sys.column_store_dictionaries (Transact-SQL)

Artykuł
02/13/2015

Contains a row for each dictionary used in xVelocity memory optimized columnstore indexes. Dictionaries are used to encode some, but not all data types, therefore not all columns in a columnstore index have dictionaries. A dictionary can exist as a primary dictionary (for all segments) and possibly for other secondary dictionaries used for a subset of the column's segments.

Column name	Data type	Description
hobt_id	bigint	ID of the heap or B-tree index (hobt) for the table that has this columnstore index.
column_id	int	ID of the columnstore column.
dictionary_id	int	Id of the dictionary.
version	int	Version of the dictionary format.
type	int	Dictionary type: 1 – Hash dictionary containing int values 2 – Not used 3 – Hash dictionary containing string values 4 – Hash dictionary containing float values For more information about dictionaries, see Columnstore Indexes.
last_id	int	The last data id in the dictionary.
entry_count	bigint	Number of entries in the dictionary.
on_disc_size	bigint	Size of dictionary in bytes.
partition_id	bigint	Indicates the partition ID. Is unique within a database.

Permissions

All columns require at least VIEW DEFINITION permission on the table. The following columns return null unless the user also has SELECT permission: last_id, entry_count, data_ptr.

The visibility of the metadata in catalog views is limited to securables that a user either owns or on which the user has been granted some permission. For more information, see Metadata Visibility Configuration.