Transaction isolation levels
transactionsIsolation level
Supported
Honored
doesn’t guarantee that lock hints will be honored in queries that access metadata
through catalog views, compatibility views, information schema views, metadata-emitting built-
in functions.
Internally, the SQL Server Database Engine only honors the
isolation level for
metadata access. If a transaction has an isolation level that is, for example,
and
within the transaction, an attempt is made to access metadata by using catalog views or
metadata-emitting built-in functions, those queries will run until they are completed as. However, under snapshot isolation, access to metadata might fail because of
concurrent DDL operations. This is because metadata isn’t versioned. Therefore, accessing the
following under snapshot isolation might fail:
Catalog views
Compatibility views
Information schema views
Metadata-emitting built-in functions
group of stored procedures
Native Client catalog procedures
Dynamic management views and functions
For more information about isolation levels, see
SET TRANSACTION ISOLATION LEVEL.
The following table provides a summary of metadata access under various isolation levels.
No
Not guaranteed
Yes
Yes
No
No
No
No
No
No
Expand table
READ COMMITTEDSERIALIZABLE
READ
COMMITTEDsp_help
READ UNCOMMITTEDREAD COMMITTEDREPEATABLE READSNAPSHOT ISOLATIONSERIALIZABLE