ifnull(column1, '') mediumtext comparison results in Sig 11 kill Exemgr - `ERROR 1815 (HY000): Internal error: InetStreamSocket::readToMagic: Remote is closed'

Here is table schema and query that causes the Seg 11 Kills Exemgr - restarting at least 3 subprocesses

CREATE TABLE `tpp_white_list` (

  `TABLE_NAME` mediumtext DEFAULT NULL,

  `COLUMN_NAME` mediumtext DEFAULT NULL,

  `CODE` mediumtext DEFAULT NULL,

  `NAME` mediumtext DEFAULT NULL,

  `CS_CODE` mediumtext DEFAULT NULL,

  `LIST_KBN` mediumtext DEFAULT NULL

) ENGINE=Columnstore DEFAULT CHARSET=utf8;

# You need the data to reproduce - see comments for data

cpimport client tpp_white_list -E '"' -s "," list.csv 

WITH

temp1 AS (select 1 as num,'aa1' as name, 111 as VALUE union all

select 2 as num,'aa2' as name, 112 as VALUE union all

select 3 as num,'aa3' as name, 113 as VALUE union all

select 4 as num, NULL as name, 'MDCDX2' as VALUE union all

select 5 as num, null as name, 115 as VALUE union all

select 4 as num, "" as name, null as VALUE union all

select 5 as num, null as name, null as VALUE union all

select 4 as num,'*1068' as name, '99D01' as VALUE union all

select 5 as num,'*1554' as NAME, '99D01' as VALUE union all

select 4 as num,'0063001' as NAME, '99D01' as VALUE

)

SELECT COUNT(1)

from temp1 a

where exists (select 1 from tpp_white_list b

WHERE b.TABLE_NAME = 'IF001'

AND (b.COLUMN_NAME = 'プロブレム１セット' OR b.COLUMN_NAME ='プロブレム２セット')

and ifnull(a.name,'') = ifnull(b.code,'') 

AND ifnull(a.value,'') = ifnull(b.cs_code,'') 

);

What actually happens
Debug.log

Apr 19 15:10:09 ip-172-31-30-7 systemd: mcs-exemgr.service: main process exited, code=killed, status=11/SEGV

Client:

ERROR 1815 (HY000): Internal error: InetStreamSocket::readToMagic: Remote is closed

What clients expect to happen
No error or restart of exemgr & ddlproc & WriteEngineServer - just the response similar to the work arounds

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

| COUNT(1) |

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

|        3 |

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

1 row in set (6.962 sec)

Work arounds

• Removing the ifnull functions around the medium text
• using varchar(1000) instead of mediumtext
• write query with a subselect

  # Subselect re-write

  WITH

  temp1 AS (select 1 as num,'aa1' as name, 111 as VALUE union all

  select 2 as num,'aa2' as name, 112 as VALUE union all

  select 3 as num,'aa3' as name, 113 as VALUE union all

  select 4 as num, NULL as name, 'MDCDX2' as VALUE union all

  select 5 as num, null as name, 115 as VALUE union all

  select 4 as num, "" as name, null as VALUE union all

  select 5 as num, null as name, null as VALUE union all

  select 4 as num,'*1068' as name, '99D01' as VALUE union all

  select 5 as num,'*1554' as NAME, '99D01' as VALUE union all

  select 4 as num,'0063001' as NAME, '99D01' as VALUE

  )

  ,temp2 as (select * from tpp_white_list)

  SELECT COUNT(1)

  from temp1 a

  where exists (select 1 from temp2 b

  WHERE b.TABLE_NAME = 'IF001'

  AND (b.COLUMN_NAME = 'プロブレム１セット' OR b.COLUMN_NAME ='プロブレム２セット')

  and ifnull(a.name,'') = ifnull(b.code,'')

  AND ifnull(a.value,'') = ifnull(b.cs_code,'')

  );