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https://issues.apache.org/jira/browse/KUDU-2494?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Ricardo Gaspar updated KUDU-2494:
---------------------------------
Description:
KuduScannerBuild API only supports the build of a scan using predicates in a
conjuctive operation.
Meaning that when using more than one predicate (p1,p2), the scan will be done
using a statement similar to:
{code:java}
WHERE p1 AND p2;{code}
In Java code:
{code:java}
kc = new KuduClient.KuduClientBuilder(kuduMasters).build();
session = kc.newSession();
KuduScanner ks =
kc.newScannerBuilder(table).addPredicate(p1).addPredicate(p2).build();
{code}
*There is no possibility to specify a OR operation that applies an disjunction
between all/some predicates*. E.g.
{code:java}
WHERE p1 OR p2;{code}
The only way to do this using the current API (1.7.1) is to use two (or more)
scanners and iterate them separately:
{code:java}
KuduScanner scanner1 = kc.newScannerBuilder(table).addPredicate(p1).build();
KuduScanner scanner2 = kc.newScannerBuilder(table).addPredicate(p2).build();
while (scanner1.hasMoreRows()) {
RowResultIterator results = scanner1.nextRows();
while (results.hasNext()) {
RowResult rowData = results.next();
//Do stuff with rowData
}
}
while (scanner2.hasMoreRows()) {
RowResultIterator results = scanner2.nextRows();
while (results.hasNext()) {
RowResult rowData = results.next();
//Do stuff with rowData
}
}
{code}
Kudu API should provide "almost" the same query processing power as IMPALA or
an SQL engine.
Programmers should rely on Kudu API to operations like these and others like:
sorting, table joins, etc.
was:
KuduScannerBuild API only supports the build of a scan using predicates in a
conjuctive operation.
Meaning that when using more than one predicate (p1,p2), the scan will be done
using a statement similar to:
{code:java}
WHERE p1 AND p2;{code}
In Java code:
{code:java}
kc = new KuduClient.KuduClientBuilder(kuduMasters).build();
session = kc.newSession();
KuduScanner ks =
kc.newScannerBuilder(table).addPredicate(p1).addPredicate(p2).build();
{code}
*There is no possibility to specify a OR operation that applies an disjunction
between all/some predicates*. E.g.
{code:java}
WHERE p1 OR p2;{code}
> KuduScannerBuilder OR operator for predicates
> ---------------------------------------------
>
> Key: KUDU-2494
> URL: https://issues.apache.org/jira/browse/KUDU-2494
> Project: Kudu
> Issue Type: Improvement
> Components: api
> Affects Versions: 1.7.1
> Reporter: Ricardo Gaspar
> Priority: Major
> Fix For: 1.8.0
>
>
> KuduScannerBuild API only supports the build of a scan using predicates in a
> conjuctive operation.
> Meaning that when using more than one predicate (p1,p2), the scan will be
> done using a statement similar to:
> {code:java}
> WHERE p1 AND p2;{code}
>
> In Java code:
>
> {code:java}
> kc = new KuduClient.KuduClientBuilder(kuduMasters).build();
> session = kc.newSession();
> KuduScanner ks =
> kc.newScannerBuilder(table).addPredicate(p1).addPredicate(p2).build();
> {code}
>
> *There is no possibility to specify a OR operation that applies an
> disjunction between all/some predicates*. E.g.
> {code:java}
> WHERE p1 OR p2;{code}
>
>
> The only way to do this using the current API (1.7.1) is to use two (or more)
> scanners and iterate them separately:
>
> {code:java}
> KuduScanner scanner1 = kc.newScannerBuilder(table).addPredicate(p1).build();
> KuduScanner scanner2 = kc.newScannerBuilder(table).addPredicate(p2).build();
> while (scanner1.hasMoreRows()) {
> RowResultIterator results = scanner1.nextRows();
> while (results.hasNext()) {
> RowResult rowData = results.next();
>
> //Do stuff with rowData
> }
> }
> while (scanner2.hasMoreRows()) {
> RowResultIterator results = scanner2.nextRows();
> while (results.hasNext()) {
> RowResult rowData = results.next();
> //Do stuff with rowData
> }
> }
> {code}
>
> Kudu API should provide "almost" the same query processing power as IMPALA or
> an SQL engine.
> Programmers should rely on Kudu API to operations like these and others like:
> sorting, table joins, etc.
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