在 Cloud Composer 中推出数据库保留政策之前，我们建议通过数据库清理 DAG 采用其他方法来自动执行数据库清理。此方法在 Cloud Composer 3 中已废弃。此 DAG 会执行多余的工作，您可以将其移除并替换为数据库保留政策，从而减少资源消耗。
数据库大小限制
随着时间的推移，环境的 Airflow 数据库会存储越来越多的数据。这些数据包括与过往 DAG 运行、任务和其他 Airflow 操作相关的信息和日志。
如果 Airflow 数据库大小超过 20 GB，则无法将环境升级到更高版本。
如果 Airflow 数据库大小超过 20 GB，则无法创建快照。
维护数据库性能
Airflow 数据库性能问题可能会导致整体 DAG 执行问题。观察“数据库 CPU 和内存用量”统计信息。如果 CPU 和内存利用率接近上限，则表示数据库过载并需要伸缩。
Airflow 数据库可用的资源量由环境的环境大小属性控制。如需扩缩数据库，请将环境大小更改为更大的层级。增加环境大小会增加环境的费用。
[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-08-29。"],[[["\u003cp\u003eThis page outlines how to manually clean up the Airflow database in Cloud Composer 3 environments, as well as automatic alternatives.\u003c/p\u003e\n"],["\u003cp\u003eCloud Composer offers a database retention policy that automatically removes records older than a specified period, and it is preferred over the older database cleanup DAG.\u003c/p\u003e\n"],["\u003cp\u003eExceeding a 20 GB database size in Airflow prevents environment upgrades and snapshot creation, making regular cleanup essential.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003egcloud composer environments run\u003c/code\u003e command can be used to manually trim the database, removing entries older than the specified retention period.\u003c/p\u003e\n"],["\u003cp\u003eDatabase performance issues can cause DAG execution problems, and scaling up the environment size can address these issues, while also using proper Xcom practices to avoid issues with the database.\u003c/p\u003e\n"]]],[],null,["# Clean up the Airflow database\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\n**Cloud Composer 3** \\| [Cloud Composer 2](/composer/docs/composer-2/cleanup-airflow-database \"View this page for Cloud Composer 2\") \\| [Cloud Composer 1](/composer/docs/composer-1/cleanup-airflow-database \"View this page for Cloud Composer 1\")\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\nThis page explains how to maintain the Airflow database in your environment.\n\nAutomatic database cleanup with a database retention policy\n-----------------------------------------------------------\n\nYou can configure automatic database cleanup for your Cloud Composer 3\nenvironment by setting a database retention policy. After you set up this\npolicy, records older than a certain period are automatically removed from the\nAirflow database daily. For more information, see\n[Configure database retention policy](/composer/docs/composer-3/configure-db-retention).\n\nDeprecated cleanup procedures\n-----------------------------\n\n| **Deprecated:** The **maintenance DAG approach is obsolete** in Cloud Composer 3. If you still use the database maintenance DAG, we recommend to remove or pause it and configure a [database retention policy](/composer/docs/composer-3/configure-db-retention) instead.\n\nBefore the database retention policy became available in\nCloud Composer, we recommended a different approach for automating\nthe database cleanup, through a [database cleanup DAG](/composer/docs/composer-2/cleanup-airflow-database). This\napproach is obsolete in Cloud Composer 3. This DAG does redundant work and you\ncan reduce the resource consumption by removing it and replacing it with a\n[database retention policy](/composer/docs/composer-3/configure-db-retention).\n\nLimits for database size\n------------------------\n\nAs the time goes, the Airflow database of your environment stores more and\nmore data. This data includes information and logs related to past DAG runs,\ntasks, and other Airflow operations.\n\n- If the Airflow database size is more than\n 20 GB,\n then you can't upgrade your environment to a later version.\n\n- If the Airflow database size is more than 20 GB,\n it is not possible to create snapshots.\n\nMaintain database performance\n-----------------------------\n\n- Airflow database performance issues can lead to overall DAG execution\n issues.\n [Observe Database CPU and memory usage](/composer/docs/composer-3/use-monitoring-dashboard#db-statistics)\n statistics. If CPU and memory utilization approaches the limits, then the\n database is overloaded and requires scaling.\n\n The amount of resources available to the Airflow database is controlled by\n the environment size property of your environment. To scale the database up\n [change the environment size](/composer/docs/composer-3/scale-environments) to a larger tier. Increasing the\n environment size increases the costs of your environment.\n\n- If you use the XCom mechanism to transfer files, make sure that you\n [use it according to Airflow's guidelines](https://airflow.apache.org/docs/apache-airflow/stable/core-concepts/xcoms.html#object-storage-xcom-backend).\n Transferring big files or a large number of files using XCom impacts\n Airflow database's performance and can lead to failures when loading\n snapshots or upgrading your environment. Consider using alternatives such\n as Cloud Storage to transfer large volumes of data.\n\nRemove entries for unused DAGs\n------------------------------\n\nYou can remove database entries for unused DAGs by\n[removing DAGs from the Airflow UI](/composer/docs/composer-3/manage-dags#delete-md).\n\nWhat's next\n-----------\n\n- [Configure database retention policy](/composer/docs/composer-3/configure-db-retention)\n- [Access Airflow command-line interface](/composer/docs/composer-3/access-airflow-cli)"]]
