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  1. MariaDB Server
  2. MDEV-4017

GET_LOCK() with negative timeouts has strange behavior

        Details

        • Type: Bug
        • Status: Closed
        • Priority: Minor
        • Resolution: Fixed
        • Affects Version/s: 10.0.0, 5.5.28a, 5.3.11, 5.2.13, 5.1.66
        • Fix Version/s: 10.0.21, 10.1.7, 5.5.45
        • Component/s: OTHER
        • Labels:
        • Environment:
          5.5

          Description

          I know that passing a negative timeout to GET_LOCK() makes no sense. But if you do it by mistake (perhaps with dynamic sql) there are 2 cases:

          • If the number is high, it is like passing 0: 
            MariaDB [(none)]> SELECT GET_LOCK('x', -100);
+---------------------+
| GET_LOCK('x', -100) |
+---------------------+
|                   0 |
+---------------------+
1 row in set (0.01 sec)
          • if number is very low, it considers it as a positive number (you will need to kill the query): 
            SELECT GET_LOCK('x', -1500000000);

            In both cases, I get no errors or warnings.

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                  f_razzoli Federico Razzoli added a comment -

                  Of course the first case is ok, but I think that the second case (very low negatives considered as positive) is a bug.

                  Show
                  f_razzoli Federico Razzoli added a comment - Of course the first case is ok, but I think that the second case (very low negatives considered as positive) is a bug.
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                  elenst Elena Stepanova added a comment -

                  It's an upstream issue, except that in MySQL up to and including 5.6 even GET_LOCK('x', -10) hangs seemingly forever (as well as in MariaDB 5.1/5.2).

                  Show
                  elenst Elena Stepanova added a comment - It's an upstream issue, except that in MySQL up to and including 5.6 even GET_LOCK('x', -10) hangs seemingly forever (as well as in MariaDB 5.1/5.2).
                  Hide
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                  svoj Sergey Vojtovich added a comment -

                  Alexander Barkov, please review fix for this bug.

                  Show
                  svoj Sergey Vojtovich added a comment - Alexander Barkov , please review fix for this bug.
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                  bar Alexander Barkov added a comment -

                  Okey to push, with a minor suggestion.

                  Show
                  bar Alexander Barkov added a comment - Okey to push, with a minor suggestion.

                    People

                    • Assignee:
                      svoj Sergey Vojtovich
                      Reporter:
                      f_razzoli Federico Razzoli
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                      Dates

                      • Created:
                        Updated:
                        Resolved: