What is the use of log files in MongoDB database
This article mainly introduces what the log files of MongoDB database are used for. The introduction in this article is very detailed and has certain reference value. Interested friends must read it!
Format of log messages
[]
For example:
2014-11-03T18:28:32.450-0500 I NETWORK [initandlisten] waiting for connections on port 27017
log message severity level
level
level description
F
Fatal
E
Error
W
Warning
I
Informational, for Verbosity Level of 0
D
Debug, for All Verbosity Levels > 0
Information Category
Journal category
English
virtools categorized
login information
ACCESS
Log in to access relevant information, such as login authentication.
command information
COMMAND
The database executes command-related information, such as queries.
control management information
CONTROL
Records control management-related information, such as database initialization.
FTDC Information
FTDC（full-time diagnostic data ）
Data information is detected throughout the process, such as server status statistics.
index information
INDEX
Index-related information, such as information on the creation process of the index.
network information
NETWORK
Network related information, such as network connection information.
query information
QUERY
Query related information, such as query plan information.
Copy Set Information
REPL
Information related to replica set, such as replica set initial process, heartbeat, rollback, etc.
slice information
SHARDING
Fragment-related information, such as mongos startup information
store information
STORAGE
Store related information, such as information to brush storage layer data to disk.
restore information
RECOVERY
Restore activity-related information
log information
JOURNAL
Log related information
write operation information
WRITE
Write information about the operation, such as the update command.
query log level of detail
MongoDB divides logs into levels of detail 0 - 5
1. 0 is the default level for MongoDB logs, which contain Informational class information.
2. Debug levels 1 - 5 log all complete requests from the client.
Command to query log level of detail.
db.getLogComponents()
Modify Log Level of Detail
There are two ways to modify log verbosity.
The first is to set the logComponentVerbosity parameter to modify it.
Another point to note is that log classification can be further refined,
For example, set systemLog to 1 as a whole, where query and storage are set to 2, and journal is set to 1.
The specific commands to modify are:
db.adminCommand( { setParameter: 1, logComponentVerbosity: { verbosity: 1, query: { verbosity: 2 }, storage: { verbosity: 2, journal: { verbosity: 1 } } }} )
The second method, modified by db.setLogLevel().
This approach is mostly directed at modifying a single log category. Another point to note is that we sometimes see a log level of-1 through db.getLogComponents(), which means the same level as its parent category.
For example, if we set the log verbosity level of the query category to the log verbosity level of the parent class (systemLog), we can execute the following command:
db.setLogLevel(-1, "query")
The above two methods are modified, so can initialization be configured? In fact, it is possible, we only need to add the corresponding parameters in the initial configuration file, and will not expand here.
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