mirror of
https://github.com/MariaDB/server.git
synced 2025-01-16 20:12:31 +01:00
fd9f1638ea
- thread_pool_size command line option upper limit increased to 100 000 (same as for max_connections) - thread_pool_size system variable upper limit is maximum of 128 or the value given at command line - thread groups are now allocated dynamically Different limit for command line option and system variable was done to avoid additional mutex for all_groups and threadpool_max_size.
282 lines
6.9 KiB
C++
282 lines
6.9 KiB
C++
/* Copyright (C) 2012 Monty Program Ab
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include <my_global.h>
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#include <violite.h>
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#include <sql_priv.h>
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#include <sql_class.h>
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#include <my_pthread.h>
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#include <scheduler.h>
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#include <sql_connect.h>
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#include <sql_audit.h>
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#include <debug_sync.h>
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#include <threadpool.h>
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/* Threadpool parameters */
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uint threadpool_min_threads;
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uint threadpool_idle_timeout;
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uint threadpool_size;
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uint threadpool_max_size;
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uint threadpool_stall_limit;
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uint threadpool_max_threads;
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uint threadpool_oversubscribe;
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/* Stats */
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TP_STATISTICS tp_stats;
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extern "C" pthread_key(struct st_my_thread_var*, THR_KEY_mysys);
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extern bool do_command(THD*);
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/*
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Worker threads contexts, and THD contexts.
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=========================================
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Both worker threads and connections have their sets of thread local variables
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At the moment it is mysys_var (this has specific data for dbug, my_error and
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similar goodies), and PSI per-client structure.
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Whenever query is executed following needs to be done:
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1. Save worker thread context.
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2. Change TLS variables to connection specific ones using thread_attach(THD*).
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This function does some additional work , e.g setting up
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thread_stack/thread_ends_here pointers.
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3. Process query
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4. Restore worker thread context.
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Connection login and termination follows similar schema w.r.t saving and
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restoring contexts.
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For both worker thread, and for the connection, mysys variables are created
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using my_thread_init() and freed with my_thread_end().
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*/
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struct Worker_thread_context
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{
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PSI_thread *psi_thread;
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st_my_thread_var* mysys_var;
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void save()
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{
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#ifdef HAVE_PSI_INTERFACE
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psi_thread= PSI_server?PSI_server->get_thread():0;
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#endif
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mysys_var= (st_my_thread_var *)pthread_getspecific(THR_KEY_mysys);
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}
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void restore()
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{
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#ifdef HAVE_PSI_INTERFACE
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if (PSI_server)
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PSI_server->set_thread(psi_thread);
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#endif
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pthread_setspecific(THR_KEY_mysys,mysys_var);
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pthread_setspecific(THR_THD, 0);
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pthread_setspecific(THR_MALLOC, 0);
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}
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};
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/*
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Attach/associate the connection with the OS thread,
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*/
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static bool thread_attach(THD* thd)
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{
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pthread_setspecific(THR_KEY_mysys,thd->mysys_var);
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thd->thread_stack=(char*)&thd;
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thd->store_globals();
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#ifdef HAVE_PSI_INTERFACE
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if (PSI_server)
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PSI_server->set_thread(thd->event_scheduler.m_psi);
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#endif
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return 0;
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}
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int threadpool_add_connection(THD *thd)
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{
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int retval=1;
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Worker_thread_context worker_context;
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worker_context.save();
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/*
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Create a new connection context: mysys_thread_var and PSI thread
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Store them in THD.
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*/
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pthread_setspecific(THR_KEY_mysys, 0);
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my_thread_init();
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thd->mysys_var= (st_my_thread_var *)pthread_getspecific(THR_KEY_mysys);
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if (!thd->mysys_var)
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{
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/* Out of memory? */
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worker_context.restore();
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return 1;
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}
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/* Create new PSI thread for use with the THD. */
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#ifdef HAVE_PSI_INTERFACE
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if (PSI_server)
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{
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thd->event_scheduler.m_psi =
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PSI_server->new_thread(key_thread_one_connection, thd, thd->thread_id);
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}
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#endif
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/* Login. */
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thread_attach(thd);
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ulonglong now= microsecond_interval_timer();
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thd->prior_thr_create_utime= now;
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thd->start_utime= now;
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thd->thr_create_utime= now;
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if (!setup_connection_thread_globals(thd))
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{
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if (!login_connection(thd))
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{
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prepare_new_connection_state(thd);
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/*
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Check if THD is ok, as prepare_new_connection_state()
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can fail, for example if init command failed.
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*/
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if (thd_is_connection_alive(thd))
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{
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retval= 0;
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thd->net.reading_or_writing= 1;
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thd->skip_wait_timeout= true;
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}
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}
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}
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worker_context.restore();
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return retval;
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}
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void threadpool_remove_connection(THD *thd)
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{
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Worker_thread_context worker_context;
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worker_context.save();
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thread_attach(thd);
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thd->net.reading_or_writing= 0;
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end_connection(thd);
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close_connection(thd, 0);
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unlink_thd(thd);
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mysql_cond_broadcast(&COND_thread_count);
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/*
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Free resources associated with this connection:
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mysys thread_var and PSI thread.
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*/
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my_thread_end();
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worker_context.restore();
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}
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/**
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Process a single client request or a single batch.
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*/
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int threadpool_process_request(THD *thd)
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{
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int retval= 0;
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Worker_thread_context worker_context;
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worker_context.save();
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thread_attach(thd);
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if (thd->killed >= KILL_CONNECTION)
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{
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/*
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killed flag was set by timeout handler
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or KILL command. Return error.
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*/
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retval= 1;
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goto end;
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}
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/*
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In the loop below, the flow is essentially the copy of thead-per-connections
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logic, see do_handle_one_connection() in sql_connect.c
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The goal is to execute a single query, thus the loop is normally executed
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only once. However for SSL connections, it can be executed multiple times
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(SSL can preread and cache incoming data, and vio->has_data() checks if it
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was the case).
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*/
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for(;;)
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{
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Vio *vio;
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thd->net.reading_or_writing= 0;
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mysql_audit_release(thd);
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if ((retval= do_command(thd)) != 0)
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goto end;
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if (!thd_is_connection_alive(thd))
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{
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retval= 1;
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goto end;
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}
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vio= thd->net.vio;
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if (!vio->has_data(vio))
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{
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/* More info on this debug sync is in sql_parse.cc*/
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DEBUG_SYNC(thd, "before_do_command_net_read");
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thd->net.reading_or_writing= 1;
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goto end;
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}
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}
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end:
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worker_context.restore();
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return retval;
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}
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static scheduler_functions tp_scheduler_functions=
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{
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0, // max_threads
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NULL,
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NULL,
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tp_init, // init
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NULL, // init_new_connection_thread
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tp_add_connection, // add_connection
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tp_wait_begin, // thd_wait_begin
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tp_wait_end, // thd_wait_end
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post_kill_notification, // post_kill_notification
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NULL, // end_thread
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tp_end // end
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};
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void pool_of_threads_scheduler(struct scheduler_functions *func,
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ulong *arg_max_connections,
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uint *arg_connection_count)
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{
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*func = tp_scheduler_functions;
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func->max_threads= threadpool_max_threads;
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func->max_connections= arg_max_connections;
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func->connection_count= arg_connection_count;
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scheduler_init();
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}
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