system.delta_lake_metadata_log

Description

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. 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. This table is primarily intended for debugging purposes.

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:

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}';

It is safe to truncate or drop this table at any time.

Columns

hostname (LowCardinality(String)) — Hostname of the server executing the query.
clickhouse_version (LowCardinality(String)) — Version of the ClickHouse server that produced the row.
system_processor (LowCardinality(String)) — CPU architecture of the ClickHouse server that produced the row.
event_date (Date) — Date of the entry.
event_time (DateTime) — Event time.
query_id (String) — Query id.
table_path (String) — Table path.
file_path (String) — File path.
content (String) — Content in a JSON format.

SQL Reference

Data Types

Engines

Functions

Formats

Interfaces

Settings

System Tables

Data Lakes

Description

Controlling log verbosity

Columns

​Description

​Controlling log verbosity

​Columns

Description

Controlling log verbosity

Columns