schemadiff: INSTANT algorithm not supported for CHANGE COLUMN and MOD…

…IFY COLUMN which specify FIRST or AFTER Signed-off-by: Shlomi Noach <[email protected]>
vitessio · Aug 29, 2024 · facaf5d · facaf5d
1 parent e785c32
commit facaf5d
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Showing 2 changed files with 31 additions and 1 deletion.
diff --git a/go/vt/schemadiff/capability.go b/go/vt/schemadiff/capability.go
@@ -185,6 +185,9 @@ func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTab
 		}
 		return capableOf(capabilities.InstantAddDropColumnFlavorCapability)
 	case *sqlparser.ChangeColumn:
+		if opt.First || opt.After != nil {
+			return false, nil
+		}
 		// We do not support INSTANT for renaming a column (ALTER TABLE ...CHANGE) because:
 		// 1. We discourage column rename
 		// 2. We do not produce CHANGE statements in declarative diff
@@ -198,6 +201,9 @@ func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTab
 		}
 		return false, nil
 	case *sqlparser.ModifyColumn:
+		if opt.First || opt.After != nil {
+			return false, nil
+		}
 		if col := findColumn(opt.NewColDefinition.Name.String()); col != nil {
 			return changeModifyColumnCapableOfInstantDDL(col, opt.NewColDefinition)
 		}

diff --git a/go/vt/schemadiff/capability_test.go b/go/vt/schemadiff/capability_test.go
@@ -225,11 +225,23 @@ func TestAlterTableCapableOfInstantDDL(t *testing.T) {
 			expectCapableOfInstantDDL: false,
 		},
 		{
-			name:                      "set column dfault value to null",
+			name:                      "set column default value to null",
 			create:                    "create table t(id int, i1 int, primary key(id))",
 			alter:                     "alter table t modify column i1 int default null",
 			expectCapableOfInstantDDL: true,
 		},
+		{
+			name:                      "rearrange column after",
+			create:                    "create table t(id int, i1 int, i2 int, primary key(id))",
+			alter:                     "alter table t modify column i1 int after i2",
+			expectCapableOfInstantDDL: false,
+		},
+		{
+			name:                      "rearrange column first",
+			create:                    "create table t(id int, i1 int, i2 int, primary key(id))",
+			alter:                     "alter table t modify column i1 int first",
+			expectCapableOfInstantDDL: false,
+		},
 		// enum/set:
 		{
 			name:                      "change enum default value",
@@ -291,6 +303,18 @@ func TestAlterTableCapableOfInstantDDL(t *testing.T) {
 			alter:                     "alter table t1 change column i1 i2 int visible",
 			expectCapableOfInstantDDL: false,
 		},
+		{
+			name:                      "change column, first",
+			create:                    "create table t1 (id int, i1 int, i2 int)",
+			alter:                     "alter table t1 change column i1 i1 int first",
+			expectCapableOfInstantDDL: false,
+		},
+		{
+			name:                      "change column, after",
+			create:                    "create table t1 (id int, i1 int, i2 int)",
+			alter:                     "alter table t1 change column i1 i1 int after i2",
+			expectCapableOfInstantDDL: false,
+		},
 		{
 			name:                      "make a column invisible via SET",
 			create:                    "create table t1 (id int, i1 int)",