如何在HBase中检索行的最后修改时间戳？

Question

Does each Cell in returned Result object have same timestamp? Is it save to do something like this?

  try (Table table = connectionFactory.getConnection().getTable(TABLE)) {
   try (ResultScanner scanner = table.getScanner(generateScan(systemId))) {
    for (Result result: scanner) {
     if (result == null) {
      break;
     }
     long ts = result.rawCells()[0].getTimestamp();
     System.out.println("Row last update time: " + ts);
    }
   }
  }

Will I obtain time stamp of the last row modification?

Answer 1

Cells in Result can have different timestamp. Each cell is a combination of CF:C:V , where CF is column family, C is a column and V is a version. Even if you store only 1 version, you can update columns of a cell independently. Cell timestamp is updated when you store something.

For example you have table user with cf:main and two columns name and age . If you update both columns in same Put they will have same timetamp. If you update only name column, timestamps will be different. So generally it depends on your usage pattern.