1 files changed, 11 insertions, 3 deletions
diff --git a/src/insert.c b/src/insert.c
index adf6ef2ed..98f00bfe3 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -1287,9 +1287,17 @@ void sqlite3GenerateConstraintChecks(
           sqlite3GenerateRowDelete(
               pParse, pTab, baseCur, regRowid, 0, pTrigger, OE_Replace
           );
-        }else if( pTab->pIndex ){
-          sqlite3MultiWrite(pParse);
-          sqlite3GenerateRowIndexDelete(pParse, pTab, baseCur, 0);
+        }else{
+          /* This OP_Delete opcode fires the pre-update-hook only. It does
+          ** not modify the b-tree. It is more efficient to let the coming
+          ** OP_Insert replace the existing entry than it is to delete the
+          ** existing entry and then insert a new one. */
+          sqlite3VdbeAddOp2(v, OP_Delete, baseCur, OPFLAG_ISNOOP);
+          sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
+          if( pTab->pIndex ){
+            sqlite3MultiWrite(pParse);
+            sqlite3GenerateRowIndexDelete(pParse, pTab, baseCur, 0);
+          }
         }
         seenReplace = 1;
         break;