Develop Reference

hbase GREATER_OR_EQAUL operator does not work as expected

i have this row in my hbase table:
{rowkey:1_1611646861574/cf:value/1611646776287/Put/vlen=8/seqid=0}
now i want to do a simple scan and find rows where their column value is greater than "1611388300000". but it does not return any record; however it returns this record when i use LESS_OR_EQUAL than 1611647500000.
the weird thing is i can get this record from apache phoenix sql query: select * from my_table where value>=1611388300000.
so number is a obviously bigger than column value and apache phoenix returns it; why hbase compare Operator does not?
here is my code:
Table table = con.getTable(TableName.valueOf("my_table"));
Scan scan = new Scan();
scan.addColumn(Bytes.toBytes("cf"), Bytes.toBytes("value"));
FilterList flist = new FilterList(FilterList.Operator.MUST_PASS_ALL);
flist.addFilter(new PrefixFilter(Bytes.toBytes("1")));
flist.addFilter(new SingleColumnValueFilter(
Bytes.toBytes("cf"), Bytes.toBytes("value"), CompareOperator.GREATER_OR_EQUAL,
new BinaryComparator(Bytes.toBytes("1611388300000"))));
scan.setFilter(flist);
ResultScanner scanner = table.getScanner(scan);
for (Result result = scanner.next(); result != null; result = scanner.next())
System.out.println("Found row : " + result);
scanner.close();

i dont exactly know why but LESS_OR_EQUAL works with string:
new SingleColumnValueFilter(
Bytes.toBytes("cf"), Bytes.toBytes("value"), CompareOperator.LESS_OR_EQUAL,
new BinaryComparator(Bytes.toBytes("1611647500000")))
but GREATER_OR_EQUAL did not work when i used quotes so i had to use number (L is added to specify Long)
new SingleColumnValueFilter(
Bytes.toBytes("ui"), Bytes.toBytes("C"), CompareOperator.GREATER_OR_EQUAL,
new BinaryComparator(Bytes.toBytes(1611388300000L)))

Since you're comparing long, you should use LongComparator instead of BinaryComparator:
https://hbase.apache.org/apidocs/org/apache/hadoop/hbase/filter/LongComparator.html

int values doesn't compare in hbase filter using SingleColumnValueFilter

Compare int values with specific qualifier isn't working.
I tried using new BinaryComparator but it doesn't work.
FilterList fl = new FilterList();
SingleColumnValueFilte filter = new SingleColumnValueFilter(
Bytes.toBytes("dynamic"),Bytes.toBytes("speed"),CompareOp.GREATER_OR_EQUAL,
new BinaryComparator(Bytes.toBytes(10));
I tried both "10" and 10 but it doesn't work.
fl.addFilter(filter);
Scan s = new Scan(Bytes.toBytes("235091871:2015-01-01T00:02:58"),Bytes.toBytes("235091871:2015-01-01T00:22:19"));
System.out.println("hello scan");
s.addColumn(Bytes.toBytes("dynamic"),Bytes.toBytes("speed"));
s.setFilter(filter);
ResultScanner rs = table.getScanner(s);
for (Result res : rs) {
for (KeyValue result : res.raw()) {
System.out.println(Bytes.toString(result.getRow())+" "+Bytes.toString(result.getValue()));
}
}
I have speed values like 10.3,10.4,11.1,9.6,8.3
The output should be 10.3,10.4,11.4 when I process or filter using CompareOp.GREATER_OR_EQUAL.
If I need to write a custom comparator please suggest how to do it with code.

How to compare a cell value with a string and count the frequency in hbase?

I am very new to hbase.
I have a two column family named as"name", "story type" and the values are like {Rajib,Clarke}, {photo,status,gif} respectively
I want to scan the rows of 'story type' when 'name' column has value "Rajib" and count the frequency of finding 'gif' with respect to "Rajib"
I have tried like below but this is not working. How can I do that??
Thanks in advance..
String columnfamily1="story type";
int countgif=0;
for (Result res: scanner)
{
if(Bytes.toString(res.getValue(Bytes.toBytes(columnfamily),null))=="Clarke"){
if(Bytes.toString(res.getValue(Bytes.toBytes(columnfamily1),null))=="gif"){
countgif=countgif+1;
}
}
}
system.out.printf("%d",countgif);

Can you put some sample data so it will be clear about your requirement.
As I understood from your question you need to filter those rows which has name as 'clarke' and story-type as 'gif'.
This can be implemented using Scan class with additional filters as
SingleColumnValueFilter filter_by_name = new SingleColumnValueFilter(
Bytes.toBytes("name" ),
Bytes.toBytes("name"),
CompareOp.EQUAL,
Bytes.toBytes("clarke"));
SingleColumnValueFilter filter_by_story = new SingleColumnValueFilter(
Bytes.toBytes("story_type" ),
Bytes.toBytes("type"),
CompareOp.EQUAL,
Bytes.toBytes("gif"));
FilterList filterList = new FilterList(FilterList.Operator.MUST_PASS_ALL);
filterList.addFilter(filter_by_name);
filterList.addFilter(filter_by_story);
Scan scan = new Scan();
scan.setFilter(filterList);
ResultScanner scanner = table.getScanner(scan);
Result result = scanner.next;
// now use iteration to print the complete value.. if you are interested only in count then just iterate and increment count
int gifCount =0;
while(result != null)
{
gifCount ++;
result =scanner.next;
}
println(gifCount);
Hope this resolves your problem.

How to get all the rows given a part of the row key in Hbase

I have the following table structure in Hbase:
Row column+cell
Mary_Ann_05/10/2013 column=cf:verified, timestamp=234454454,value=2,2013-02-12
Mary_Ann_06/10/2013 column=cf:verified, timestamp=2345454454,value=3,2013-02-12
Mary_Ann_07/10/2013 column=cf:verified, timestamp=2345454522454,value=4,2013-02-12
Mary_Ann_08/10/2013 column=cf:verified, timestamp=23433333454,value=1,2013-12-12
I want to retrieve all the records that start with Mary_Ann using java. How do I do that?

You could achieve that using PrefixFilter. Given a prefix, specified when you instantiate the filter instance, all rows that match this prefix are returned to the client. The constructor is : public PrefixFilter(byte[] prefix)
Usage :
Filter filter = new PrefixFilter(Bytes.toBytes("Mary_Ann"));
Scan scan = new Scan();
scan.setFilter(filter);
ResultScanner scanner = table.getScanner(scan);
for (Result result : scanner) {
for (KeyValue kv : result.raw()) {
System.out.println("KV: " + kv + ", Value: " +
Bytes.toString(kv.getValue()));
}
}
scanner.close();
HTH

How to read data from Hbase?

Hi there I'm use to SQL, but I need to read data from a HBase table. Any help on this would be great. A book or maybe just some sample code to read from the table. Someone said using a scanner would do the trick, but I do not know how to use it.

From the website:
// Sometimes, you won't know the row you're looking for. In this case, you
// use a Scanner. This will give you cursor-like interface to the contents
// of the table. To set up a Scanner, do like you did above making a Put
// and a Get, create a Scan. Adorn it with column names, etc.
Scan s = new Scan();
s.addColumn(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"));
ResultScanner scanner = table.getScanner(s);
try {
// Scanners return Result instances.
// Now, for the actual iteration. One way is to use a while loop like so:
for (Result rr = scanner.next(); rr != null; rr = scanner.next()) {
// print out the row we found and the columns we were looking for
System.out.println("Found row: " + rr);
}
// The other approach is to use a foreach loop. Scanners are iterable!
// for (Result rr : scanner) {
// System.out.println("Found row: " + rr);
// }
} finally {
// Make sure you close your scanners when you are done!
// Thats why we have it inside a try/finally clause
scanner.close();
}

I would like to offer solution without deprecated methods
Configuration conf = HBaseConfiguration.create();
Connection connection = ConnectionFactory.createConnection(conf);
Admin admin = connection.getAdmin();
// list the tables
Arrays.stream(admin.listTables()).forEach(System.out::println);
// let's insert some data in 'mytable' and get the row
TableName tableName = TableName.valueOf("test_1");
Table table = connection.getTable(tableName);
//Put
Put thePut = new Put(Bytes.toBytes("rowkey1"));
String columnFamily = "m";
String columnQualifier1 = "col1";
String outValue1 = "value1";
String columnQualifier2 = "col2";
String outValue2 = "value2";
thePut.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(columnQualifier1), Bytes.toBytes(outValue1));
thePut.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(columnQualifier2), Bytes.toBytes(outValue2));
table.put(thePut);
//Get
Get theGet = new Get(Bytes.toBytes("rowkey1"));
Result result = table.get(theGet);
//get value first column
String inValue1 = Bytes.toString(result.value());
//get value by ColumnFamily and ColumnName
byte[] inValueByte = result.getValue(Bytes.toBytes(columnFamily), Bytes.toBytes(columnQualifier1));
String inValue2 = Bytes.toString(inValueByte);
//loop for result
for (Cell cell : result.listCells()) {
String qualifier = Bytes.toString(CellUtil.cloneQualifier(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.printf("Qualifier : %s : Value : %s%n", qualifier, value);
}
//create Map by result and print it
Map<String, String> getResult = result.listCells().stream().collect(Collectors.toMap(e -> Bytes.toString(CellUtil.cloneQualifier(e)), e -> Bytes.toString(CellUtil.cloneValue(e))));
getResult.entrySet().stream().forEach(e -> System.out.printf("Qualifier : %s : Value : %s%n", e.getKey(), e.getValue()));
System.out.println("---------Scan---------");
Scan scan = new Scan();
ResultScanner resultScan = table.getScanner(scan);
resultScan.forEach(e -> {
System.out.printf("Row \"%s\"%n", Bytes.toString(e.getRow()));
Map<String, String> getResultScan = e.listCells().stream().collect(Collectors.toMap(d -> Bytes.toString(CellUtil.cloneQualifier(d)), d -> Bytes.toString(CellUtil.cloneValue(d))));
getResultScan.entrySet().stream().forEach(d -> System.out.printf("column \"%s\", value \"%s\"%n", d.getKey(), d.getValue()));
System.out.println();
});

I used that but to get the String value you must use method getValue from Result.
byte[] bytes = rr.getValue(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"));
System.out.println(new String(bytes));