Project: ClickHouse (App Definition and Development / Database)
File: parts.md

slug: /en/operations/system-tables/parts Contains information about parts of tables. Each row describes one data part. Columns: `partition` () The partition name. To learn what a partition is, see the description of the query. Formats: `YYYYMM` for automatic partitioning by month. `any_string` when partitioning manually. `name` () Name of the data part. `part_type` () The data part storing format. Possible Values: `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 `minbytesforwidepart` and `minrowsforwidepart` settings of the table. `active` () Flag that indicates whether the data part is active. If a data part is active, its used in a table. Otherwise, its deleted. Inactive data parts remain after merging. `marks` () 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` () The number of rows. `bytesondisk` () Total size of all the data part files in bytes. `datacompressedbytes` () Total size of compressed data in the data part. All the auxiliary files (for example, files with marks) are not included. `datauncompressedbytes` () Total size of uncompressed data in the data part. All the auxiliary files (for example, files with marks) are not included. `primarykeysize` () The amount of memory (in bytes) used by primary key values in the primary.idx/cidx file on disk. `marks_bytes` () The size of the file with marks. `secondaryindicescompressed_bytes` () Total size of compressed data for secondary indices in the data part. All the auxiliary files (for example, files with marks) are not included. `secondaryindicesuncompressed_bytes` () Total size of uncompressed data for secondary indices in the data part. All the auxiliary files (for example, files with marks) are not included. `secondaryindicesmarks_bytes` () The size of the file with marks for secondary indices. `modification_time` () The time the directory with the data part was modified. This usually corresponds to the time of data part creation. `remove_time` () The time when the data part became inactive. `refcount` () 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` () The minimum value of the date key in the data part. `max_date` () The maximum value of the date key in the data part. `min_time` () The minimum value of the date and time key in the data

`max_time`() The maximum value of the date and time key in the data part. `partition_id` () ID of the partition. `minblocknumber` () The minimum number of data parts that make up the current part after merging. `maxblocknumber` () The maximum number of data parts that make up the current part after merging. `level` () Depth of the merge tree. Zero means that the current part was created by insert rather than by merging other parts. `dataversion` () Number that is used to determine which mutations should be applied to the data part (mutations with a version higher than `dataversion`). `primarykeybytesinmemory` () The amount of memory (in bytes) used by primary key values. `primarykeybytesinmemory_allocated` () The amount of memory (in bytes) reserved for primary key values. `is_frozen` () Flag that shows that a partition data backup exists. 1, the backup exists. 0, the backup does not exist. For more details, see `database` () Name of the database. `table` () Name of the table. `engine` () Name of the table engine without parameters. `path` () Absolute path to the folder with data part files. `disk_name` () Name of a disk that stores the data part. `hashofall_files` () of compressed files. `hashofuncompressed_files` () of uncompressed files (files with marks, index file etc.). `uncompressedhashofcompressedfiles` () of data in the compressed files as if they were uncompressed. `deletettlinfo_min` () The minimum value of the date and time key for . `deletettlinfo_max` () The maximum value of the date and time key for . `movettlinfo.expression` (()) Array of expressions. Each expression defines a . :::note The `movettlinfo.expression` array is kept mostly for backward compatibility, now the simplest way to check `TTL MOVE` rule is to use the `movettlinfo.min` and `movettlinfo.max` fields. ::: `movettlinfo.min` (()) Array of date and time values. Each element describes the minimum key value for a . `movettlinfo.max` (()) Array of date and time values. Each element describes the maximum key value for a . `bytes` () Alias for `bytesondisk`. `markssize` () Alias for `marksbytes`. Example ``` sql SELECT * FROM system.parts LIMIT 1 FORMAT Vertical; ``` ``` text Row 1: partition: tuple() name: all1416 part_type: Wide active: 1 marks: 2 rows: 6 bytesondisk: 310 datacompressedbytes: 157 datauncompressedbytes: 91 secondaryindicescompressed_bytes: 58 secondaryindicesuncompressed_bytes: 6 secondaryindicesmarks_bytes: 48 marks_bytes: 144 modification_time: 2020-06-18 13:01:49 remove_time: 1970-01-01 00:00:00 refcount: 1 min_date: 1970-01-01 max_date: 1970-01-01 min_time: 1970-01-01 00:00:00 max_time: 1970-01-01 00:00:00 partition_id: all minblocknumber: 1 maxblocknumber: 4 level: 1 data_version: 6 primarykeybytesinmemory: 8 primarykeybytesinmemory_allocated: 64 is_frozen: 0 database: default table: months engine: MergeTree disk_name: default path: /var/lib/clickhouse/data/default/months/all1416/ hashofall_files: 2d0657a16d9430824d35e327fcbd87bf hashofuncompressed_files: 84950cc30ba867c77a408ae21332ba29 uncompressedhashofcompressedfiles: 1ad78f1c6843bbfb99a2c931abe7df7d deletettlinfo_min: 1970-01-01 00:00:00 deletettlinfo_max: 1970-01-01 00:00:00 movettlinfo.expression: [] movettlinfo.min: [] movettlinfo.max: [] ``` See Also