[jira] [Commented] (HBASE-3562) ValueFilter is being evaluated before performing the column match

["Esteban Gutierrez (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-3562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15671544#comment-15671544 ] 

Esteban Gutierrez commented on HBASE-3562:
------------------------------------------

[~Apache9] any thoughts on this? There seems that the unit tests in the patch would be helpful and there is an addition to the ColumnTracker that might be helpful in other cases.

> ValueFilter is being evaluated before performing the column match
> -----------------------------------------------------------------
>
>                 Key: HBASE-3562
>                 URL: https://issues.apache.org/jira/browse/HBASE-3562
>             Project: HBase
>          Issue Type: Bug
>          Components: Filters
>    Affects Versions: 0.90.0, 0.94.7
>            Reporter: Evert Arckens
>         Attachments: HBASE-3562.patch
>
>
> When performing a Get operation where a both a column is specified and a ValueFilter, the ValueFilter is evaluated before making the column match as is indicated in the javadoc of Get.setFilter()  : " {@link Filter#filterKeyValue(KeyValue)} is called AFTER all tests for ttl, column match, deletes and max versions have been run. "
> The is shown in the little test below, which uses a TestComparator extending a WritableByteArrayComparable.
> public void testFilter() throws Exception {
> 	byte[] cf = Bytes.toBytes("cf");
> 	byte[] row = Bytes.toBytes("row");
> 	byte[] col1 = Bytes.toBytes("col1");
> 	byte[] col2 = Bytes.toBytes("col2");
> 	Put put = new Put(row);
> 	put.add(cf, col1, new byte[]{(byte)1});
> 	put.add(cf, col2, new byte[]{(byte)2});
> 	table.put(put);
> 	Get get = new Get(row);
> 	get.addColumn(cf, col2); // We only want to retrieve col2
> 	TestComparator testComparator = new TestComparator();
> 	Filter filter = new ValueFilter(CompareOp.EQUAL, testComparator);
> 	get.setFilter(filter);
> 	Result result = table.get(get);
> }
> public class TestComparator extends WritableByteArrayComparable {
>     /**
>      * Nullary constructor, for Writable
>      */
>     public TestComparator() {
>         super();
>     }
>     
>     @Override
>     public int compareTo(byte[] theirValue) {
>         if (theirValue[0] == (byte)1) {
>             // If the column match was done before evaluating the filter, we should never get here.
>             throw new RuntimeException("I only expect (byte)2 in col2, not (byte)1 from col1");
>         }
>         if (theirValue[0] == (byte)2) {
>             return 0;
>         }
>         else return 1;
>     }
> }
> When only one column should be retrieved, this can be worked around by using a SingleColumnValueFilter instead of the ValueFilter.



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