ColumnStore automatically restarted

ColumnStore automatically restarted after the following messages were logged to warning.log:

Jan 4 15:23:57 db1 messagequeue[179600]: 57.847109 |0|0|0| W 31 CAL0000: Client read close socket for InetStreamSocket::readToMagic: Remote is closed

Jan 4 15:23:58 db1 joblist[179600]: 58.092497 |0|0|0| C 05 CAL0000: /home/builder/mariadb-columnstore-server/mariadb-columnstore-engine/dbcon/execplan/clientrotator.cpp @ 318 Could not get a ExeMgr connection.

I assume that the ExeMgr error is related to the preceding network error, since the documentation says that ExeMgr listens on a TCP/IP port:

Execution Manager: ExeMgr

ExeMgr listens on a TCP/IP port for query parse trees from mysqld. ExeMgr is responsible for converting the query parse tree into a job list, which is a construct in MariaDB ColumnStore that represents the sequence of instructions necessary to answer the query. ExeMgr walks the query parse tree and iteratively generates job steps, optimizing and re-optimizing the job list as it goes. The major categories of job steps are application of a column filter, processing a table join, and projection of returned columns. Each operation in a query plan is executed in parallel by the job list itself and has the capability of running entirely on the User Module, entirely on the Performance Module or in some combination. Each node uses the Extent Map to determine which Performance Modules to send work orders to (see ColumnStore Storage Architecture for details on the Extent).

https://mariadb.com/kb/en/library/columnstore-user-module/

Would this ExeMgr error have led to the auto-restart of ColumnStore? If so, then I think the error message should be improved. e.g. it could say something like:

Lost TCP/IP connection to ExeMgr process. ColumnStore might automatically restart to restore functionality!

The message is short, but it clearly says that all of the following are related:

• The network error.
• The ExeMgr error.
• The auto-restart.