MDEV-32567 Remove thr_alarm from server codebase

This allows to simplify net_real_read() and net_real_write() a bit. Removed some superfluous #ifdef/ifndef MYSQL_SERVER from net_serv.cc The code always runs in server, either normal or embedded. Dead code for switching socket between blocking and non-blocking modes, is also removed. Removed pthread_kill() with alarm signal that woke up main thread on server shutdown. Used shutdown(2) on polling sockets instead, to the same effect. Removed yet another superstitious pthread_kill(), that ran on non-Windows in terminate_slave_thread().
MariaDB · Nov 23, 2023 · 013fc02 · 013fc02
1 parent 3424ed7
commit 013fc02
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Showing 19 changed files with 123 additions and 1,513 deletions.
diff --git a/config.h.cmake b/config.h.cmake
@@ -384,7 +384,6 @@
 #cmakedefine HAVE_GCC_C11_ATOMICS 1
 #cmakedefine HAVE_SOLARIS_ATOMIC 1
 #cmakedefine NO_FCNTL_NONBLOCK 1
-#cmakedefine NO_ALARM 1
 
 #cmakedefine _LARGE_FILES 1
 #cmakedefine _LARGEFILE_SOURCE 1

diff --git a/configure.cmake b/configure.cmake
@@ -836,7 +836,6 @@ CHECK_CXX_SOURCE_COMPILES("
   "
   HAVE_SOLARIS_STYLE_GETHOST)
 
-SET(NO_ALARM 1 CACHE BOOL  "No need to use alarm to implement timeout")
 
 # As a consequence of ALARMs no longer being used, thread
 # notification for KILL must close the socket to wake up

diff --git a/include/my_pthread.h b/include/my_pthread.h
@@ -181,7 +181,6 @@ extern int my_pthread_create_detached;
 #define PTHREAD_CREATE_DETACHED &my_pthread_create_detached
 #define PTHREAD_SCOPE_SYSTEM  PTHREAD_SCOPE_GLOBAL
 #define PTHREAD_SCOPE_PROCESS PTHREAD_SCOPE_LOCAL
-#define USE_ALARM_THREAD
 #endif /* defined(PTHREAD_SCOPE_GLOBAL) && !defined(PTHREAD_SCOPE_SYSTEM) */
 
 #if defined(_BSDI_VERSION) && _BSDI_VERSION < 199910

diff --git a/include/thr_alarm.h b/include/thr_alarm.h
diff --git a/mysql-test/suite/sys_vars/r/debug_no_thread_alarm_basic.result b/mysql-test/suite/sys_vars/r/debug_no_thread_alarm_basic.result
diff --git a/mysql-test/suite/sys_vars/r/sysvars_debug.result b/mysql-test/suite/sys_vars/r/sysvars_debug.result
@@ -46,21 +46,6 @@ ENUM_VALUE_LIST	OFF,ON
 READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	OPTIONAL
 GLOBAL_VALUE_PATH	NULL
-VARIABLE_NAME	DEBUG_NO_THREAD_ALARM
-SESSION_VALUE	NULL
-GLOBAL_VALUE	OFF
-GLOBAL_VALUE_ORIGIN	COMPILE-TIME
-DEFAULT_VALUE	OFF
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BOOLEAN
-VARIABLE_COMMENT	Disable system thread alarm calls. Disabling it may be useful in debugging or testing, never do it in production
-NUMERIC_MIN_VALUE	NULL
-NUMERIC_MAX_VALUE	NULL
-NUMERIC_BLOCK_SIZE	NULL
-ENUM_VALUE_LIST	OFF,ON
-READ_ONLY	YES
-COMMAND_LINE_ARGUMENT	OPTIONAL
-GLOBAL_VALUE_PATH	NULL
 VARIABLE_NAME	DEBUG_SYNC
 SESSION_VALUE	ON - current signals: ''
 GLOBAL_VALUE	NULL

diff --git a/mysql-test/suite/sys_vars/t/debug_no_thread_alarm_basic.test b/mysql-test/suite/sys_vars/t/debug_no_thread_alarm_basic.test
diff --git a/mysys/CMakeLists.txt b/mysys/CMakeLists.txt
@@ -34,7 +34,7 @@ SET(MYSYS_SOURCES  array.c charset-def.c charset.c my_default.c
 				my_static.c my_symlink.c my_symlink2.c my_sync.c my_thr_init.c 
 				my_basename.c
 				my_write.c ptr_cmp.c queues.c stacktrace.c
-				string.c thr_alarm.c thr_lock.c thr_mutex.c
+				string.c thr_lock.c thr_mutex.c
 				thr_rwlock.c thr_timer.c
                                 tree.c typelib.c base64.c my_memmem.c
                                 my_getpagesize.c

diff --git a/mysys/my_init.c b/mysys/my_init.c
@@ -468,7 +468,7 @@ PSI_mutex_key key_LOCK_localtime_r;
 
 PSI_mutex_key key_BITMAP_mutex, key_IO_CACHE_append_buffer_lock,
   key_IO_CACHE_SHARE_mutex, key_KEY_CACHE_cache_lock,
-  key_LOCK_alarm, key_LOCK_timer,
+  key_LOCK_timer,
   key_my_thread_var_mutex, key_THR_LOCK_charset, key_THR_LOCK_heap,
   key_THR_LOCK_lock, key_THR_LOCK_malloc,
   key_THR_LOCK_mutex, key_THR_LOCK_myisam, key_THR_LOCK_net,
@@ -487,7 +487,6 @@ static PSI_mutex_info all_mysys_mutexes[]=
   { &key_IO_CACHE_append_buffer_lock, "IO_CACHE::append_buffer_lock", 0},
   { &key_IO_CACHE_SHARE_mutex, "IO_CACHE::SHARE_mutex", 0},
   { &key_KEY_CACHE_cache_lock, "KEY_CACHE::cache_lock", 0},
-  { &key_LOCK_alarm, "LOCK_alarm", PSI_FLAG_GLOBAL},
   { &key_LOCK_timer, "LOCK_timer", PSI_FLAG_GLOBAL},
   { &key_my_thread_var_mutex, "my_thread_var::mutex", 0},
   { &key_THR_LOCK_charset, "THR_LOCK_charset", PSI_FLAG_GLOBAL},
@@ -504,13 +503,12 @@ static PSI_mutex_info all_mysys_mutexes[]=
   { &key_LOCK_uuid_generator, "LOCK_uuid_generator", PSI_FLAG_GLOBAL }
 };
 
-PSI_cond_key key_COND_alarm, key_COND_timer, key_IO_CACHE_SHARE_cond,
+PSI_cond_key key_COND_timer, key_IO_CACHE_SHARE_cond,
   key_IO_CACHE_SHARE_cond_writer, key_my_thread_var_suspend,
   key_THR_COND_threads, key_WT_RESOURCE_cond;
 
 static PSI_cond_info all_mysys_conds[]=
 {
-  { &key_COND_alarm, "COND_alarm", PSI_FLAG_GLOBAL},
   { &key_COND_timer, "COND_timer", PSI_FLAG_GLOBAL},
   { &key_IO_CACHE_SHARE_cond, "IO_CACHE_SHARE::cond", 0},
   { &key_IO_CACHE_SHARE_cond_writer, "IO_CACHE_SHARE::cond_writer", 0},
@@ -526,16 +524,10 @@ static PSI_rwlock_info all_mysys_rwlocks[]=
   { &key_SAFEHASH_mutex, "SAFE_HASH::mutex", 0}
 };
 
-#ifdef USE_ALARM_THREAD
-PSI_thread_key key_thread_alarm;
-#endif
 PSI_thread_key key_thread_timer;
 
 static PSI_thread_info all_mysys_threads[]=
 {
-#ifdef USE_ALARM_THREAD
-  { &key_thread_alarm, "alarm", PSI_FLAG_GLOBAL},
-#endif
   { &key_thread_timer, "statement_timer", PSI_FLAG_GLOBAL}
 };
 

diff --git a/mysys/my_pthread.c b/mysys/my_pthread.c
@@ -20,7 +20,6 @@
 #include "mysys_priv.h"
 #include <signal.h>
 #include <m_string.h>
-#include <thr_alarm.h>
 #include <my_pthread.h>
 
 #if (defined(__BSD__) || defined(_BSDI_VERSION))
@@ -234,11 +233,7 @@ void *sigwait_thread(void *set_arg)
       sigaction(i, &sact, (struct sigaction*) 0);
     }
   }
-  /* Ensure that init_thr_alarm() is called */
-  DBUG_ASSERT(thr_client_alarm);
-  sigaddset(set, thr_client_alarm);
   pthread_sigmask(SIG_UNBLOCK,(sigset_t*) set,(sigset_t*) 0);
-  alarm_thread=pthread_self();			/* For thr_alarm */
 
   for (;;)
   {						/* Wait for signals */

diff --git a/mysys/mysys_priv.h b/mysys/mysys_priv.h
@@ -43,20 +43,17 @@ extern PSI_mutex_key key_LOCK_localtime_r;
 #endif /* !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R) */
 
 extern PSI_mutex_key key_BITMAP_mutex, key_IO_CACHE_append_buffer_lock,
-  key_IO_CACHE_SHARE_mutex, key_KEY_CACHE_cache_lock, key_LOCK_alarm,
+  key_IO_CACHE_SHARE_mutex, key_KEY_CACHE_cache_lock,
   key_my_thread_var_mutex, key_THR_LOCK_charset, key_THR_LOCK_heap,
   key_THR_LOCK_lock, key_THR_LOCK_malloc,
   key_THR_LOCK_mutex, key_THR_LOCK_myisam, key_THR_LOCK_net,
   key_THR_LOCK_open, key_THR_LOCK_threads, key_LOCK_uuid_generator,
   key_TMPDIR_mutex, key_THR_LOCK_myisam_mmap, key_LOCK_timer;
 
-extern PSI_cond_key key_COND_alarm, key_COND_timer, key_IO_CACHE_SHARE_cond,
+extern PSI_cond_key key_COND_timer, key_IO_CACHE_SHARE_cond,
   key_IO_CACHE_SHARE_cond_writer, key_my_thread_var_suspend,
   key_THR_COND_threads;
 
-#ifdef USE_ALARM_THREAD
-extern PSI_thread_key key_thread_alarm;
-#endif /* USE_ALARM_THREAD */
 extern PSI_thread_key key_thread_timer;
 extern PSI_rwlock_key key_SAFEHASH_mutex;