WL#1595 "Optionally fsync() the binlog after every statement":

New option --sync-binlog=x (and global settable variable) which will fsync the binlog
after every x-th disk write to it. That is, if in autocommit mode, after every x-th statement
written to the binlog; if using transactions, after every x-th transaction written to the binlog.
x==0 means no fsync. x==1 is the slowest.
There is no test added for this, I have just checked that it works as --sync-binlog=1 dramatically
slows down mysqld.
Made sync-frm a global settable variable.


sql/log.cc:
  every sync_binlog_period-th disk binlog write, we fsync the binlog
sql/mysql_priv.h:
  new option sync_binlog
sql/mysqld.cc:
  new option sync_binlog
sql/set_var.cc:
  Making sync-frm a settable global option.
  New settable global option sync-binlog.
sql/set_var.h:
  new global settable variable sync_binlog needs a specific ::update because it needs to take LOCK_log

1 files changed, 9 insertions, 1 deletions

diff --git a/sql/set_var.h b/sql/set_var.h
index 64bdfdb718b..9bed6f01dcc 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -462,7 +462,7 @@ public:
 };
 
 
-#ifndef EMBEDDED_LIBRARY
+#ifdef HAVE_REPLICATION
 class sys_var_slave_skip_counter :public sys_var
 {
 public:
@@ -475,6 +475,14 @@ public:
     type() or value_ptr()
   */
 };
+
+class sys_var_sync_binlog_period :public sys_var_long_ptr
+{
+public:
+  sys_var_sync_binlog_period(const char *name_arg, ulong *value_ptr)
+    :sys_var_long_ptr(name_arg,value_ptr) {}
+  bool update(THD *thd, set_var *var);
+};
 #endif
 
 class sys_var_rand_seed1 :public sys_var