This is a known issue.
MariaDB [mytest]> create table t1 (c1 bigint) engine=columnstore;
Query OK, 0 rows affected (0.34 sec)
MariaDB [mytest]> insert into t1 values (9223372036854775807), (9223372036854775807);
Query OK, 2 rows affected (0.18 sec)
Records: 2 Duplicates: 0 Warnings: 0
MariaDB [mytest]> select sum(c1) from t1;
ERROR 1815 (HY000): Internal error: An unexpected condition within the query caused an internal processing error within InfiniDB. Please check the log files for more details. Additional Information: aggregation data overflow.
Feb 10 15:45:18 ip-172-30-0-236 joblist: 18.318893 |26|0|0| C 05 CAL0000: Aggregation overflow.: 9223283296451814817+152123350462331 > 9223372036854775807
I discuss with the InfiniDB engineers on this issue before. I believe the issue is that the datatype of the variable used to hold intermediate and final aggregation result is 64 bit. Summing two hugh 64 bit values would trigger this error. I believe this issue is system wide, rather than one specific area so we need to look at it from a system design point of view.