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system.detached_parts

Description​

Contains information about detached parts of MergeTree tables. The reason column specifies why the part was detached.

For user-detached parts, the reason is empty. Such parts can be attached with ALTER TABLE ATTACH PARTITION|PART command.

For the description of other columns, see system.parts.

If part name is invalid, values of some columns may be NULL. Such parts can be deleted with ALTER TABLE DROP DETACHED PART.

Columns​

  • database (String) — The name of the database this part belongs to.
  • table (String) — The name of the table this part belongs to.
  • partition_id (Nullable(String)) — The identifier of the partition this part belongs to.
  • name (String) — The name of the part.
  • bytes_on_disk (UInt64) — Total size of all the data part files in bytes.
  • modification_time (DateTime) — The time the directory with the data part was modified. This usually corresponds to the time when detach happened.
  • disk (String) — The name of the disk that stores this data part.
  • path (String) — The path of the disk to the file of this data part.
  • reason (Nullable(String)) — The explanation why this part was detached.
  • min_block_number (Nullable(Int64)) — The minimum number of data parts that make up the current part after merging.
  • max_block_number (Nullable(Int64)) — The maximum number of data parts that make up the current part after merging.
  • level (Nullable(UInt32)) — Depth of the merge tree. Zero means that the current part was created by insert rather than by merging other parts.