Update 2: Do not use the new dbsrv17 -k option unless you want to disable all the performance-related properties like PROPERTY ( 'ActiveReq' ).
Update 1: This connection does not appear if you start the server with the -k option.
It does seem to be a persistent connection that appears as soon as a new empty 18.104.22.1683 database is started.
"%SQLANY17%\bin64\dbinit.exe"^ -dba dba,sql^ -mpl 3^ ddd17.db
It does not seem to appear when a 22.214.171.1242 database is started with 126.96.36.1993 software.
It does not seem to show up in the database-level ConnCount property.
It does not seem to have a non-zero connection-level ParentConnection property.
It does seem to always have 'Executing' in the connection-level ReqStatus property.
It does not seem to consume any resources, not even after several hours, or several periods of high-CPU intra-query parallelism activity involving 8 INT:Exchange child connections on an 8 CPU system.
No, it's not mentioned in the DCX Help.
Motivation for the question: Foxhound 4 now supports SQL Anywhere 17, and with 17.0.4 the database-level "Parent, Child Conns" columns (ConnCount, ParentConnection) don't add up to the same total as the "Executing, Idle, Waiting Conns" columns (ReqStatus), so the Foxhound Help needs to do some explaining ( sigh :)
I'm certain it is related to the new statement performance monitoring gear (see http://dcx.sap.com/index.html#sqla170/en/html/85df02cf9625474683ac870846782ad1.html ) but I do not know anything about how the parent connection value is maintained.