diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 66fb2e4231..9fe6855945 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -73,11 +73,11 @@ static LWLockTranche MainLWLockTranche;
 
 /*
  * We use this structure to keep track of locked LWLocks for release
- * during error recovery.  The maximum size could be determined at runtime
- * if necessary, but it seems unlikely that more than a few locks could
- * ever be held simultaneously.
+ * during error recovery.  Normally, only a few will be held at once, but
+ * occasionally the number can be much higher; for example, the pg_buffercache
+ * extension locks all buffer partitions simultaneously.
  */
-#define MAX_SIMUL_LWLOCKS	100
+#define MAX_SIMUL_LWLOCKS	200
 
 static int	num_held_lwlocks = 0;
 static LWLock *held_lwlocks[MAX_SIMUL_LWLOCKS];
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 90ae7d443d..02c8f1aa8c 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -136,7 +136,7 @@ extern PGDLLIMPORT LWLockPadded *MainLWLockArray;
  */
 
 /* Number of partitions of the shared buffer mapping hashtable */
-#define NUM_BUFFER_PARTITIONS  16
+#define NUM_BUFFER_PARTITIONS  128
 
 /* Number of partitions the shared lock tables are divided into */
 #define LOG2_NUM_LOCK_PARTITIONS  4