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system.backup_log

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Description

Contains logging entries with information about BACKUP and RESTORE operations.

Columns

  • hostname (LowCardinality(String)) — Hostname of the server executing the query.
  • event_date (Date) — Date of the entry.
  • event_time (DateTime) — Time of the entry.
  • event_time_microseconds (DateTime64(6)) — Time of the entry with microseconds precision.
  • id (String) — Identifier of the backup or restore operation.
  • name (String) — Name of the backup storage (the contents of the FROM or TO clause).
  • base_backup_name (String) — The name of base backup in case incremental one.
  • query_id (String) — The ID of a query associated with a backup operation.
  • status (Enum8(‘CREATING_BACKUP’ = 0, ‘BACKUP_CREATED’ = 1, ‘BACKUP_FAILED’ = 2, ‘RESTORING’ = 3, ‘RESTORED’ = 4, ‘RESTORE_FAILED’ = 5, ‘BACKUP_CANCELLED’ = 6, ‘RESTORE_CANCELLED’ = 7)) — Operation status.
  • error (String) — Error message of the failed operation (empty string for successful operations).
  • start_time (DateTime64(6)) — Start time of the operation.
  • end_time (DateTime64(6)) — End time of the operation.
  • num_files (UInt64) — Number of files stored in the backup.
  • total_size (UInt64) — Total size of files stored in the backup.
  • num_entries (UInt64) — Number of entries in the backup, i.e. the number of files inside the folder if the backup is stored as a folder, or the number of files inside the archive if the backup is stored as an archive. It is not the same as num_files if it’s an incremental backup or if it contains empty files or duplicates. The following is always true: num_entries ≤ num_files.
  • uncompressed_size (UInt64) — Uncompressed size of the backup.
  • compressed_size (UInt64) — Compressed size of the backup. If the backup is not stored as an archive it equals to uncompressed_size.
  • files_read (UInt64) — Number of files read during the restore operation.
  • bytes_read (UInt64) — Total size of files read during the restore operation.
  • settings (Map(LowCardinality(String), String)) — Backup/restore-specific settings effectively used for this operation (from the SETTINGS clause, including defaults). Sensitive settings are not exposed.
  • engine_settings (Map(LowCardinality(String), String)) — Settings effectively used by the backup engine’s reader/writer (e.g. S3 allow_native_copy). Empty when the operation involves more than one engine that a flat map cannot represent: incremental backups and restores, lightweight snapshot restores, and non-internal ON CLUSTER operations.

Example

BACKUP TABLE test_db.my_table TO Disk('backups_disk', '1.zip')
┌─id───────────────────────────────────┬─status─────────┐
│ e5b74ecb-f6f1-426a-80be-872f90043885 │ BACKUP_CREATED │
└──────────────────────────────────────┴────────────────┘
SELECT hostname, event_date, event_time_microseconds, id, name, status, error, start_time, end_time, num_files, total_size, num_entries, uncompressed_size, compressed_size, files_read, bytes_read FROM system.backup_log WHERE id = 'e5b74ecb-f6f1-426a-80be-872f90043885' ORDER BY event_date, event_time_microseconds \G
Row 1:
──────
hostname:                clickhouse.eu-central1.internal
event_date:              2023-08-19
event_time_microseconds: 2023-08-19 11:05:21.998566
id:                      e5b74ecb-f6f1-426a-80be-872f90043885
name:                    Disk('backups_disk', '1.zip')
status:                  CREATING_BACKUP
error:                   
start_time:              2023-08-19 11:05:21
end_time:                1970-01-01 03:00:00
num_files:               0
total_size:              0
num_entries:             0
uncompressed_size:       0
compressed_size:         0
files_read:              0
bytes_read:              0

Row 2:
──────
hostname:                clickhouse.eu-central1.internal
event_date:              2023-08-19
event_time:              2023-08-19 11:08:56
event_time_microseconds: 2023-08-19 11:08:56.916192
id:                      e5b74ecb-f6f1-426a-80be-872f90043885
name:                    Disk('backups_disk', '1.zip')
status:                  BACKUP_CREATED
error:                   
start_time:              2023-08-19 11:05:21
end_time:                2023-08-19 11:08:56
num_files:               57
total_size:              4290364870
num_entries:             46
uncompressed_size:       4290362365
compressed_size:         3525068304
files_read:              0
bytes_read:              0
RESTORE TABLE test_db.my_table FROM Disk('backups_disk', '1.zip')
┌─id───────────────────────────────────┬─status───┐
│ cdf1f731-52ef-42da-bc65-2e1bfcd4ce90 │ RESTORED │
└──────────────────────────────────────┴──────────┘
SELECT hostname, event_date, event_time_microseconds, id, name, status, error, start_time, end_time, num_files, total_size, num_entries, uncompressed_size, compressed_size, files_read, bytes_read FROM system.backup_log WHERE id = 'cdf1f731-52ef-42da-bc65-2e1bfcd4ce90' ORDER BY event_date, event_time_microseconds \G
Row 1:
──────
hostname:                clickhouse.eu-central1.internal
event_date:              2023-08-19
event_time_microseconds: 2023-08-19 11:09:19.718077
id:                      cdf1f731-52ef-42da-bc65-2e1bfcd4ce90
name:                    Disk('backups_disk', '1.zip')
status:                  RESTORING
error:                   
start_time:              2023-08-19 11:09:19
end_time:                1970-01-01 03:00:00
num_files:               0
total_size:              0
num_entries:             0
uncompressed_size:       0
compressed_size:         0
files_read:              0
bytes_read:              0

Row 2:
──────
hostname:                clickhouse.eu-central1.internal
event_date:              2023-08-19
event_time_microseconds: 2023-08-19 11:09:29.334234
id:                      cdf1f731-52ef-42da-bc65-2e1bfcd4ce90
name:                    Disk('backups_disk', '1.zip')
status:                  RESTORED
error:                   
start_time:              2023-08-19 11:09:19
end_time:                2023-08-19 11:09:29
num_files:               57
total_size:              4290364870
num_entries:             46
uncompressed_size:       4290362365
compressed_size:         4290362365
files_read:              57
bytes_read:              4290364870

This is essentially the same information that is written in the system table system.backups:

SELECT id, name, status, error, start_time, end_time, num_files, total_size, num_entries, uncompressed_size, compressed_size, files_read, bytes_read FROM system.backups ORDER BY start_time
┌─id───────────────────────────────────┬─name──────────────────────────┬─status─────────┬─error─┬──────────start_time─┬────────────end_time─┬─num_files─┬─total_size─┬─num_entries─┬─uncompressed_size─┬─compressed_size─┬─files_read─┬─bytes_read─┐
│ e5b74ecb-f6f1-426a-80be-872f90043885 │ Disk('backups_disk', '1.zip') │ BACKUP_CREATED │       │ 2023-08-19 11:05:21 │ 2023-08-19 11:08:56 │        57 │ 4290364870 │          46 │        4290362365 │      3525068304 │          0 │          0 │
│ cdf1f731-52ef-42da-bc65-2e1bfcd4ce90 │ Disk('backups_disk', '1.zip') │ RESTORED       │       │ 2023-08-19 11:09:19 │ 2023-08-19 11:09:29 │        57 │ 4290364870 │          46 │        4290362365 │      4290362365 │         57 │ 4290364870 │
└──────────────────────────────────────┴───────────────────────────────┴────────────────┴───────┴─────────────────────┴─────────────────────┴───────────┴────────────┴─────────────┴───────────────────┴─────────────────┴────────────┴────────────┘

See Also

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