Apache Commons CSV performance comparison

[mageddo]

Apache Commons CSV --> 01:27

2023-02-16T02:34:38.933511 ProxiedStatement: getConnection
2023-02-16T02:34:39.141314 m=streamSelect, sql=SELECT * FROM TMP, autoCommit=true
2023-02-16T02:34:39.160498 m=streamSelect, status=executed, sql=SELECT * FROM TMP
2023-02-16T02:34:39.586226 status=printingRecords
2023-02-16T02:36:06.345703 status=csvWritten
2023-02-16T02:36:14.271099 status=linesCount, lines=7000000
2023-02-16T02:36:14.271566 m=getWarnings

private int extractQueryToCsv() throws SQLException {
  try {
    CsvTableDaos.streamSelect(this.connection, this.csvStm.getExtractSql(), (rs) -> {
      try (final CSVPrinter printer = this.createCsvPrinter()) {
        Log.log("status=printingRecords");
        printer.printRecords(rs, true);
      }
    });
  } catch (Exception e) {
    throw new SQLException(e);
  }
  Log.log("status=csvWritten");
  try {
    final int lines = Files.countLines(this.csvStm.getFile()) - HEADER_COUNT;
    Log.log("status=linesCount, lines={}", lines);
    return lines;
  } catch (IOException e) {
    throw new SQLException(e);
  }
}

Vanilla BufferedWritter --> 01:08

2023-02-16T02:41:39.530363 ProxiedStatement: getConnection
2023-02-16T02:41:40.230132 m=streamSelect, sql=SELECT * FROM TMP, autoCommit=true
2023-02-16T02:41:40.251840 m=streamSelect, status=executed, sql=SELECT * FROM TMP
2023-02-16T02:42:48.085736 m=getWarnings
2023-02-16T02:42:48.086107 m=clearWarnings
2023-02-16T02:42:48.086320 ProxiedStatement: getWarnings
2023-02-16T02:42:48.086503 ProxiedStatement: clearWarnings
2023-02-16T02:42:48.086680 m=getMetaData
2023-02-16T02:42:48.086866 ProxiedStatement: getUpdateCount
20

private int extractQueryToCsv0() throws SQLException {
  try {
    final BufferedWriter out = java.nio.file.Files.newBufferedWriter(this.csvStm.getFile());
    CsvTableDaos.streamSelect(this.connection, this.csvStm.getExtractSql(), (rs) -> {
//        try (final CSVPrinter printer = this.createCsvPrinter()) {
      final int columns = rs
          .getMetaData()
          .getColumnCount();
      while (rs.next()){
        for (int i = 1; i <= columns; i++) {
          out.write(rs.getString(i));
          out.write(", ");
        }
        out.write('\n');
      }
//          printer.printRecords(rs, true);
//        }
    });
  } catch (Exception e) {
    throw new SQLException(e);
  }
  try {
    return Files.countLines(this.csvStm.getFile()) - HEADER_COUNT;
  } catch (IOException e) {
    throw new SQLException(e);
  }
}