Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-17575

Embedded server does not convert to a bound MYSQL_TYPE_TIME out buffer properly

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Open (View Workflow)
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 5.5, 10.0, 10.1, 10.2, 10.3, 10.4
    • Fix Version/s: 10.4
    • Component/s: Embedded Server
    • Labels:
      None

      Description

      There is a problem in libmysqld/libmysql.c in the function fetch_long_with_conversion(), in this fragment:

        case MYSQL_TYPE_TIME:
        case MYSQL_TYPE_DATE:
        case MYSQL_TYPE_TIMESTAMP:
        case MYSQL_TYPE_DATETIME:
        {
          int error;
          value= number_to_datetime(value, 0, (MYSQL_TIME *) buffer, 0, &error);
          *param->error= MY_TEST(error);
          break;
        }
      

      Note, for MYSQL_TYPE_TIME it should call number_to_time() instead of number_to_datetime().

      Note, on the contrary, fetch_string_with_conversion() is OK: it correctly calls str_to_time() for MYSQL_TYPE_TIME, while str_to_datetime() for DATE, TIMESTAMP and DATETIME

      The attached program demonstrates the problem: it binds expressions of various data types to MYSQL_TYPE_TIME, and it returns the following results:

      Program output (wrong)

      SELECT TIME'800:33:44' -> TIME = TIME      0000-00-00 800:33:44.000000
      SELECT 1010            -> TIME = DATE      2000-10-10 00:00:00.000000
      SELECT 20101010        -> TIME = DATE      2010-10-10 00:00:00.000000
      SELECT 20101010223344  -> TIME = DATETIME  2010-10-10 22:33:44.000000
      SELECT 8003344         -> TIME             mysql_stmt_fetch() failed: error=''
      SELECT 8001112         -> TIME             mysql_stmt_fetch() failed: error=''
      SELECT 10001112        -> TIME = DATE      1000-11-12 00:00:00.000000
      

      One would expect that data type conversion will happen in the same way with what happens on the server side with CAST(AS TIME).

      Server-side conversion with CAST (correct)

      SELECT
        CAST(TIME'800:33:44' AS TIME),
        CAST(1010 AS TIME),
        CAST(20101010 AS TIME),
        CAST(20101010223344 AS TIME),
        CAST(8003344 AS TIME),
        CAST(8001112 AS TIME),
        CAST(10001112 AS TIME)\G
      

      CAST(TIME'800:33:44' AS TIME): 800:33:44
                 CAST(1010 AS TIME): 00:10:10
             CAST(20101010 AS TIME): 00:00:00
       CAST(20101010223344 AS TIME): 22:33:44
              CAST(8003344 AS TIME): 800:33:44
              CAST(8001112 AS TIME): 800:11:12
             CAST(10001112 AS TIME): 00:00:00
      

      However this is not the case.

      Observations on totally wrong results in the program output:

      • Conversion from 1010 to TIME returns DATETIME '2000-10-10 00:00:00.000000', which looks wrong. The expected result is TIME'00:10:10', i.e what CAST(1010 AS TIME) does.
      • Conversion from 8003344 returns an error. The expected result is TIME'800:33:44'.
      • Conversion from 8001112 returns an error. The expected result is TIME'800:11:12'.

      Observations on less fatal but still unpleasant results in the program output:

      • Conversion from 20101010 returns a DATE. The expected result is zero time. No conversion from DATE to TIME happened.
      • Conversion from 20101010223344 returns a full datetime. The expected result is TIME'22:33:44'. No conversion from DATETIME to TIME happened.
      • Conversion from 10001112 returns a DATE. The expected result is zero time. No conversion from DATE to TIME happened.

        Attachments

        1. bind.c
          3 kB
        2. Makefile
          0.3 kB

          Activity

            People

            Assignee:
            bar Alexander Barkov
            Reporter:
            bar Alexander Barkov
            Votes:
            0 Vote for this issue
            Watchers:
            1 Start watching this issue

              Dates

              Created:
              Updated:

                Git Integration

                Error rendering 'com.xiplink.jira.git.jira_git_plugin:git-issue-webpanel'. Please contact your Jira administrators.