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  1. MariaDB Server
  2. MDEV-8894

Inserting fractional seconds into MySQL 5.6 master breaks consistency on MariaDB 10 slave

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    Description

      Inserting a fractional second into MySQL 5.6 and MariaDB yields different results, and as a consequence, replicating from a MySQL 5.6 master into a MariaDB 10 slave creates an inconsistent slave.

      On Oracle/Percona MySQL 5.6 the value is rounded:

       
      		 
      master>create table test_datetime (dt datetime not null);
      		 
      Query OK, 0 rows affected (0.06 sec)
      		 
       
      		 
      master>insert into test_datetime  values ('2015-10-05 10:00:00.501');
      		 
      Query OK, 1 row affected (0.12 sec)
      		 
       
      		 
      master>select * from test_datetime;
      		 
      +---------------------+
      		 
      | dt                  |
      		 
      +---------------------+
      		 
      | 2015-10-05 10:00:01 |
      		 
      +---------------------+
      		 
      1 row in set (0.00 sec)

      On MariaDB 10 it is not:

      MariaDB slave [rick]> insert into test_datetime  values ('2015-10-05 10:00:00.501');
      		 
      Query OK, 1 row affected (0.00 sec)
      		 
       
      		 
      MariaDB slave [rick]> select * from test_datetime;
      		 
      +---------------------+
      		 
      | dt                  |
      		 
      +---------------------+
      		 
      | 2015-10-05 10:00:00 |
      		 
      +---------------------+
      		 
      2 rows in set (0.00 sec)

      Inconsistent MariaDB slave test:

      master>insert into test_datetime  values ('2015-10-05 10:00:00.501');
      		 
      Query OK, 1 row affected (0.00 sec)
      		 
      master>select * from test_datetime;
      		 
      +---------------------+
      		 
      | dt                  |
      		 
      +---------------------+
      		 
      | 2015-10-05 10:00:01 |
      		 
      +---------------------+
      		 
      1 row in set (0.00 sec)
      		 
       
      		 
      MariaDB slave [rick]> select * from test_datetime;
      		 
      +---------------------+
      		 
      | dt                  |
      		 
      +---------------------+
      		 
      | 2015-10-05 10:00:00 |
      		 
      +---------------------+
      		 
      1 row in set (0.00 sec)

      This issue affects both datetime and timestamp column types.

      MariaDB should have same behaviour regarding fractional seconds as Oracle and Percona, or interoperability is compromised. For example, a pt-table-checksum always fails due to these rounding differences when comparing a MariaDB slave against a non MariaDB master.

      Until this bug is fixed we will be unable to use multi source replication, which was the primary reason for us to use MariaDB.

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        Issue Links

          is blocked by

          Bug - A problem which impairs or prevents the functions of the product. MDEV-13995 MAX(timestamp) returns a wrong result near DST change

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15176 Storing DATETIME-alike VARCHAR data into TIME produces wrong results

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15205 Remove mysql_type_to_time_type()

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15262 Wrong results for SELECT..WHERE non_indexed_datetime_column=indexed_time_column

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15287 Bad result for LEAST/GREATEST(datetime_alike_string, time)

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15289 Binding an out-of-range DATETIME value in binary protocol breaks replication

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15293 CAST(AS TIME) returns bad results for LAST_VALUE(),NAME_CONST(),SP variable

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15340 Wrong result HOUR(case_expression_with_time_and_datetime)

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15363 Wrong result for CAST(LAST_DAY(TIME'00:00:00') AS TIME)

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15406 NO_ZERO_IN_DATE erroneously affects how CAST(AS DATE) warns about fractional digit truncation

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-16910 Add class VDec

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-16928 Move MYSQL_TIME initialization from Field_xxx::store_time_dec() to new constructors Time() and Datetime()

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-16935 Change the parameter of Field_xxx::store_TIME_with_dec() to const Datetime* and const Time*

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-16938 Move Item::get_time_with_conversion() to Time

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-16939 Move TIMESTAMP truncation code to Field_timestamp::store_TIME_with_warn

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-16991 Rounding vs truncation for TIME, DATETIME, TIMESTAMP

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-15225 Can't import .ibd file with temporal type format differing from mysql56_temporal_format

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-17216 Assertion `!dt->fraction_remainder(decimals())' failed in Field_temporal_with_date::store_TIME_with_warning

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

          Web Link MySQL Bug#68760

          Web Link MySQL Bug#76948

          Web Link MySQL Bug#78802

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              bar Alexander Barkov
              leopardus2 Rick Pizzi
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                Updated:
                Resolved:

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