How to mass delete multiple rows in hbase?

Question

I have the following rows with these keys in hbase table "mytable"

user_1
user_2
user_3
...
user_9999999

I want to use the Hbase shell to delete rows from:

user_500 to user_900

I know there is no way to delete, but is there a way I could use the "BulkDeleteProcessor" to do this?

I see here:

https://github.com/apache/hbase/blob/master/hbase-examples/src/test/java/org/apache/hadoop/hbase/coprocessor/example/TestBulkDeleteProtocol.java

I want to just paste in imports and then paste this into the shell, but have no idea how to go about this. Does anyone know how I can use this endpoint from the jruby hbase shell?

   Table ht = TEST_UTIL.getConnection().getTable("my_table");
    long noOfDeletedRows = 0L;
    Batch.Call<BulkDeleteService, BulkDeleteResponse> callable =
      new Batch.Call<BulkDeleteService, BulkDeleteResponse>() {
      ServerRpcController controller = new ServerRpcController();
      BlockingRpcCallback<BulkDeleteResponse> rpcCallback =
        new BlockingRpcCallback<BulkDeleteResponse>();

      public BulkDeleteResponse call(BulkDeleteService service) throws IOException {
        Builder builder = BulkDeleteRequest.newBuilder();
        builder.setScan(ProtobufUtil.toScan(scan));
        builder.setDeleteType(deleteType);
        builder.setRowBatchSize(rowBatchSize);
        if (timeStamp != null) {
          builder.setTimestamp(timeStamp);
        }
        service.delete(controller, builder.build(), rpcCallback);
        return rpcCallback.get();
      }
    };
    Map<byte[], BulkDeleteResponse> result = ht.coprocessorService(BulkDeleteService.class, scan
        .getStartRow(), scan.getStopRow(), callable);
    for (BulkDeleteResponse response : result.values()) {
      noOfDeletedRows += response.getRowsDeleted();
    }
    ht.close();

If there exists no way to do this through JRuby, Java or alternate way to quickly delete multiple rows is fine.

Answer 1

Do you really want to do it in shell because there are various other better ways. One way is using the native java API

• Construct an array list of deletes
• pass this array list to Table.delete method

Method 1: if you already know the range of keys.

public void massDelete(byte[] tableName) throws IOException {
    HTable table=(HTable)hbasePool.getTable(tableName);

    String tablePrefix = "user_";
    int startRange = 500;
    int endRange = 999;

    List<Delete> listOfBatchDelete = new ArrayList<Delete>();

    for(int i=startRange;i<=endRange;i++){
        String key = tablePrefix+i; 
        Delete d=new Delete(Bytes.toBytes(key));
        listOfBatchDelete.add(d);  
    }

    try {
        table.delete(listOfBatchDelete);
    } finally {
        if (hbasePool != null && table != null) {
            hbasePool.putTable(table);
        }
    }
}

Method 2: If you want to do a batch delete on the basis of a scan result.

public bulkDelete(final HTable table) throws IOException {
    Scan s=new Scan();
    List<Delete> listOfBatchDelete = new ArrayList<Delete>();
    //add your filters to the scanner
    s.addFilter();
    ResultScanner scanner=table.getScanner(s);
    for (Result rr : scanner) {
        Delete d=new Delete(rr.getRow());
        listOfBatchDelete.add(d);
    }
    try {
        table.delete(listOfBatchDelete);
    } catch (Exception e) {
        LOGGER.log(e);

    }
}

Now coming down to using a CoProcessor. only one advice, 'DON'T USE CoProcessor' unless you are an expert in HBase. CoProcessors have many inbuilt issues if you need I can provide a detailed description to you. Secondly when you delete anything from HBase it's never directly deleted from Hbase there is tombstone marker get attached to that record and later during a major compaction it gets deleted, so no need to use a coprocessor which is highly resource exhaustive.

Modified code to support batch operation.

int batchSize = 50;
int batchCounter=0;
for(int i=startRange;i<=endRange;i++){

String key = tablePrefix+i;
Delete d=new Delete(Bytes.toBytes(key));
listOfBatchDelete.add(d);  
batchCounter++;

if(batchCounter==batchSize){
    try {
        table.delete(listOfBatchDelete);
        listOfBatchDelete.clear();
        batchCounter=0;
    }
}}

Creating HBase conf and getting table instance.

Configuration hConf = HBaseConfiguration.create(conf);
hConf.set("hbase.zookeeper.quorum", "Zookeeper IP");
hConf.set("hbase.zookeeper.property.clientPort", ZookeeperPort);

HTable hTable = new HTable(hConf, tableName);

Answer 2

If you already aware of the rowkeys of the records that you want to delete from HBase table then you can use the following approach

1.First create a List objects with these rowkeys

for (int rowKey = 1; rowKey <= 10; rowKey++) {
    deleteList.add(new Delete(Bytes.toBytes(rowKey + "")));
}

2.Then get the Table object by using HBase Connection

Table table = connection.getTable(TableName.valueOf(tableName));

3.Once you have table object call delete() by passing the list

table.delete(deleteList);

The complete code will look like below

Configuration config = HBaseConfiguration.create();
config.addResource(new Path("/etc/hbase/conf/hbase-site.xml"));
config.addResource(new Path("/etc/hadoop/conf/core-site.xml"));

String tableName = "users";

Connection connection = ConnectionFactory.createConnection(config);
Table table = connection.getTable(TableName.valueOf(tableName));

List<Delete> deleteList = new ArrayList<Delete>();

for (int rowKey = 500; rowKey <= 900; rowKey++) {
    deleteList.add(new Delete(Bytes.toBytes("user_" + rowKey)));
}

table.delete(deleteList);