diff --git a/integration-tests/__tests__/alter-table.spec.js b/integration-tests/__tests__/alter-table.spec.js
index 2daf16730..cb8c198f4 100644
--- a/integration-tests/__tests__/alter-table.spec.js
+++ b/integration-tests/__tests__/alter-table.spec.js
@@ -119,6 +119,7 @@ async function testTableDiff(engine, conn, driver, mangle, changedTable = 't1')
 
 const TESTED_COLUMNS = ['col_pk', 'col_std', 'col_def', 'col_fk', 'col_ref', 'col_idx', 'col_uq'];
 // const TESTED_COLUMNS = ['col_pk'];
+// const TESTED_COLUMNS = ['col_fk'];
 // const TESTED_COLUMNS = ['col_idx'];
 // const TESTED_COLUMNS = ['col_def'];
 // const TESTED_COLUMNS = ['col_std'];
diff --git a/packages/tools/src/alterPlan.ts b/packages/tools/src/alterPlan.ts
index 5462efab8..1143ff165 100644
--- a/packages/tools/src/alterPlan.ts
+++ b/packages/tools/src/alterPlan.ts
@@ -337,7 +337,13 @@ export class AlterPlan {
             return opRes;
           }),
           op,
-        ];
+        ].filter(op => {
+          // filter duplicated drops
+          const existingDrop = this.operations.find(
+            o => o.operationType == 'dropConstraint' && o.oldObject === op['oldObject']
+          );
+          return existingDrop == null;
+        });
         return res;
       }