Query Log All Filter

Overview

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.

Configuration

A minimal configuration is below.

[MyLogFilter]
type=filter
module=qlafilter
filebase=/tmp/SqlQueryLog

[MyService]
type=service
router=readconnroute
servers=server1
user=myuser
password=mypasswd
filters=MyLogFilter

Log Rotation

The qlafilter logs can be rotated by executing the maxctrl rotate logs command. This will cause the log files to be reopened when the next message is written to the file. This applies to both unified and session type logging.

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.

filebase

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.

filebase=/tmp/SqlQueryLog

match, exclude and options

Theseregular expression settings limit which queries are logged.

match=select.*from.*customer.*where
exclude=^insert
options=case,extended

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. Ifsource is defined, only sessions with a matching client source address are logged.

user=john
source=127.0.0.1

log_type

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

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

log_type=session

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

log_data

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
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

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

flush=true

append

Append new entries to log files instead of overwriting them. The default is true. NOTE: the default was changed from false to true, as of the following versions: 2.4.18, 2.5.16 and 6.2.

append=true

separator

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

separator=" | "

newline_replacement

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 "

Examples

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:

[ProductsSelectLogger]
type=filter
module=qlafilter
match=SELECT.*from.*PRODUCTS .*
exclude=WHERE.*PRODUCT_ID.*
filebase=/var/logs/qla/SelectProducts

[Product-Service]
type=service
router=readconnroute
servers=server1
user=myuser
password=mypasswd
filters=ProductsSelectLogger

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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