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system.projection_parts_columns

This table contains information about columns in projection parts for tables of the MergeTree family.

Columns​

  • partition (String) — The partition name.
  • name (String) — Name of the data part.
  • part_type (String) — The data part storing format.
  • parent_name (String) — The name of the source (parent) data part.
  • parent_uuid (UUID) — The UUID of the source (parent) data part.
  • parent_part_type (String) — The source (parent) data part storing format.
  • active (UInt8) — Flag that indicates whether the data part is active
  • marks (UInt64) — The number of marks.
  • rows (UInt64) — The number of rows.
  • bytes_on_disk (UInt64) — Total size of all the data part files in bytes.
  • data_compressed_bytes (UInt64) — Total size of compressed data in the data part. All the auxiliary files (for example, files with marks) are not included.
  • data_uncompressed_bytes (UInt64) — Total size of uncompressed data in the data part. All the auxiliary files (for example, files with marks) are not included.
  • marks_bytes (UInt64) — The size of the file with marks.
  • parent_marks (UInt64) — The number of marks in the source (parent) part.
  • parent_rows (UInt64) — The number of rows in the source (parent) part.
  • parent_bytes_on_disk (UInt64) — Total size of all the source (parent) data part files in bytes.
  • parent_data_compressed_bytes (UInt64) — Total size of compressed data in the source (parent) data part.
  • parent_data_uncompressed_bytes (UInt64) — Total size of uncompressed data in the source (parent) data part.
  • parent_marks_bytes (UInt64) — The size of the file with marks in the source (parent) data part.
  • modification_time (DateTime) — The time the directory with the data part was modified. This usually corresponds to the time of data part creation.
  • remove_time (DateTime) — The time when the data part became inactive.
  • refcount (UInt32) — The number of places where the data part is used. A value greater than 2 indicates that the data part is used in queries or merges.
  • min_date (Date) — The minimum value for the Date column if that is included in the partition key.
  • max_date (Date) — The maximum value for the Date column if that is included in the partition key.
  • min_time (DateTime) — The minimum value for the DateTime column if that is included in the partition key.
  • max_time (DateTime) — The maximum value for the DateTime column if that is included in the partition key.
  • partition_id (String) — ID of the partition.
  • min_block_number (Int64) — The minimum number of data parts that make up the current part after merging.
  • max_block_number (Int64) — The maximum number of data parts that make up the current part after merging.
  • level (UInt32) — Depth of the merge tree. Zero means that the current part was created by insert rather than by merging other parts.
  • data_version (UInt64) — Number that is used to determine which mutations should be applied to the data part (mutations with a version higher than data_version).
  • primary_key_bytes_in_memory (UInt64) — The amount of memory (in bytes) used by primary key values.
  • primary_key_bytes_in_memory_allocated (UInt64) — The amount of memory (in bytes) reserved for primary key values.
  • database (String) — Name of the database.
  • table (String) — Name of the table.
  • engine (String) — Name of the table engine without parameters.
  • disk_name (String) — Name of a disk that stores the data part.
  • path (String) — Absolute path to the folder with data part files.
  • column (String) — Name of the column.
  • type (String) — Column type.
  • column_position (UInt64) — Ordinal position of a column in a table starting with 1.
  • default_kind (String) — Expression type (DEFAULT, MATERIALIZED, ALIAS) for the default value, or an empty string if it is not defined.
  • default_expression (String) — Expression for the default value, or an empty string if it is not defined.
  • column_bytes_on_disk (UInt64) — Total size of the column in bytes.
  • column_data_compressed_bytes (UInt64) — Total size of compressed data in the column, in bytes.
  • column_data_uncompressed_bytes (UInt64) — Total size of the decompressed data in the column, in bytes.
  • column_marks_bytes (UInt64) — The size of the column with marks, in bytes.
  • column_modification_time (Nullable(DateTime)) — The last time the column was modified.