Each row describes one data part.
YYYYMMfor automatic partitioning by month.
any_stringwhen partitioning manually.
name (String) — Name of the data part.
part_type (String) — The data part storing format.
Wide— Each column is stored in a separate file in a filesystem.
Compact— All columns are stored in one file in a filesystem.
Data storing format is controlled by the
min_rows_for_wide_part settings of the MergeTree table.
active (UInt8) — Flag that indicates whether the data part is active. If a data part is active, it’s used in a table. Otherwise, it’s deleted. Inactive data parts remain after merging.
marks (UInt64) — The number of marks. To get the approximate number of rows in a data part, multiply
marks by the index granularity (usually 8192) (this hint does not work for adaptive granularity).
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.
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 of the date key in the data part.
max_date (Date) — The maximum value of the date key in the data part.
partition_id (String) — ID of the partition.
min_block_number (UInt64) — The minimum number of data parts that make up the current part after merging.
max_block_number (UInt64) — 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
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 (
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.
bytes (UInt64) — Alias for
marks_size (UInt64) — Alias for
SELECT * FROM system.parts_columns LIMIT 1 FORMAT Vertical;
Row 1: ────── partition: tuple() name: all_1_2_1 part_type: Wide active: 1 marks: 2 rows: 2 bytes_on_disk: 155 data_compressed_bytes: 56 data_uncompressed_bytes: 4 marks_bytes: 96 modification_time: 2020-09-23 10:13:36 remove_time: 2106-02-07 06:28:15 refcount: 1 min_date: 1970-01-01 max_date: 1970-01-01 partition_id: all min_block_number: 1 max_block_number: 2 level: 1 data_version: 1 primary_key_bytes_in_memory: 2 primary_key_bytes_in_memory_allocated: 64 database: default table: 53r93yleapyears engine: MergeTree disk_name: default path: /var/lib/clickhouse/data/default/53r93yleapyears/all_1_2_1/ column: id type: Int8 column_position: 1 default_kind: default_expression: column_bytes_on_disk: 76 column_data_compressed_bytes: 28 column_data_uncompressed_bytes: 2 column_marks_bytes: 48
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