[#MCOL-1026] Ghost entry created by mxs

Create a table on Master.

MySQL [test]> create table t3 (a int, b int);

Query OK, 0 rows affected (0.14 sec)

On ColumnStore side, create corresponding table

MariaDB [test]> CREATE TABLE test.t3 (a int, b int) ENGINE=ColumnStore;

Query OK, 0 rows affected (1.15 sec)

MariaDB [test]> select * from t3;

Empty set (0.11 sec)

Now back on master insert one row

MySQL [test]> insert into t3 values (0, 1);

Query OK, 1 row affected (0.04 sec)

Start mxs_adapter as following

./mxs_adapter -h 172.21.0.7 -P 4001 -u cdcuser -p cdc -r 5 -n test t3

2 rows and 0 transactions inserted in 5.19347 seconds. GTID = 0-1-44

Check the inserted rows on ColumnStore

MariaDB [test]> select * from t3;

+------+---------+

| a    | b       |

+------+---------+

|    0 |       1 |

|    0 | 4673075 |

+------+---------+

2 rows in set (0.02 sec)

Note the ghost entry with b = 4673075

Further adding new rows on master side, results in duplicates and ghost entries
on columnstore side

MySQL [test]> insert into t3 values (0, 2);

Query OK, 1 row affected (0.05 sec)

MySQL [test]> insert into t3 values (0, 3);

Query OK, 1 row affected (0.02 sec)

MySQL [test]> insert into t3 values (0, 4);

Query OK, 1 row affected (0.04 sec)

MySQL [test]> insert into t3 values (0, 5);

Query OK, 1 row affected (0.07 sec)

MySQL [test]> insert into t3 values (0, 6);

Query OK, 1 row affected (0.04 sec)

mxs_adapter output

/mxs_adapter -h 172.21.0.7 -P 4001 -u cdcuser -p cdc -r 5 -n test t3

2 rows and 0 transactions inserted in 5.19347 seconds. GTID = 0-1-44

4 rows and 2 transactions inserted in 453.084 seconds. GTID = 0-1-46

3 rows and 1 transactions inserted in 5.1652 seconds. GTID = 0-1-47

6 rows and 2 transactions inserted in 7.22207 seconds. GTID = 0-1-49

Data on columnstore side

MariaDB [test]> select * from t3;

+-----------+---------+

| a         | b       |

+-----------+---------+

|         0 |       1 |

|         0 | 4673075 |

|         0 |       2 |

|     35011 |       2 |

|         0 |       3 |

|  15905396 |       3 |

|         0 |       4 |

|         0 |       4 |

| 553692535 |       4 |

|         0 |       5 |

|         0 |       5 |

| 553649421 |       5 |

|         0 |       6 |

|         0 |       6 |

| 889194386 |       6 |

+-----------+---------+

15 rows in set (0.03 sec)

Note the duplicate and ghost entries

[MCOL-1026] Ghost entry created by mxs_adapter Created: 2017-11-10 Updated: 2023-10-26 Resolved: 2017-11-20
Status:	Closed
Project:	MariaDB ColumnStore
Component/s:	?
Affects Version/s:	1.1.1
Fix Version/s:	Icebox