diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 7378beb684..d409011ba7 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -290,7 +290,8 @@ static void ReorderBufferToastAppendChunk(ReorderBuffer *rb, ReorderBufferTXN *t
  */
 static Size ReorderBufferChangeSize(ReorderBufferChange *change);
 static void ReorderBufferChangeMemoryUpdate(ReorderBuffer *rb,
-											ReorderBufferChange *change, bool addition);
+											ReorderBufferChange *change,
+											bool addition, Size sz);
 
 /*
  * Allocate a new ReorderBuffer and clean out any old serialized state from
@@ -474,7 +475,8 @@ ReorderBufferReturnChange(ReorderBuffer *rb, ReorderBufferChange *change,
 {
 	/* update memory accounting info */
 	if (upd_mem)
-		ReorderBufferChangeMemoryUpdate(rb, change, false);
+		ReorderBufferChangeMemoryUpdate(rb, change, false,
+										ReorderBufferChangeSize(change));
 
 	/* free contained data */
 	switch (change->action)
@@ -792,7 +794,8 @@ ReorderBufferQueueChange(ReorderBuffer *rb, TransactionId xid, XLogRecPtr lsn,
 	txn->nentries_mem++;
 
 	/* update memory accounting information */
-	ReorderBufferChangeMemoryUpdate(rb, change, true);
+	ReorderBufferChangeMemoryUpdate(rb, change, true,
+									ReorderBufferChangeSize(change));
 
 	/* process partial change */
 	ReorderBufferProcessPartialChange(rb, txn, change, toast_insert);
@@ -3100,9 +3103,8 @@ ReorderBufferAddNewCommandId(ReorderBuffer *rb, TransactionId xid,
 static void
 ReorderBufferChangeMemoryUpdate(ReorderBuffer *rb,
 								ReorderBufferChange *change,
-								bool addition)
+								bool addition, Size sz)
 {
-	Size		sz;
 	ReorderBufferTXN *txn;
 	ReorderBufferTXN *toptxn;
 
@@ -3127,8 +3129,6 @@ ReorderBufferChangeMemoryUpdate(ReorderBuffer *rb,
 	else
 		toptxn = txn;
 
-	sz = ReorderBufferChangeSize(change);
-
 	if (addition)
 	{
 		txn->size += sz;
@@ -4359,7 +4359,8 @@ ReorderBufferRestoreChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 	 * update the accounting too (subtracting the size from the counters). And
 	 * we don't want to underflow there.
 	 */
-	ReorderBufferChangeMemoryUpdate(rb, change, true);
+	ReorderBufferChangeMemoryUpdate(rb, change, true,
+									ReorderBufferChangeSize(change));
 }
 
 /*
@@ -4605,17 +4606,19 @@ ReorderBufferToastReplace(ReorderBuffer *rb, ReorderBufferTXN *txn,
 	TupleDesc	toast_desc;
 	MemoryContext oldcontext;
 	ReorderBufferTupleBuf *newtup;
+	Size        old_size;
 
 	/* no toast tuples changed */
 	if (txn->toast_hash == NULL)
 		return;
 
 	/*
-	 * We're going to modify the size of the change, so to make sure the
-	 * accounting is correct we'll make it look like we're removing the change
-	 * now (with the old size), and then re-add it at the end.
+	 * We're going to modify the size of the change. So, to make sure the
+	 * accounting is correct we record the current change size and then after
+	 * re-computing the change we'll subtract the recorded size and then
+	 * re-add the new change size at the end.
 	 */
-	ReorderBufferChangeMemoryUpdate(rb, change, false);
+	old_size = ReorderBufferChangeSize(change);
 
 	oldcontext = MemoryContextSwitchTo(rb->context);
 
@@ -4766,8 +4769,11 @@ ReorderBufferToastReplace(ReorderBuffer *rb, ReorderBufferTXN *txn,
 
 	MemoryContextSwitchTo(oldcontext);
 
+	/* substract the old change size */
+	ReorderBufferChangeMemoryUpdate(rb, change, false, old_size);
 	/* now add the change back, with the correct size */
-	ReorderBufferChangeMemoryUpdate(rb, change, true);
+	ReorderBufferChangeMemoryUpdate(rb, change, true,
+									ReorderBufferChangeSize(change));
 }
 
 /*