[jira] [Commented] (PHOENIX-4841) Filters that uses RVC with pk columns where with DESC sort order don't work correctly

["James Taylor (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PHOENIX-4841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16575078#comment-16575078 ] 

James Taylor commented on PHOENIX-4841:
---------------------------------------

With RVC expressions, we only have one comparison operator, so we don't have a way of expressing a mix of < and >:
{code:java}
WHERE B<~'b' OR (B=~'b' AND C>'3'){code}
You might try playing around with wrapping the column with an INVERT call, something like this:
{code:java}
WHERE (INVERT(B), C) > (INVERT('b'), '3'){code}
Or internally adding the INVERT of B.

A last resort would be to not optimize a mix of ASC, DESC primary key columns into the scan (which would fix the correctness issue).

 

> 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
>            Priority: Major
>
> 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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