VDiff: Support diffing tables without a defined Primary Key

go/test/endtoend/vreplication/config_test.go

@@ -60,6 +60,7 @@ create table geom_tbl (id int, g geometry, p point, ls linestring, pg polygon, m
 create table  ` + "`blüb_tbl`" + ` (id int, val1 varchar(20), ` + "`blöb1`" + ` blob, val2 varbinary(20), ` + "`bl@b2`" + ` longblob, txt1 text, blb3 tinyblob, txt2 longtext, blb4 mediumblob, primary key(id));
 create table reftable (id int, val1 varchar(20), primary key(id), key(val1));
 create table loadtest (id int, name varchar(256), primary key(id), key(name));
+create table nopk (name varchar(128), age int unsigned);
 `
 	// These should always be ignored in vreplication
 	internalSchema = `
@@ -94,6 +95,7 @@ create table loadtest (id int, name varchar(256), primary key(id), key(name));
     "db_order_test": {},
     "vdiff_order": {},
     "datze": {},
+    "nopk": {},
     "reftable": {
       "type": "reference"
     }
@@ -216,6 +218,14 @@ create table loadtest (id int, name varchar(256), primary key(id), key(name));
         }
       ]
     },
+    "nopk": {
+      "column_vindexes": [
+        {
+          "columns": ["name"],
+          "name": "unicode_loose_md5"
+        }
+      ]
+    },
     "reftable": {
       "type": "reference"
     }

go/test/endtoend/vreplication/vdiff2_test.go

@@ -70,7 +70,7 @@ var testCases = []*testCase{
 		sourceShards:        "0",
 		targetShards:        "-80,80-",
 		tabletBaseID:        200,
-		tables:              "customer,Lead,Lead-1",
+		tables:              "customer,Lead,Lead-1,nopk",
 		autoRetryError:      true,
 		retryInsert:         `insert into customer(cid, name, typ) values(1991234, 'Testy McTester', 'soho')`,
 		resume:              true,
@@ -117,7 +117,7 @@ func TestVDiff2(t *testing.T) {
 	sourceShards := []string{"0"}
 	targetKs := "customer"
 	targetShards := []string{"-80", "80-"}
-	// This forces us to use multiple vstream packets even with small test tables
+	// This forces us to use multiple vstream packets even with small test tables.
 	extraVTTabletArgs = []string{"--vstream_packet_size=1"}
 
 	vc = NewVitessCluster(t, "TestVDiff2", strings.Split(allCellNames, ","), mainClusterConfig)
@@ -150,7 +150,11 @@ func TestVDiff2(t *testing.T) {
 	query := `insert into customer(cid, name, typ, sport) values(1001, null, 'soho','')`
 	execVtgateQuery(t, vtgateConn, fmt.Sprintf("%s:%s", sourceKs, sourceShards[0]), query)
 
-	generateMoreCustomers(t, sourceKs, 100)
+	generateMoreCustomers(t, sourceKs, 1000)
+
+	// Create rows in the nopk table using the customer names and random ages between 20 and 100.
+	_, err = vtgateConn.ExecuteFetch(fmt.Sprintf("insert into %s.nopk(name, age) select name, floor(rand()*80)+20 from %s.customer", sourceKs, sourceKs), -1, false)
+	require.NoError(t, err, "failed to insert rows into nopk table: %v", err)
 
 	// The primary tablet is only added in the first cell.
 	// We ONLY add primary tablets in this test.

go/vt/mysqlctl/mysql_daemon.go

@@ -94,7 +94,6 @@ type MysqlDaemon interface {
 	GetSchema(ctx context.Context, dbName string, request *tabletmanagerdatapb.GetSchemaRequest) (*tabletmanagerdatapb.SchemaDefinition, error)
 	GetColumns(ctx context.Context, dbName, table string) ([]*querypb.Field, []string, error)
 	GetPrimaryKeyColumns(ctx context.Context, dbName, table string) ([]string, error)
-	GetPrimaryKeyEquivalentColumns(ctx context.Context, dbName, table string) ([]string, string, error)
 	PreflightSchemaChange(ctx context.Context, dbName string, changes []string) ([]*tabletmanagerdatapb.SchemaChangeResult, error)
 	ApplySchemaChange(ctx context.Context, dbName string, change *tmutils.SchemaChange) (*tabletmanagerdatapb.SchemaChangeResult, error)
 

go/vt/mysqlctl/schema.go

@@ -579,13 +579,7 @@ func (mysqld *Mysqld) ApplySchemaChange(ctx context.Context, dbName string, chan
 // defined PRIMARY KEY then it may return the columns for
 // that index if it is likely the most efficient one amongst
 // the available PKE indexes on the table.
-func (mysqld *Mysqld) GetPrimaryKeyEquivalentColumns(ctx context.Context, dbName, table string) ([]string, string, error) {
-	conn, err := getPoolReconnect(ctx, mysqld.dbaPool)
-	if err != nil {
-		return nil, "", err
-	}
-	defer conn.Recycle()
-
+func GetPrimaryKeyEquivalentColumns(ctx context.Context, exec func(string, int, bool) (*sqltypes.Result, error), dbName, table string) ([]string, string, error) {
 	// We use column name aliases to guarantee lower case for our named results.
 	sql := `
             SELECT index_cols.COLUMN_NAME AS column_name, index_cols.INDEX_NAME as index_name FROM information_schema.STATISTICS AS index_cols INNER JOIN
@@ -629,7 +623,7 @@ func (mysqld *Mysqld) GetPrimaryKeyEquivalentColumns(ctx context.Context, dbName
 	encodedDbName := encodeEntityName(dbName)
 	encodedTable := encodeEntityName(table)
 	sql = fmt.Sprintf(sql, encodedDbName, encodedTable, encodedDbName, encodedTable, encodedDbName, encodedTable)
-	qr, err := conn.Conn.ExecuteFetch(sql, 1000, true)
+	qr, err := exec(sql, 1000, true)
 	if err != nil {
 		return nil, "", err
 	}

go/vt/vttablet/tabletmanager/vdiff/framework_test.go

@@ -100,16 +100,26 @@ var (
 				Columns:           []string{"id", "dt"},
 				PrimaryKeyColumns: []string{"id"},
 				Fields:            sqltypes.MakeTestFields("id|dt", "int64|datetime"),
+			}, {
+				Name:    "nopk",
+				Columns: []string{"c1", "c2", "c3"},
+				Fields:  sqltypes.MakeTestFields("c1|c2|c3", "int64|int64|int64"),
+			}, {
+				Name:    "nopkwithpke",
+				Columns: []string{"c1", "c2", "c3"},
+				Fields:  sqltypes.MakeTestFields("c1|c2|c3", "int64|int64|int64"),
 			},
 		},
 	}
 	tableDefMap = map[string]int{
-		"t1":        0,
-		"nonpktext": 1,
-		"pktext":    2,
-		"multipk":   3,
-		"aggr":      4,
-		"datze":     5,
+		"t1":          0,
+		"nonpktext":   1,
+		"pktext":      2,
+		"multipk":     3,
+		"aggr":        4,
+		"datze":       5,
+		"nopk":        6,
+		"nopkwithpke": 7,
 	}
 )
 

go/vt/vttablet/tabletmanager/vdiff/table_plan.go

@@ -17,21 +17,23 @@ limitations under the License.
 package vdiff
 
 import (
+	"context"
 	"fmt"
 	"strings"
 
 	"vitess.io/vitess/go/mysql/collations"
 	"vitess.io/vitess/go/sqltypes"
 	"vitess.io/vitess/go/vt/binlog/binlogplayer"
-	tabletmanagerdatapb "vitess.io/vitess/go/vt/proto/tabletmanagerdata"
-	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
-	"vitess.io/vitess/go/vt/vterrors"
-
 	"vitess.io/vitess/go/vt/log"
-	querypb "vitess.io/vitess/go/vt/proto/query"
+	"vitess.io/vitess/go/vt/mysqlctl"
 	"vitess.io/vitess/go/vt/sqlparser"
+	"vitess.io/vitess/go/vt/vterrors"
 	"vitess.io/vitess/go/vt/vtgate/engine"
 	"vitess.io/vitess/go/vt/vtgate/engine/opcode"
+
+	querypb "vitess.io/vitess/go/vt/proto/query"
+	tabletmanagerdatapb "vitess.io/vitess/go/vt/proto/tabletmanagerdata"
+	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
 )
 
 const sqlSelectColumnCollations = "select column_name as column_name, collation_name as collation_name from information_schema.columns where table_schema=%a and table_name=%a and column_name in %a"
@@ -75,7 +77,7 @@ func (td *tableDiffer) buildTablePlan(dbClient binlogplayer.DBClient, dbName str
 
 	sourceSelect := &sqlparser.Select{}
 	targetSelect := &sqlparser.Select{}
-	// aggregates is the list of Aggregate functions, if any.
+	// Aggregates is the list of Aggregate functions, if any.
 	var aggregates []*engine.AggregateParams
 	for _, selExpr := range sel.SelectExprs {
 		switch selExpr := selExpr.(type) {
@@ -153,10 +155,25 @@ func (td *tableDiffer) buildTablePlan(dbClient binlogplayer.DBClient, dbName str
 		},
 	}
 
+	if len(tp.table.PrimaryKeyColumns) == 0 {
+		// We use the columns from a PKE if there is one.
+		pkeCols, err := tp.getPKEquivalentColumns(dbClient)
+		if err != nil {
+			return nil, vterrors.Wrapf(err, "error getting PK equivalent columns for table %s", tp.table.Name)
+		}
+		if len(pkeCols) > 0 {
+			tp.table.PrimaryKeyColumns = append(tp.table.PrimaryKeyColumns, pkeCols...)
+		} else {
+			// We use every column together as a substitute PK.
+			tp.table.PrimaryKeyColumns = append(tp.table.PrimaryKeyColumns, tp.table.Columns...)
+		}
+	}
+
 	err = tp.findPKs(dbClient, targetSelect, collationEnv)
 	if err != nil {
 		return nil, err
 	}
+
 	// Remove in_keyrange. It's not understood by mysql.
 	sourceSelect.Where = sel.Where // removeKeyrange(sel.Where)
 	// The source should also perform the group by.
@@ -178,6 +195,9 @@ func (td *tableDiffer) buildTablePlan(dbClient binlogplayer.DBClient, dbName str
 
 // findPKs identifies PKs and removes them from the columns to do data comparison.
 func (tp *tablePlan) findPKs(dbClient binlogplayer.DBClient, targetSelect *sqlparser.Select, collationEnv *collations.Environment) error {
+	if len(tp.table.PrimaryKeyColumns) == 0 {
+		return nil
+	}
 	var orderby sqlparser.OrderBy
 	for _, pk := range tp.table.PrimaryKeyColumns {
 		found := false
@@ -196,7 +216,7 @@ func (tp *tablePlan) findPKs(dbClient binlogplayer.DBClient, targetSelect *sqlpa
 				tp.compareCols[i].isPK = true
 				tp.comparePKs = append(tp.comparePKs, tp.compareCols[i])
 				tp.selectPks = append(tp.selectPks, i)
-				// We'll be comparing pks separately. So, remove them from compareCols.
+				// We'll be comparing PKs separately. So, remove them from compareCols.
 				tp.pkCols = append(tp.pkCols, i)
 				found = true
 				break
@@ -224,6 +244,9 @@ func (tp *tablePlan) findPKs(dbClient binlogplayer.DBClient, targetSelect *sqlpa
 // saves the collations in the tablePlan's comparePKs column info
 // structs for those subsequent operations.
 func (tp *tablePlan) getPKColumnCollations(dbClient binlogplayer.DBClient, collationEnv *collations.Environment) error {
+	if len(tp.comparePKs) == 0 {
+		return nil
+	}
 	columnList := make([]string, len(tp.comparePKs))
 	for i := range tp.comparePKs {
 		columnList[i] = tp.comparePKs[i].colName
@@ -259,3 +282,17 @@ func (tp *tablePlan) getPKColumnCollations(dbClient binlogplayer.DBClient, colla
 	}
 	return nil
 }
+
+func (tp *tablePlan) getPKEquivalentColumns(dbClient binlogplayer.DBClient) ([]string, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), BackgroundOperationTimeout/2)
+	defer cancel()
+	executeFetch := func(query string, maxrows int, wantfields bool) (*sqltypes.Result, error) {
+		// This sets wantfields to true.
+		return dbClient.ExecuteFetch(query, maxrows)
+	}
+	pkeCols, _, err := mysqlctl.GetPrimaryKeyEquivalentColumns(ctx, executeFetch, tp.dbName, tp.table.Name)
+	if err != nil {
+		return nil, err
+	}
+	return pkeCols, nil
+}