Query Log All Filter

Query Log All Filter


The Query Log All (QLA) filter logs query content. Logs are written to a file in CSV format. Log elements are configurable and include the time submitted and the SQL statement text, among others.


A minimal configuration is below.



Filter Options

The QLA filter accepts the following options.

Option Description
ignorecase Use case-insensitive matching
case Use case-sensitive matching
extended Use extended regular expression syntax (ERE)

To use multiple filter options, list them in a comma-separated list. If no options are given, default will be used. Multiple options can be enabled simultaneously.


Note: older the version of the QLA filter in 0.7 of MariaDB MaxScale used the options to define the location of the log files. This functionality is not supported anymore and the filebase parameter should be used instead.

Filter Parameters

The QLA filter has one mandatory parameter, filebase, and a number of optional parameters. These were introduced in the 1.0 release of MariaDB MaxScale.


The basename of the output file created for each session. A session index is added to the filename for each written session file. For unified log files, .unified is appended. This is a mandatory parameter.


The filebase may also be set as the filter option. If both option and parameter are set, the parameter setting will be used and the filter option ignored.

match and exclude

These optional parameters limit logging on a query level. The parameter values are regular expressions which are matched against the SQL query text. Only SQL statements that match the regular expression in match but do not match the exclude expression are logged.


match is checked before exclude. If match is empty, all queries are considered matching. If exclude is empty, no query is exluded. If both are empty, all queries are logged.

user and source

These optional parameters limit logging on a session level. If user is defined, only the sessions with a matching client username are logged. If source is defined, only sessions with a matching client source address are logged.



The type of log file to use. The default value is session.

Value Description
session Write to session-specific files
unified Use one file for all sessions

If both logs are required, define log_type=session,unified.


Type of data to log in the log files. The parameter value is a comma separated list of the following elements. By default the date, user and query options are enabled.

Value Description
service Service name
session Unique session id (ignored for session files)
date Timestamp
user User and hostname of client
reply_time Response time (ms until first reply from server)
query Query
log_data=date, user, query

If reply_time is enabled, the log entry is written when the first reply from server is received. Otherwise, the entry is written when receiving query from client.


Flush log files after every write. The default is false.



Append new entries to log files instead of overwriting them. The default is false.



Default value is "," (a comma). Defines the separator string between elements of a log entry. The value should be enclosed in quotes.

separator=" | "


Default value is " " (one space). SQL-queries may include line breaks, which, if printed directly to the log, may break automatic parsing. This parameter defines what should be written in the place of a newline sequence (\r, \n or \r\n). If this is set as the empty string, then newlines are not replaced and printed as is to the output. The value should be enclosed in quotes.

newline_replacement=" NL "


Example 1 - Query without primary key

Imagine you have observed an issue with a particular table and you want to determine if there are queries that are accessing that table but not using the primary key of the table. Let's assume the table name is PRODUCTS and the primary key is called PRODUCT_ID. Add a filter with the following definition:

match=SELECT.*from.*PRODUCTS .*

[Product Service]

The result of using this filter with the service used by the application would be a log file of all select queries querying PRODUCTS without using the PRODUCT_ID primary key in the predicates of the query. Executing SELECT * FROM PRODUCTS would log the following into /var/logs/qla/SelectProducts:

07:12:56.324 7/01/2016, SELECT * FROM PRODUCTS


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