Sergei Golubchik added a comment - 2019-08-06 11:16 trans_register_ha() and trx_register_for_2pc() are very fast, no locks, just few assignments. It doesn't make much sense to have a special thread state for that, you'll almost never see a thread in that state.

Geoff Montee (Inactive) added a comment - 2019-08-06 18:24 The reason that I created this task is that I saw threads hanging in this section of code. Since the thread state used in this section of code is "System lock", the user assumed that the hung threads were waiting on some system lock required for the query. I eventually tracked down the root cause to the audit plugin performance issue, MDEV-18661 / MDEV-19291 . This occurred due to the call to the mysql_audit_external_lock() function in the handler::ha_external_lock() function: https://github.com/MariaDB/server/blob/mariadb-10.3.7/sql/handler.cc#L6125 https://github.com/MariaDB/server/blob/mariadb-10.3.7/sql/sql_audit.h#L285 Since the problem ended up being related to the audit plugin API, maybe adding a new thread state like the one in MDEV-20269 would be better.