From 70373f8cb0a3fe404c1e51e0ade0c98b83aa0014 Mon Sep 17 00:00:00 2001
From: Dan Gudmundsson <dgud@erlang.org>
Date: Wed, 12 Feb 2014 14:50:49 +0100
Subject: mnesia: Add explicit sync_log command

For performance reasons the file data is not synced to disk in mnesia,
data loss can happen between each dump.

mnesia:dump_log() can be used explicitly to ensure data is written to disk.
But that can take a long time, so mnesia:sync_log() which just
sync the log have been added.
---
 lib/mnesia/src/mnesia.erl         | 6 +++++-
 lib/mnesia/src/mnesia_monitor.erl | 7 +++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

(limited to 'lib/mnesia/src')

diff --git a/lib/mnesia/src/mnesia.erl b/lib/mnesia/src/mnesia.erl
index 70466d10d7..b791e1221f 100644
--- a/lib/mnesia/src/mnesia.erl
+++ b/lib/mnesia/src/mnesia.erl
@@ -104,7 +104,8 @@
 	 set_master_nodes/1, set_master_nodes/2,
 
 	 %% Misc admin
-	 dump_log/0, subscribe/1, unsubscribe/1, report_event/1,
+	 dump_log/0, sync_log/0,
+	 subscribe/1, unsubscribe/1, report_event/1,
 
 	 %% Snmp
 	 snmp_open_table/2, snmp_close_table/1,
@@ -2554,6 +2555,9 @@ set_master_nodes(Tab, Nodes) ->
 dump_log() ->
     mnesia_controller:sync_dump_log(user).
 
+sync_log() ->
+    mnesia_monitor:sync_log(latest_log).
+
 subscribe(What) ->
     mnesia_subscr:subscribe(self(), What).
 
diff --git a/lib/mnesia/src/mnesia_monitor.erl b/lib/mnesia/src/mnesia_monitor.erl
index c7b905a1bf..7b56613ad7 100644
--- a/lib/mnesia/src/mnesia_monitor.erl
+++ b/lib/mnesia/src/mnesia_monitor.erl
@@ -44,6 +44,7 @@
 	 set_env/2,
 	 start/0,
 	 start_proc/4,
+	 sync_log/1,
 	 terminate_proc/3,
 	 unsafe_close_dets/1,
 	 unsafe_close_log/1,
@@ -118,6 +119,9 @@ open_log(Args) ->
 reopen_log(Name, Fname, Head) ->
     unsafe_call({reopen_log, Name, Fname, Head}).
 
+sync_log(Name) ->
+    unsafe_call({sync_log, Name}).
+
 close_log(Name) ->
     unsafe_call({close_log, Name}).
 
@@ -382,6 +386,9 @@ handle_call({reopen_log, Name, Fname, Head}, _From, State) ->
  	    {noreply, State}
     end;
 
+handle_call({sync_log, Name}, _From, State) ->
+    {reply, disk_log:sync(Name), State};
+
 handle_call({close_log, Name}, _From, State) ->
     case disk_log:close(Name) of
 	ok ->
-- 
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