CODEWITHSUNDEEP
javaaccumulo
user2737670
user2737670

Reputation: 33

Scan accumulo using rowid

How do I use the Java API to scan accumulo using only the rowid. For example accumulo has the following row entry when I scan the table using the accumulo shell:

12lj314t1u43td1 Documents:Entity [U] {values}

I know the rowid in Java which is '12lj314t1u43td1'. I want to retrieve {values} for all possible column families and qualifiers. I already checked the accumulo documentation on scanner's but they do not say how to set the Ranges to only return based on the rowid.

Upvotes: 1

Views: 2368

Answers (2)

Christopher
Christopher

Reputation: 2512

You can scan over a range in the shell with scan -b startRow -e endRow. See scan --help for more options.

Note: you should use the Java API if you want performance, but this gets you a range for the shell.

Upvotes: 2

FuriousGeorge
FuriousGeorge

Reputation: 4681

If there is just one rowID that you are interested in, than you can use the Scanner to accomplish this:

Scanner scanner = connector.createScanner(myTable, new Authorizations("U"));
scanner.setRange(new Range("12lj314t1u43td1"));

for(Entry<Key,Value> entry : scanner){
    System.out.println(entry);
}

This will give you every "12lj314t1u43td1" row. If you only wanted the rows with the Documents cf, you'd add this after the setRange line

scanner.fetchColumnFamily(new Text("Documents"));

or if you wanted just the Documents with the Entity CQ you'd do

scanner.fetchColumn(new Text("Documents"), new Text("Entity"));

If you are looking for lots of discontiguous rows, then you might want to try the BatchScanner. It is also possible to use a myriad of iterators and regex's, but this should get you what you want.

Upvotes: 4

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