[metamodel] 07/16: A filter that will only return the first KV from each row.This filter can be used to more efficiently perform row count operations.

[ka...@apache.org]

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kaspersor pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/metamodel.git

commit 7250ba1e5d968fa49d81b02ffaa4aaa685c39a7a
Author: 李小保 <li...@mininglamp.com>
AuthorDate: Fri Mar 29 13:49:25 2019 +0800

    A filter that will only return the first KV from each row.This filter can be used to more efficiently perform row count operations.
---
 hbase/src/main/java/org/apache/metamodel/hbase/HBaseDataContext.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/hbase/src/main/java/org/apache/metamodel/hbase/HBaseDataContext.java b/hbase/src/main/java/org/apache/metamodel/hbase/HBaseDataContext.java
index 1d0db49..fd2125e 100644
--- a/hbase/src/main/java/org/apache/metamodel/hbase/HBaseDataContext.java
+++ b/hbase/src/main/java/org/apache/metamodel/hbase/HBaseDataContext.java
@@ -31,6 +31,7 @@ import org.apache.hadoop.hbase.client.Result;
 import org.apache.hadoop.hbase.client.ResultScanner;
 import org.apache.hadoop.hbase.client.Scan;
 import org.apache.hadoop.hbase.client.TableDescriptor;
+import org.apache.hadoop.hbase.filter.FirstKeyOnlyFilter;
 import org.apache.hadoop.hbase.filter.PageFilter;
 import org.apache.metamodel.DataContext;
 import org.apache.metamodel.MetaModelException;
@@ -171,7 +172,9 @@ public class HBaseDataContext extends QueryPostprocessDataContext implements Upd
         long result = 0;
         final org.apache.hadoop.hbase.client.Table hTable = getHTable(table.getName());
         try {
-            ResultScanner scanner = hTable.getScanner(new Scan());
+            Scan scan = new Scan();
+            scan.setFilter(new FirstKeyOnlyFilter());
+            ResultScanner scanner = hTable.getScanner(scan);
             try {
                 while (scanner.next() != null) {
                     result++;