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Venkatesh Duggirala
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Bug #18808072 MYSQLBINLOG USES LOCALTIME() TO PRINT EVENTS, CAUSES KERNEL MUTEX CONTENTION
Problem: For every event read, mysqlbinlog calls localtime() which in turn calls stat(/etc/localtime) which is causing kernel mutex contention. Analysis and Fix: localtime() calls stat(/etc/localtime) for every instance of the call where as localtime_r() the reentrant version was optimized to store the read only tz internal structure. Hence it will not call stat(/etc/localtime). It will call only once at the beginning. The mysql server is calling localtime_r() and mysqlbinlog tool is one place where we are still using localtime(). Once the process (mysqlbinlog) is started if timezone is changed it will be not picked up the the process and it will continue with the same values as the beginning of the process. This behavior is in-lined with mysql server. Also adding localtime_r() and gmtime_r() support for windows.
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‎client/mysqlbinlog.cc‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
2+
Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
33
44
This program is free software; you can redistribute it and/or modify
55
it under the terms of the GNU General Public License as published by
@@ -2102,6 +2102,7 @@ int main(int argc, char** argv)
21022102
DBUG_PROCESS(argv[0]);
21032103

21042104
my_init_time(); // for time functions
2105+
tzset(); // set tzname
21052106

21062107
if (load_defaults("my", load_default_groups, &argc, &argv))
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exit(1);

‎cmake/os/WindowsCache.cmake‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
# Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
1+
# Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
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#
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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
@@ -88,7 +88,7 @@ SET(HAVE_GETRLIMIT CACHE INTERNAL "")
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SET(HAVE_GETRUSAGE CACHE INTERNAL "")
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SET(HAVE_GETTIMEOFDAY CACHE INTERNAL "")
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SET(HAVE_GETWD CACHE INTERNAL "")
91-
SET(HAVE_GMTIME_R CACHE INTERNAL "")
91+
SET(HAVE_GMTIME_R 1 CACHE INTERNAL "")
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SET(HAVE_GRP_H CACHE INTERNAL "")
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SET(HAVE_IA64INTRIN_H CACHE INTERNAL "")
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SET(HAVE_IEEEFP_H CACHE INTERNAL "")
@@ -109,7 +109,7 @@ SET(HAVE_LANGINFO_H CACHE INTERNAL "")
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SET(HAVE_LDIV 1 CACHE INTERNAL "")
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SET(HAVE_LIMITS_H 1 CACHE INTERNAL "")
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SET(HAVE_LOCALE_H 1 CACHE INTERNAL "")
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SET(HAVE_LOCALTIME_R CACHE INTERNAL "")
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SET(HAVE_LOCALTIME_R 1 CACHE INTERNAL "")
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SET(HAVE_LOG2 CACHE INTERNAL "")
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SET(HAVE_LONGJMP 1 CACHE INTERNAL "")
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SET(HAVE_LRAND48 CACHE INTERNAL "")

‎include/my_pthread.h‎

Lines changed: 13 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
1+
/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
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33
This program is free software; you can redistribute it and/or modify
44
it under the terms of the GNU General Public License as published by
@@ -142,8 +142,18 @@ int pthread_attr_init(pthread_attr_t *connect_att);
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int pthread_attr_setstacksize(pthread_attr_t *connect_att,DWORD stack);
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int pthread_attr_destroy(pthread_attr_t *connect_att);
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int my_pthread_once(my_pthread_once_t *once_control,void (*init_routine)(void));
145-
struct tm *localtime_r(const time_t *timep,struct tm *tmp);
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struct tm *gmtime_r(const time_t *timep,struct tm *tmp);
145+
146+
static inline struct tm *localtime_r(const time_t *timep, struct tm *tmp)
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{
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localtime_s(tmp, timep);
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return tmp;
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}
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static inline struct tm *gmtime_r(const time_t *clock, struct tm *res)
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{
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gmtime_s(res, clock);
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return res;
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}
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void pthread_exit(void *a);
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int pthread_join(pthread_t thread, void **value_ptr);

‎mysys/my_wincond.c‎

Lines changed: 1 addition & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
1+
/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
44
it under the terms of the GNU General Public License as published by
@@ -344,26 +344,4 @@ int pthread_attr_destroy(pthread_attr_t *connect_att)
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return 0;
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}
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347-
/****************************************************************************
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** Fix localtime_r() to be a bit safer
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****************************************************************************/
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struct tm *localtime_r(const time_t *timep,struct tm *tmp)
352-
{
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if (*timep == (time_t) -1) /* This will crash win32 */
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{
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bzero(tmp,sizeof(*tmp));
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}
357-
else
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{
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struct tm *res=localtime(timep);
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if (!res) /* Wrong date */
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{
362-
bzero(tmp,sizeof(*tmp)); /* Keep things safe */
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return 0;
364-
}
365-
*tmp= *res;
366-
}
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return tmp;
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}
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#endif /* __WIN__ */

‎sql/log_event.cc‎

Lines changed: 0 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -2162,13 +2162,8 @@ void Log_event::print_timestamp(IO_CACHE* file, time_t* ts)
21622162
DBUG_ENTER("Log_event::print_timestamp");
21632163
if (!ts)
21642164
ts = &when;
2165-
#ifdef MYSQL_SERVER // This is always false
21662165
struct tm tm_tmp;
21672166
localtime_r(ts,(res= &tm_tmp));
2168-
#else
2169-
res=localtime(ts);
2170-
#endif
2171-
21722167
my_b_printf(file,"%02d%02d%02d %2d:%02d:%02d",
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res->tm_year % 100,
21742169
res->tm_mon+1,

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