system.blob_storage_log

System table containing logging entries with information about various blob storage operations such as uploads and deletes.

Querying in ClickHouse Cloud

The data in this system table is held locally on each node in ClickHouse Cloud. Obtaining a complete view of all data, therefore, requires the clusterAllReplicas function. See here for further details.

Description

Contains logging entries with information about various blob storage operations such as uploads and deletes.

Columns

• hostname (LowCardinality(String)) — Hostname of the server executing the query.
• event_date (Date) — Date of the event.
• event_time (DateTime) — Time of the event.
• event_time_microseconds (DateTime64(6)) — Time of the event with microseconds precision.
• event_type (Enum8(‘Upload’ = 1, ‘Delete’ = 2, ‘MultiPartUploadCreate’ = 3, ‘MultiPartUploadWrite’ = 4, ‘MultiPartUploadComplete’ = 5, ‘MultiPartUploadAbort’ = 6, ‘Read’ = 7)) — Type of the event. Possible values: ‘Upload’, ‘Delete’, ‘MultiPartUploadCreate’, ‘MultiPartUploadWrite’, ‘MultiPartUploadComplete’, ‘MultiPartUploadAbort’, ‘Read’
• query_id (String) — Identifier of the query associated with the event, if any.
• thread_id (UInt64) — Identifier of the thread performing the operation.
• thread_name (String) — Name of the thread performing the operation.
• disk_name (LowCardinality(String)) — Name of the associated disk.
• bucket (String) — Name of the bucket.
• remote_path (String) — Path to the remote resource.
• local_path (String) — Path to the metadata file on the local system, which references the remote resource.
• data_size (UInt64) — Size of the data involved in the upload event.
• elapsed_microseconds (UInt64) — Elapsed time for the operation, in microseconds.
• error_code (Int32) — Error code of the operation. 0 if there was no error.
• error (String) — Error message associated with the event, if any.

Example

Suppose a blob storage operation uploads a file, and an event is logged:

SELECT * FROM system.blob_storage_log WHERE query_id = '7afe0450-504d-4e4b-9a80-cd9826047972' ORDER BY event_date, event_time_microseconds \G

Row 1:
──────
hostname:                clickhouse.eu-central1.internal
event_date:              2023-10-31
event_time:              2023-10-31 16:03:40
event_time_microseconds: 2023-10-31 16:03:40.481437
event_type:              Upload
query_id:                7afe0450-504d-4e4b-9a80-cd9826047972
thread_id:               2381740
disk_name:               disk_s3
bucket:                  bucket1
remote_path:             rrr/kxo/tbnqtrghgtnxkzgtcrlutwuslgawe
local_path:              store/654/6549e8b3-d753-4447-8047-d462df6e6dbe/tmp_insert_all_1_1_0/checksums.txt
data_size:               259
error:

In this example, upload operation was associated with the INSERT query with ID 7afe0450-504d-4e4b-9a80-cd9826047972. The local metadata file store/654/6549e8b3-d753-4447-8047-d462df6e6dbe/tmp_insert_all_1_1_0/checksums.txt refers to remote path rrr/kxo/tbnqtrghgtnxkzgtcrlutwuslgawe in bucket bucket1 on disk disk_s3, with a size of 259 bytes.

See also

• External Disks for Storing Data