摘要:
Techniques are provided for processing, within a database server, a database statement, where at least one subtask required by the database statement is to be executed in parallel by a slave set. The database server determines whether the database statement includes an external expression, relative to the subtask, that (a) produces information that is required by slave processes in the slave set in order to perform the subtask, and (b) is not to be evaluated by each slave process in the slave set. During execution of the statement, if the database statement includes an external expression, then one or more external values are generated by causing the external expression to be evaluated, and the one or more external values are communicated to slaves of the slave set to allow the slave processes to perform respective portions of the subtask in parallel, without requiring each slave of the slave set to evaluate the external expression.
摘要:
Techniques are provided for processing, within a database server, a database statement, where at least one subtask required by the database statement is to be executed in parallel by a slave set. The database server determines whether the database statement includes an external expression, relative to the subtask, that (a) produces information that is required by slave processes in the slave set in order to perform the subtask, and (b) is not to be evaluated by each slave process in the slave set. During execution of the statement, if the database statement includes an external expression, then one or more external values are generated by causing the external expression to be evaluated, and the one or more external values are communicated to slaves of the slave set to allow the slave processes to perform respective portions of the subtask in parallel, without requiring each slave of the slave set to evaluate the external expression.
摘要:
Techniques are provided for processing a database statement that includes a table function capable of parallel execution, where the input of the table function is specified in a subquery. During compilation of the database statement, a global cursor is generated for the database statement. The global cursor includes a first plan component for executing the table function and a second plan component for generating input for the table function. A “dummy” cursor is then generated. When slaves execute the table function, they call the dummy cursor for input. When a slave calls the dummy cursor for input, the dummy cursor causes a context switch back to the global cursor, so that the second plan component within the first cursor generates the input for the slave.
摘要:
Techniques are provided for processing a database statement that includes a table function capable of parallel execution, where the input of the table function is specified in a subquery. During compilation of the database statement, a global cursor is generated for the database statement. The global cursor includes a first plan component for executing the table function and a second plan component for generating input for the table function. A “dummy” cursor is then generated. When slaves execute the table function, they call the dummy cursor for input. When a slave calls the dummy cursor for input, the dummy cursor causes a context switch back to the global cursor, so that the second plan component within the first cursor generates the input for the slave.
摘要:
Embodiments are directed to declaratively managing software applications, dynamically applying configuration changes to a specified software application based on a service level objective (SLO) and to efficiently performing an impact analysis for a specified service level agreement SLO.
摘要:
A cache region can be created in a cache in response to receiving a cache region creation request from an application. A storage request from the application can identify the cache region and one or more objects to be stored in the cache region. Those objects can be stored in the cache region in response to receiving the storage request.
摘要:
Systems and methods that provide for a canonical representation in a structured form of a query, against a data model platform. A parser component can parse the SQL query to generate the abstract class that represent the query (command tree). Moreover, a view generation component can supply a mapping between a rich structure (e.g., on the client side) and the relational side. Accordingly, a query can be represented by an abstract class in form of a tree structure with nodes, which has metadata tied therewith.
摘要:
Systems and methods that track changes in a database via a change tracking layer that enables separation of change tracking and change enumeration. Such an arrangement enables multiple change enumeration and sync technologies over a single change tracking layer, while reducing amount of tracking information that are maintained.
摘要:
Methods and apparatus for efficiently storing data in a variable array (VARRAY) of a database system are disclosed. A method for storing data in a VARRAY having an associated large object segment in a system having a memory and a kernel includes determining a size of data to be inserted into the VARRAY. The method also includes determining when the size of the data is less than a threshold value, and storing the data as inline raw data in a column of the VARRAY that is present in the memory when the size of the data is less than the threshold value. When the size of the data is not less than the threshold value, the data is stored in a large object that is associated with the VARRAY. Further, when a VARRAY type is evolved to have a larger maximum size, existing data is not migrated or transformed.
摘要:
Techniques for replicating a database object of a relational database managed by a database system from a first node on a network to a second node on the network include determining that the database object on the first node includes a user-defined object. A first routine of the database system is invoked. The first routine performs the step of copying the database object to the second node of the network. The first routine copies a name of a user-defined defined type of the user-defined object from the first node to the second node. The first routine also copies a first definition of the user-defined type from the first node to the second node. The first routine then copies a second definition of the database object from the first node to the second node. The second definition includes the name of the user-defined type. These techniques provide the benefits of peer-to-peer replication in a distributed database to users of object-relational databases that including user-defined objects.