// TestSchemaChangeCommandsWithPendingMutations tests how schema change
// commands behave when they are referencing schema elements that are
// mutations that are not yet live.
func TestSchemaChangeCommandsWithPendingMutations(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	params, _ := createTestServerParams()
	params.Knobs.SQLSchemaChangeManager = &csql.SchemaChangeManagerTestingKnobs{
		AsyncSchemaChangerExecNotification: schemaChangeManagerDisabled,
	}
	server, sqlDB, kvDB := serverutils.StartServer(t, params)
	defer server.Stopper().Stop()

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (a CHAR PRIMARY KEY, b CHAR, c CHAR, INDEX foo (c));
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor
	tableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")

	mt := mutationTest{
		T:         t,
		kvDB:      kvDB,
		sqlDB:     sqlDB,
		tableDesc: tableDesc,
	}

	// Test CREATE INDEX in the presence of mutations.

	// Add index DROP mutation "foo""
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`CREATE INDEX foo ON t.test (c)`); !testutils.IsError(err, `index "foo" being dropped, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()

	// "foo" is being added.
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`CREATE INDEX foo ON t.test (c)`); !testutils.IsError(err, `duplicate index name: "foo"`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// Add column DROP mutation "b"
	mt.writeColumnMutation("b", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`CREATE INDEX bar ON t.test (b)`); !testutils.IsError(err, `index "bar" contains unknown column "b"`) {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()
	// "b" is being added.
	mt.writeColumnMutation("b", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	// An index referencing a column mutation that is being added
	// is allowed to be added.
	if _, err := sqlDB.Exec(`CREATE INDEX bar ON t.test (b)`); err != nil {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()

	// Test DROP INDEX in the presence of mutations.

	// Add index DROP mutation "foo""
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	// Noop.
	if _, err := sqlDB.Exec(`DROP INDEX t.test@foo`); err != nil {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// "foo" is being added.
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`DROP INDEX t.test@foo`); !testutils.IsError(err, `index "foo" in the middle of being added, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// Test ALTER TABLE ADD/DROP column in the presence of mutations.

	// Add column DROP mutation "b"
	mt.writeColumnMutation("b", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD b CHAR`); !testutils.IsError(err, `column "b" being dropped, try again later`) {
		t.Fatal(err)
	}
	// Noop.
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP b`); err != nil {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()
	// "b" is being added.
	mt.writeColumnMutation("b", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD b CHAR`); !testutils.IsError(err, `duplicate column name: "b"`) {
		t.Fatal(err)
	}
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP b`); !testutils.IsError(err, `column "b" in the middle of being added, try again later`) {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()

	// Test ALTER TABLE ADD CONSTRAINT in the presence of mutations.

	// Add index DROP mutation "foo""
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT foo UNIQUE (c)`); !testutils.IsError(err, `index "foo" being dropped, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// "foo" is being added.
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT foo UNIQUE (c)`); !testutils.IsError(err, `duplicate index name: "foo"`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// Add column mutation "b"
	mt.writeColumnMutation("b", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT bar UNIQUE (b)`); !testutils.IsError(err, `index "bar" contains unknown column "b"`) {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()
	// "b" is being added.
	mt.writeColumnMutation("b", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	// Noop.
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT bar UNIQUE (b)`); err != nil {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()

	// Test DROP CONSTRAINT in the presence of mutations.

	// Add index mutation "foo""
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	// Noop.
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP CONSTRAINT foo`); err != nil {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// "foo" is being added.
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP CONSTRAINT foo`); !testutils.IsError(err, `constraint "foo" in the middle of being added, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()

	// Rename column/index, while index is under mutation.

	// Add index mutation "foo""
	mt.writeIndexMutation("foo", sqlbase.DescriptorMutation{})
	if _, err := sqlDB.Exec(`ALTER INDEX t.test@foo RENAME to ufo`); err != nil {
		mt.Fatal(err)
	}
	if _, err := sqlDB.Exec(`ALTER TABLE t.test RENAME COLUMN c TO d`); err != nil {
		mt.Fatal(err)
	}
	// The mutation in the table descriptor has changed and we would like
	// to update our copy to make it live.
	mt.tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")

	// Make "ufo" live.
	mt.makeMutationsActive()
	// The index has been renamed to ufo, and the column to d.
	_ = mt.checkQueryResponse("SHOW INDEXES FROM t.test", [][]string{{"test", "primary", "true", "1", "a", "ASC", "false"}, {"test", "ufo", "false", "1", "d", "ASC", "false"}})

	// Rename column under mutation works properly.

	// Add column mutation "b".
	mt.writeColumnMutation("b", sqlbase.DescriptorMutation{})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test RENAME COLUMN b TO e`); err != nil {
		mt.Fatal(err)
	}

	// The mutation in the table descriptor has changed and we would like
	// to update our copy to make it live.
	mt.tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")

	// Make column "e" live.
	mt.makeMutationsActive()
	// Column b changed to d.
	_ = mt.checkQueryResponse("SHOW COLUMNS FROM t.test", [][]string{{"a", "STRING", "false", "NULL"}, {"d", "STRING", "true", "NULL"}, {"e", "STRING", "true", "NULL"}})

	// Try to change column defaults while column is under mutation.
	mt.writeColumnMutation("e", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ALTER COLUMN e SET DEFAULT 'a'`); !testutils.IsError(
		err, `column "e" in the middle of being added`) {
		t.Fatal(err)
	}
	mt.makeMutationsActive()
	mt.writeColumnMutation("e", sqlbase.DescriptorMutation{Direction: sqlbase.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ALTER COLUMN e SET DEFAULT 'a'`); !testutils.IsError(
		err, `column "e" in the middle of being dropped`) {
		t.Fatal(err)
	}
	mt.makeMutationsActive()
}
func TestOperationsWithIndexMutation(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	params, _ := createTestServerParams()
	params.Knobs.SQLSchemaChangeManager = &csql.SchemaChangeManagerTestingKnobs{
		AsyncSchemaChangerExecNotification: schemaChangeManagerDisabled,
	}
	server, sqlDB, kvDB := serverutils.StartServer(t, params)
	defer server.Stopper().Stop()

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, INDEX foo (v));
`); err != nil {
		t.Fatal(err)
	}

	// read table descriptor
	tableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")

	mTest := mutationTest{
		T:         t,
		kvDB:      kvDB,
		sqlDB:     sqlDB,
		tableDesc: tableDesc,
	}

	starQuery := `SELECT * FROM t.test`
	indexQuery := `SELECT v FROM t.test@foo`
	// See the effect of the operations depending on the state.
	for _, state := range []sqlbase.DescriptorMutation_State{sqlbase.DescriptorMutation_DELETE_ONLY, sqlbase.DescriptorMutation_WRITE_ONLY} {
		// Init table with some entries.
		if _, err := sqlDB.Exec(`TRUNCATE TABLE t.test`); err != nil {
			t.Fatal(err)
		}
		initRows := [][]string{{"a", "z"}, {"b", "y"}}
		for _, row := range initRows {
			if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ($1, $2)`, row[0], row[1]); err != nil {
				t.Fatal(err)
			}
		}
		_ = mTest.checkQueryResponse(starQuery, initRows)
		// Index foo is visible.
		_ = mTest.checkQueryResponse(indexQuery, [][]string{{"y"}, {"z"}})

		// Index foo is invisible once it's a mutation.
		mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: state})
		if _, err := sqlDB.Query(indexQuery); !testutils.IsError(err, `index "foo" not found`) {
			t.Fatal(err)
		}

		// Insert a new entry.
		if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('c', 'x')`); err != nil {
			t.Fatal(err)
		}
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}, {"b", "y"}, {"c", "x"}})

		// Make index "foo" live so that we can read it.
		mTest.makeMutationsActive()
		if state == sqlbase.DescriptorMutation_DELETE_ONLY {
			// "x" didn't get added to the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"y"}, {"z"}})
		} else {
			// "x" got added to the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"x"}, {"y"}, {"z"}})
		}

		// Make "foo" a mutation.
		mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: state})
		// Update.
		if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'w' WHERE k = 'c'`); err != nil {
			t.Fatal(err)
		}
		// Update "v" to its current value "z" in row "a".
		if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'z' WHERE k = 'a'`); err != nil {
			t.Fatal(err)
		}
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}, {"b", "y"}, {"c", "w"}})

		// Make index "foo" live so that we can read it.
		mTest.makeMutationsActive()
		if state == sqlbase.DescriptorMutation_DELETE_ONLY {
			// updating "x" -> "w" is a noop on the index,
			// updating "z" -> "z" results in "z" being deleted from the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"y"}, {"z"}})
		} else {
			// updating "x" -> "w" results in the index updating from "x" -> "w",
			// updating "z" -> "z" is a noop on the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"w"}, {"y"}, {"z"}})
		}

		// Make "foo" a mutation.
		mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: state})
		// Delete row "b".
		if _, err := sqlDB.Exec(`DELETE FROM t.test WHERE k = 'b'`); err != nil {
			t.Fatal(err)
		}
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}, {"c", "w"}})

		// Make index "foo" live so that we can read it.
		mTest.makeMutationsActive()
		// Deleting row "b" deletes "y" from the index.
		if state == sqlbase.DescriptorMutation_DELETE_ONLY {
			mTest.checkQueryResponse(indexQuery, [][]string{{"z"}})
		} else {
			mTest.checkQueryResponse(indexQuery, [][]string{{"w"}, {"z"}})
		}
	}

	// Check that a mutation can only be inserted with an explicit mutation state.
	tableDesc = mTest.tableDesc
	tableDesc.Mutations = []sqlbase.DescriptorMutation{{Descriptor_: &sqlbase.DescriptorMutation_Index{Index: &tableDesc.Indexes[len(tableDesc.Indexes)-1]}}}
	tableDesc.Indexes = tableDesc.Indexes[:len(tableDesc.Indexes)-1]
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction NONE, index foo, id 2") {
		t.Fatal(err)
	}
}
// TestOperationsWithUniqueColumnMutation tests all the operations while an
// index mutation refers to a column mutation.
func TestOperationsWithUniqueColumnMutation(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	params, _ := createTestServerParams()
	params.Knobs.SQLSchemaChangeManager = &csql.SchemaChangeManagerTestingKnobs{
		AsyncSchemaChangerExecNotification: schemaChangeManagerDisabled,
	}
	server, sqlDB, kvDB := serverutils.StartServer(t, params)
	defer server.Stopper().Stop()

	// Create a table with column i and an index on v and i.
	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, i CHAR, INDEX foo (i, v));
`); err != nil {
		t.Fatal(err)
	}

	// read table descriptor
	tableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")

	mTest := mutationTest{
		T:         t,
		kvDB:      kvDB,
		sqlDB:     sqlDB,
		tableDesc: tableDesc,
	}

	starQuery := `SELECT * FROM t.test`
	indexQuery := `SELECT i FROM t.test@foo`
	// Run the tests for both states for a column and an index.
	for _, state := range []sqlbase.DescriptorMutation_State{
		sqlbase.DescriptorMutation_DELETE_ONLY,
		sqlbase.DescriptorMutation_WRITE_ONLY,
	} {
		for _, idxState := range []sqlbase.DescriptorMutation_State{
			sqlbase.DescriptorMutation_DELETE_ONLY,
			sqlbase.DescriptorMutation_WRITE_ONLY,
		} {
			// Ignore the impossible column in DELETE_ONLY state while index
			// is in the WRITE_ONLY state.
			if state == sqlbase.DescriptorMutation_DELETE_ONLY &&
				idxState == sqlbase.DescriptorMutation_WRITE_ONLY {
				continue
			}
			// Init table to start state.
			if _, err := sqlDB.Exec(`TRUNCATE TABLE t.test`); err != nil {
				t.Fatal(err)
			}
			initRows := [][]string{{"a", "z", "q"}, {"b", "y", "r"}}
			for _, row := range initRows {
				if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ($1, $2, $3)`, row[0], row[1], row[2]); err != nil {
					t.Fatal(err)
				}
			}
			// Check that the table only contains the initRows.
			_ = mTest.checkQueryResponse(starQuery, initRows)

			// Add index "foo" as a mutation.
			mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: idxState})
			// Make column "i" a mutation.
			mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})

			// Insert a row into the table.
			if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('c', 'x')`); err != nil {
				t.Error(err)
			}

			// Make column "i" and index "foo" live.
			mTest.makeMutationsActive()
			// column "i" has no entry.
			_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z", "q"}, {"b", "y", "r"}, {"c", "x", "NULL"}})
			if idxState == sqlbase.DescriptorMutation_DELETE_ONLY {
				// No index entry for row "c"
				_ = mTest.checkQueryResponse(indexQuery, [][]string{{"q"}, {"r"}})
			} else {
				// Index entry for row "c"
				_ = mTest.checkQueryResponse(indexQuery, [][]string{{"NULL"}, {"q"}, {"r"}})
			}

			// Add index "foo" as a mutation.
			mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: idxState})
			// Make column "i" a mutation.
			mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})

			// Updating column "i" for a row fails.
			if _, err := sqlDB.Exec(`UPDATE t.test SET (v, i) = ('u', 'u') WHERE k = 'a'`); !testutils.IsError(err, `column "i" does not exist`) {
				t.Error(err)
			}

			// Update a row without specifying  mutation column "i".
			if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'u' WHERE k = 'a'`); err != nil {
				t.Error(err)
			}
			// Make column "i" and index "foo" live.
			mTest.makeMutationsActive()

			// The update to column "v" is seen; there is no effect on column "i".
			_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "u", "q"}, {"b", "y", "r"}, {"c", "x", "NULL"}})
			if idxState == sqlbase.DescriptorMutation_DELETE_ONLY {
				// Index entry for row "a" is deleted.
				_ = mTest.checkQueryResponse(indexQuery, [][]string{{"r"}})
			} else {
				// No change in index "foo"
				_ = mTest.checkQueryResponse(indexQuery, [][]string{{"NULL"}, {"q"}, {"r"}})
			}

			// Add index "foo" as a mutation.
			mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: idxState})
			// Make column "i" a mutation.
			mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})

			// Delete row "b".
			if _, err := sqlDB.Exec(`DELETE FROM t.test WHERE k = 'b'`); err != nil {
				t.Error(err)
			}
			// Make column "i" and index "foo" live.
			mTest.makeMutationsActive()
			// Row "b" is deleted. numVals is the number of non-NULL values seen,
			// or the number of KV values belonging to all the rows in the table
			// excluding row "b" since it's deleted.
			numVals := mTest.checkQueryResponse(starQuery, [][]string{{"a", "u", "q"}, {"c", "x", "NULL"}})
			// idxVals is the number of index values seen.
			var idxVals int
			if idxState == sqlbase.DescriptorMutation_DELETE_ONLY {
				// Index entry for row "b" is deleted.
				idxVals = mTest.checkQueryResponse(indexQuery, [][]string{})
			} else {
				// Index entry for row "b" is deleted. idxVals doesn't account for
				// the NULL value seen.
				idxVals = mTest.checkQueryResponse(indexQuery, [][]string{{"NULL"}, {"q"}})
				// Increment idxVals to account for the NULL value seen above.
				idxVals++
			}
			// Check that there are no hidden KV values for row "b", and column
			// "i" for row "b" was deleted. Also check that the index values are
			// all accounted for.
			mTest.checkTableSize(numVals + idxVals)
		}
	}
}
func TestCommandsWithPendingMutations(t *testing.T) {
	defer leaktest.AfterTest(t)
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	defer csql.TestDisableAsyncSchemaChangeExec()()
	server, sqlDB, kvDB := setup(t)
	defer cleanup(server, sqlDB)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (a CHAR PRIMARY KEY, b CHAR, c CHAR, INDEX foo (c));
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor
	nameKey := csql.MakeNameMetadataKey(keys.MaxReservedDescID+1, "test")
	gr, err := kvDB.Get(nameKey)
	if err != nil {
		t.Fatal(err)
	}
	if !gr.Exists() {
		t.Fatalf("Name entry %q does not exist", nameKey)
	}
	descKey := csql.MakeDescMetadataKey(csql.ID(gr.ValueInt()))
	desc := &csql.Descriptor{}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}

	mt := mutationTest{
		T:       t,
		kvDB:    kvDB,
		sqlDB:   sqlDB,
		descKey: descKey,
		desc:    desc,
	}

	// Test CREATE INDEX in the presence of mutations.

	// Add index DROP mutation "foo""
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`CREATE INDEX foo ON t.test (c)`); !testutils.IsError(err, `index "foo" being dropped, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()

	// "foo" is being added.
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`CREATE INDEX foo ON t.test (c)`); !testutils.IsError(err, `duplicate index name: "foo"`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// Add column DROP mutation "b"
	mt.writeColumnMutation("b", csql.DescriptorMutation{Direction: csql.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`CREATE INDEX bar ON t.test (b)`); !testutils.IsError(err, `index "bar" contains unknown column "b"`) {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()
	// "b" is being added.
	mt.writeColumnMutation("b", csql.DescriptorMutation{Direction: csql.DescriptorMutation_ADD})
	// An index referencing a column mutation that is being added
	// is allowed to be added.
	if _, err := sqlDB.Exec(`CREATE INDEX bar ON t.test (b)`); err != nil {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()

	// Test DROP INDEX in the presence of mutations.

	// Add index DROP mutation "foo""
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_DROP})
	// Noop.
	if _, err := sqlDB.Exec(`DROP INDEX t.test@foo`); err != nil {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// "foo" is being added.
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`DROP INDEX t.test@foo`); !testutils.IsError(err, `index "foo" in the middle of being added, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// Test ALTER TABLE ADD/DROP column in the presence of mutations.

	// Add column DROP mutation "b"
	mt.writeColumnMutation("b", csql.DescriptorMutation{Direction: csql.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD b CHAR`); !testutils.IsError(err, `column "b" being dropped, try again later`) {
		t.Fatal(err)
	}
	// Noop.
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP b`); err != nil {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()
	// "b" is being added.
	mt.writeColumnMutation("b", csql.DescriptorMutation{Direction: csql.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD b CHAR`); !testutils.IsError(err, `duplicate column name: "b"`) {
		t.Fatal(err)
	}
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP b`); !testutils.IsError(err, `column "b" in the middle of being added, try again later`) {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()

	// Test ALTER TABLE ADD CONSTRAINT in the presence of mutations.

	// Add index DROP mutation "foo""
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT foo UNIQUE (c)`); !testutils.IsError(err, `index "foo" being dropped, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// "foo" is being added.
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT foo UNIQUE (c)`); !testutils.IsError(err, `duplicate index name: "foo"`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// Add column mutation "b"
	mt.writeColumnMutation("b", csql.DescriptorMutation{Direction: csql.DescriptorMutation_DROP})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT bar UNIQUE (b)`); !testutils.IsError(err, `index "bar" contains unknown column "b"`) {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()
	// "b" is being added.
	mt.writeColumnMutation("b", csql.DescriptorMutation{Direction: csql.DescriptorMutation_ADD})
	// Noop.
	if _, err := sqlDB.Exec(`ALTER TABLE t.test ADD CONSTRAINT bar UNIQUE (b)`); err != nil {
		t.Fatal(err)
	}
	// Make "b" live.
	mt.makeMutationsActive()

	// Test DROP CONSTRAINT in the presence of mutations.

	// Add index mutation "foo""
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_DROP})
	// Noop.
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP CONSTRAINT foo`); err != nil {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()
	// "foo" is being added.
	mt.writeIndexMutation("foo", csql.DescriptorMutation{Direction: csql.DescriptorMutation_ADD})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test DROP CONSTRAINT foo`); !testutils.IsError(err, `constraint "foo" in the middle of being added, try again later`) {
		t.Fatal(err)
	}
	// Make "foo" live.
	mt.makeMutationsActive()

	// Rename column/index, while index is under mutation.

	// Add index mutation "foo""
	mt.writeIndexMutation("foo", csql.DescriptorMutation{})
	if _, err := sqlDB.Exec(`ALTER INDEX t.test@foo RENAME to ufo`); err != nil {
		mt.Fatal(err)
	}
	if _, err := sqlDB.Exec(`ALTER TABLE t.test RENAME COLUMN c TO d`); err != nil {
		mt.Fatal(err)
	}
	// The mutation in the table descriptor has changed and we would like
	// to update our copy to make it live.
	if err := mt.kvDB.GetProto(mt.descKey, mt.desc); err != nil {
		mt.Fatal(err)
	}
	// Make "ufo" live.
	mt.makeMutationsActive()
	// The index has been renamed to ufo, and the column to d.
	_ = mt.checkQueryResponse("SHOW INDEX FROM t.test", [][]string{{"test", "primary", "true", "1", "a", "ASC", "false"}, {"test", "ufo", "false", "1", "d", "ASC", "false"}})

	// Rename column under mutation works properly.

	// Add column mutation "b".
	mt.writeColumnMutation("b", csql.DescriptorMutation{})
	if _, err := sqlDB.Exec(`ALTER TABLE t.test RENAME COLUMN b TO e`); err != nil {
		mt.Fatal(err)
	}
	// The mutation in the table descriptor has changed and we would like
	// to update our copy to make it live.
	if err := mt.kvDB.GetProto(mt.descKey, mt.desc); err != nil {
		mt.Fatal(err)
	}
	// Make column "e" live.
	mt.makeMutationsActive()
	// Column b changed to d.
	_ = mt.checkQueryResponse("SHOW COLUMNS FROM t.test", [][]string{{"a", "STRING", "true", "NULL"}, {"d", "STRING", "true", "NULL"}, {"e", "STRING", "true", "NULL"}})
}
func TestOperationsWithColumnMutation(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	params, _ := createTestServerParams()
	params.Knobs.SQLSchemaChangeManager = &csql.SchemaChangeManagerTestingKnobs{
		AsyncSchemaChangerExecNotification: schemaChangeManagerDisabled,
	}
	server, sqlDB, kvDB := serverutils.StartServer(t, params)
	defer server.Stopper().Stop()

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, i CHAR DEFAULT 'i');
`); err != nil {
		t.Fatal(err)
	}

	// read table descriptor
	tableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")

	mTest := mutationTest{
		T:         t,
		kvDB:      kvDB,
		sqlDB:     sqlDB,
		tableDesc: tableDesc,
	}

	starQuery := `SELECT * FROM t.test`
	// Run the tests for both states.
	for _, state := range []sqlbase.DescriptorMutation_State{sqlbase.DescriptorMutation_DELETE_ONLY, sqlbase.DescriptorMutation_WRITE_ONLY} {
		// Init table to start state.
		if _, err := sqlDB.Exec(`TRUNCATE TABLE t.test`); err != nil {
			t.Fatal(err)
		}
		initRows := [][]string{{"a", "z", "q"}}
		for _, row := range initRows {
			if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ($1, $2, $3)`, row[0], row[1], row[2]); err != nil {
				t.Fatal(err)
			}
		}
		// Check that the table only contains the initRows.
		_ = mTest.checkQueryResponse(starQuery, initRows)

		// Add column "i" as a mutation.
		mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})
		// A direct read of column "i" fails.
		if _, err := sqlDB.Query(`SELECT i FROM t.test`); err == nil {
			t.Fatalf("Read succeeded despite column being in %v state", sqlbase.DescriptorMutation{State: state})
		}
		// The table only contains columns "k" and "v".
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}})

		// The column backfill uses Put instead of CPut because it depends on
		// an INSERT of a column in the WRITE_ONLY state failing. These two
		// tests guarantee that.

		// Inserting a row into the table while specifying column "i" results in an error.
		if _, err := sqlDB.Exec(`INSERT INTO t.test (k, v, i) VALUES ('b', 'y', 'i')`); !testutils.IsError(err, `column "i" does not exist`) {
			t.Fatal(err)
		}
		// Repeating the same without specifying the columns results in a different error.
		if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('b', 'y', 'i')`); !testutils.IsError(err, "INSERT error: table t.test has 2 columns but 3 values were supplied") {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// Check that we can read all the rows and columns.
		_ = mTest.checkQueryResponse(starQuery, initRows)

		var afterInsert, afterUpdate, afterDelete [][]string
		if state == sqlbase.DescriptorMutation_DELETE_ONLY {
			// The default value of "i" for column "i" is not written.
			afterInsert = [][]string{{"a", "z", "q"}, {"c", "x", "NULL"}}
			// Update is a noop for column "i".
			afterUpdate = [][]string{{"a", "u", "q"}, {"c", "x", "NULL"}}
			// Delete also deletes column "i".
			afterDelete = [][]string{{"c", "x", "NULL"}}
		} else {
			// The default value of "i" for column "i" is written.
			afterInsert = [][]string{{"a", "z", "q"}, {"c", "x", "i"}}
			// Update is a noop for column "i".
			afterUpdate = [][]string{{"a", "u", "q"}, {"c", "x", "i"}}
			// Delete also deletes column "i".
			afterDelete = [][]string{{"c", "x", "i"}}
		}
		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})
		// Insert a row into the table.
		if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('c', 'x')`); err != nil {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// Notice that the default value of "i" is only written when the
		// descriptor is in the WRITE_ONLY state.
		_ = mTest.checkQueryResponse(starQuery, afterInsert)

		// The column backfill uses Put instead of CPut because it depends on
		// an UPDATE of a column in the WRITE_ONLY state failing. This test
		// guarantees that.

		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})
		// Updating column "i" for a row fails.
		if _, err := sqlDB.Exec(`UPDATE t.test SET (v, i) = ('u', 'u') WHERE k = 'a'`); !testutils.IsError(err, `column "i" does not exist`) {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// The above failed update was a noop.
		_ = mTest.checkQueryResponse(starQuery, afterInsert)

		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})
		// Update a row without specifying  mutation column "i".
		if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'u' WHERE k = 'a'`); err != nil {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// The update to column "v" is seen; there is no effect on column "i".
		_ = mTest.checkQueryResponse(starQuery, afterUpdate)

		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})
		// Delete row "a".
		if _, err := sqlDB.Exec(`DELETE FROM t.test WHERE k = 'a'`); err != nil {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// Row "a" is deleted. numVals is the number of non-NULL values seen,
		// or the number of KV values belonging to all the rows in the table
		// excluding row "a" since it's deleted.
		numVals := mTest.checkQueryResponse(starQuery, afterDelete)
		// Check that there are no hidden KV values for row "a",
		// and column "i" for row "a" was deleted.
		mTest.checkTableSize(numVals)
	}

	// Check that a mutation can only be inserted with an explicit mutation state, and direction.
	tableDesc = mTest.tableDesc
	tableDesc.Mutations = []sqlbase.DescriptorMutation{{}}
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction NONE, and no column/index descriptor") {
		t.Fatal(err)
	}
	tableDesc.Mutations = []sqlbase.DescriptorMutation{{Descriptor_: &sqlbase.DescriptorMutation_Column{Column: &tableDesc.Columns[len(tableDesc.Columns)-1]}}}
	tableDesc.Columns = tableDesc.Columns[:len(tableDesc.Columns)-1]
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction NONE, col i, id 3") {
		t.Fatal(err)
	}
	tableDesc.Mutations[0].State = sqlbase.DescriptorMutation_DELETE_ONLY
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state DELETE_ONLY, direction NONE, col i, id 3") {
		t.Fatal(err)
	}
	tableDesc.Mutations[0].State = sqlbase.DescriptorMutation_UNKNOWN
	tableDesc.Mutations[0].Direction = sqlbase.DescriptorMutation_DROP
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction DROP, col i, id 3") {
		t.Fatal(err)
	}
}
func TestOperationsWithColumnMutation(t *testing.T) {
	defer leaktest.AfterTest(t)
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	defer csql.TestDisableAsyncSchemaChangeExec()()
	server, sqlDB, kvDB := setup(t)
	defer cleanup(server, sqlDB)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, i CHAR DEFAULT 'i');
`); err != nil {
		t.Fatal(err)
	}

	// read table descriptor
	nameKey := csql.MakeNameMetadataKey(keys.MaxReservedDescID+1, "test")
	gr, err := kvDB.Get(nameKey)
	if err != nil {
		t.Fatal(err)
	}
	if !gr.Exists() {
		t.Fatalf("Name entry %q does not exist", nameKey)
	}
	descKey := csql.MakeDescMetadataKey(csql.ID(gr.ValueInt()))
	desc := &csql.Descriptor{}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}

	mTest := mutationTest{
		T:       t,
		kvDB:    kvDB,
		sqlDB:   sqlDB,
		descKey: descKey,
		desc:    desc,
	}

	starQuery := `SELECT * FROM t.test`
	// Run the tests for both states.
	for _, state := range []csql.DescriptorMutation_State{csql.DescriptorMutation_DELETE_ONLY, csql.DescriptorMutation_WRITE_ONLY} {
		// Init table to start state.
		if _, err := sqlDB.Exec(`TRUNCATE TABLE t.test`); err != nil {
			t.Fatal(err)
		}
		initRows := [][]string{{"a", "z", "q"}}
		for _, row := range initRows {
			if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ($1, $2, $3)`, row[0], row[1], row[2]); err != nil {
				t.Fatal(err)
			}
		}
		// Check that the table only contains the initRows.
		_ = mTest.checkQueryResponse(starQuery, initRows)

		// Add column "i" as a mutation.
		mTest.writeColumnMutation("i", csql.DescriptorMutation{State: state})
		// A direct read of column "i" fails.
		if _, err := sqlDB.Query(`SELECT i FROM t.test`); err == nil {
			t.Fatalf("Read succeeded despite column being in %v state", csql.DescriptorMutation{State: state})
		}
		// The table only contains columns "k" and "v".
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}})

		// Inserting a row into the table while specifying column "i" results in an error.
		if _, err := sqlDB.Exec(`INSERT INTO t.test (k, v, i) VALUES ('b', 'y', 'i')`); !testutils.IsError(err, `column "i" does not exist`) {
			t.Fatal(err)
		}
		// Repeating the same without specifying the columns results in a different error.
		if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('b', 'y', 'i')`); !testutils.IsError(err, "INSERT has more expressions than target columns: 3/2") {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// Check that we can read all the rows and columns.
		_ = mTest.checkQueryResponse(starQuery, initRows)

		var afterInsert, afterUpdate, afterDelete [][]string
		if state == csql.DescriptorMutation_DELETE_ONLY {
			// The default value of "i" for column "i" is not written.
			afterInsert = [][]string{{"a", "z", "q"}, {"c", "x", "NULL"}}
			// Update is a noop for column "i".
			afterUpdate = [][]string{{"a", "u", "q"}, {"c", "x", "NULL"}}
			// Delete also deletes column "i".
			afterDelete = [][]string{{"c", "x", "NULL"}}
		} else {
			// The default value of "i" for column "i" is written.
			afterInsert = [][]string{{"a", "z", "q"}, {"c", "x", "i"}}
			// Update is a noop for column "i".
			afterUpdate = [][]string{{"a", "u", "q"}, {"c", "x", "i"}}
			// Delete also deletes column "i".
			afterDelete = [][]string{{"c", "x", "i"}}
		}
		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", csql.DescriptorMutation{State: state})
		// Insert a row into the table.
		if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('c', 'x')`); err != nil {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// Notice that the default value of "i" is only written when the
		// descriptor is in the WRITE_ONLY state.
		_ = mTest.checkQueryResponse(starQuery, afterInsert)

		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", csql.DescriptorMutation{State: state})
		// Updating column "i" for a row fails.
		if _, err := sqlDB.Exec(`UPDATE t.test SET (v, i) = ('u', 'u') WHERE k = 'a'`); !testutils.IsError(err, `column "i" does not exist`) {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// The above failed update was a noop.
		_ = mTest.checkQueryResponse(starQuery, afterInsert)

		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", csql.DescriptorMutation{State: state})
		// Update a row without specifying  mutation column "i".
		if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'u' WHERE k = 'a'`); err != nil {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// The update to column "v" is seen; there is no effect on column "i".
		_ = mTest.checkQueryResponse(starQuery, afterUpdate)

		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", csql.DescriptorMutation{State: state})
		// Delete row "a".
		if _, err := sqlDB.Exec(`DELETE FROM t.test WHERE k = 'a'`); err != nil {
			t.Fatal(err)
		}
		// Make column "i" live so that it is read.
		mTest.makeMutationsActive()
		// Row "a" is deleted. numVals is the number of non-NULL values seen,
		// or the number of KV values belonging to all the rows in the table
		// excluding row "a" since it's deleted.
		numVals := mTest.checkQueryResponse(starQuery, afterDelete)
		// Check that there are no hidden KV values for row "a",
		// and column "i" for row "a" was deleted.
		mTest.checkTableSize(numVals)
	}

	// Check that a mutation can only be inserted with an explicit mutation state, and direction.
	tableDesc := desc.GetTable()
	tableDesc.Mutations = []csql.DescriptorMutation{{}}
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction NONE, and no column/index descriptor") {
		t.Fatal(err)
	}
	tableDesc.Mutations = []csql.DescriptorMutation{{Descriptor_: &csql.DescriptorMutation_Column{Column: &tableDesc.Columns[len(tableDesc.Columns)-1]}}}
	tableDesc.Columns = tableDesc.Columns[:len(tableDesc.Columns)-1]
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction NONE, col i, id 3") {
		t.Fatal(err)
	}
	tableDesc.Mutations[0].State = csql.DescriptorMutation_DELETE_ONLY
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state DELETE_ONLY, direction NONE, col i, id 3") {
		t.Fatal(err)
	}
	tableDesc.Mutations[0].State = csql.DescriptorMutation_UNKNOWN
	tableDesc.Mutations[0].Direction = csql.DescriptorMutation_DROP
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction DROP, col i, id 3") {
		t.Fatal(err)
	}
}
func TestOperationsWithIndexMutation(t *testing.T) {
	defer leaktest.AfterTest(t)
	// The descriptor changes made must have an immediate effect.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	defer csql.TestDisableAsyncSchemaChangeExec()()
	server, sqlDB, kvDB := setup(t)
	defer cleanup(server, sqlDB)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, INDEX foo (v));
`); err != nil {
		t.Fatal(err)
	}

	// read table descriptor
	nameKey := csql.MakeNameMetadataKey(keys.MaxReservedDescID+1, "test")
	gr, err := kvDB.Get(nameKey)
	if err != nil {
		t.Fatal(err)
	}
	if !gr.Exists() {
		t.Fatalf("Name entry %q does not exist", nameKey)
	}
	descKey := csql.MakeDescMetadataKey(csql.ID(gr.ValueInt()))
	desc := &csql.Descriptor{}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}

	mTest := mutationTest{
		T:       t,
		kvDB:    kvDB,
		sqlDB:   sqlDB,
		descKey: descKey,
		desc:    desc,
	}

	starQuery := `SELECT * FROM t.test`
	indexQuery := `SELECT * FROM t.test@foo`
	// See the effect of the operations depending on the state.
	for _, state := range []csql.DescriptorMutation_State{csql.DescriptorMutation_DELETE_ONLY, csql.DescriptorMutation_WRITE_ONLY} {
		// Init table with some entries.
		if _, err := sqlDB.Exec(`TRUNCATE TABLE t.test`); err != nil {
			t.Fatal(err)
		}
		initRows := [][]string{{"a", "z"}, {"b", "y"}}
		for _, row := range initRows {
			if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ($1, $2)`, row[0], row[1]); err != nil {
				t.Fatal(err)
			}
		}
		_ = mTest.checkQueryResponse(starQuery, initRows)
		// Index foo is visible.
		_ = mTest.checkQueryResponse(indexQuery, [][]string{{"y"}, {"z"}})

		// Index foo is invisible once it's a mutation.
		mTest.writeIndexMutation("foo", csql.DescriptorMutation{State: state})
		if _, err := sqlDB.Query(indexQuery); !testutils.IsError(err, `index "foo" not found`) {
			t.Fatal(err)
		}

		// Insert a new entry.
		if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('c', 'x')`); err != nil {
			t.Fatal(err)
		}
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}, {"b", "y"}, {"c", "x"}})

		// Make index "foo" live so that we can read it.
		mTest.makeMutationsActive()
		if state == csql.DescriptorMutation_DELETE_ONLY {
			// "x" didn't get added to the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"y"}, {"z"}})
		} else {
			// "x" got added to the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"x"}, {"y"}, {"z"}})
		}

		// Make "foo" a mutation.
		mTest.writeIndexMutation("foo", csql.DescriptorMutation{State: state})
		// Update.
		if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'w' WHERE k = 'c'`); err != nil {
			t.Fatal(err)
		}
		// Update "v" to its current value "z" in row "a".
		if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'z' WHERE k = 'a'`); err != nil {
			t.Fatal(err)
		}
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}, {"b", "y"}, {"c", "w"}})

		// Make index "foo" live so that we can read it.
		mTest.makeMutationsActive()
		if state == csql.DescriptorMutation_DELETE_ONLY {
			// updating "x" -> "w" is a noop on the index,
			// updating "z" -> "z" results in "z" being deleted from the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"y"}, {"z"}})
		} else {
			// updating "x" -> "w" results in the index updating from "x" -> "w",
			// updating "z" -> "z" is a noop on the index.
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"w"}, {"y"}, {"z"}})
		}

		// Make "foo" a mutation.
		mTest.writeIndexMutation("foo", csql.DescriptorMutation{State: state})
		// Delete row "b".
		if _, err := sqlDB.Exec(`DELETE FROM t.test WHERE k = 'b'`); err != nil {
			t.Fatal(err)
		}
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z"}, {"c", "w"}})

		// Make index "foo" live so that we can read it.
		mTest.makeMutationsActive()
		// Deleting row "b" deletes "y" from the index.
		if state == csql.DescriptorMutation_DELETE_ONLY {
			mTest.checkQueryResponse(indexQuery, [][]string{{"z"}})
		} else {
			mTest.checkQueryResponse(indexQuery, [][]string{{"w"}, {"z"}})
		}
	}

	// Check that a mutation can only be inserted with an explicit mutation state.
	tableDesc := desc.GetTable()
	tableDesc.Mutations = []csql.DescriptorMutation{{Descriptor_: &csql.DescriptorMutation_Index{Index: &tableDesc.Indexes[len(tableDesc.Indexes)-1]}}}
	tableDesc.Indexes = tableDesc.Indexes[:len(tableDesc.Indexes)-1]
	if err := tableDesc.Validate(); !testutils.IsError(err, "mutation in state UNKNOWN, direction NONE, index foo, id 2") {
		t.Fatal(err)
	}
}
// TestOperationsWithUniqueColumnMutation tests all the operations while an
// index mutation refers to a column mutation.
func TestOperationsWithUniqueColumnMutation(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	ctx, _ := createTestServerContext()
	ctx.TestingKnobs.SQLSchemaChangeManager = &csql.SchemaChangeManagerTestingKnobs{
		AsyncSchemaChangerExecNotification: schemaChangeManagerDisabled,
	}
	server, sqlDB, kvDB := setupWithContext(t, &ctx)
	defer cleanup(server, sqlDB)

	// Create a table with column i and an index on v and i.
	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, i CHAR, INDEX foo (i, v));
`); err != nil {
		t.Fatal(err)
	}

	// read table descriptor
	nameKey := sqlbase.MakeNameMetadataKey(keys.MaxReservedDescID+1, "test")
	gr, err := kvDB.Get(nameKey)
	if err != nil {
		t.Fatal(err)
	}
	if !gr.Exists() {
		t.Fatalf("Name entry %q does not exist", nameKey)
	}
	descKey := sqlbase.MakeDescMetadataKey(sqlbase.ID(gr.ValueInt()))
	desc := &sqlbase.Descriptor{}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}

	mTest := mutationTest{
		T:       t,
		kvDB:    kvDB,
		sqlDB:   sqlDB,
		descKey: descKey,
		desc:    desc,
	}

	starQuery := `SELECT * FROM t.test`
	indexQuery := `SELECT i FROM t.test@foo`
	// Run the tests for both states.
	for _, state := range []sqlbase.DescriptorMutation_State{
		sqlbase.DescriptorMutation_DELETE_ONLY,
		sqlbase.DescriptorMutation_WRITE_ONLY,
	} {
		// Init table to start state.
		if _, err := sqlDB.Exec(`TRUNCATE TABLE t.test`); err != nil {
			t.Fatal(err)
		}
		initRows := [][]string{{"a", "z", "q"}}
		for _, row := range initRows {
			if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ($1, $2, $3)`, row[0], row[1], row[2]); err != nil {
				t.Fatal(err)
			}
		}
		// Check that the table only contains the initRows.
		_ = mTest.checkQueryResponse(starQuery, initRows)

		// Add index "foo" as a mutation.
		mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: state})
		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})

		// Insert a row into the table.
		if _, err := sqlDB.Exec(`INSERT INTO t.test VALUES ('c', 'x')`); err != nil {
			t.Error(err)
		}

		// Make column "i" and index "foo" live.
		mTest.makeMutationsActive()
		// column "i" has no entry.
		_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "z", "q"}, {"c", "x", "NULL"}})
		if state == sqlbase.DescriptorMutation_DELETE_ONLY {
			// No index entry for row "c"
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"q"}})
		} else {
			// Index entry for row "c"
			_ = mTest.checkQueryResponse(indexQuery, [][]string{{"NULL"}, {"q"}})
		}

		// Add index "foo" as a mutation.
		mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: state})
		// Make column "i" a mutation.
		mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})

		// Updating column "i" for a row fails.
		if _, err := sqlDB.Exec(`UPDATE t.test SET (v, i) = ('u', 'u') WHERE k = 'a'`); !testutils.IsError(err, `column "i" does not exist`) {
			t.Error(err)
		}

		// TODO(vivek): Fix #6691.
		// Update a row without specifying  mutation column "i".
		//if _, err := sqlDB.Exec(`UPDATE t.test SET v = 'u' WHERE k = 'a'`); err != nil {
		//	t.Error(err)
		//}
		// Make column "i" and index "foo" live.
		mTest.makeMutationsActive()

		// The update to column "v" is seen; there is no effect on column "i".
		//_ = mTest.checkQueryResponse(starQuery, [][]string{{"a", "u", "q"}, {"c", "x", "NULL"}})
		// No change in index "foo"
		//if state == sqlbase.DescriptorMutation_DELETE_ONLY {
		//	_ = mTest.checkQueryResponse(indexQuery, [][]string{{"q"}})
		//} else {
		//	_ = mTest.checkQueryResponse(indexQuery, [][]string{{"NULL"}, {"q"}})
		//}

		// Add index "foo" as a mutation.
		//mTest.writeIndexMutation("foo", sqlbase.DescriptorMutation{State: state})
		// Make column "i" a mutation.
		//mTest.writeColumnMutation("i", sqlbase.DescriptorMutation{State: state})

		// Delete row "a".
		//if _, err := sqlDB.Exec(`DELETE FROM t.test WHERE k = 'a'`); err != nil {
		//	t.Error(err)
		//}
		// Make column "i" and index "foo" live.
		// mTest.makeMutationsActive()
		// Row "a" is deleted. numVals is the number of non-NULL values seen,
		// or the number of KV values belonging to all the rows in the table
		// excluding row "a" since it's deleted.
		//numVals := mTest.checkQueryResponse(starQuery, [][]string{{"c", "x", "NULL"}})
		//if state == sqlbase.DescriptorMutation_DELETE_ONLY {
		//	_ = mTest.checkQueryResponse(indexQuery, [][]string{})
		//} else {
		//	_ = mTest.checkQueryResponse(indexQuery, [][]string{{"NULL"}})
		//}
		// Check that there are no hidden KV values for row "a",
		// and column "i" for row "a" was deleted.
		//mTest.checkTableSize(numVals)
	}
}
func TestAsyncSchemaChanger(t *testing.T) {
	defer leaktest.AfterTest(t)
	// Disable synchronous schema change execution so
	// the asynchronous schema changer executes all
	// schema changes.
	defer csql.TestDisableSyncSchemaChangeExec()()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	server, sqlDB, kvDB := setup(t)
	defer cleanup(server, sqlDB)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR);
INSERT INTO t.test VALUES ('a', 'b'), ('c', 'd');
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor for version.
	nameKey := csql.MakeNameMetadataKey(keys.MaxReservedDescID+1, "test")
	gr, err := kvDB.Get(nameKey)
	if err != nil {
		t.Fatal(err)
	}
	if !gr.Exists() {
		t.Fatalf("Name entry %q does not exist", nameKey)
	}
	descKey := csql.MakeDescMetadataKey(csql.ID(gr.ValueInt()))
	desc := &csql.Descriptor{}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	// A long running schema change operation runs through
	// a state machine that increments the version by 3.
	expectedVersion := desc.GetTable().Version + 3

	// Run some schema change
	if _, err := sqlDB.Exec(`
CREATE INDEX foo ON t.test (v)
`); err != nil {
		t.Fatal(err)
	}

	retryOpts := retry.Options{
		InitialBackoff: 20 * time.Millisecond,
		MaxBackoff:     200 * time.Millisecond,
		Multiplier:     2,
	}

	// Wait until index is created.
	for r := retry.Start(retryOpts); r.Next(); {
		if err := kvDB.GetProto(descKey, desc); err != nil {
			t.Fatal(err)
		}
		if len(desc.GetTable().Indexes) == 1 {
			break
		}
	}

	// Ensure that the indexes have been created.
	mTest := mutationTest{
		T:       t,
		kvDB:    kvDB,
		sqlDB:   sqlDB,
		descKey: descKey,
		desc:    desc,
	}
	indexQuery := `SELECT * FROM t.test@foo`
	_ = mTest.checkQueryResponse(indexQuery, [][]string{{"b"}, {"d"}})

	// Ensure that the version has been incremented.
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	newVersion := desc.GetTable().Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}

	// Apply a schema change that only sets the UpVersion bit.
	expectedVersion = newVersion + 1

	if _, err := sqlDB.Exec(`
ALTER INDEX t.test@foo RENAME TO ufo
`); err != nil {
		t.Fatal(err)
	}

	for r := retry.Start(retryOpts); r.Next(); {
		// Ensure that the version gets incremented.
		if err := kvDB.GetProto(descKey, desc); err != nil {
			t.Fatal(err)
		}
		name := desc.GetTable().Indexes[0].Name
		if name != "ufo" {
			t.Fatalf("bad index name %s", name)
		}
		newVersion = desc.GetTable().Version
		if newVersion == expectedVersion {
			break
		}
	}

	// Run many schema changes simultaneously and check
	// that they all get executed.
	count := 5
	for i := 0; i < count; i++ {
		cmd := fmt.Sprintf(`CREATE INDEX foo%d ON t.test (v)`, i)
		if _, err := sqlDB.Exec(cmd); err != nil {
			t.Fatal(err)
		}
	}
	// Wait until indexes are created.
	for r := retry.Start(retryOpts); r.Next(); {
		if err := kvDB.GetProto(descKey, desc); err != nil {
			t.Fatal(err)
		}
		if len(desc.GetTable().Indexes) == count+1 {
			break
		}
	}
	for i := 0; i < count; i++ {
		indexQuery := fmt.Sprintf(`SELECT * FROM t.test@foo%d`, i)
		_ = mTest.checkQueryResponse(indexQuery, [][]string{{"b"}, {"d"}})
	}
}
func TestSchemaChangeProcess(t *testing.T) {
	defer leaktest.AfterTest(t)
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	defer csql.TestDisableAsyncSchemaChangeExec()()
	server, sqlDB, kvDB := setup(t)
	defer cleanup(server, sqlDB)
	var id = csql.ID(keys.MaxReservedDescID + 2)
	var node = roachpb.NodeID(2)
	db := server.DB()
	leaseMgr := csql.NewLeaseManager(0, *db, hlc.NewClock(hlc.UnixNano))
	changer := csql.NewSchemaChangerForTesting(id, 0, node, *db, leaseMgr)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, INDEX foo(v));
INSERT INTO t.test VALUES ('a', 'b'), ('c', 'd');
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor for version.
	nameKey := csql.MakeNameMetadataKey(keys.MaxReservedDescID+1, "test")
	gr, err := kvDB.Get(nameKey)
	if err != nil {
		t.Fatal(err)
	}
	if !gr.Exists() {
		t.Fatalf("Name entry %q does not exist", nameKey)
	}
	descKey := csql.MakeDescMetadataKey(csql.ID(gr.ValueInt()))
	desc := &csql.Descriptor{}

	// Check that MaybeIncrementVersion doesn't increment the version
	// when the up_version bit is not set.
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	expectedVersion := desc.GetTable().Version

	if err := changer.MaybeIncrementVersion(); err != nil {
		t.Fatal(err)
	}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	newVersion := desc.GetTable().Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err := changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", desc.GetTable())
	}

	// Check that MaybeIncrementVersion increments the version
	// correctly.
	expectedVersion++
	desc.GetTable().UpVersion = true
	if err := kvDB.Put(descKey, desc); err != nil {
		t.Fatal(err)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if isDone {
		t.Fatalf("table expected to have an outstanding schema change: %v", desc.GetTable())
	}
	if err := changer.MaybeIncrementVersion(); err != nil {
		t.Fatal(err)
	}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	newVersion = desc.GetTable().Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", desc.GetTable())
	}

	// Check that RunStateMachineBeforeBackfill doesn't do anything
	// if there are no mutations queued.
	if err := changer.RunStateMachineBeforeBackfill(); err != nil {
		t.Fatal(err)
	}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	newVersion = desc.GetTable().Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}

	// Check that RunStateMachineBeforeBackfill functions properly.
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	table := desc.GetTable()
	expectedVersion = table.Version
	// Make a copy of the index for use in a mutation.
	index := proto.Clone(&table.Indexes[0]).(*csql.IndexDescriptor)
	index.Name = "bar"
	index.ID = table.NextIndexID
	table.NextIndexID++
	changer = csql.NewSchemaChangerForTesting(id, table.NextMutationID, node, *db, leaseMgr)
	table.Mutations = append(table.Mutations, csql.DescriptorMutation{
		Descriptor_: &csql.DescriptorMutation_Index{Index: index},
		Direction:   csql.DescriptorMutation_ADD,
		State:       csql.DescriptorMutation_DELETE_ONLY,
		MutationID:  table.NextMutationID,
	})
	table.NextMutationID++

	// Run state machine in both directions.
	for _, direction := range []csql.DescriptorMutation_Direction{csql.DescriptorMutation_ADD, csql.DescriptorMutation_DROP} {
		table.Mutations[0].Direction = direction
		expectedVersion++
		if err := kvDB.Put(descKey, desc); err != nil {
			t.Fatal(err)
		}
		// The expected end state.
		expectedState := csql.DescriptorMutation_WRITE_ONLY
		if direction == csql.DescriptorMutation_DROP {
			expectedState = csql.DescriptorMutation_DELETE_ONLY
		}
		// Run two times to ensure idempotency of operations.
		for i := 0; i < 2; i++ {
			if err := changer.RunStateMachineBeforeBackfill(); err != nil {
				t.Fatal(err)
			}
			if err := kvDB.GetProto(descKey, desc); err != nil {
				t.Fatal(err)
			}
			table = desc.GetTable()
			newVersion = table.Version
			if newVersion != expectedVersion {
				t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
			}
			state := table.Mutations[0].State
			if state != expectedState {
				t.Fatalf("bad state; e = %d, v = %d", expectedState, state)
			}
		}
	}
	// RunStateMachineBeforeBackfill() doesn't complete the schema change.
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if isDone {
		t.Fatalf("table expected to have an outstanding schema change: %v", desc.GetTable())
	}

}
func TestAsyncSchemaChanger(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable synchronous schema change execution so the asynchronous schema
	// changer executes all schema changes.
	params, _ := createTestServerParams()
	params.Knobs = base.TestingKnobs{
		SQLExecutor: &csql.ExecutorTestingKnobs{
			SyncSchemaChangersFilter: func(tscc csql.TestingSchemaChangerCollection) {
				tscc.ClearSchemaChangers()
			},
		},
		SQLSchemaChangeManager: &csql.SchemaChangeManagerTestingKnobs{
			AsyncSchemaChangerExecQuickly: true,
		},
	}
	s, sqlDB, kvDB := serverutils.StartServer(t, params)
	defer s.Stopper().Stop()

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR);
INSERT INTO t.test VALUES ('a', 'b'), ('c', 'd');
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor for version.
	tableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")

	// A long running schema change operation runs through
	// a state machine that increments the version by 3.
	expectedVersion := tableDesc.Version + 3

	// Run some schema change
	if _, err := sqlDB.Exec(`
CREATE INDEX foo ON t.test (v)
`); err != nil {
		t.Fatal(err)
	}

	retryOpts := retry.Options{
		InitialBackoff: 20 * time.Millisecond,
		MaxBackoff:     200 * time.Millisecond,
		Multiplier:     2,
	}

	// Wait until index is created.
	for r := retry.Start(retryOpts); r.Next(); {
		tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")
		if len(tableDesc.Indexes) == 1 {
			break
		}
	}

	// Ensure that the indexes have been created.
	mTest := mutationTest{
		T:         t,
		kvDB:      kvDB,
		sqlDB:     sqlDB,
		tableDesc: tableDesc,
	}
	indexQuery := `SELECT v FROM t.test@foo`
	_ = mTest.checkQueryResponse(indexQuery, [][]string{{"b"}, {"d"}})

	// Ensure that the version has been incremented.
	tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")
	newVersion := tableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}

	// Apply a schema change that only sets the UpVersion bit.
	expectedVersion = newVersion + 1

	if _, err := sqlDB.Exec(`
ALTER INDEX t.test@foo RENAME TO ufo
`); err != nil {
		t.Fatal(err)
	}

	for r := retry.Start(retryOpts); r.Next(); {
		// Ensure that the version gets incremented.
		tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")
		name := tableDesc.Indexes[0].Name
		if name != "ufo" {
			t.Fatalf("bad index name %s", name)
		}
		newVersion = tableDesc.Version
		if newVersion == expectedVersion {
			break
		}
	}

	// Run many schema changes simultaneously and check
	// that they all get executed.
	count := 5
	for i := 0; i < count; i++ {
		cmd := fmt.Sprintf(`CREATE INDEX foo%d ON t.test (v)`, i)
		if _, err := sqlDB.Exec(cmd); err != nil {
			t.Fatal(err)
		}
	}
	// Wait until indexes are created.
	for r := retry.Start(retryOpts); r.Next(); {
		tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")
		if len(tableDesc.Indexes) == count+1 {
			break
		}
	}
	for i := 0; i < count; i++ {
		indexQuery := fmt.Sprintf(`SELECT v FROM t.test@foo%d`, i)
		_ = mTest.checkQueryResponse(indexQuery, [][]string{{"b"}, {"d"}})
	}
}
func TestSchemaChangeProcess(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()

	params, _ := createTestServerParams()
	// Disable external processing of mutations.
	params.Knobs.SQLSchemaChangeManager = &csql.SchemaChangeManagerTestingKnobs{
		AsyncSchemaChangerExecNotification: schemaChangeManagerDisabled,
	}
	s, sqlDB, kvDB := serverutils.StartServer(t, params)
	defer s.Stopper().Stop()

	var id = sqlbase.ID(keys.MaxReservedDescID + 2)
	var node = roachpb.NodeID(2)
	stopper := stop.NewStopper()
	leaseMgr := csql.NewLeaseManager(0, *kvDB, hlc.NewClock(hlc.UnixNano), csql.LeaseManagerTestingKnobs{}, stopper)
	defer stopper.Stop()
	changer := csql.NewSchemaChangerForTesting(id, 0, node, *kvDB, leaseMgr)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, INDEX foo(v));
INSERT INTO t.test VALUES ('a', 'b'), ('c', 'd');
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor for version.
	tableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")

	expectedVersion := tableDesc.Version

	desc, err := changer.MaybeIncrementVersion()
	if err != nil {
		t.Fatal(err)
	}
	tableDesc = desc.GetTable()
	newVersion := tableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err := changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", tableDesc)
	}

	// Check that MaybeIncrementVersion increments the version
	// correctly.
	expectedVersion++
	tableDesc.UpVersion = true
	if err := kvDB.Put(
		sqlbase.MakeDescMetadataKey(tableDesc.ID),
		sqlbase.WrapDescriptor(tableDesc),
	); err != nil {
		t.Fatal(err)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if isDone {
		t.Fatalf("table expected to have an outstanding schema change: %v", desc.GetTable())
	}
	desc, err = changer.MaybeIncrementVersion()
	if err != nil {
		t.Fatal(err)
	}
	tableDesc = desc.GetTable()
	savedTableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")
	newVersion = tableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version in returned desc; e = %d, v = %d", expectedVersion, newVersion)
	}
	newVersion = savedTableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version in saved desc; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", tableDesc)
	}

	// Check that RunStateMachineBeforeBackfill doesn't do anything
	// if there are no mutations queued.
	if err := changer.RunStateMachineBeforeBackfill(); err != nil {
		t.Fatal(err)
	}

	tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")
	newVersion = tableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}

	// Check that RunStateMachineBeforeBackfill functions properly.
	expectedVersion = tableDesc.Version
	// Make a copy of the index for use in a mutation.
	index := protoutil.Clone(&tableDesc.Indexes[0]).(*sqlbase.IndexDescriptor)
	index.Name = "bar"
	index.ID = tableDesc.NextIndexID
	tableDesc.NextIndexID++
	changer = csql.NewSchemaChangerForTesting(id, tableDesc.NextMutationID, node, *kvDB, leaseMgr)
	tableDesc.Mutations = append(tableDesc.Mutations, sqlbase.DescriptorMutation{
		Descriptor_: &sqlbase.DescriptorMutation_Index{Index: index},
		Direction:   sqlbase.DescriptorMutation_ADD,
		State:       sqlbase.DescriptorMutation_DELETE_ONLY,
		MutationID:  tableDesc.NextMutationID,
	})
	tableDesc.NextMutationID++

	// Run state machine in both directions.
	for _, direction := range []sqlbase.DescriptorMutation_Direction{sqlbase.DescriptorMutation_ADD, sqlbase.DescriptorMutation_DROP} {
		tableDesc.Mutations[0].Direction = direction
		expectedVersion++
		if err := kvDB.Put(
			sqlbase.MakeDescMetadataKey(tableDesc.ID),
			sqlbase.WrapDescriptor(tableDesc),
		); err != nil {
			t.Fatal(err)
		}
		// The expected end state.
		expectedState := sqlbase.DescriptorMutation_WRITE_ONLY
		if direction == sqlbase.DescriptorMutation_DROP {
			expectedState = sqlbase.DescriptorMutation_DELETE_ONLY
		}
		// Run two times to ensure idempotency of operations.
		for i := 0; i < 2; i++ {
			if err := changer.RunStateMachineBeforeBackfill(); err != nil {
				t.Fatal(err)
			}

			tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")
			newVersion = tableDesc.Version
			if newVersion != expectedVersion {
				t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
			}
			state := tableDesc.Mutations[0].State
			if state != expectedState {
				t.Fatalf("bad state; e = %d, v = %d", expectedState, state)
			}
		}
	}
	// RunStateMachineBeforeBackfill() doesn't complete the schema change.
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if isDone {
		t.Fatalf("table expected to have an outstanding schema change: %v", tableDesc)
	}

}