Audit Plugin Log Format
Understand the structure of audit log entries. This guide breaks down the fields in the log records, including timestamps, server IDs, user details, and the specific operations performed.
The audit plugin logs user access to MariaDB and its objects. The audit trail (that is, the audit log) is a set of records, written as a list of fields to a file in a plain‐text format. The fields in the log are separated by commas. The format used for the plugin's own log file is slightly different from the format used if it logs to the system log because it has its own standard format.
Formal Specification
When the MariaDB Audit Plugin (v1) writes to a dedicated file, it uses a comma-separated (CSV) format. For tool developers, it is essential to map the connectionid to the server's global connection identifier to enable cross-log analysis.
Template: <timestamp>,<serverhost>,<username>,<host>:<port>,<connectionid>,<queryid>,<operation>,<database>,<object>,<retcode>
Template: <timestamp>,<serverhost>,<username>,<host>,<connectionid>,<queryid>,<operation>,<database>,<object>,<retcode>
1
timestamp
DateTime
Formatted as %Y%m%d %H:%i:%s (the default), or as specified in server_audit_timestamp_format.
2
serverhost
String
Hostname of the originating server.
3
username
String
The MariaDB user account that triggered the event.
4
host:port
String
The client host the user connected from, followed by a colon and the client's TCP port. From MariaDB 12.0.1. When the client did not connect over TCP/IP, such as over a Unix socket or a named pipe, the colon and the port are both omitted and the field holds the host alone. Before MariaDB 12.0.1, the field is always the host alone.
5
connectionid
Unsigned Int
Standardized: Thread ID. Matches the Thread ID in Error, General, and Slow logs.
6
queryid
Unsigned Int
A unique identifier for the specific query, used to correlate QUERY and TABLE events.
7
operation
String
Action type (e.g., CONNECT, QUERY, READ, WRITE). The change-user connection event is logged as CHANGEUSER, without an underscore.
8
database
String
The database the event applies to.
9
object
String
The table or object involved in the operation, or the statement text on QUERY events. Connection events use this field for other values: from MariaDB 12.0.1, the negotiated TLS version, and on PROXY_CONNECT records, the proxy user.
10
retcode
Integer
Result code (0 for success).
Changed in MariaDB 12.0.1
Two changes to the log format require updates to tools that parse the audit log:
The
hostfield now contains a colon and the client's TCP port, unless the client did not connect over TCP/IP.On connection events, the
objectfield now carries the negotiated TLS version. The record still has ten fields and still ends withretcode.
Audit Log Format with Syslog
If server_audit_output_type is set to SYSLOG, the standard CSV line is prefixed with syslog metadata: <timestamp> <syslog_host> <syslog_ident>: <syslog_info> [Standard CSV Fields]
Various events result in different audit records. Some events do not return a value for some fields (for instance, when the active database is not set when connecting to the server).
Below is a generic example of the output for connect events, with placeholders representing data. These are events in which a user connected, disconnected, or tried unsuccessfully to connect to the server.
Starting with MariaDB 12.0.1, connection events record the client port alongside the host and report the negotiated TLS version in the object field:
The third record is an unencrypted Unix socket connection: the host carries no port suffix, and the TLS version is empty.
Here is the one audit record generated for each query event:
Below are generic examples of records that are entered in the audit log for each type of table event:
Passwords are hidden in the log for certain types of queries. They are replaced with asterisks for GRANT, CREATE USER, CREATE MASTER, CREATE SERVER, and ALTER SERVER statements. Passwords, however, are not replaced for the PASSWORD() and OLD_PASSWORD() functions when they are used inside other SQL statements (i.e., SET PASSWORD).
For Galera Cluster replication applier operations, audit log plugin logs events with a generic name of <wsrep_applier> .
This addresses an issue where the user was logged on the primary node, but stripped from other cluster nodes. See MDEV-35511 for details.
For Galera Cluster replication applier operations, audit log plugin logs events without indicating what user initiates them.
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