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>,<connectionid>,<queryid>,<operation>,<database>,<object>,<retcode>

Field	Component	Data Type	Standardized Name / Description
1	timestamp	DateTime	Formatted as YYYYMMDD HH:MM:SS.
2	serverhost	String	Hostname of the originating server.
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).
10	retcode	Integer	Result code (0 for success).

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.

[timestamp],[serverhost],[username],[host],[connectionid],0,CONNECT,[database],,0 
[timestamp],[serverhost],[username],[host],[connectionid],0,DISCONNECT,,,0 
[timestamp],[serverhost],[username],[host],[connectionid],0,FAILED_CONNECT,,,[retcode]

Here is the one audit record generated for each query event:

[timestamp],[serverhost],[username],[host],[connectionid],[queryid],QUERY,[database],[object], [retcode]

Below are generic examples of records that are entered in the audit log for each type of table event:

[timestamp],[serverhost],[username],[host],[connectionid],[queryid],CREATE,[database],[object], 
[timestamp],[serverhost],[username],[host],[connectionid],[queryid],READ,[database],[object], 
[timestamp],[serverhost],[username],[host],[connectionid],[queryid],WRITE,[database],[object], 
[timestamp],[serverhost],[username],[host],[connectionid],[queryid],ALTER,[database],[object], 
[timestamp],[serverhost],[username],[host],[connectionid],[queryid],RENAME,[database], 
[object_old]|[database_new].[object_new], 
[timestamp],[serverhost],[username],[host],[connectionid],[queryid],DROP,[database],[object],

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).

Current

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.

< 10.11.16

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