Jaa

Limitations for Stretch Database

  • Artikkeli

Applies to: SQL Server 2016 (13.x) and later - Windows only

Important

Stretch Database is deprecated in SQL Server 2022 (16.x) and Azure SQL Database. This feature will be removed in a future version of the Database Engine. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.

Learn about limitations for Stretch-enabled tables, and about limitations that currently prevent you from enabling Stretch for a table.

Limitations for Stretch-enabled tables

Stretch-enabled tables have the following limitations.

Constraints

  • Uniqueness isn't enforced for UNIQUE constraints and PRIMARY KEY constraints in the Azure table that contains the migrated data.

DML operations

  • You can't UPDATE or DELETE rows that have been migrated, or rows that are eligible for migration, in a Stretch-enabled table or in a view that includes Stretch-enabled tables.

  • You can't INSERT rows into a Stretch-enabled table on a linked server.

Indexes

  • You can't create an index for a view that includes Stretch-enabled tables.

  • Filters on SQL Server indexes aren't propagated to the remote table.

Limitations that currently prevent you from enabling Stretch for a table

The following items currently prevent you from enabling Stretch for a table.

Table properties

  • Tables that have more than 1,023 columns or more than 998 indexes

  • FileTables or tables that contain FILESTREAM data

  • Tables that are replicated, or that are actively using Change Tracking or Change Data Capture

  • Memory-optimized tables

Data types

  • text, ntext and image
  • timestamp
  • sql_variant
  • xml
  • CLR data types including geometry, geography, hierarchyid, and CLR user-defined types

Column types

  • COLUMN_SET

  • Computed columns

Constraints

  • Default constraints and check constraints

  • Foreign key constraints that reference the table. In a parent-child relationship (for example, Order and Order_Detail), you can enable Stretch for the child table (Order_Detail) but not for the parent table (Order).

Indexes

  • Full text indexes

  • XML indexes

  • Spatial indexes

  • Indexed views that reference the table

See also