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https://issues.apache.org/jira/browse/HBASE-9115?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13728716#comment-13728716
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Lars Hofhansl commented on HBASE-9115:
--------------------------------------
I shouldn't have started this whole discussion, sorry about that.
n will be small anyway (we're doing a get for all the columns on the server,
then looping over the result set and then match it up with the passed columns,
then we upsert into the memstore, finding old versions of the KVs first,
removing them, followed by finally inserting the new ones). Like Increment the
cost of the sorting here will negligible compared to all this.
The fix should have been on the server only. There's a convenience doing this
client side, but doesn't imply that we should not do the right thing, sorting
on both sides seems pointless. The server should do the validation (we're not
good about this generally, but we shouldn't add to this).
The other reason is that ultimately only the (H)Store has the right comparator
anyway, if we have have a store that sorts with a different comparator this
might break again.
> HTableInterface.append operation may overwrites values
> ------------------------------------------------------
>
> Key: HBASE-9115
> URL: https://issues.apache.org/jira/browse/HBASE-9115
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.94.10
> Environment: MAC OS X 10.8.4, Hbase in the pseudo-distributed mode,
> hadoop v1.2.0, Hbase Java API based client.
> *hdfs-site.xml*:
> {code:xml}
> <configuration>
> <property>
> <name>dfs.replication</name>
> <value>1</value>
> </property>
> <property>
> <name>dfs.support.append</name>
> <value>true</value>
> </property>
> </configuration>
> {code}
> *hbase-site.xml*:
> {code:xml}
> <configuration>
> <property>
> <name>hbase.rootdir</name>
> <value>hdfs://localhost:9000/hbase</value>
> </property>
> <property>
> <name>hbase.cluster.distributed</name>
> <value>true</value>
> </property>
> <property>
> <name>hbase.zookeeper.quorum</name>
> <value>localhost</value>
> </property>
> <property>
> <name>dfs.support.append</name>
> <value>true</value>
> </property>
> </configuration>
> {code}
> Reporter: Aleksandr B
> Assignee: Ted Yu
> Priority: Critical
> Fix For: 0.98.0, 0.95.2, 0.94.11
>
> Attachments: 9115-0.94.txt, 9115-0.94-v2.txt, 9115-trunk.addendum,
> 9115-trunk.addendum2, 9115-trunk.txt
>
>
> I use Hbase Java API and I try to append values Bytes.toBytes("one two") and
> Bytes.toBytes(" three") in 3 columns.
> Only for 2 out of these 3 columns the result is "one two three".
> *Output from the hbase shell:*
> {noformat}
> hbase(main):008:0* scan "mytesttable"
> ROW COLUMN+CELL
>
> mytestRowKey column=TestA:dlbytes,
> timestamp=1375436156140, value=one two three
>
> mytestRowKey column=TestA:tbytes,
> timestamp=1375436156140, value=one two three
>
> mytestRowKey column=TestA:ulbytes,
> timestamp=1375436156140, value= three
>
> 1 row(s) in 0.0280 seconds
> {noformat}
> *My test code:*
> {code:title=Database.java|borderStyle=solid}
> import static org.junit.Assert.*;
> import java.io.IOException;
>
> import org.apache.hadoop.conf.Configuration;
> import org.apache.hadoop.hbase.HBaseConfiguration;
> import org.apache.hadoop.hbase.HColumnDescriptor;
> import org.apache.hadoop.hbase.HTableDescriptor;
> import org.apache.hadoop.hbase.client.HBaseAdmin;
> import org.apache.hadoop.hbase.client.HTableInterface;
> import org.apache.hadoop.hbase.client.HTablePool;
> import org.apache.hadoop.hbase.client.Append;
> import org.apache.hadoop.hbase.client.Result;
> import org.apache.hadoop.hbase.util.Bytes;
> import org.junit.Test;
> ...
> @Test
> public void testAppend() throws IOException {
> byte [] rowKey = Bytes.toBytes("mytestRowKey");
> byte [] column1 = Bytes.toBytes("ulbytes");
> byte [] column2 = Bytes.toBytes("dlbytes");
> byte [] column3 = Bytes.toBytes("tbytes");
> String part11 = "one two";
> String part12 = " three";
> String cFamily = "TestA";
> String TABLE = "mytesttable";
> Configuration conf = HBaseConfiguration.create();
> HTablePool pool = new HTablePool(conf, 10);
> HBaseAdmin admin = new HBaseAdmin(conf);
>
> if(admin.tableExists(TABLE)){
> admin.disableTable(TABLE);
> admin.deleteTable(TABLE);
> }
>
> HTableDescriptor tableDescriptor = new HTableDescriptor(TABLE);
> HColumnDescriptor hcd = new HColumnDescriptor(cFamily);
> hcd.setMaxVersions(1);
> tableDescriptor.addFamily(hcd);
> admin.createTable(tableDescriptor);
> HTableInterface table = pool.getTable(TABLE);
>
> Append a = new Append(rowKey);
> a.setReturnResults(false);
> a.add(Bytes.toBytes(cFamily), column1, Bytes.toBytes(part11));
> a.add(Bytes.toBytes(cFamily), column2, Bytes.toBytes(part11));
> a.add(Bytes.toBytes(cFamily), column3, Bytes.toBytes(part11));
> table.append(a);
> a = new Append(rowKey);
> a.add(Bytes.toBytes(cFamily), column1, Bytes.toBytes(part12));
> a.add(Bytes.toBytes(cFamily), column2, Bytes.toBytes(part12));
> a.add(Bytes.toBytes(cFamily), column3, Bytes.toBytes(part12));
> Result result = table.append(a);
> byte [] resultForColumn1 = result.getValue(Bytes.toBytes(cFamily),
> column1);
> byte [] resultForColumn2 = result.getValue(Bytes.toBytes(cFamily),
> column2);
> byte [] resultForColumn3 = result.getValue(Bytes.toBytes(cFamily),
> column3);
> if (resultForColumn1 == null || resultForColumn2 == null ||
> resultForColumn3 == null)
> System.out.println("The DB table contains these values but they
> are never given back, strange...");
> else {
> assertEquals(0, Bytes.compareTo(Bytes.toBytes(part11 + part12),
> resultForColumn1));
> assertEquals(0, Bytes.compareTo(Bytes.toBytes(part11 + part12),
> resultForColumn2));
> assertEquals(0, Bytes.compareTo(Bytes.toBytes(part11 + part12),
> resultForColumn3));
> }
> HTable t = new HTable(conf, TABLE);
> Get getOperation = new Get(rowKey);
> getOperation.addColumn(Bytes.toBytes(cFamily), column1);
> Result res = t.get(getOperation);
> assertEquals(0, Bytes.compareTo(Bytes.toBytes(part11 + part12),
> res.getValue(Bytes.toBytes(cFamily), column1)));
> }
> {code}
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