import SystemTableCloud from '@site/docs/_snippets/_system_table_cloud.md';

system.delta_lake_metadata_log

The system.delta_lake_metadata_log table records metadata access and parsing events for Delta Lake tables read by ClickHouse. It provides detailed information about each metadata file, which is useful for debugging, auditing, and understanding Delta table structure evolution.

Purpose {#purpose}

This table logs every metadata file read from Delta Lake tables. It helps users trace how ClickHouse interprets Delta table metadata and diagnose issues related to schema evolution, snapshot resolution, or query planning.

:::note This table is primarily intended for debugging purposes. :::

Columns {#columns}

Name	Type	Description
`event_date`	Date	Date of the log file.
`event_time`	DateTime	Timestamp of the event.
`query_id`	String	Query ID that triggered the metadata read.
`table_path`	String	Path to the Delta Lake table.
`file_path`	String	Path to the root metadata JSON file.
`content`	String	Content in JSON format (raw metadata from .json).

Controlling log verbosity {#controlling-log-verbosity}

You can control which metadata events are logged using the delta_lake_log_metadata setting.

To log all metadata used in the current query:

sql

SELECT * FROM my_delta_table SETTINGS delta_lake_log_metadata = 1;

SYSTEM FLUSH LOGS delta_lake_metadata_log;

SELECT *
FROM system.delta_lake_metadata_log
WHERE query_id = '{previous_query_id}';