The problem:
Every one or two minutes, the mongo clients halt for about 3 seconds. Normal operation time for updates is about 1 or 2 milliseconds. When this slowness appear, we have a bunch of updates lasting 1 to 3 seconds.
慢速查询日志(log)没有显示与此相关的任何内容.调试mongo客户端(mongo php客户端)也是如此.
当前的体系 struct 在副本集中有一个主、一个从和一个仲裁器.
执行的查询总是相同的排序(按_id向上插入,用new MongoId插入).没有"每隔几分钟我们就会运行这个超级昂贵的更新"
堵塞似乎是由局部原因造成的.oplog.rs.至少,这是mongotop的输出在下面显示的.我还没有发现任何迹象表明次级系统导致了这个问题,因为下面所有命令的输出似乎都是稳定的.我也没有发现任何信息表明这种慢度是由特定的查询引起的.
我们存储数据的方式背后的 idea 是预聚合报告.我们有很多更新(每秒几百次),但查询率非常低.
"indexSizes" : {
"_id_" : 1967,
"owner_date" : 230,
"flow_date" : 231,
"date" : 170
},
大多数其他集合的索引大小不超过100Mb.在所有的Collection 中,_id索引是最大的一个.值得注意的是,此ID是手动生成的(基于元数据,因此插入是作为upsert进行的,而不是增量的)
FollowUp:
Edit1:在进一步挖掘之后,当刷新到磁盘时,锁定似乎与日志(log)的rsync过程有关.日志(log)与数据文件位于同一个文件系统中,但由于磁盘是快速ssd设备,因此在中的速度不是预期的.
Edit2:经过一些测试后,磁盘的写入能力不是问题.我们通常以每秒数兆字节的速度写入.在磁盘上运行一些测试,它可以毫无问题地接受150mb/s的速度
The expected answer:
为什么会发生这种停机?
- 指向可能的原因,以便进一步调查
- 基于类似 case 的经验/解决方案
Issue Explanation:
The following commands are run in the primary node
每次缓慢出现时,我们都会在mongostat中看到以下内容(两个示例)
insert query update delete getmore command % dirty % used flushes vsize res qr|qw ar|aw netIn netOut conn set repl time
10 *0 141 *0 93 120|0 0.4 80.0 0 11.5G 9.4G 0|1 1|0 110k 71k 274 rs0 PRI 13:15:44
12 *0 178 *0 72 105|0 0.2 80.0 1 11.5G 9.4G 0|0 1|0 111k 79k 274 rs0 PRI 13:15:45
47 *0 7 *0 0 159|0 0.1 80.0 0 11.5G 9.4G 0|0 2|1 15k 44k 274 rs0 PRI 13:15:49 !!!!HERE
14 *0 929 *0 99 170|0 0.2 80.0 0 11.5G 9.4G 0|0 1|0 419k 417k 274 rs0 PRI 13:15:50
21 *0 287 *0 124 181|0 0.2 80.0 0 11.5G 9.4G 0|0 1|0 187k 122k 274 rs0 PRI 13:15:51
insert query update delete getmore command % dirty % used flushes vsize res qr|qw ar|aw netIn netOut conn set repl time
10 *0 145 *0 70 108|0 0.3 79.9 0 11.5G 9.4G 0|0 1|0 98k 71k 274 rs0 PRI 13:16:48
11 *0 155 *0 72 111|0 0.2 79.9 1 11.5G 9.4G 0|0 1|0 103k 75k 274 rs0 PRI 13:16:49
44 *0 3 *0 0 144|0 0.0 79.9 0 11.5G 9.4G 0|2 1|0 11k 75k 274 rs0 PRI 13:16:53 !!!!HERE
11 *0 837 *0 94 134|0 0.2 79.9 0 11.5G 9.4G 0|0 1|0 377k 348k 274 rs0 PRI 13:16:54
12 *0 180 *0 86 139|0 0.2 79.9 0 11.5G 9.4G 0|0 1|0 122k 85k 274 rs0 PRI 13:16:55
14 *0 195 *0 83 124|0 0.2 79.9 0 11.5G 9.4G 0|0 2|0 125k 89k 274 rs0 PRI 13:16:56
更新列中有一个下拉列表,下面的一个下拉列表中有更多更新.还要注意的是,我们使用的mongostat有1秒的延迟.当慢度出现时,mongostat会在几秒钟内停止回复.
这是发生此问题时mongotop的输出(2015-07-07T13:29:38):
(在here中可以找到一个有更多上下文的例子)
ns total read write 2015-07-07T13:29:33+02:00
database_name.d_date_flow_owner 555ms 550ms 4ms
local.oplog.rs 61ms 53ms 7ms
database_name.client_context_bbbbbbb 15ms 0ms 15ms
database_name.d_date_landing_owner 15ms 0ms 15ms
database_name.d_date_billing_owner 10ms 0ms 10ms
database_name.w_bl_carrier_country_date_device_flow_landing_manager_op1_os_owner_prod_site 7ms 0ms 7ms
database_name.d_carrier_country_date_device_flow_landing_op1_os_owner_site 5ms 0ms 5ms
database_name.d_country_date_owner 5ms 0ms 5ms
database_name.d_date_device_owner 5ms 0ms 5ms
database_name.d_date_os_owner 5ms 0ms 5ms
ns total read write 2015-07-07T13:29:37+02:00
database_name.client_context_bbbbbbb 2ms 0ms 2ms
database_name.client_context_aaaaaaaaa 1ms 0ms 1ms
admin.system.backup_users 0ms 0ms 0ms
admin.system.namespaces 0ms 0ms 0ms
admin.system.new_users 0ms 0ms 0ms
admin.system.profile 0ms 0ms 0ms
admin.system.roles 0ms 0ms 0ms
admin.system.users 0ms 0ms 0ms
admin.system.version 0ms 0ms 0ms
database_name 0ms 0ms 0ms
ns total read write 2015-07-07T13:29:38+02:00
local.oplog.rs 8171ms 4470ms 3701ms
database_name.d_date_op1_owner 45ms 0ms 45ms
database_name.d_date_device_owner 39ms 0ms 39ms
database_name.m_date_owner 34ms 0ms 34ms
database_name.d_date_owner 32ms 0ms 32ms
database_name.d_date_owner_site 31ms 0ms 31ms
database_name.d_carrier_date_owner 30ms 0ms 30ms
database_name.d_date_flow_owner 30ms 0ms 30ms
database_name.d_date_owner_product 28ms 0ms 28ms
database_name.d_carrier_country_date_device_flow_landing_op1_os_owner_site 27ms 0ms 27ms
ns total read write 2015-07-07T13:29:39+02:00
database_name.d_date_flow_owner 558ms 552ms 6ms
local.oplog.rs 62ms 61ms 1ms
database_name.d_carrier_date_owner 17ms 0ms 17ms
database_name.d_date_owner 16ms 0ms 16ms
database_name.w_bl_carrier_country_date_device_flow_landing_manager_op1_os_owner_prod_site 7ms 0ms 7ms
database_name.d_date_billing_owner 6ms 0ms 6ms
database_name.d_carrier_country_date_device_flow_landing_op1_os_owner_site 5ms 0ms 5ms
database_name.d_country_date_owner 5ms 0ms 5ms
database_name.d_date_device_owner 5ms 0ms 5ms
database_name.d_date_op1_owner 5ms 0ms 5ms
显示问题的php mongo客户端的调试(最后两行"PhpMongoClient调试"):
(在here中可以找到一个有更多上下文的例子)
Update duration: 2ms
Update duration: 1ms
Update duration: 1ms
Update duration: 4006ms
PhpMongoClient debug: 2015-07-07 10:40:26 - PARSE (INFO): Parsing mongodb://primary_host.lan,secondary_host.lan
PhpMongoClient debug: 2015-07-07 10:40:26 - PARSE (INFO): - Found node: primary_host.lan:27017
[....]
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): limiting by credentials: done
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): sorting servers by priority and ping time
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): - connection: type: PRIMARY, socket: 42, ping: 0, hash: primary_host.lan:27017;rs0;database_name/user/5ca571e7db198eeee3abee35857bfd53;30751
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): sorting servers: done
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): selecting near servers
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): selecting near servers: nearest is 0ms
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): - connection: type: PRIMARY, socket: 42, ping: 0, hash: primary_host.lan:27017;rs0;database_name/user/5ca571e7db198eeee3abee35857bfd53;30751
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (FINE): selecting near server: done
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (INFO): pick server: random element 0
PhpMongoClient debug: 2015-07-07 10:40:26 - REPLSET (INFO): - connection: type: PRIMARY, socket: 42, ping: 0, hash: primary_host.lan:27017;rs0;database_name/user/5ca571e7db198eeee3abee35857bfd53;30751
PhpMongoClient debug: 2015-07-07 10:40:26 - CON (FINE): No timeout changes for primary_host.lan:27017;rs0;database_name/user/5ca571e7db198eeee3abee35857bfd53;30751
PhpMongoClient debug: 2015-07-07 10:40:30 - CON (FINE): No timeout changes for primary_host.lan:27017;rs0;database_name/user/5ca571e7db198eeee3abee35857bfd53;30751
Update duration: 3943ms
Update duration: 3476ms
Update duration: 2008ms
Update duration: 961ms
Update duration: 956ms
Update duration: 20ms
Update duration: 20ms
Update duration: 3ms
Update duration: 42ms
Update duration: 24ms
Update duration: 25ms
Update duration: 56ms
Update duration: 24ms
Update duration: 11ms
Update duration: 11ms
Update duration: 3ms
Update duration: 2ms
Update duration: 3ms
Update duration: 1ms
Update duration: 1ms
Update duration: 1ms
Update duration: 2ms
Mongo Information:
- Mongo版本:3.0.3
- 带有1个从机和1个仲裁器的副本集
- 复制延迟在0到4秒之间变化
- 引擎:WiredTiger
- 文件系统:XFS
- 操作系统:Red Hat Enterprise Linux Server 7.1版
- 内存:24Gb.htop报告使用率为40%,缓存率为60%