From 70373f8cb0a3fe404c1e51e0ade0c98b83aa0014 Mon Sep 17 00:00:00 2001 From: Dan Gudmundsson 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/doc/src/mnesia.xml | 26 ++++++++++++++++++++++---- lib/mnesia/src/mnesia.erl | 6 +++++- lib/mnesia/src/mnesia_monitor.erl | 7 +++++++ lib/mnesia/test/mnesia_nice_coverage_test.erl | 3 ++- 4 files changed, 36 insertions(+), 6 deletions(-) (limited to 'lib/mnesia') diff --git a/lib/mnesia/doc/src/mnesia.xml b/lib/mnesia/doc/src/mnesia.xml index 914ec77721..72e9bd7e8f 100644 --- a/lib/mnesia/doc/src/mnesia.xml +++ b/lib/mnesia/doc/src/mnesia.xml @@ -4,7 +4,7 @@
- 19962013 + 19962014 Ericsson AB. All Rights Reserved. @@ -1204,7 +1204,11 @@ mnesia:create_table(person,

Performs a user initiated dump of the local log file. This is usually not necessary since Mnesia, by default, - manages this automatically.

+ manages this automatically. + See configuration parameters + dump_log_time_threshold and + dump_log_write_threshold. +

@@ -2207,6 +2211,18 @@ mnesia:create_table(employee, Mnesia User's Guide for more details.

 + + sync_log() -> ok | {error, Reason} + Perform a file sync of the local log file. + +

Ensures that the local transaction log file is synced to disk. + On a single node system data written to disk tables, since the last dump, + can be lost in case of a power outage. + See dump_log/0. +

+ + + sync_transaction(Fun, [[, Args], Retries]) -> {aborted, Reason} | {atomic, ResultOfFun} Synchronously execute a transaction. @@ -2445,7 +2461,7 @@ mnesia:create_table(employee, table(Tab [,[Option]]) -> QueryHandle Return a QLC query handle. -

+

Returns a QLC (Query List Comprehension) query handle, see qlc(3).The module qlc implements a query language, it can use mnesia tables as sources of data. Calling @@ -3015,6 +3031,7 @@ raise(Name, Amount) -> performed on the original data file. The default is true

+

-mnesia dump_log_write_threshold Max, where Max is an integer which specifies the maximum number of writes allowed to the transaction log before a new dump of the log @@ -3022,13 +3039,14 @@ raise(Name, Amount) ->

+

-mnesia dump_log_time_threshold Max, where Max is an integer which specifies the dump log interval in milliseconds. It defaults to 3 minutes. If a dump has not been performed within dump_log_time_threshold milliseconds, then a new dump is performed regardless of how many writes have been - performed. + performed.

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 -> diff --git a/lib/mnesia/test/mnesia_nice_coverage_test.erl b/lib/mnesia/test/mnesia_nice_coverage_test.erl index 78eab67b11..4b28ac634f 100644 --- a/lib/mnesia/test/mnesia_nice_coverage_test.erl +++ b/lib/mnesia/test/mnesia_nice_coverage_test.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1996-2010. All Rights Reserved. +%% Copyright Ericsson AB 1996-2014. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in @@ -189,6 +189,7 @@ adm(Attrs, Node1, Node2) -> ?match({atomic, ok}, mnesia:move_table_copy(nice_tab, Node2, Node1)), ?match(yes, mnesia:force_load_table(nice_counter_tab)), + ?match(ok, mnesia:sync_log()), ?match(dumped, mnesia:dump_log()), ok. -- cgit v1.2.3