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from your mail Vladislav:

=> static thread_group_t all_groups[MAX_THREAD_GROUPS];

=> static uint group_count;  

                  "group_count" is the max value of a loop using all_groups var?

                  something realted to "threadpool_max_threads", with a limit of group_count<MAX_THREAD_GROUPS?

a request is a "php mysql_connect"? each new tcp/ip connection create a new request?

=> struct thread_group_t

{

 mysql_mutex_t mutex;

 connection_queue_t queue;

 worker_list_t waiting_threads;

 worker_thread_t *listener;       (listener thread? maybe it have a THD and we could show the query_id/thread_id or some information?)

 pthread_attr_t *pthread_attr;   (what is pthread_attr? i didn't found in threadpool*)

 int  pollfd;                             (a fd to kevent and others libs?)

 int  thread_count;                  (number of threads in this thread group?!)

 int  active_thread_count;        (active threads running this thread group?!)

 int  connection_count;           (active connections in this thread group?!)

 int io_event_count;                (io event count? what is this? network io?)

  int queue_event_count;          (queue event count? maybe the COUNT(*) for connection_queue_t queue ?)

 ulonglong last_thread_creation_time;   (last thread create time, it's a unixtimestamp * 1.000.000 (us)? )

 int  shutdown_pipe[2];           (maybe rpc to call a server shutdown?)

 bool shutdown;                     (shutdown information?)

 bool stalled;                         (hum... stall (nice name), well i must study about threadpool stall yet, but i think it's a nice information to report to DBA =] )

 

} MY_ALIGNED(512);

I don't know yet how   I_P_List<> and I_P_List_adapter<> work, but i will search about it in code... it's like a C++ object with ->legth and others easy to use tools? something like "foreach" (connection_queue_t as xxx) and interact with each connection_t inside connection_queue_t using xxx?

typedef I_P_List<connection_t,

                     I_P_List_adapter<connection_t,

                                      &connection_t::next_in_queue,

                                      &connection_t::prev_in_queue>,

                     I_P_List_null_counter,

                     I_P_List_fast_push_back<connection_t> >

=> connection_queue_t;

typedef I_P_List<worker_thread_t, I_P_List_adapter<worker_thread_t,

                 &worker_thread_t::next_in_list,

                 &worker_thread_t::prev_in_list> 

                 >

=> worker_list_t;

=> struct worker_thread_t

{

 ulonglong  event_count; /* number of request handled by this thread */

 thread_group_t* thread_group;   (it's point to thread_group inside all_groups? does it have an ID about what index of all_groups we are?)

 worker_thread_t *next_in_list;

 worker_thread_t **prev_in_list;

 

 mysql_cond_t  cond;  (what is this?)

 bool          woken;       (what is this?)

};

=> struct connection_t

{

 THD *thd;

 thread_group_t *thread_group;

 connection_t *next_in_queue;

 connection_t **prev_in_queue;

 ulonglong abs_wait_timeout;    (what is this?)

 bool logged_in;     (hummm waiting password?)

 bool bound_to_poll_descriptor;    (what is this?)

 bool waiting;                              (connection in waiting queue state?)

};

=> pthread_attr_t ??? (didn't found in threadpool* files, i will search with time about it, maybe something to linux/unix pthread lib?)

well now i'm thinking right about information_schema tables using the variables from the top of this email... :

1) all_groups variable => THREADPOOL_THREAD_GROUPS table

columns:

THREAD_GROUP_ID        INT NOT NULL DEFAULT 0,

THREAD_COUNT        INT NOT NULL DEFAULT 0,

ACTIVE_THREAD_COUNT        INT NOT NULL DEFAULT 0,

CONNECTION_COUNT        INT NOT NULL DEFAULT 0,

IO_EVENT_COUNT        INT NOT NULL DEFAULT 0 COMMENT "WHAT IS THIS? NETWORK I/O?",

QUEUE_EVENT_COUNT        INT NOT NULL DEFAULT 0,

LAST_THREAD_CREATION_TIME       DECIMAL UNSIGNED? UNIXTIMESTAMP?

SHUTDOWN       ENUM('Y','N') NOT NULL DEFAULT 'N'

STALLED      ENUM('Y','N') NOT NULL DEFAULT 'N'

maybe we should put information about LISTERNER_THREAD_ID (thd->query_id / thd->thread_id) ?

LISTENER_QUERY_ID      BIGINT NOT NULL DEFAULT 0,

LISTENER_THREAD_ID      BIGINT NOT NULL DEFAULT 0

2) connection_queue_t queue => THREADPOOL_CONNECTION_QUEUE table

columns

from queue->thd

QUERY_ID         INT NOT NULL DEFAULT 0,   (does it exists? or just after parser?)

THREAD_ID       INT NOT NULL DEFAULT 0,

queue->thread_group

THREAD_GROUP_ID        INT NOT NULL DEFAULT 0,   ( i didn't found a ID for each thread_group, there's something for it? like am all_groups[] index?

queue->cond (mysql_cond_t)  ??? (what is this?)

queue->woken (bool) ???? (what is this?)

3) worker_list_t waiting_threads => THREADPOOL_WAITING_THREADS table, maybe WAITING_QUEUE?

THREAD_GROUP_ID       INT NOT NULL DEFAULT 0, (thread_group_t* thread_group)

EVENT_COUNT      BIGINT UNSIGNED NOT NULL DEFAULT 0, (ulonglong  event_count; /* number of request handled by this thread */ what is this?)

->cond (mysql_cond_t)  ??? (what is this?)

->woken (bool) ???? (what is this?)

                i didn't found a THD, for this (query_id/thread_id)

 

pthread_attr_t *pthread_attr; what is this?