RDS for PostgreSQL database log files - Amazon Relational Database Service
Publishing PostgreSQL logs to Amazon CloudWatch Logs

RDS for PostgreSQL database log files

RDS for PostgreSQL logs database activities to the default PostgreSQL log file. For an on-premises PostgreSQL DB instance, these messages are stored locally in log/postgresql.log. For an RDS for PostgreSQL DB instance, the log file is available on the Amazon RDS instance. Also, you must use the Amazon RDS Console to view or download its contents. The default logging level captures login failures, fatal server errors, deadlocks, and query failures.

For more information about how you can view, download, and watch file-based database logs, see Monitoring Amazon RDS log files. To learn more about PostgreSQL logs, see Working with Amazon RDS and Aurora PostgreSQL logs: Part 1 and Working with Amazon RDS and Aurora PostgreSQL logs: Part 2.

In addition to the standard PostgreSQL logs discussed in this topic, RDS for PostgreSQL also supports the PostgreSQL Audit extension (pgAudit). Most regulated industries and government agencies need to maintain an audit log or audit trail of changes made to data to comply with legal requirements. For information about installing and using pgAudit, see Using pgAudit to log database activity.

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Publishing PostgreSQL logs to Amazon CloudWatch Logs

To store your PostgreSQL log records in highly durable storage, you can use Amazon CloudWatch Logs. With CloudWatch Logs, you can also perform real-time analysis of log data and use CloudWatch to view metrics and create alarms. For example, if you set log_statement to ddl, you can set up an alarm to alert you whenever a DDL statement is executed. You can choose to have your PostgreSQL logs uploaded to CloudWatch Logs during the process of creating your RDS for PostgreSQL DB instance. If you chose not to upload logs at that time, you can later modify your instance to start uploading logs from that point forward. In other words, existing logs aren't uploaded. Only new logs are uploaded as they're created on your modified RDS for PostgreSQL DB instance.

All currently available RDS for PostgreSQL versions support publishing log files to CloudWatch Logs. For more information, see Amazon RDS for PostgreSQL updates in the Amazon RDS for PostgreSQL Release Notes..

To work with CloudWatch Logs, configure your RDS for PostgreSQL DB instance to publish log data to a log group.

You can publish the following log types to CloudWatch Logs for RDS for PostgreSQL:

  • Postgresql log

  • Upgrade log

After you complete the configuration, Amazon RDS publishes the log events to log streams within a CloudWatch log group. For example, the PostgreSQL log data is stored within the log group /aws/rds/instance/my_instance/postgresql. To view your logs, open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.

To publish PostgreSQL logs to CloudWatch Logs using the console

  1. Open the Amazon RDS console at https://console.aws.amazon.com/rds/.

  2. In the navigation pane, choose Databases.

  3. Choose the DB instance that you want to modify, and then choose Modify.

  4. In the Log exports section, choose the logs that you want to start publishing to CloudWatch Logs.

    The Log exports section is available only for PostgreSQL versions that support publishing to CloudWatch Logs.

  5. Choose Continue, and then choose Modify DB Instance on the summary page.

You can publish PostgreSQL logs with the AWS CLI. You can call the modify-db-instance command with the following parameters.

  • --db-instance-identifier

  • --cloudwatch-logs-export-configuration

Note

A change to the --cloudwatch-logs-export-configuration option is always applied to the DB instance immediately. Therefore, the --apply-immediately and --no-apply-immediately options have no effect.

You can also publish PostgreSQL logs by calling the following CLI commands:

Run one of these CLI commands with the following options:

  • --db-instance-identifier

  • --enable-cloudwatch-logs-exports

  • --db-instance-class

  • --engine

Other options might be required depending on the CLI command you run.

Example Modify an instance to publish logs to CloudWatch Logs

The following example modifies an existing PostgreSQL DB instance to publish log files to CloudWatch Logs. The --cloudwatch-logs-export-configuration value is a JSON object. The key for this object is EnableLogTypes, and its value is an array of strings with any combination of postgresql and upgrade.

For Linux, macOS, or Unix:

aws rds modify-db-instance \
    --db-instance-identifier mydbinstance \
    --cloudwatch-logs-export-configuration '{"EnableLogTypes":["postgresql", "upgrade"]}'

For Windows:

aws rds modify-db-instance ^
    --db-instance-identifier mydbinstance ^
    --cloudwatch-logs-export-configuration '{"EnableLogTypes":["postgresql","upgrade"]}'
Example Create an instance to publish logs to CloudWatch Logs

The following example creates a PostgreSQL DB instance and publishes log files to CloudWatch Logs. The --enable-cloudwatch-logs-exports value is a JSON array of strings. The strings can be any combination of postgresql and upgrade.

For Linux, macOS, or Unix:

aws rds create-db-instance \
    --db-instance-identifier mydbinstance \
    --enable-cloudwatch-logs-exports '["postgresql","upgrade"]' \
    --db-instance-class db.m4.large \
    --engine postgres

For Windows:

aws rds create-db-instance ^
    --db-instance-identifier mydbinstance ^
    --enable-cloudwatch-logs-exports '["postgresql","upgrade"]' ^
    --db-instance-class db.m4.large ^
    --engine postgres

You can publish PostgreSQL logs with the RDS API. You can call the ModifyDBInstance action with the following parameters:

  • DBInstanceIdentifier

  • CloudwatchLogsExportConfiguration

Note

A change to the CloudwatchLogsExportConfiguration parameter is always applied to the DB instance immediately. Therefore, the ApplyImmediately parameter has no effect.

You can also publish PostgreSQL logs by calling the following RDS API operations:

Run one of these RDS API operations with the following parameters:

  • DBInstanceIdentifier

  • EnableCloudwatchLogsExports

  • Engine

  • DBInstanceClass

Other parameters might be required depending on the operation that you run.