摘要:
Techniques are provided for efficiently collecting statistics for hierarchically-organized collections of data. A database system leverages container-level modification time stamps and stored subtree-level change information to gather statistical information from only those resources in a hierarchical collection for which the statistics have changed since the last time that statistics were gathered for the collection. A lockless data structure is also described for storing the subtree-level change information in which an identifier corresponding to each subtree in a collection containing a changed resource may be stored. This data structure may be a table that is distinct from one or more tables representing the collection. In one embodiment of the invention, the immediate parent resource of a particular modified resource may be omitted from the subtree table by leveraging modification time stamps while gathering statistics based on tracked subtree-level information.
摘要:
Techniques are provided to achieve performance improvements for path-based access to hierarchical data and for utilizing an extensible indexing framework. Extensible operators may be optimized by evaluating the operators using functions native to the database system instead of using functions defined through an extensible indexing mechanism. Furthermore, the database system may resolve a resource path of a query when the query is compiled, and may store the mapping of the resource path to one or more resources in a cursor for the query execution plan to avoid resolving the resource path each time the cursor is used to run the query. The cursor may be made dependent on the one or more resources to which the resource path refers at compile time. This takes advantage of the observation that the mapping of the resource path to particular resources rarely changes between evaluations of a particular query.
摘要:
Techniques are provided to achieve performance improvements for path-based access to hierarchical data and for utilizing an extensible indexing framework. Extensible operators may be optimized by evaluating the operators using functions native to the database system instead of using functions defined through an extensible indexing mechanism. Furthermore, the database system may resolve a resource path of a query when the query is compiled, and may store the mapping of the resource path to one or more resources in a cursor for the query execution plan to avoid resolving the resource path each time the cursor is used to run the query. The cursor may be made dependent on the one or more resources to which the resource path refers at compile time. This takes advantage of the observation that the mapping of the resource path to particular resources rarely changes between evaluations of a particular query.
摘要:
Techniques are provided to achieve performance improvements for path-based access to hierarchical data and for utilizing an extensible indexing framework. Extensible operators may be optimized by evaluating the operators using functions native to the database system instead of using functions defined through an extensible indexing mechanism. Furthermore, the database system may resolve a resource path of a query when the query is compiled, and may store the mapping of the resource path to one or more resources in a cursor for the query execution plan to avoid resolving the resource path each time the cursor is used to run the query. The cursor may be made dependent on the one or more resources to which the resource path refers at compile time. This takes advantage of the observation that the mapping of the resource path to particular resources rarely changes between evaluations of a particular query.
摘要:
Techniques are provided to achieve performance improvements for path-based access to hierarchical data and for utilizing an extensible indexing framework. Extensible operators may be optimized by evaluating the operators using functions native to the database system instead of using functions defined through an extensible indexing mechanism. Furthermore, the database system may resolve a resource path of a query when the query is compiled, and may store the mapping of the resource path to one or more resources in a cursor for the query execution plan to avoid resolving the resource path each time the cursor is used to run the query. The cursor may be made dependent on the one or more resources to which the resource path refers at compile time. This takes advantage of the observation that the mapping of the resource path to particular resources rarely changes between evaluations of a particular query.
摘要:
Techniques for implementing fast loading of binary XML into a binary XML database repository are provided. A client application reduces the processing burden on the repository by doing pre-processing of the binary XML data prior to loading.
摘要:
Techniques for implementing fast loading of binary XML into a binary XML database repository are provided. A client application reduces the processing burden on the repository by doing pre-processing of the binary XML data prior to loading.
摘要:
Techniques are provided for efficiently collecting statistics for hierarchically-organized collections of data. A database system leverages container-level modification time stamps and stored subtree-level change information to gather statistical information from only those resources in a hierarchical collection for which the statistics have changed since the last time that statistics were gathered for the collection. A lockless data structure is also described for storing the subtree-level change information in which an identifier corresponding to each subtree in a collection containing a changed resource may be stored. This data structure may be a table that is distinct from one or more tables representing the collection. In one embodiment of the invention, the immediate parent resource of a particular modified resource may be omitted from the subtree table by leveraging modification time stamps while gathering statistics based on tracked subtree-level information.
摘要:
In a multi-tier data server system, data from the first tier is cached in a mid-tier cache of the middle tier. Access control information from the first tier for the data is also cached within the mid-tier cache. Caching the security information in the middle tier allows the middle tier to make access control decisions regarding requests for data made by clients in the outer tier.
摘要:
A method and apparatus for performing an action in response to a file system event is provided. According to one aspect, sets of “event listeners” are associated with a file hierarchy and/or the nodes thereof. Each event listener contains a set of “event handlers.” Each event handler corresponds to a separate type of event that may occur relative to the file hierarchy's nodes. When an event is going to occur relative to the hierarchy or a node thereof, all event listeners that are associated with that hierarchy/node are inspected to determine whether those event listeners contain any event handlers that correspond to the event's type. Those event handlers that correspond to the event's type are placed in an ordered list of event handlers to be invoked. As the event handlers in the list are invoked, programmatic mechanisms that correspond to those event handlers are executed to perform customized user-specified actions.