摘要:
A suggested query execution plan is used as a constraint on a guided optimization process such that all execution plans that do not conform to the suggested execution plan are eliminated as possible alternatives. If the guided optimization process successfully generates a resulting execution plan, then the result will conform to the suggested execution plan. If the guided optimization process fails to generate a resulting execution plan, then it may be determined that the suggested execution plan is invalid.
摘要:
A suggested query execution plan is used as a constraint on a guided optimization process such that all execution plans that do not conform to the suggested execution plan are eliminated as possible alternatives. If the guided optimization process successfully generates a resulting execution plan, then the result will conform to the suggested execution plan. If the guided optimization process fails to generate a resulting execution plan, then it may be determined that the suggested execution plan is invalid.
摘要:
A system and method for creation, modification and/or use of plan guide(s) is provided. Plan guide(s) can be employed to optimize the performance of query(ies) when it is not possible and/or desirable to change the text of the query directly. Plan guides can be useful, for example, when a small subset of queries in a database application deployed from a third-party vendor is not performing as expected. Plan guides influence optimization of queries by attaching query hints to them. In accordance with an aspect of the subject invention, a query plan execution system is provided. The system includes an execution component, a query optimizer, and, a plan cache. Plan guides and other associated metadata are stored in a plan guide metadata store.
摘要:
Various embodiments of the present invention enable functions, procedures, and triggers to be written in any of the .NET languages and executed by the RDBMS. User code can access data from the local or other SQL servers using the SQL Programming Model and both the SqlServer or SqlClient implementations respectively. Moreover, to improve upon the previous extensibility mechanism, a set of APIs (commonly known as “the in-process provider” or “inproc provider”) is utilized to provide efficient and easy to use data access while running inproc, a data access API that is an implementation of the ADO.net programming model.
摘要:
Systems and methodologies are provided as part of a computing environment that implements an enhanced tabular data stream (TDS) protocol. Such enhanced TDS protocol can mitigate synchronization inconsistencies between client and servers, improve robustness of the data transfer, facilitate password specification as part of login procedures, and reduce administration overhead. Various headers are provided as part of the data stream protocol, and a versioning scheme is established that facilitates proper communication between servers and clients having different release dates and versions of the TDS protocol.
摘要:
A number of members of a user defined type may be designated as delayable members. During an initial fetch of the type, the type may be returned from the database without the delayable members, thereby preserving valuable bandwidth and reducing the amount of time required to perform the initial fetch. Upon request, selected delayable members may be re-fetched from the database at a later time without returning the other members provided during the initial fetch.
摘要:
A base table is scanned with a delete marker and an insert marker. The delete marker identifies a last change committed to the base table as part of a transaction prior to execution of a statement, and the insert marker identifies a last change committed to base table as part of the transaction during execution of the statement. The results of the delete marker scan are filtered with deletions stored in a delta table, and a delete table is populated with the filtered rows. The results of the insert scan are filtered with insertions stored in the delta table, and an insert table is populated with the filtered rows.
摘要:
A number of members of a user defined type may be designated as delayable members. During an initial fetch of the type, the type may be returned from the database without the delayable members, thereby preserving valuable bandwidth and reducing the amount of time required to perform the initial fetch. Upon request, selected delayable members may be re-fetched from the database at a later time without returning the other members provided during the initial fetch.