sys.column_store_dictionaries (Transact-SQL)
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.
See Also
Reference
Object Catalog Views (Transact-SQL)
sys.all_columns (Transact-SQL)
sys.computed_columns (Transact-SQL)
sys.column_store_segments (Transact-SQL)