feat: support batch insert (wip)

internal/populatedb/populatedb.go

@@ -18,12 +18,16 @@ import (
 const (
 	dialectMySQL = "mysql"
 
-	stmtInsert = "INSERT INTO %s (%s) VALUES (%s);"
+	// 2^16
+	maxQuestionMarks = 65536
+
+	stmtInsert = "INSERT INTO %s (%s) VALUES %s;"
 )
 
 var (
-	ErrNotSupportDialect = errors.New("not support dialect")
-	ErrTableNotExist     = errors.New("table not exist")
+	ErrNotSupportDialect    = errors.New("not support dialect")
+	ErrTableNotExist        = errors.New("table not exist")
+	ErrMaximumQuestionMarks = errors.New("maximum question marks")
 )
 
 type Populator interface {
@@ -94,32 +98,19 @@ func NewPopulator(
 }
 
 func (p *populator) Insert(ctx context.Context, tableName string, numberRecord int) error {
-	table, ok := p.tables[tableName]
-	if !ok {
-		return fmt.Errorf("table [%s] not exist: %w", tableName, ErrTableNotExist)
-	}
-
-	columnNames := make([]string, 0, len(table.Columns))
-	questionMarks := make([]string, 0, len(table.Columns))
-	argFns := make([]func() any, 0, len(table.Columns))
-	for _, column := range table.Columns {
-		dt, err := ParseDatabaseType(column.Type)
-		if err != nil {
-			return fmt.Errorf("failed to parse database type [%s]: %w", column.Type, err)
-		}
-
-		columnNames = append(columnNames, column.Name)
-		questionMarks = append(questionMarks, "?")
-		argFns = append(argFns, dt.Generate)
+	columnNames, questionMarks, argFns, err := p.prepareInsert(tableName)
+	if err != nil {
+		return err
 	}
 
 	queryInsert := fmt.Sprintf(stmtInsert,
 		tableName,
 		strings.Join(columnNames, ", "),
-		strings.Join(questionMarks, ", "),
+		fmt.Sprintf("(%s)", strings.Join(questionMarks, ", ")),
 	)
 
 	for i := 0; i < numberRecord; i++ {
+		// Generate each time insert for different value
 		args := make([]any, 0, len(argFns))
 		for _, argFn := range argFns {
 			args = append(args, argFn())
@@ -138,3 +129,100 @@ func (p *populator) Insert(ctx context.Context, tableName string, numberRecord i
 
 	return nil
 }
+
+func (p *populator) BatchInsert(ctx context.Context, tableName string, numberRecord int) error {
+	columnNames, questionMarks, argFns, err := p.prepareInsert(tableName)
+	if err != nil {
+		return err
+	}
+
+	if len(columnNames) == 0 {
+		return nil
+	}
+
+	numberRecordEachBatch := maxQuestionMarks / len(questionMarks)
+	if numberRecordEachBatch == 0 {
+		return fmt.Errorf("maxium question marks [%d]: %w", len(questionMarks), ErrMaximumQuestionMarks)
+	}
+
+	numberBatch := numberRecord/numberRecordEachBatch + 1
+	numberRecordLastBatch := numberRecord - (numberBatch-1)*numberRecordEachBatch
+
+	generateQueryArgsInsertFn := func(tempNumberRecord int) (string, []any) {
+		valuesQuestionMarks := make([]string, 0, tempNumberRecord)
+		argsInsert := make([]any, 0, tempNumberRecord*len(argFns))
+		for i := 0; i < tempNumberRecord; i++ {
+			valuesQuestionMarks = append(valuesQuestionMarks, fmt.Sprintf("(%s)", strings.Join(questionMarks, ", ")))
+
+			// Generate each time insert for different value
+			args := make([]any, 0, len(argFns))
+			for _, argFn := range argFns {
+				args = append(args, argFn())
+			}
+			argsInsert = append(argsInsert, args...)
+		}
+
+		queryInsert := fmt.Sprintf(stmtInsert,
+			tableName,
+			strings.Join(columnNames, ", "),
+			strings.Join(valuesQuestionMarks, ", "),
+		)
+
+		return queryInsert, argsInsert
+	}
+
+	for i := 0; i < numberBatch-1; i++ {
+		queryInsert, argsInsert := generateQueryArgsInsertFn(numberRecordEachBatch)
+
+		if p.verbose {
+			fmt.Println(i, queryInsert, argsInsert)
+		}
+
+		if !p.dryRun {
+			if _, err := p.db.ExecContext(ctx, queryInsert, argsInsert...); err != nil {
+				return fmt.Errorf("database: failed to exec [%s]: %w", queryInsert, err)
+			}
+		}
+	}
+
+	{
+		// Last batch
+		queryInsert, argsInsert := generateQueryArgsInsertFn(numberRecordLastBatch)
+
+		if p.verbose {
+			fmt.Println(numberBatch-1, queryInsert, argsInsert)
+		}
+
+		if !p.dryRun {
+			if _, err := p.db.ExecContext(ctx, queryInsert, argsInsert...); err != nil {
+				return fmt.Errorf("database: failed to exec [%s]: %w", queryInsert, err)
+			}
+		}
+	}
+
+	return nil
+}
+
+// Return columnNames, questionMarks, argFns
+func (p *populator) prepareInsert(tableName string) ([]string, []string, []func() any, error) {
+	table, ok := p.tables[tableName]
+	if !ok {
+		return nil, nil, nil, fmt.Errorf("table [%s] not exist: %w", tableName, ErrTableNotExist)
+	}
+
+	columnNames := make([]string, 0, len(table.Columns))
+	questionMarks := make([]string, 0, len(table.Columns))
+	argFns := make([]func() any, 0, len(table.Columns))
+	for _, column := range table.Columns {
+		dt, err := ParseDatabaseType(column.Type)
+		if err != nil {
+			return nil, nil, nil, fmt.Errorf("failed to parse database type [%s]: %w", column.Type, err)
+		}
+
+		columnNames = append(columnNames, column.Name)
+		questionMarks = append(questionMarks, "?")
+		argFns = append(argFns, dt.Generate)
+	}
+
+	return columnNames, questionMarks, argFns, nil
+}