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[HBase][Get] Row retrievable using shell but not through Java API

New Contributor

 

I am working on a simple code to get a row from HBase which is not working through HBase Java API but the same row is retrievable from the shell.

Example row Ids:

 

  1. F\x0A@z\x11\x0D\xB4\xD3\x05"S273320039#999279720
  2. =\x0A@z\x1AI\xA4\xD8h\x12\x09754427158#999598625
  3. F\x0A@z\x11\x0D\xA6@\x0C\x04\xDA490229991#999279958
  4. M\x0A@z\x13\x092\x89a\x12\x111059947933#999223281
  5. \x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#5241968320


Result from one of the RowId through shell:

 

 

 

hbase(main):003:0> get 'OSMNodes_z3_geometry_ingestionTimestamp_v6',"\x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#5241968320"
COLUMN                            CELL                                                                                            
 d:                               timestamp=1588532276719, value=\x03\x00\x06\x02\x00\x12\x00-\x005\x00=\x00R\x00Y\x01x\x00\x00\x0
                                  0\x00\x01\x08\x03\xC0V\xE9\x9AU\x81;\xD5\xBF\xF5\xA7FE^\xAE\xE2\x7F\xF8\x00\x00\x00\x00\x00\x00\
                                  x00\x00\x01q\x9Av\xA9\x00\x00\x00\x01q\x9B\x89Q\x801447846881#524196832\xB0geojso\xEE\xDE\x04{"g
                                  eometry":{"type":"Point","coordinates":[-91.6500448,-1.3533385]},"id":"5241968320","properties":
                                  {"tags":{},"changesetId":53988821,"version":1,"uid":1975220,"user":"jptolosa87","featureSource":
                                  "OSM","sourceTimestamp":"2017-11-22 00:01:26","ingestionTimestamp":"2020-04-21 02:00:00"}}

 

 



Java API Code

 

 

 

    public static void main(String[] args) {

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

        try {
            HBaseAdmin.checkHBaseAvailable(conf);
        } catch (Exception e) {
            e.printStackTrace();
            return;
        }

        Map<String, String> argVector = parseArgVector(args);

        final String fileName = argVector.get("fileName");
        final String hbaseTableName = argVector.get("hbaseTableName");
        final String rowId = argVector.get("rowId");
        final HTable table = getTable(hbaseTableName, conf);

        Result result = getRow(table, rowId);
        System.out.println(result);
        System.out.println(result.isEmpty());
        System.out.println(Bytes.toString(result.getRow()));
        System.out.println(Bytes.toString(result.getValue(Bytes.toBytes("d"), Bytes.toBytes(""))));
    }

    private static Result getRow(final HTable table, final String rowId) {
        try {
            Get get = new Get(Bytes.toBytes(rowId));
            System.out.println(Bytes.toString(get.getRow()));
            return table.get(get);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

 

 

1 ACCEPTED SOLUTION

New Contributor

The rowId used in our HBase tables is not exactly composed of hex strings. It is a mix as pointed out in earlier correspondence of this thread.

 

\x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#524196832

 

The solution to this, as I was able to find, was to use the function provided by the Bytes library called toBytesBinary.

 

This method considers the hex representation of characters in a string and treat each of those as unit instead of breaking it further up.

 

Hope this helps!!

 

View solution in original post

6 REPLIES 6

Super Collaborator

Some additional information you could provide to help the community answer the question:

Are there any errors that Java returns when querying HBase or does it just silently not show any rows?
Is the same user executing both tasks (through shell and java)?

Can any other rows be retrieved from Java?

New Contributor

Are there any errors that Java returns when querying HBase or does it just silently not show any rows?

 

> The return is null in the Result object

 

Is the same user executing both tasks (through shell and java)?

 

> Yes

 

Can any other rows be retrieved from Java?

 

> From a different table, which has comparatively less complex row key.

Super Collaborator

Perhaps something about how Java interprets the args you pass to it when you run your code? It may be different from how shell client interprets them (relevant discussion here).

Can you show how the command that executes your Java code, complete with the arguments passed to it?

Also, include printed arguments (e.g. System.out.println(rowId)) in your code.

 

Execute the code for the same key as you did in shell (i.e. \x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#5241968320)

 

New Contributor

Can you show how the command that executes your Java code, complete with the arguments passed to it?

 

> java -cp hadoop-lib/*:hbase-lib/*: GetFeature --hbaseTableName "OSMNodes_z3_geometry_ingestionTimestamp_v6" --rowId "\x00\x0A@E\xFFn[\x18

\x9F\xD4-1447846881#5241968320"

 

Also, include printed arguments (e.g. System.out.println(rowId)) in your code.

 

> Table name: OSMNodes_z3_geometry_ingestionTimestamp_v6
> rowId: \x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#5241968320

 

Execute the code for the same key as you did in shell (i.e. \x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#5241968320)

 

> There is a different behavior when I execute the get for this rowId depending upon the quotes.

> If I use a double quote around the mentioned rowId, I get a different row than the one I get If I use a single quote around.

> Example (Look out at the column name for distinction)

 

hbase(main):027:0> get 'OSMNodes_z3_geometry_ingestionTimestamp_v6',"\x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#5241968320"
COLUMN                         CELL                                                                                    
 d:                            timestamp=1590532417003, value=\x5Cx03\x5Cx00\x5Cx06\x5Cx02\x5Cx00\x5Cx12\x5Cx00-\x5Cx00
                               5\x5Cx00=\x5Cx00R\x5Cx00Y\x5Cx01x\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx01\x5Cx08\x5Cx03\x5CxC
                               0V\x5CxE9\x5Cx9AU\x5Cx81;\x5CxD5\x5CxBF\x5CxF5\x5CxA7FE^\x5CxAE\x5CxE2\x5Cx7F\x5CxF8\x5C
                               x00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx01q\x5Cx9Av\x5CxA9\x5Cx00\x5Cx0
                               0\x5Cx00\x5Cx01q\x5Cx9B\x5Cx89Q\x5Cx801447846881#524196832\x5CxB0geojso\x5CxEE\x5CxDE\x5
                               Cx04{"geometry":{"type":"Point","coordinates":[-91.6500448,-1.3533385]},"id":"5241968320
                               ","properties":{"tags":{},"changesetId":53988821,"version":1,"uid":1975220,"user":"jptol
                               osa87","featureSource":"OSM","sourceTimestamp":"2017-11-22 00:01:26","ingestionTimestamp
                               ":"2020-04-21 02:00:00"}}                                                               
1 row(s) in 0.0070 seconds

hbase(main):028:0> get 'OSMNodes_z3_geometry_ingestionTimestamp_v6','\x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#5241968320'
COLUMN                         CELL                                                                                    
 d:d                           timestamp=1590532440913, value=\x5Cx03\x5Cx00\x5Cx06\x5Cx02\x5Cx00\x5Cx12\x5Cx00-\x5Cx00
                               5\x5Cx00=\x5Cx00R\x5Cx00Y\x5Cx01x\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx01\x5Cx08\x5Cx03\x5CxC
                               0V\x5CxE9\x5Cx9AU\x5Cx81;\x5CxD5\x5CxBF\x5CxF5\x5CxA7FE^\x5CxAE\x5CxE2\x5Cx7F\x5CxF8\x5C
                               x00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx00\x5Cx01q\x5Cx9Av\x5CxA9\x5Cx00\x5Cx0
                               0\x5Cx00\x5Cx01q\x5Cx9B\x5Cx89Q\x5Cx801447846881#524196832\x5CxB0geojso\x5CxEE\x5CxDE\x5
                               Cx04{"geometry":{"type":"Point","coordinates":[-91.6500448,-1.3533385]},"id":"5241968320
                               ","properties":{"tags":{},"changesetId":53988821,"version":1,"uid":1975220,"user":"jptol
                               osa87","featureSource":"OSM","sourceTimestamp":"2017-11-22 00:01:26","ingestionTimestamp
                               ":"2020-04-21 02:00:00"}}                                                               
1 row(s) in 0.0060 seconds

hbase(main):029:0> 

 

 

Super Collaborator

Ok, so regarding single quotes vs. double quotes, you have to use double quotes in shell every time. Text in single quotes is treated as liternal (see p.271 of HBase Definitive Guide).

 

After some more research I came across this post which seems to describe your problem exactly, along with two solutions on how to modify your Java code. To summarize, Java client for HBase expects row keys to be in human readable format, not their hexadecimal representation. Solution is to read your args as Double type, not String. 

 

Hope that finally resolves it.

New Contributor

The rowId used in our HBase tables is not exactly composed of hex strings. It is a mix as pointed out in earlier correspondence of this thread.

 

\x00\x0A@E\xFFn[\x18\x9F\xD4-1447846881#524196832

 

The solution to this, as I was able to find, was to use the function provided by the Bytes library called toBytesBinary.

 

This method considers the hex representation of characters in a string and treat each of those as unit instead of breaking it further up.

 

Hope this helps!!

 

; ;