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  1. MariaDB Server
  2. MDEV-25477

Auto-create breaks replication when triggering event was not replicated

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      Description

      Partitioning auto-creation cannot be enabled in a replication topology, unless only non-transactional engines are used (which is hardly realistic these days).

      The reason is that when a partition is auto-created within a transaction, but the transaction is later rolled back, there will be nothing written in the binary log. Thus, the master will have the new partition, but the slave will not. This discrepancy will almost inevitably cause a replication abort some time later.

      If it's intentional, at the very least it has to be documented, as it is a pretty big limitation.

      Example:

      --source include/have_partition.inc
      --source include/have_innodb.inc
      --source include/master-slave.inc
       
      create table t (a int) engine=InnoDB with system versioning
        partition by system_time interval 1 hour auto;
       
      insert into t values (1),(2);
      set @@timestamp= @@timestamp+3601;
       
      start transaction;
      delete from t;
      rollback;
       
      show create table t;
       
      --sync_slave_with_master
       
      show create table t;
       
      --connection master
      alter table t drop partition p0;
       
      --sync_slave_with_master
      

      After rollback, the master has 2 historical partitions, while the slave has only one:

      bb-10.6-midenok-MDEV-17554 edbc73ac4

      show create table t;
      Table	Create Table
      t	CREATE TABLE `t` (
        `a` int(11) DEFAULT NULL
      ) ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING
       PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR STARTS TIMESTAMP'2021-04-21 23:00:00' AUTO
      PARTITIONS 3
      connection slave;
      show create table t;
      Table	Create Table
      t	CREATE TABLE `t` (
        `a` int(11) DEFAULT NULL
      ) ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING
       PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR STARTS TIMESTAMP'2021-04-21 23:00:00' AUTO
      PARTITIONS 2
      

      So, the master is allowed to drop partition p0, but the slave is not:

      Last_Errno	4128
      Last_Error	Error 'Wrong partitions for `t`: must have at least one HISTORY and exactly one last CURRENT' on query. Default database: 'test'. Query: 'alter table t drop partition p0'
      

      Also test case from MDEV-25478 must be considered.

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              Assignee:
              midenok Aleksey Midenkov
              Reporter:
              elenst Elena Stepanova
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                Updated:
                Resolved:

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