[release-17.0] vtexplain: Fix setting up the column information (#15275…

…) (#15280)

Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
Co-authored-by: vitess-bot[bot] <108069721+vitess-bot[bot]@users.noreply.github.com>

go/vt/mysqlctl/schema.go

@@ -60,12 +60,6 @@ func (mysqld *Mysqld) executeSchemaCommands(sql string) error {
 	return mysqld.executeMysqlScript(params, strings.NewReader(sql))
 }
 
-func encodeEntityName(name string) string {
-	var buf strings.Builder
-	sqltypes.NewVarChar(name).EncodeSQL(&buf)
-	return buf.String()
-}
-
 // tableListSQL returns an IN clause "('t1', 't2'...) for a list of tables."
 func tableListSQL(tables []string) (string, error) {
 	if len(tables) == 0 {
@@ -74,7 +68,7 @@ func tableListSQL(tables []string) (string, error) {
 
 	encodedTables := make([]string, len(tables))
 	for i, tableName := range tables {
-		encodedTables[i] = encodeEntityName(tableName)
+		encodedTables[i] = sqltypes.EncodeStringSQL(tableName)
 	}
 
 	return "(" + strings.Join(encodedTables, ", ") + ")", nil
@@ -302,9 +296,9 @@ func GetColumnsList(dbName, tableName string, exec func(string, int, bool) (*sql
 	if dbName == "" {
 		dbName2 = "database()"
 	} else {
-		dbName2 = encodeEntityName(dbName)
+		dbName2 = sqltypes.EncodeStringSQL(dbName)
 	}
-	query := fmt.Sprintf(GetColumnNamesQuery, dbName2, encodeEntityName(sqlescape.UnescapeID(tableName)))
+	query := fmt.Sprintf(GetColumnNamesQuery, dbName2, sqltypes.EncodeStringSQL(sqlescape.UnescapeID(tableName)))
 	qr, err := exec(query, -1, true)
 	if err != nil {
 		return "", err
@@ -391,7 +385,7 @@ func (mysqld *Mysqld) getPrimaryKeyColumns(ctx context.Context, dbName string, t
             FROM information_schema.STATISTICS
             WHERE TABLE_SCHEMA = %s AND TABLE_NAME IN %s AND LOWER(INDEX_NAME) = 'primary'
             ORDER BY table_name, SEQ_IN_INDEX`
-	sql = fmt.Sprintf(sql, encodeEntityName(dbName), tableList)
+	sql = fmt.Sprintf(sql, sqltypes.EncodeStringSQL(dbName), tableList)
 	qr, err := conn.ExecuteFetch(sql, len(tables)*100, true)
 	if err != nil {
 		return nil, err
@@ -620,8 +614,8 @@ func (mysqld *Mysqld) GetPrimaryKeyEquivalentColumns(ctx context.Context, dbName
             ) AS pke ON index_cols.INDEX_NAME = pke.INDEX_NAME
             WHERE index_cols.TABLE_SCHEMA = %s AND index_cols.TABLE_NAME = %s AND NON_UNIQUE = 0 AND NULLABLE != 'YES'
             ORDER BY SEQ_IN_INDEX ASC`
-	encodedDbName := encodeEntityName(dbName)
-	encodedTable := encodeEntityName(table)
+	encodedDbName := sqltypes.EncodeStringSQL(dbName)
+	encodedTable := sqltypes.EncodeStringSQL(table)
 	sql = fmt.Sprintf(sql, encodedDbName, encodedTable, encodedDbName, encodedTable, encodedDbName, encodedTable)
 	qr, err := conn.ExecuteFetch(sql, 1000, true)
 	if err != nil {

go/vt/vtexplain/vtexplain_vttablet.go

@@ -454,8 +454,8 @@ func newTabletEnvironment(ddls []sqlparser.DDLStatement, opts *Options) (*tablet
 			}
 			tEnv.addResult(query, tEnv.getResult(likeQuery))
 
-			likeQuery = fmt.Sprintf(mysqlctl.GetColumnNamesQuery, "database()", sqlescape.UnescapeID(likeTable))
-			query = fmt.Sprintf(mysqlctl.GetColumnNamesQuery, "database()", sqlescape.UnescapeID(table))
+			likeQuery = fmt.Sprintf(mysqlctl.GetColumnNamesQuery, "database()", sqltypes.EncodeStringSQL(sqlescape.UnescapeID(likeTable)))
+			query = fmt.Sprintf(mysqlctl.GetColumnNamesQuery, "database()", sqltypes.EncodeStringSQL(sqlescape.UnescapeID(table)))
 			if tEnv.getResult(likeQuery) == nil {
 				return nil, fmt.Errorf("check your schema, table[%s] doesn't exist", likeTable)
 			}
@@ -496,7 +496,7 @@ func newTabletEnvironment(ddls []sqlparser.DDLStatement, opts *Options) (*tablet
 		tEnv.addResult("SELECT * FROM "+backtickedTable+" WHERE 1 != 1", &sqltypes.Result{
 			Fields: rowTypes,
 		})
-		query := fmt.Sprintf(mysqlctl.GetColumnNamesQuery, "database()", sqlescape.UnescapeID(table))
+		query := fmt.Sprintf(mysqlctl.GetColumnNamesQuery, "database()", sqltypes.EncodeStringSQL(sqlescape.UnescapeID(table)))
 		tEnv.addResult(query, &sqltypes.Result{
 			Fields: colTypes,
 			Rows:   colValues,
@@ -598,7 +598,7 @@ func (t *explainTablet) handleSelect(query string) (*sqltypes.Result, error) {
 
 	// Gen4 supports more complex queries so we now need to
 	// handle multiple FROM clauses
-	tables := make([]*sqlparser.AliasedTableExpr, len(selStmt.From))
+	tables := make([]*sqlparser.AliasedTableExpr, 0, len(selStmt.From))
 	for _, from := range selStmt.From {
 		tables = append(tables, getTables(from)...)
 	}

go/vt/vtexplain/vtexplain_vttablet_test.go

@@ -71,6 +71,10 @@ create table t2 (
 	require.NoError(t, err)
 	defer vte.Stop()
 
+	// Check if the correct schema query is registered.
+	_, found := vte.globalTabletEnv.schemaQueries["SELECT COLUMN_NAME as column_name\n\t\tFROM INFORMATION_SCHEMA.COLUMNS\n\t\tWHERE TABLE_SCHEMA = database() AND TABLE_NAME = 't1'\n\t\tORDER BY ORDINAL_POSITION"]
+	assert.True(t, found)
+
 	sql := "SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id"
 
 	_, err = vte.Run(sql)