TiDB开启慢查询日志记录

方法1：
--开启慢查询日志：
在所有的TiDB节点操作：
mysql> show variables like '%general%log%';
+------------------+-------------------------------------+
| Variable_name    | Value                               |
+------------------+-------------------------------------+
| tidb_general_log | 0                                   |
| general_log      | OFF                                 |
| general_log_file | /usr/local/mysql/data/localhost.log |
+------------------+-------------------------------------+
3 rows in set (0.01 sec)

mysql> set global tidb_general_log=1;
ERROR 1105 (HY000): Variable 'tidb_general_log' is a SESSION variable and can't be used with SET GLOBAL
mysql> set tidb_general_log=1;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%general%log%';
+------------------+-------------------------------------+
| Variable_name    | Value                               |
+------------------+-------------------------------------+
| tidb_general_log | 1                                   |
| general_log      | OFF                                 |
| general_log_file | /usr/local/mysql/data/localhost.log |
+------------------+-------------------------------------+
3 rows in set (0.01 sec)

方法2：
2.在中控机上开启配置文件中的慢查询：

cd /home/tidb/tidb-ansible/conf
vim tidb.yml 

log:
  # Log level: debug, info, warn, error, fatal.
  # level: "info"

  # Log format, one of json, text, console.
  # format: "text"

  # Disable automatic timestamps in output
  # disable-timestamp: false

  # Queries with execution time greater than this value will be logged. (Milliseconds)
  # slow-threshold: 300

  # Queries with internal result greater than this value will be logged.
  # expensive-threshold: 10000

  # Maximum query length recorded in log.
  # query-log-max-len: 2048

  # File logging.
  file:
    # Max log file size in MB. (upper limit to 4096MB).
    # max-size: 300

 # Max log file keep days. No clean up by default.
    # max-days: 0

 # Maximum number of old log files to retain. No clean up by default.
    # max-backups: 0

 # Rotate log by day
    # log-rotate: true
慢查询的日志级别设置：
默认值采用info，输出格式为txt,超过300ms即0.3s为慢查询，日志文件默认为300MB，日志文件默认永久保留,按照天自动保留日志。

slow-threshold: 300  -->200
max-size: 300  -->128
 max-days: 0  -->7
 max-backups: 0 -->10
 
 慢查询日志默认记录到 tidb.log 中(默认的位置：/data/deploy/log/tidb.log)，如果希望生成单独的慢查询日志文件，修改 inventory.ini 配置文件的参数 enable_slow_query_log 为 True。
 
 
 开启TiDB cluster 的binlog文件：
 /home/tidb/tidb-ansible
 #vim inventory.ini
 ## binlog trigger
enable_binlog = False  --> True
# store slow query log into seperate file
enable_slow_query_log = False  --> True


修改上述参数后 执行：
执行 ansible-playbook rolling_update.yml --tags=tidb
实现tiDB的滚动升级

tidb-server 将在 tidb_slow_query.log 文件中记录慢查询日志。

登录tidb节点查看慢查询日志：
# pwd
/data/deploy/log
# ls -l tidb_slow_query.log 
-rw-r--r-- 1 tidb tidb 887055 Aug 23 14:55 tidb_slow_query.log

慢查询日志信息格式：

# tail -f tidb_slow_query.log 
2018/08/23 14:41:46.846 adapter.go:364: [warning] [SLOW_QUERY] cost_time:467.845041ms succ:true con:28 user:[email protected] txn_start_ts:402392745545826315 database: table_ids:[6433],index_ids:[1],sql:UPDATE `ProductDB`.`productstore` SET `Id` = '5980a327d33c41cc9a296b6fed865781', `City_Id` = 420, `Warehouse_Id` = 4201, `TotalCount_MinUnit` = 432, `ProductSpecification_Id` = 7478, `OwnerType` = 0, `Owner_Id` = NULL, `OwnerName` = NULL, `CreateTime` = '2017-09-05 02:00:07', `LastUpdateTime` = '2018-08-23 14:41:43', `SaleTotalCount_MinUnit` = 696, `productionDate` = '2018-07-27', `LastModifyTime` = '2018-08-23 14:41:43', `productSku_Id` = 42000007478623 WHERE `Id` = '5980a327d33c41cc9a296b6fed865781' LIMIT 1;
2018/08/23 14:43:19.082 adapter.go:364: [warning] [SLOW_QUERY] cost_time:6m6.056520641s succ:true con:405 user:[email protected] txn_start_ts:402392673941192710 database:benchmark sql:CREATE INDEX k_10 ON sbtest10(k)
2018/08/23 14:45:21.652 adapter.go:364: [warning] [SLOW_QUERY] cost_time:7m0.055470947s succ:true con:387 user:[email protected] txn_start_ts:402392691924271106 database:benchmark sql:CREATE INDEX k_21 ON sbtest21(k)
2018/08/23 14:47:25.688 adapter.go:364: [warning] [SLOW_QUERY] cost_time:9m3.069588427s succ:true con:394 user:[email protected] txn_start_ts:402392692186415114 database:benchmark sql:CREATE INDEX k_31 ON sbtest31(k)
2018/08/23 14:49:20.969 adapter.go:364: [warning] [SLOW_QUERY] cost_time:10m54.048474535s succ:true con:364 user:[email protected] txn_start_ts:402392693313634308 database:benchmark sql:CREATE INDEX k_23 ON sbtest23(k)
2018/08/23 14:49:40.336 adapter.go:364: [warning] [SLOW_QUERY] cost_time:1.520935603s succ:true con:486 user:[email protected] txn_start_ts:402392869448187908 database:benchmark table_ids:[7299],sql:select count(1) from sbtest1
2018/08/23 14:51:23.101 adapter.go:364: [warning] [SLOW_QUERY] cost_time:12m54.026793359s succ:true con:372 user:[email protected] txn_start_ts:402392693877243912 database:benchmark sql:CREATE INDEX k_18 ON sbtest18(k)
2018/08/23 14:53:23.773 adapter.go:364: [warning] [SLOW_QUERY] cost_time:14m51.035969934s succ:true con:370 user:[email protected] txn_start_ts:402392694834069517 database:benchmark sql:CREATE INDEX k_29 ON sbtest29(k)
2018/08/23 14:55:15.747 adapter.go:364: [warning] [SLOW_QUERY] cost_time:16m39.067074879s succ:true con:356 user:[email protected] txn_start_ts:402392695869538313 database:benchmark sql:CREATE INDEX k_8 ON sbtest8(k)
2018/08/23 14:57:14.879 adapter.go:364: [warning] [SLOW_QUERY] cost_time:18m36.104647133s succ:true con:382 user:[email protected] txn_start_ts:402392696420040711 database:benchmark sql:CREATE INDEX k_22 ON sbtest22(k)