wlad Some more information about version and circumstances (especially which application) would be helpful:

COM_STMT_RESET will be send in mysql_stmt_internal_reset, if parameter is_close is zero. This happens only when calling mysql_stmt_reset api function, which isn't used internally by Connector/C.

I'd suggest analyzing mariadb server logs https://jira.mariadb.org/secure/attachment/57593/mariadb_logs.7z attached to https://jira.mariadb.org/browse/ODBC-313 as a starting point. It has a lot of resets in the mariadb query log. Those resets come from our ODBC driver, which has zero mysql_stmt_reset API functions in its code (at least, this is what git grep tells me) .

The version I encountered it was 3.1 somewhere in October last year, when debugging something unrelated.

Thanks for the information. Actual version in October 2020 was ODBC 3.1.10:

georg@beethoven:~/work/mariadb/conn/odbc$ git checkout tags/3.1.10

georg@beethoven:~/work/mariadb/conn/odbc$ git branch

* (HEAD detached at 3.1.10)

georg@beethoven:~/work/mariadb/conn/odbc$ git grep mysql_stmt_reset

ma_statement.c:        mysql_stmt_reset(Stmt->stmt);

ma_statement.c:            mysql_stmt_reset(Stmt->MultiStmts[i]);

That was fixed in 3.1.13