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https://issues.apache.org/jira/browse/PHOENIX-4841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16652114#comment-16652114
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Thomas D'Silva commented on PHOENIX-4841:
-----------------------------------------
If the rvc has all the leading columns of the primary key we try to push it to
the startRow of the scan. If the sort order of the columns of the RVC changes
we have to stop extracting nodes from the where filter (see the changes in
WhereOptimizer) and then filter on the remaining columns. That patch modifies
the ComparisonExpression to handle RVC with desc sort order (by adding a COERCE
to ascending).
> Filters that uses RVC with pk columns where with DESC sort order don't work
> correctly
> -------------------------------------------------------------------------------------
>
> Key: PHOENIX-4841
> URL: https://issues.apache.org/jira/browse/PHOENIX-4841
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 4.15.0, 5.1.0
> Reporter: Thomas D'Silva
> Assignee: Daniel Wong
> Priority: Major
> Labels: DESC
> Attachments: PHOENIX-4841-v2.patch, PHOENIX-4841-v3.patch,
> PHOENIX-4841-v4.patch, PHOENIX-4841.patch
>
>
> If we filter on pk columns where one of the columns is DESC, we don't get the
> expected results. If the PK columns are of sorted by ASC we get the correct
> results. For eg. the following test fails:
> {code}
> @Test
> public void testRVCWithDescAndAscPK() throws Exception {
> String fullTableName = generateUniqueName();
> // create base table and global view using global connection
> try (Connection conn = DriverManager.getConnection(getUrl())) {
> Statement stmt = conn.createStatement();
> stmt.execute("CREATE TABLE " + fullTableName + "(\n" +
> " A VARCHAR NOT NULL,\n" +
> " B VARCHAR NOT NULL,\n" +
> " C VARCHAR NOT NULL,\n" +
> " CONSTRAINT PK PRIMARY KEY (A, B DESC, C))");
>
> conn.createStatement().execute("UPSERT INTO " + fullTableName + "
> VALUES ('x', 'd', '1')");
> conn.createStatement().execute("UPSERT INTO " + fullTableName + "
> VALUES ('x', 'c', '2')");
> conn.createStatement().execute("UPSERT INTO " + fullTableName + "
> VALUES ('x', 'b', '3')");
> conn.createStatement().execute("UPSERT INTO " + fullTableName + "
> VALUES ('x', 'b', '4')");
> conn.createStatement().execute("UPSERT INTO " + fullTableName + "
> VALUES ('x', 'a', '4')");
> conn.commit();
> }
> // validate that running query using global view gives same results
> try (Connection conn = DriverManager.getConnection(getUrl())) {
> ResultSet rs =
> conn.createStatement().executeQuery(
> "SELECT B, C FROM " + fullTableName + " WHERE (B, C)
> > ('b', '3')");
> assertTrue(rs.next());
> assertEquals("d", rs.getString(1));
> assertEquals("1", rs.getString(2));
> assertTrue(rs.next());
> assertEquals("c", rs.getString(1));
> assertEquals("2", rs.getString(2));
> assertTrue(rs.next());
> assertEquals("b", rs.getString(1));
> assertEquals("4", rs.getString(2));
> assertFalse(rs.next());
> }
> }
> {code}
> The comparison expression for the above query is
> {code}
> (PK[-1], PK[-1]) > (TO_VARCHAR('b'), '3')
> {code}
> When the first row is evaluated the lhs bytes is:
> {code}
> [-101, -1, 49]
> {code}
> and rhs bytes:
> {code}
> [-99, -1, 51]
> {code}
> We invert the bytes of the B column but since the greater than comparison
> operator usedthe row is filtered out (even though it should be returned).
> [~jamestaylor]
> When a column is DESC order do we need to rewrite the comparison expression?
> Instead of
> {code}
> WHERE (B, C) > ('b', '3')
> {code}
> we need something like
> {code}
> WHERE B<~'b' OR (B=~'b' AND C>'3')
> {code}
> Is there a better way to handle this?
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