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https://issues.apache.org/jira/browse/HBASE-3562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13011248#comment-13011248
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Jonathan Gray commented on HBASE-3562:
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The counter in ColumnTracker is responsible for tracking setMaxVersions. You
may have queried for only the latest version, so once the ColumnTracker sees a
given column, it will reject subsequent version of that columns. Currently
there's no way for the CT to know that subsequent filters actually prevented it
from being returned so it should not be included in the count of returned
versions.
We would need to introduce something like {{skippedPreviousKeyValue}} that
could be sent back to the CT so it could undo the previous count.
> 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
> Reporter: Evert Arckens
>
> 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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