コード例 #1
0
ファイル: bench_test.go プロジェクト: segmentio/pgx
// note this function is only used for benchmarks -- it doesn't escape tableName
// or columnNames
func multiInsert(conn *pgx.Conn, tableName string, columnNames []string, rowSrc pgx.CopyToSource) (int, error) {
	maxRowsPerInsert := 65535 / len(columnNames)
	rowsThisInsert := 0
	rowCount := 0

	sqlBuf := &bytes.Buffer{}
	args := make(pgx.QueryArgs, 0)

	resetQuery := func() {
		sqlBuf.Reset()
		fmt.Fprintf(sqlBuf, "insert into %s(%s) values", tableName, strings.Join(columnNames, ", "))

		args = args[0:0]

		rowsThisInsert = 0
	}
	resetQuery()

	tx, err := conn.Begin()
	if err != nil {
		return 0, err
	}
	defer tx.Rollback()

	for rowSrc.Next() {
		if rowsThisInsert > 0 {
			sqlBuf.WriteByte(',')
		}

		sqlBuf.WriteByte('(')

		values, err := rowSrc.Values()
		if err != nil {
			return 0, err
		}

		for i, val := range values {
			if i > 0 {
				sqlBuf.WriteByte(',')
			}
			sqlBuf.WriteString(args.Append(val))
		}

		sqlBuf.WriteByte(')')

		rowsThisInsert++

		if rowsThisInsert == maxRowsPerInsert {
			_, err := tx.Exec(sqlBuf.String(), args...)
			if err != nil {
				return 0, err
			}

			rowCount += rowsThisInsert
			resetQuery()
		}
	}

	if rowsThisInsert > 0 {
		_, err := tx.Exec(sqlBuf.String(), args...)
		if err != nil {
			return 0, err
		}

		rowCount += rowsThisInsert
	}

	if err := tx.Commit(); err != nil {
		return 0, nil
	}

	return rowCount, nil

}