Shulou(Shulou.com)06/01 Report--

In HBase, there is only one row for the same column corresponding to a row. Use scan or get to get the latest data

If we change the column corresponding to this row, we will not generate another piece of data, unlike RDBMS.

One more record is generated in insert, and the modification or insertion of the same data in HBase is only a put operation, and all you see in the end is

The latest data, other data is saved in different version, just like hidden things.

So how can I see these hidden version values?

Get get = new Get (startRow)

Get.setMaxVersions ()

Result result = table.get (get)

List list = result.list ()

For (final KeyValue v:list) {

Logger.info ("value:" + v + "str:" + Bytes.toString (v.getValue ()

}

Add the setMaxVersions () method and you can take out all the versions

Example code:

@ Test public void test4 () throws Exception {Configuration config = HBaseConfiguration.create (); config.set ("hbase.zookeeper.quorum", "hadoop1,hadoop2,hadoop3"); HTable hTable = new HTable (config, "t_xuanxuan"); Get get = new Get ("29129101029" 1444038378601 ".getBytes ()); get.setMaxVersions () / / 2 Result result = hTable.get (get); System.out.println (result.size ()); List list = result.list (); for (final KeyValue v:list) {System.out.println ("value:" + v + "str:" + Bytes.toString (v.getValue () }}

The number of result will be 2, because it is hidden, so it can not be queried on the hbase command line, only this way.

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