From 01a887efada79e0eca3ca3a83f537a64e9dc9e6b Mon Sep 17 00:00:00 2001
From: Mr Chen <midoks@163.com>
Date: Sun, 12 Nov 2023 13:12:58 +0800
Subject: [PATCH] sync_binlog
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

默认，sync_binlog=0，表示MySQL不控制binlog的刷新，由文件系统自己控制它的缓存的刷新。这时候的性能是最好的，但是风险也是最大的。因为一旦系统Crash，在binlog_cache中的所有binlog信息都会被丢失。

如果sync_binlog>0，表示每sync_binlog次事务提交，MySQL调用文件系统的刷新操作将缓存刷下去。最安全的就是sync_binlog=1了，表示每次事务提交，MySQL都会把binlog刷下去，是最安全但是性能损耗最大的设置。这样的话，在数据库所在的主机操作系统损坏或者突然掉电的情况下，系统才有可能丢失1个事务的数据。但是binlog虽然是顺序IO，但是设置sync_binlog=1，多个事务同时提交，同样很大的影响MySQL和IO性能。虽然可以通过group commit的补丁缓解，但是刷新的频率过高对IO的影响也非常大。对于高并发事务的系统来说，“sync_binlog”设置为0和设置为1的系统写入性能差距可能高达5倍甚至更多
---
 plugins/mysql/conf/my5.5.cnf | 2 ++
 plugins/mysql/conf/my5.6.cnf | 2 ++
 plugins/mysql/conf/my5.7.cnf | 3 +++
 plugins/mysql/conf/my8.0.cnf | 2 ++
 4 files changed, 9 insertions(+)

diff --git a/plugins/mysql/conf/my5.5.cnf b/plugins/mysql/conf/my5.5.cnf
index 24a6023c3..70b5c1c66 100644
--- a/plugins/mysql/conf/my5.5.cnf
+++ b/plugins/mysql/conf/my5.5.cnf
@@ -59,6 +59,8 @@ relay-log=mdserver
 relay-log-index=mdserver
 
 #master
+#sync_binlog=1
+
 #binlog-do-db
 binlog-ignore-db = test
 binlog-ignore-db = mysql
diff --git a/plugins/mysql/conf/my5.6.cnf b/plugins/mysql/conf/my5.6.cnf
index fb8c8c171..35a9c3a7e 100644
--- a/plugins/mysql/conf/my5.6.cnf
+++ b/plugins/mysql/conf/my5.6.cnf
@@ -62,6 +62,8 @@ relay-log=mdserver
 relay-log-index=mdserver
 
 #master
+#sync_binlog=1
+
 #binlog-do-db
 binlog-ignore-db = test
 binlog-ignore-db = mysql
diff --git a/plugins/mysql/conf/my5.7.cnf b/plugins/mysql/conf/my5.7.cnf
index 28bcdfec5..c6f722823 100644
--- a/plugins/mysql/conf/my5.7.cnf
+++ b/plugins/mysql/conf/my5.7.cnf
@@ -63,6 +63,8 @@ relay-log=mdserver
 relay-log-index=mdserver
 
 #master
+#sync_binlog=1
+
 #binlog-do-db
 binlog-ignore-db = test
 binlog-ignore-db = mysql
@@ -84,6 +86,7 @@ replicate-ignore-db = test
 master_info_repository = table
 relay_log_info_repository = table
 
+
 innodb_data_home_dir = {$SERVER_APP_PATH}/data
 innodb_data_file_path = ibdata1:10M:autoextend
 innodb_log_group_home_dir = {$SERVER_APP_PATH}/data
diff --git a/plugins/mysql/conf/my8.0.cnf b/plugins/mysql/conf/my8.0.cnf
index ca92ae86c..c0574c3dc 100644
--- a/plugins/mysql/conf/my8.0.cnf
+++ b/plugins/mysql/conf/my8.0.cnf
@@ -61,6 +61,8 @@ relay-log=mdserver
 relay-log-index=mdserver
 
 #master
+#sync_binlog=1
+
 #binlog-do-db
 binlog-ignore-db = test
 binlog-ignore-db = mysql