system.projection_parts

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Description

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Columns

• partition (String) — The partition name.
• name (String) — Name of the data part.
• part_type (String) — The data part storing format. Possible Values: Wide (a file per column) and Compact (a single file for all columns).
• 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. If a data part is active, it’s used in a table. Otherwise, it’s about to be deleted. Inactive data parts appear after merging and mutating operations.
• 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.
• 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 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 (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.
• is_frozen (UInt8) — Flag that shows that a partition data backup exists. 1, the backup exists. 0, the backup does not exist.
• 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.
• hash_of_all_files (String) — sipHash128 of compressed files.
• hash_of_uncompressed_files (String) — sipHash128 of uncompressed files (files with marks, index file etc.).
• uncompressed_hash_of_compressed_files (String) — sipHash128 of data in the compressed files as if they were uncompressed.
• delete_ttl_info_min (DateTime) — The minimum value of the date and time key for TTL DELETE rule.
• delete_ttl_info_max (DateTime) — The maximum value of the date and time key for TTL DELETE rule.
• move_ttl_info.expression (Array(String)) — Array of expressions. Each expression defines a TTL MOVE rule.
• move_ttl_info.min (Array(DateTime)) — Array of date and time values. Each element describes the minimum key value for a TTL MOVE rule.
• move_ttl_info.max (Array(DateTime)) — Array of date and time values. Each element describes the maximum key value for a TTL MOVE rule.
• default_compression_codec (String) — The name of the codec used to compress this data part (in case when there is no explicit codec for columns). UNKNOWN means this codec could not be recovered exactly from the part metadata.
• recompression_ttl_info.expression (Array(String)) — The TTL expression.
• recompression_ttl_info.min (Array(DateTime)) — The minimum value of the calculated TTL expression within this part. Used to understand whether we have at least one row with expired TTL.
• recompression_ttl_info.max (Array(DateTime)) — The maximum value of the calculated TTL expression within this part. Used to understand whether we have all rows with expired TTL.
• group_by_ttl_info.expression (Array(String)) — The TTL expression.
• group_by_ttl_info.min (Array(DateTime)) — The minimum value of the calculated TTL expression within this part. Used to understand whether we have at least one row with expired TTL.
• group_by_ttl_info.max (Array(DateTime)) — The maximum value of the calculated TTL expression within this part. Used to understand whether we have all rows with expired TTL.
• rows_where_ttl_info.expression (Array(String)) — The TTL expression.
• rows_where_ttl_info.min (Array(DateTime)) — The minimum value of the calculated TTL expression within this part. Used to understand whether we have at least one row with expired TTL.
• rows_where_ttl_info.max (Array(DateTime)) — The maximum value of the calculated TTL expression within this part. Used to understand whether we have all rows with expired TTL.
• is_broken (UInt8) — Whether projection part is broken
• exception_code (Int32) — Exception message explaining broken state of the projection part
• exception (String) — Exception code explaining broken state of the projection part

• bytes — Alias for bytes_on_disk.
• marks_size — Alias for marks_bytes.
• part_name — Alias for name.