Setting Up Database Monitoring for self hosted MySQL
Database Monitoring provides deep visibility into your MySQL databases by exposing query metrics, query samples, explain plans, connection data, system metrics, and telemetry for the InnoDB storage engine.
The Agent collects telemetry directly from the database by logging in as a read-only user. Do the following setup to enable Database Monitoring with your MySQL database:
- Configure database parameters
- Grant the Agent access to the database
- Install the Agent
Before you begin
- Supported MySQL versions
- 5.6, 5.7, or 8.0+
- Supported MariaDB versions
- 10.5, 10.6, 10.11, or 11.1
Database Monitoring for MariaDB is supported with known limitations. - Supported Agent versions
- 7.36.1+
- Performance impact
- The default Agent configuration for Database Monitoring is conservative, but you can adjust settings such as the collection interval and query sampling rate to better suit your needs. For most workloads, the Agent represents less than one percent of query execution time on the database and less than one percent of CPU.
Database Monitoring runs as an integration on top of the base Agent (see benchmarks). - Proxies, load balancers, and connection poolers
- The Datadog Agent must connect directly to the host being monitored. For self-hosted databases,
127.0.0.1
or the socket is preferred. The Agent should not connect to the database through a proxy, load balancer, or connection pooler. If the Agent connects to different hosts while it is running (as in the case of failover, load balancing, and so on), the Agent calculates the difference in statistics between two hosts, producing inaccurate metrics. - Data security considerations
- See Sensitive information for information about what data the Agent collects from your databases and how to ensure it is secure.
To collect query metrics, samples, and explain plans, enable the MySQL Performance Schema and configure the following Performance Schema Options, either on the command line or in configuration files (for example, mysql.conf
):
Parameter | Value | Description |
---|
performance_schema | ON | Required. Enables the Performance Schema. |
max_digest_length | 4096 | Required for collection of larger queries. If left at the default value then queries longer than 1024 characters will not be collected. |
performance_schema_max_digest_length
| 4096 | Must match max_digest_length . |
performance-schema-consumer-events-statements-current | ON | Required. Enables monitoring of currently running queries. |
performance-schema-consumer-events-waits-current | ON | Required. Enables the collection of wait events. |
performance-schema-consumer-events-statements-history-long | ON | Recommended. Enables tracking of a larger number of recent queries across all threads. If enabled it increases the likelihood of capturing execution details from infrequent queries. |
performance-schema-consumer-events-statements-history | ON | Optional. Enables tracking recent query history per thread. If enabled it increases the likelihood of capturing execution details from infrequent queries. |
Parameter | Value | Description |
---|
performance_schema | ON | Required. Enables the Performance Schema. |
max_digest_length | 4096 | Required for collection of larger queries. If left at the default value then queries longer than 1024 characters will not be collected. |
performance_schema_max_digest_length
| 4096 | Must match max_digest_length . |
performance_schema_max_sql_text_length
| 4096 | Must match max_digest_length . |
performance-schema-consumer-events-statements-current | ON | Required. Enables monitoring of currently running queries. |
performance-schema-consumer-events-waits-current | ON | Required. Enables the collection of wait events. |
performance-schema-consumer-events-statements-history-long | ON | Recommended. Enables tracking of a larger number of recent queries across all threads. If enabled it increases the likelihood of capturing execution details from infrequent queries. |
performance-schema-consumer-events-statements-history | ON | Optional. Enables tracking recent query history per thread. If enabled it increases the likelihood of capturing execution details from infrequent queries. |
Note: A recommended practice is to allow the agent to enable the performance-schema-consumer-*
settings dynamically at runtime, as part of granting the Agent access. See Runtime setup consumers.
Grant the Agent access
The Datadog Agent requires read-only access to the database in order to collect statistics and queries.
The following instructions grant the Agent permission to login from any host using datadog@'%'
. You can restrict the datadog
user to be allowed to login only from localhost by using datadog@'localhost'
. See the MySQL documentation for more info.
Create the datadog
user and grant basic permissions:
CREATE USER datadog@'%' IDENTIFIED BY '<UNIQUEPASSWORD>';
GRANT REPLICATION CLIENT ON *.* TO datadog@'%' WITH MAX_USER_CONNECTIONS 5;
GRANT PROCESS ON *.* TO datadog@'%';
GRANT SELECT ON performance_schema.* TO datadog@'%';
Create the datadog
user and grant basic permissions:
CREATE USER datadog@'%' IDENTIFIED by '<UNIQUEPASSWORD>';
ALTER USER datadog@'%' WITH MAX_USER_CONNECTIONS 5;
GRANT REPLICATION CLIENT ON *.* TO datadog@'%';
GRANT PROCESS ON *.* TO datadog@'%';
GRANT SELECT ON performance_schema.* TO datadog@'%';
Create the following schema:
CREATE SCHEMA IF NOT EXISTS datadog;
GRANT EXECUTE ON datadog.* to datadog@'%';
GRANT CREATE TEMPORARY TABLES ON datadog.* TO datadog@'%';
Create the explain_statement
procedure to enable the Agent to collect explain plans:
DELIMITER $$
CREATE PROCEDURE datadog.explain_statement(IN query TEXT)
SQL SECURITY DEFINER
BEGIN
SET @explain := CONCAT('EXPLAIN FORMAT=json ', query);
PREPARE stmt FROM @explain;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END $$
DELIMITER ;
Additionally, create this procedure in every schema from which you want to collect explain plans. Replace <YOUR_SCHEMA>
with your database schema:
DELIMITER $$
CREATE PROCEDURE <YOUR_SCHEMA>.explain_statement(IN query TEXT)
SQL SECURITY DEFINER
BEGIN
SET @explain := CONCAT('EXPLAIN FORMAT=json ', query);
PREPARE stmt FROM @explain;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END $$
DELIMITER ;
GRANT EXECUTE ON PROCEDURE <YOUR_SCHEMA>.explain_statement TO datadog@'%';
Runtime setup consumers
Datadog recommends that you create the following procedure to give the Agent the ability to enable performance_schema.events_*
consumers at runtime.
DELIMITER $$
CREATE PROCEDURE datadog.enable_events_statements_consumers()
SQL SECURITY DEFINER
BEGIN
UPDATE performance_schema.setup_consumers SET enabled='YES' WHERE name LIKE 'events_statements_%';
UPDATE performance_schema.setup_consumers SET enabled='YES' WHERE name = 'events_waits_current';
END $$
DELIMITER ;
GRANT EXECUTE ON PROCEDURE datadog.enable_events_statements_consumers TO datadog@'%';
Securely store your password
Store your password using secret management software such as Vault. You can then reference this password as ENC[<SECRET_NAME>]
in your Agent configuration files: for example, ENC[datadog_user_database_password]
. See Secrets Management for more information.
The examples on this page use datadog_user_database_password
to refer to the name of the secret where your password is stored. It is possible to reference your password in plain text, but this is not recommended.
Install the Agent
Installing the Datadog Agent also installs the MySQL check which is required for Database Monitoring on MySQL. If you haven’t already installed the Agent for your MySQL database host, see the Agent installation instructions.
To configure this check for an Agent running on a host:
Edit the mysql.d/conf.yaml
file, in the conf.d/
folder at the root of your Agent’s configuration directory to start collecting your MySQL metrics and logs. See the sample mysql.d/conf.yaml for all available configuration options, including those for custom metrics.
Metric collection
Add this configuration block to your mysql.d/conf.yaml
to collect MySQL metrics:
init_config:
instances:
- dbm: true
host: 127.0.0.1
port: 3306
username: datadog
password: 'ENC[datadog_user_database_password]' # from the CREATE USER step earlier
Note that the datadog
user should be set up in the MySQL integration configuration as host: 127.0.0.1
instead of localhost
. Alternatively, you may also use sock
.
Restart the Agent to start sending MySQL metrics to Datadog.
Log collection (optional)
In addition to telemetry collected from the database by the Agent, you can also choose to send your database logs directly to Datadog.
By default MySQL logs everything in /var/log/syslog
which requires root access to read. To make the logs more accessible, follow these steps:
- Edit
/etc/mysql/conf.d/mysqld_safe_syslog.cnf
and comment out all lines. - Edit
/etc/mysql/my.cnf
to enable the desired logging settings. For example, to enable general, error, and slow query logs, use the following configuration:
[mysqld_safe]
log_error = /var/log/mysql/mysql_error.log
[mysqld]
general_log = on
general_log_file = /var/log/mysql/mysql.log
log_error = /var/log/mysql/mysql_error.log
slow_query_log = on
slow_query_log_file = /var/log/mysql/mysql_slow.log
long_query_time = 3
- Save the file and restart MySQL.
- Make sure the Agent has read access to the
/var/log/mysql
directory and all of the files within. Double-check your logrotate
configuration to make sure these files are taken into account and that the permissions are correctly set.
In /etc/logrotate.d/mysql-server
there should be something similar to:
/var/log/mysql.log /var/log/mysql/mysql.log /var/log/mysql/mysql_slow.log {
daily
rotate 7
missingok
create 644 mysql adm
Compress
}
Collecting logs is disabled by default in the Datadog Agent, enable it in your datadog.yaml
file:
Add this configuration block to your mysql.d/conf.yaml
file to start collecting your MySQL logs:
logs:
- type: file
path: "<ERROR_LOG_FILE_PATH>"
source: mysql
service: "<SERVICE_NAME>"
- type: file
path: "<SLOW_QUERY_LOG_FILE_PATH>"
source: mysql
service: "<SERVICE_NAME>"
log_processing_rules:
- type: multi_line
name: new_slow_query_log_entry
pattern: "# Time:"
# If mysqld was started with `--log-short-format`, use:
# pattern: "# Query_time:"
# If using mysql version <5.7, use the following rules instead:
# - type: multi_line
# name: new_slow_query_log_entry
# pattern: "# Time|# User@Host"
# - type: exclude_at_match
# name: exclude_timestamp_only_line
# pattern: "# Time:"
- type: file
path: "<GENERAL_LOG_FILE_PATH>"
source: mysql
service: "<SERVICE_NAME>"
# For multiline logs, if they start by the date with the format yyyy-mm-dd uncomment the following processing rule
# log_processing_rules:
# - type: multi_line
# name: new_log_start_with_date
# pattern: \d{4}\-(0?[1-9]|1[012])\-(0?[1-9]|[12][0-9]|3[01])
# If the logs start with a date with the format yymmdd but include a timestamp with each new second, rather than with each log, uncomment the following processing rule
# log_processing_rules:
# - type: multi_line
# name: new_logs_do_not_always_start_with_timestamp
# pattern: \t\t\s*\d+\s+|\d{6}\s+\d{,2}:\d{2}:\d{2}\t\s*\d+\s+
Restart the Agent.
Validate
Run the Agent’s status subcommand and look for mysql
under the Checks section. Or visit the Databases page to get started!
Example Agent Configurations
One agent connecting to multiple hosts
It is common to configure a single Agent host to connect to multiple remote database instances (see Agent installation architectures for DBM). To connect to multiple hosts, create an entry for each host in the MySQL integration config.
In these cases, Datadog recommends limiting the number of instances per Agent to a maximum of 10 database instances to guarantee reliable performance.
init_config:
instances:
- dbm: true
host: example-service-primary.example-host.com
port: 3306
username: datadog
password: 'ENC[datadog_user_database_password]'
tags:
- 'env:prod'
- 'team:team-discovery'
- 'service:example-service'
- dbm: true
host: example-service-replica-1.example-host.com
port: 3306
username: datadog
password: 'ENC[datadog_user_database_password]'
options:
replication: true
tags:
- 'env:prod'
- 'team:team-discovery'
- 'service:example-service'
- dbm: true
host: example-service-replica-2.example-host.com
port: 3306
username: datadog
password: 'ENC[datadog_user_database_password]'
options:
replication: true
tags:
- 'env:prod'
- 'team:team-discovery'
- 'service:example-service'
[...]
Running custom queries
To collect custom metrics, use the custom_queries
option. See the sample mysql.d/conf.yaml for more details.
init_config:
instances:
- dbm: true
host: localhost
port: 3306
username: datadog
password: 'ENC[datadog_user_database_password]'
custom_queries:
- query: SELECT age, salary, hours_worked, name FROM hr.employees;
columns:
- name: custom.employee_age
type: gauge
- name: custom.employee_salary
type: gauge
- name: custom.employee_hours
type: count
- name: name
type: tag
tags:
- 'table:employees'
Working with hosts through a proxy
If the Agent must connect through a proxy such as the Cloud SQL Auth proxy, all telemetry is tagged with the hostname of the proxy rather than the database instance. Use the reported_hostname
option to set a custom override of the hostname detected by the Agent.
init_config:
instances:
- dbm: true
host: localhost
port: 5000
username: datadog
password: 'ENC[datadog_user_database_password]'
reported_hostname: example-service-primary
- dbm: true
host: localhost
port: 5001
username: datadog
password: 'ENC[datadog_user_database_password]'
reported_hostname: example-service-replica-1
Troubleshooting
If you have installed and configured the integrations and Agent as described and it is not working as expected, see Troubleshooting.
Further reading
Additional helpful documentation, links, and articles: