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  1. MariaDB Server
  2. MDEV-558

DNAMES: Adding a column with a too long name corrupts previously inserted data

        Details

        • Type: Bug
        • Status: Closed
        • Priority: Major
        • Resolution: Not a Bug
        • Affects Version/s: None
        • Fix Version/s: 10.0.1
        • Component/s: None
        • Labels:
          None

          Description

          First, we insert a value into column col1 (and check that it's inserted correctly). Then we add a column with a long name, and expectedly get a warning about truncated data. But then we try to read the value of 'col1' again and find out that it's not the same as it used to be.

          drop table if exists t1;
CREATE TABLE t1 (f1 tinyblob);
INSERT INTO t1 VALUES (COLUMN_CREATE('col1', REPEAT('a',30)));
select column_get(f1,'col1' as char(30)) from t1;
# +-----------------------------------+
# | column_get(f1,'col1' as char(30)) |
# +-----------------------------------+
# | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa    |
# +-----------------------------------+

UPDATE t1 SET f1 = COLUMN_ADD( f1, REPEAT('c',211), 'val3' );
show warnings;
# +---------+------+-----------------------------------------+
# | Level   | Code | Message                                 |
# +---------+------+-----------------------------------------+
# | Warning | 1265 | Data truncated for column 'f1' at row 1 |
# +---------+------+-----------------------------------------+

select column_get(f1,'col1' as char(30)) from t1;
# +-----------------------------------+
# | column_get(f1,'col1' as char(30)) |
# +-----------------------------------+
# | aaaaaaaaaaaaaaaaaaaaaaaa¦¦¦¦¦¦          |
# +-----------------------------------+

 select column_get(f1,'col1' as char(30)) = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' as test from t1; 
# +------+
# | test |
# +------+
# |    0 |
# +------+

          Test case (same as above, but only essential commands)

          drop table if exists t1;
CREATE TABLE t1 (f1 tinyblob);
INSERT INTO t1 VALUES (COLUMN_CREATE('col1', REPEAT('a',30)));
UPDATE t1 SET f1 = COLUMN_ADD( f1, REPEAT('c',211), 'val3' );
select column_get(f1,'col1' as char(30)) from t1;

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                Issue Links

                relates to

                Task - A task that needs to be done. MDEV-377 Name support for dynamic columns

                • Critical - Crashes, loss of data, severe memory leak.
                • Closed

                  Activity

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                  sanja Oleksandr Byelkin added a comment -

                  It is expected behavior - tyniblob can be 256 bytes max, so the string was cut (see warning) and so corrupted.

                  Show
                  sanja Oleksandr Byelkin added a comment - It is expected behavior - tyniblob can be 256 bytes max, so the string was cut (see warning) and so corrupted.

                    People

                    • Assignee:
                      sanja Oleksandr Byelkin
                      Reporter:
                      elenst Elena Stepanova
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                      Dates

                      • Created:
                        Updated:
                        Resolved: