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From "Mike Matrigali (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-4240) An index cause SQL ORDER BY can't return correct result
Date Thu, 21 May 2009 15:20:45 GMT

     [ https://issues.apache.org/jira/browse/DERBY-4240?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Mike Matrigali updated DERBY-4240:
----------------------------------


This reproduces for me in trunk using the included script against both ibm16 and ibm15 jvms.
Here is the query plan:
2009-05-21 15:09:30.671 GMT Thread[main,5,main] (XID = 288), (SESSIONID = 1), SELECT t1.id,
t1.name FROM test2 t2 INNER JOIN test1 t1 ON t2.rel_id = t
1.id WHERE t2.entity_id = 1 ORDER BY t1.id ASC ******* Project-Restrict ResultSet (6):
Number of opens = 1
Rows seen = 3
Rows filtered = 0
restriction = false
projection = true
    constructor time (milliseconds) = 0
    open time (milliseconds) = 0
    next time (milliseconds) = 0
    close time (milliseconds) = 0
    restriction time (milliseconds) = 0
    projection time (milliseconds) = 0
    optimizer estimated row count:            3.00
    optimizer estimated cost:           62.07

Source result set:
    Nested Loop Exists Join ResultSet:
    Number of opens = 1
    Rows seen from the left = 3
    Rows seen from the right = 3
    Rows filtered = 0
    Rows returned = 3
        constructor time (milliseconds) = 0
        open time (milliseconds) = 0
        next time (milliseconds) = 0
        close time (milliseconds) = 0
        optimizer estimated row count:            3.00
        optimizer estimated cost:           62.07

    Left result set:
        Index Row to Base Row ResultSet for TEST2:
        Number of opens = 1
        Rows seen = 3
        Columns accessed from heap = {0, 1}
            constructor time (milliseconds) = 0
            open time (milliseconds) = 0
            next time (milliseconds) = 0
            close time (milliseconds) = 0
            optimizer estimated row count:            3.00
            optimizer estimated cost:           40.57

            Index Scan ResultSet for TEST2 using index IDX_TEST2 at read committed isolation
level using share row locking chosen by the optimizer
            Number of opens = 1
            Rows seen = 3
            Rows filtered = 0
            Fetch Size = 1
                constructor time (milliseconds) = 0
                open time (milliseconds) = 0
                next time (milliseconds) = 0
                close time (milliseconds) = 0
                next time in milliseconds/row = 0

            scan information:
                Bit set of columns fetched=All
                Number of columns fetched=2
                Number of deleted rows visited=0
                Number of pages visited=1
                Number of rows qualified=3
                Number of rows visited=3
                Scan type=btree
                Tree height=-1
                start position:
    >= on first 1 column(s).
    Ordered null semantics on the following columns:

                stop position:
    > on first 1 column(s).
    Ordered null semantics on the following columns:

                qualifiers:
None
                optimizer estimated row count:            3.00
                optimizer estimated cost:           40.57
    Right result set:
        Index Row to Base Row ResultSet for TEST1:
        Number of opens = 3
        Rows seen = 3
        Columns accessed from heap = {1}
            constructor time (milliseconds) = 0
            open time (milliseconds) = 0
            next time (milliseconds) = 0
            close time (milliseconds) = 0
            optimizer estimated row count:            3.00
            optimizer estimated cost:           21.50

            Index Scan ResultSet for TEST1 using constraint SQL090521080928600 at read committed
isolation level using share row locking cho
 optimizer
            Number of opens = 3
            Rows seen = 3
            Rows filtered = 0
            Fetch Size = 1
                constructor time (milliseconds) = 0
                open time (milliseconds) = 0
                next time (milliseconds) = 0
                close time (milliseconds) = 0
                next time in milliseconds/row = 0

            scan information:
                Bit set of columns fetched=All
                Number of columns fetched=2
                Number of deleted rows visited=0
                Number of pages visited=3
                Number of rows qualified=3
                Number of rows visited=3
                Scan type=btree
                Tree height=1
                start position:
    >= on first 1 column(s).
    Ordered null semantics on the following columns:

                stop position:
    > on first 1 column(s).
    Ordered null semantics on the following columns:

                qualifiers:
None
                optimizer estimated row count:            3.00
                optimizer estimated cost:           21.50

> An index cause SQL ORDER BY can't return correct result
> -------------------------------------------------------
>
>                 Key: DERBY-4240
>                 URL: https://issues.apache.org/jira/browse/DERBY-4240
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 10.4.2.0
>            Reporter: Simon Meng
>
> Following snippet  is a SQL example program. It can reproduce a database issue. 
> DROP TABLE test1;
> DROP TABLE test2;
> CREATE TABLE test1 (id BIGINT NOT NULL, name VARCHAR(255), PRIMARY KEY (id));
> CREATE TABLE test2 (entity_id BIGINT, rel_id BIGINT);
> CREATE INDEX idx_test2 ON test2 (entity_id);
> INSERT INTO test1 (id, name) VALUES (102, 'Tom');
> INSERT INTO test1 (id, name) VALUES (1, null);
> INSERT INTO test1 (id, name) VALUES (103, 'Jerry');
> INSERT INTO test1 (id, name) VALUES (101, 'Pupy');
> INSERT INTO test2 (entity_id, rel_id) VALUES (1, 102);
> INSERT INTO test2 (entity_id, rel_id) VALUES (1, 101);
> INSERT INTO test2 (entity_id, rel_id) VALUES (1, 103);
> SELECT t1.id, t1.name FROM test2 t2 INNER JOIN test1 t1 ON t2.rel_id = t1.id WHERE t2.entity_id
= 1 ORDER BY t1.id ASC;
> The expected result should be 
> ID                  NAME
> --------------------------
> 101                Pupy
> 102                Tom
> 103                Jerry
> When running the program, I got below result.
> ID                  NAME
> --------------------------
> 102                Tom
> 101                Pupy
> 103                Jerry
> The result is obviously wrong. Using ORDER BY ASC does not get expected result. I found
ORDER BY DESC works fine.
> Note: there is an index (idx_test2). This index affects the SQL query. If the index is
dropped, ORDER BY ASC can return correct result..

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