THREADPOOL - Create Information Schema Table for Threadpool

CREATE TABLE information_schema.THREAD_POOL(

  thread_pool_group BIGINT NOT NULL DEFAULT 0,

  thread_id BIGINT NOT NULL DEFAULT 0, (that's not the THD->thread_id variable, it's the real system thread, maybe a listerner, a worker or a work queue (is work queue a thread?) )

  work ENUM('listener','worker','queue') NOT NULL DEFAULT 'queue', (this show what this thread do in this thread pool group)

  connection_id BIGINT DEFAULT 0, (that's the THD->thread_id variable)

others columns? maybe timeouts and others informations from internall scheduller? maybe timers for windows or others vars... must check the scheduller code

)

Hi Roberto,

The structures you need are in sql/threadpool_unix.cc

Global all_groups array contains  all thread groups . Every thread_group_t has list of waiting threads , called “waiting_threads”,  and queue of not yet handled requests, called “queue” (request is represented by connection_t ), a listener  etc.

“Active” connections, i.e connections that currently are executing queries , can neither  be found in threadpool’s waiting_threads, nor there is a different “active” list for them. So you may want to introduce special handling for those (i.e iterate the global “threads” list looking for active connections, get corresponding connection_t* struct from thd->event_scheduler.data, and do something with it, e.g look which thread group it belongs)

On Windows,  I doubt you can implement any information_schema plugin for the threadpool. This is because threadpool is native OS threadpool, and OS structure representing it  PTP_POOL structure is opaque, and there is not much info you can extract from it (well, maybe you can , if you debug with a kernel debugger, but not otherwise)

Wlad