MySQL 5.7 Reference Manual
MySQL 5.7 Release Notes
Table of Contents
The following sections describe the
INFORMATION_SCHEMA tables associated with the
thread pool plugin (see MySQL Enterprise Thread Pool). They provide
information about thread pool operation:
TP_THREAD_GROUP_STATE: Information about thread pool thread group statesTP_THREAD_GROUP_STATS: Thread group statisticsTP_THREAD_STATE: Information about thread pool thread states
Rows in these tables represent snapshots in time. In the case of
TP_THREAD_STATE, all rows for a thread
group comprise a snapshot in time. Thus, the MySQL server holds the
mutex of the thread group while producing the snapshot. But it does
not hold mutexes on all thread groups at the same time, to prevent a
statement against TP_THREAD_STATE from
blocking the entire MySQL server.
The thread pool INFORMATION_SCHEMA tables are
implemented by individual plugins and the decision whether to load
one can be made independently of the others (see
Thread Pool Installation). However, the content of
all the tables depends on the thread pool plugin being enabled. If a
table plugin is enabled but the thread pool plugin is not, the table
becomes visible and can be accessed, but is empty.