| title | description | author | ms.author | ms.date | ms.service | ms.subservice | ms.topic | f1_keywords | helpviewer_keywords | dev_langs | ||||||
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sys.column_store_dictionaries (Transact-SQL) |
sys.column_store_dictionaries (Transact-SQL) |
rwestMSFT |
randolphwest |
06/10/2016 |
sql |
system-objects |
reference |
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|
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[!INCLUDESQL Server 2012 Azure SQL Managed Instance]
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 starting with 1. The first column has ID = 1, the second column has ID = 2, etc. |
| dictionary_id | int | There can be two kinds of dictionaries, global and local, associated with a column segment. A dictionary_id of 0 represents the global dictionary that is shared across all column segments (one for each row group) for that column. |
| 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 Guide. |
| last_id | int | The last data ID in the dictionary. |
| entry_count | bigint | Number of entries in the dictionary. |
| on_disk_size | bigint | Size of dictionary in bytes. |
| partition_id | bigint | Indicates the partition ID. Is unique within a database. |
Requires VIEW DEFINITION permission on the table. The following columns return null unless the user also has SELECT permission: last_id, entry_count, data_ptr.
[!INCLUDEssCatViewPerm] For more information, see Metadata Visibility Configuration.
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