If I startup the MySQL client (mcsmysql), and paste the query to execute, it worked. But if I save the query in a file, such as /tmp/test.sql, then run

mcsmysql mytest -vvv < /tmp/test.sql

then I got:
ERROR 1815 (HY000) at line 1: Internal error: Lost connection to ExeMgr. Please contact your administrator

ExeMgr got restarted.

I encountered this when running all 22 queries in the dbt3 test suite and I finally narrowed it down to this strange behavior.

My blind theory is idb_cleanQuery() in sql/sql_parse.cc is messing up the query when stripping the newline codes. Thus causing a corrupted query which spills crap into ExeMgr causing that to crash. I could be wrong, but it looks fun to debug anyway

The issue may not have anything to do with the stripping of the newline codes. My bad that I provided the incorrect information during the meeting today. I executed the single line query and it worked, because I executed it on a different database, which has more data <sigh>

The issue I am having is on a 1gb database. Since the same query worked on a database with more data, I am running the same test on a 10gb database. I will report back later.

The 10g query also did not work on the 10g dbt3 database.

On both 1g and 10g database test runs, ExeMgr did not crash. Instead, it was restarted by ProcessMonitor. The reason still needs to be determined.

No problem. It will still be an interesting one to debug.

I did further investigation on the issue and found that it is a bug in Columnstore. After few iterations of simplifying the original query, here is a simpler queries that would cause exemgr to restart:

select n_regionkey, sum(n_nationkey) from nation group by n_regionkey having sum(n_nationkey) > (select n_nationkey from nation where n_nationkey=100);

The issue is the subquery return a null value. If "n_nationkey = 1" is used in the subquery, a value will be returned and the query will run.

The subquery returned NULL because of the issue described in MCOL-281. When working on the ticket, you can adjust the subquery so that a NULL result will be returned.

MCOL-281 caused DBT3 query #11 to trigger the bug reported in this ticket.

Crash is a segment fault in

void getCorrelatedFilters(ParseTree* pt, void* obj)

Caused by the dynamic_cast of this line:

SimpleFilter* sf = dynamic_cast<SimpleFilter*>(pt->data());

Fix in https://github.com/mariadb-corporation/mariadb-columnstore-engine/pull/7

For QA I recommend tweaking the query slightly so that the subquery has an empty result, such as setting the n_name = 'PERUA'

Move to Daniel for QA.

Build tested:

mscadmin> getsoft
getsoftwareinfo Tue Sep 13 10:02:34 2016

Name : mariadb-columnstore-platform
Version : 1.0.3
Release : 1
Architecture: x86_64
Install Date: Tue 13 Sep 2016 09:26:32 AM CDT

select n_regionkey, sum(n_nationkey) from nation group by n_regionkey having sum(n_nationkey) > (select n_nationkey from nation where n_nationkey=1);
-----------------------------+

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

-----------------------------+
5 rows in set (0.16 sec)

MariaDB [tpch1c]> select n_regionkey, sum(n_nationkey) from nation group by n_regionkey having sum(n_nationkey) > (select n_nationkey from nation where n_nationkey=100);
ERROR 1815 (HY000): Internal error: Lost connection to ExeMgr. Please contact your administrator

Needs to be reopened due to Daniel finding a similar bug with a slightly different query.

Moving back to QA. Issue is the first set of 1.0.3 RPMs don't have the fix. Daniel's test didn't actually test the fix.

GDB with a non-debug build made me thing it was a different issue, but it isn't.

mscadmin> getsoft
getsoftwareinfo Thu Sep 15 12:06:24 2016

Name : mariadb-columnstore-platform
Version : 1.0.3
Release : 1
Architecture: x86_64
Install Date: Thu 15 Sep 2016 11:39:01 AM CDT
Group : Applications
Size : 25431329
License : Copyright (c) 2016 MariaDB Corporation Ab., all rights reserved; redistributable under the terms of the GPL, see the file COPYING for details.
Signature : (none)
Source RPM : mariadb-columnstore-1.0.3-1.src.rpm
Build Date : Thu 15 Sep 2016 09:56:11 AM CDT

MariaDB [tpch1c]> select n_regionkey, sum(n_nationkey) from nation group by n_regionkey having sum(n_nationkey) > (select n_nationkey from nation where n_nationkey=1);
-----------------------------+

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

-----------------------------+
5 rows in set (0.63 sec)

MariaDB [tpch1c]> select n_regionkey, sum(n_nationkey) from nation group by n_regionkey having sum(n_nationkey) > (select n_nationkey from nation where n_nationkey=100);
Empty set (0.01 sec)