摘要:
A method for performing multiple merge operations with a source data structure and a plurality of destination data structures, in which the source data structure is scanned one time in order to obtain source data that is then used for multiple merge operations. The source data is then used consecutively in order to merge the source data into the one or more destination data structures. Each merge is performed using the same scan of the source data structure and within the same execution of a database command.
摘要:
A method for performing multiple merge operations with a source data structure and a plurality of destination data structures, in which the source data structure is scanned one time in order to obtain source data that is then used for multiple merge operations. The source data is then used consecutively in order to merge the source data into the one or more destination data structures. Each merge is performed using the same scan of the source data structure and within the same execution of a database command.
摘要:
A method for performing multiple merge operations with a source data structure and a plurality of destination data structures, in which the source data structure is scanned one time in order to obtain source data that is then used for multiple merge operations. The source data is then used consecutively in order to merge the source data into the one or more destination data structures. Each merge is performed using the same scan of the source data structure and within the same execution of a database command.
摘要:
A method for performing multiple merge operations with a source data structure and a plurality of destination data structures, in which the source data structure is scanned one time in order to obtain source data that is then used for multiple merge operations. The source data is then used consecutively in order to merge the source data into the one or more destination data structures. Each merge is performed using the same scan of the source data structure and within the same execution of a database command.
摘要:
Techniques are described herein for supporting pipelining operations involving DML (Data manipulation Language) and query. In an embodiment, a DML operation is performed for the purpose of changing data in a database system from a first state to a second state. Before the data in the database system is changed by the DML operation, the DML operation has an in-memory representation of such data. In an embodiment, a subsequent query operation that logically depends on the data in the database system in the second state is granted access to the in-memory representation of such data in the second state before the data in the database system is changed by the DML operation to the second state. As a result, operations may be executed in a pipelined fashion with minimum blocking.
摘要:
Techniques are described herein for supporting pipelining operations involving DML (Data manipulation Language) and query. In an embodiment, a DML operation is performed for the purpose of changing data in a database system from a first state to a second state. Before the data in the database system is changed by the DML operation, the DML operation has an in-memory representation of such data. In an embodiment, a subsequent query operation that logically depends on the data in the database system in the second state is granted access to the in-memory representation of such data in the second state before the data in the database system is changed by the DML operation to the second state. As a result, operations may be executed in a pipelined fashion with minimum blocking.
摘要:
An array update operation which specifies number of (row-identifier, value) pairs for updating rows in a table of a database is implemented as follows. A block-identifier of a block (on disk) that holds a row identified by a row-identifier in a specified pair is looked up using a database index, and the block-identifier thus found is stored in a structure. Use of a row-identifier to look up the corresponding block-identifier, and the storage of the block-identifier in the structure are repeatedly performed, for each of several specified pairs. Next, a vector read is performed, to read and store in a cache, each block identified by a block-identifier in the structure, and all the blocks that have been read are stored in the cache during a single function call. Thereafter, rows identified in specified pairs are modified, in blocks currently in the cache, using the values in the specified pairs.