Slow query log to file now displays queries with microsecond precission

--long-query-time is now given in seconds with microseconds as decimals
--min_examined_row_limit added for slow query log
long_query_time user variable is now double with 6 decimals
Added functions to get time in microseconds
Added faster time() functions for system that has gethrtime()  (Solaris)
We now do less time() calls.
Added field->in_read_set() and field->in_write_set() for easier field manipulation by handlers
set_var.cc and my_getopt() can now handle DOUBLE variables.
All time() calls changed to my_time()
my_time() now does retry's if time() call fails.
Added debug function for stopping in mysql_admin_table() when tables are locked
Some trivial function and struct variable renames to avoid merge errors.
Fixed compiler warnings
Initialization of some time variables on windows moved to my_init() 


include/my_getopt.h:
  Added support for double arguments
include/my_sys.h:
  Fixed wrong type to packfrm()
  Added new my_time functions
include/mysql/plugin.h:
  Added support for DOUBLE
libmysql/CMakeLists.txt:
  Added new time functions
libmysql/Makefile.shared:
  Added new time functions
mysql-test/r/variables.result:
  Testing of long_query_time
mysql-test/t/variables.test:
  Testing of long_query_time
mysys/charset.c:
  Fixed compiler warnings
mysys/default_modify.c:
  Fixed compiler warnings
mysys/hash.c:
  Fixed compiler warnings
mysys/mf_getdate.c:
  Use my_time()
mysys/mf_iocache2.c:
  Fixed compiler warnings
mysys/mf_pack.c:
  Fixed compiler warnings
mysys/mf_path.c:
  Fixed compiler warnings
mysys/my_append.c:
  Fixed compiler warnings
mysys/my_compress.c:
  Fixed compiler warnings
mysys/my_copy.c:
  Fixed compiler warnings
mysys/my_gethwaddr.c:
  Fixed compiler warnings
mysys/my_getopt.c:
  Added support for double arguments
mysys/my_getsystime.c:
  Added functions to get time in microseconds.
  Added faster time() functions for system that has gethrtime()  (Solaris)
  Moved windows initialization code to my_init()
mysys/my_init.c:
  Added initializing of variables needed for windows time functions
mysys/my_static.c:
  Added variables needed for windows time functions
mysys/my_static.h:
  Added variables needed for windows time functions
mysys/my_thr_init.c:
  Added THR_LOCK_time, used for faster my_time()
mysys/mysys_priv.h:
  Added THR_LOCK_time, used for faster my_time()
mysys/thr_alarm.c:
  time() -> my_time()
sql/event_data_objects.cc:
  end_time() -> set_current_time()
sql/event_queue.cc:
  end_time() -> set_current_time()
sql/event_scheduler.cc:
  Fixed compiler warnings
sql/field.h:
  Added field->in_read_set() and field->in_write_set() for easier field manipulation by handlers
sql/item.h:
  Added decimal to Item_float(double)
sql/item_cmpfunc.h:
  Added decimal to Item_float(double)
sql/item_timefunc.cc:
  time() -> my_time()
sql/item_xmlfunc.cc:
  Fixed compiler warning
sql/lock.cc:
  lock_time() -> set_time_after_lock()
sql/log.cc:
  Timing in slow query log to file is now done in microseconds
  Changed some while() loops to for() loops.
  Fixed indentation
  time() -> my_time()
sql/log.h:
  Slow query logging is now done based on microseconds
sql/log_event.cc:
  time() -> my_time()
  Fixed arguments to new Item_float()
sql/mysql_priv.h:
  Fixed compiler warnings
  Added opt_log_slow_slave_statements
sql/mysqld.cc:
  Added --log_slow_slave_statements and --min_examined_row_limit
  --long-query-time now takes a double argument with microsecond resolution
  Don't write shutdown message when using --help
  Removed not needed \n
  Thread create time and connect time is now done in microseconds
  time() -> my_time()
  Avoid some time() calls
sql/net_serv.cc:
  Fixed compiler warnings
sql/parse_file.cc:
  time() -> my_time()
sql/set_var.cc:
  Added support for DOUBLE variables
  Added support for variables that are given in seconds with microsecond resolution
sql/set_var.h:
  Added support for variables that are given in seconds with microsecond resolution
sql/slave.cc:
  Allow logging of slave queries to slow query log if 'opt_log_slow_slave_statements' is given
  time() -> my_time()
sql/sql_cache.h:
  Fixed compiler warning()
sql/sql_class.cc:
  Initialize new THD variables
sql/sql_class.h:
  long_query_time is now in microseconds
  Added min_examined_row_limit
  Reordered some THD elements for higher efficency
  Added timers in microseconds (connect_utime, thr_create_utime, start_utime and utime_after_lock)
  Start of query is now recorded both in seconds and in microseconds.
  Following renames was made for more clarity and avoid merge problems from earlier versions:
  connect_time -> connect_utime
  thr_create_time -> thr_create_utime
  end_time()  -> set_current_time()
  lock_time() -> set_time_after_lock()
  
  Added THD::start_utime, which is start of query in microseconds from some arbitary time
  Added function THD::current_utime()
  
  Removed safe_time() as retry's are handled in my_time()
sql/sql_connect.cc:
  User resources are now using microsecond resolution
sql/sql_insert.cc:
  end_time() -> set_current_time()
sql-common/client.c:
  time() -> my_time()
sql/sql_parse.cc:
  Testing if we should print to slow_query_log() is now done with microsecond precission.
  If min_examined_row_limit is given, only log queries to slow query log that has examined more rows than this.
sql/sql_select.cc:
  Simplify code now that Item_float() takes decimals as argument
sql/sql_show.cc:
  time() -> my_time()
  Added support for SYS_DOUBLE
sql/sql_table.cc:
  Added debug function for stopping in mysql_admin_table() when tables are locked
sql/structs.h:
  intime -> reset_utime

sql/sql_parse.cc

@@ -1297,7 +1297,6 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
 
 void log_slow_statement(THD *thd)
 {
-  time_t start_of_query;
   DBUG_ENTER("log_slow_statement");
 
   /*
@@ -1308,25 +1307,24 @@ void log_slow_statement(THD *thd)
   if (unlikely(thd->in_sub_stmt))
     DBUG_VOID_RETURN;                           // Don't set time for sub stmt
 
-  start_of_query= thd->start_time;
-  thd->end_time();				// Set start time
-
   /*
     Do not log administrative statements unless the appropriate option is
     set; do not log into slow log if reading from backup.
   */
   if (thd->enable_slow_log && !thd->user_time)
   {
-    thd->proc_info="logging slow query";
+    ulonglong end_utime_of_query= thd->current_utime();
 
-    if ((ulong) (thd->start_time - thd->time_after_lock) >
-	thd->variables.long_query_time ||
-	((thd->server_status &
-	  (SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED)) &&
-	 opt_log_queries_not_using_indexes))
+    thd->proc_info="logging slow query";
+    if (((end_utime_of_query - thd->utime_after_lock) >
+         thd->variables.long_query_time ||
+         ((thd->server_status &
+           (SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED)) &&
+          opt_log_queries_not_using_indexes)) &&
+        thd->examined_row_count >= thd->variables.min_examined_row_limit)
     {
       thd->status_var.long_query_count++;
-      slow_log_print(thd, thd->query, thd->query_length, start_of_query);
+      slow_log_print(thd, thd->query, thd->query_length, end_utime_of_query);
     }
   }
   DBUG_VOID_RETURN;