I created a jira to improve the Javadoc for the `nextRows` API here: https://issues.apache.org/jira/browse/KUDU-2891
If you are interested in contributing it would be a super simple contribution. On Thu, Jul 11, 2019 at 1:00 PM Grant Henke <[email protected]> wrote: > Hi John, > > If you can leverage the newly released Kudu 1.10.0 client, the KuduScanner > in the Java client is now iterable. Additionally the KuduScannerIterator > will automatically make scanner keep alive calls to ensure scanners do not > time out while iterating. This means the you can use a Java for each loop > and all the details are handled: > > *for (RowResult row : scanner) {* > > * .... }* > > If you can't use Kudu 1.10.0, it is expected that `nextRows` could be > empty and you need to keep calling it until `scanner.hasMoreRows()` is > empty. This often looks something like: > > while (scanner.hasMoreRows()) { > for (RowResult result : scanner.nextRows()) { > ... > } > } > > > Please keep us update on your project and progress, it looks very > interesting! > > Thanks, > Grant > > On Thu, Jul 11, 2019 at 11:00 AM John Mora <[email protected]> wrote: > >> Hi all. >> >> I am John Mora, a GSoC student that is working with the Apache Gora >> Community in order to implement a Kudu DataStore for Gora. >> >> Currently, I am having some issues with KuduScanner, so please could you >> give some ideas of what I am doing wrong. >> >> I am using kudu-client for java [1] and testing my code with >> KuduTestHarness [2]. >> >> My code looks like this. >> >> List<ColumnSchema> columns = new ArrayList<>(); >> columns.add(new ColumnSchema.ColumnSchemaBuilder("pkurl", >> Type.STRING).key(true).build()); >> columns.add(new ColumnSchema.ColumnSchemaBuilder("content", >> Type.BINARY).nullable(true).build()); >> columns.add(new ColumnSchema.ColumnSchemaBuilder("parsedContent", >> Type.STRING).nullable(true).build()); >> >> List<String> keys = new ArrayList<>(); >> keys.add("pkurl"); >> >> Schema sch = new Schema(columns); >> CreateTableOptions cto = new CreateTableOptions(); >> cto.setRangePartitionColumns(keys); >> >> PartialRow lowerPar1 = sch.newPartialRow(); >> PartialRow upperPar1 = sch.newPartialRow(); >> >> upperPar1.addString("pkurl", "http://bar.com/";); >> cto.addRangePartition(lowerPar1, upperPar1); >> >> PartialRow lowerPar2 = sch.newPartialRow(); >> PartialRow upperPar2 = sch.newPartialRow(); >> >> lowerPar2.addString("pkurl", "http://bar.com/";); >> cto.addRangePartition(lowerPar2, upperPar2); >> >> >> table = client.createTable(kuduMapping.getTableName(), sch, cto); >> >> // Insert some data using table.newInsert(); >> // {pkurl:"http://foo.com/1.html";, content:[...], parsedContent:[..]} >> // {pkurl:"http://baz.com/1.jsp&q=barbaz";, content:[...], >> parsedContent:[..]} >> // {pkurl:"http://baz.com/1.jsp&q=barbaz&p=foo";, content:[...], >> parsedContent:[..]} >> >> //Scanner >> KuduScanner.KuduScannerBuilder scannerBuilder = >> client.newScannerBuilder(table); >> List<String> dbFields = new ArrayList<>(); >> dbFields.add("pkurl"); >> dbFields.add("content"); >> dbFields.add("parsedContent"); >> scannerBuilder.setProjectedColumnNames(dbFields); >> KuduScanner build = scannerBuilder.build(); >> RowResultIterator resultIt = build.nextRows(); >> //Actual: RowResultIterator is Empty >> //Expected: RowResultIterator has 3 entries. >> >> I tested the same code with cto.addHashPartitions(keys, 2); instead of >> addRangePartition. >> And it works fine. >> >> Why do I get an empty result when using addRangePartition? . >> >> >> >> Cheers, >> John >> >> [1] https://kudu.apache.org/docs/developing.html#_maven_artifacts >> [2] >> https://kudu.apache.org/docs/developing.html#_jvm_based_integration_testing >> > > > -- > Grant Henke > Software Engineer | Cloudera > [email protected] | twitter.com/gchenke | linkedin.com/in/granthenke > -- Grant Henke Software Engineer | Cloudera [email protected] | twitter.com/gchenke | linkedin.com/in/granthenke
