCount++] = proc;
 	remaining->procAdded[proc->pgprocno] = true;
diff --git a/src/include/distributed/backend_data.h b/src/include/distributed/backend_data.h
index 5388f8d42..8a4d64080 100644
--- a/src/include/distributed/backend_data.h
+++ b/src/include/distributed/backend_data.h
@@ -13,6 +13,7 @@
 #define BACKEND_DATA_H
 
 
+#include "access/twophase.h"
 #include "datatype/timestamp.h"
 #include "distributed/transaction_identifier.h"
 #include "nodes/pg_list.h"
@@ -21,6 +22,9 @@
 #include "storage/s_lock.h"
 
 
+#define TotalProcs (MaxBackends + NUM_AUXILIARY_PROCS + max_prepared_xacts)
+
+
 /*
  * Each backend's active distributed transaction information is tracked via
  * BackendData in shared memory.