Contains information about parts of MergeTree tables.
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_partsettings 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
marksby 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.
secondary_indices_compressed_bytes(UInt64) – Total size of compressed data for secondary indices in the data part. All the auxiliary files (for example, files with marks) are not included.
secondary_indices_uncompressed_bytes(UInt64) – Total size of uncompressed data for secondary indices in the data part. All the auxiliary files (for example, files with marks) are not included.
secondary_indices_marks_bytes(UInt64) – The size of the file with marks for secondary indices.
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.
min_time(DateTime) – The minimum value of the date and time key in the data part.
max_time(DateTime) – The maximum value of the date and time 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.
path(String) – Absolute path to the folder with data part files.
disk_name(String) – Name of a disk that stores the data part.
move_ttl_info.expression array is kept mostly for backward compatibility, now the simpliest way to check
TTL MOVE rule is to use the
bytes(UInt64) – Alias for
marks_size(UInt64) – Alias for
SELECT * FROM system.parts LIMIT 1 FORMAT Vertical;
modification_time: 2020-06-18 13:01:49
remove_time: 1970-01-01 00:00:00
min_time: 1970-01-01 00:00:00
max_time: 1970-01-01 00:00:00
delete_ttl_info_min: 1970-01-01 00:00:00
delete_ttl_info_max: 1970-01-01 00:00:00