Oracle International Corporation

Richard Yu Gu

Ashish Thusoo

Harmeek Singh Bedi

Amit Ganesh

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.

Pipleline merge operations using source data and multiple destination data structures

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.

Pipelining operations involving DML and query

Method and apparatus for performing multi-table merge operations in a database environment

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.

Vector reads for array updates

Technique for using a current lookup for performing multiple merge operations using source data that is modified in between the merge operations

Method and apparatus for performing multiple merge operations using source data that is modified in between the merge operations

Conditional functionality is provided for database merge operations. A merge operation, for merging data from a source to a destination, involves performing a default operation for each source record. Default operations associated with a MERGE statement include UPDATE and INSERT operations. Which default operation is performed depends on whether any destination record corresponds to a given source record. In an embodiment, whether a specified condition is satisfied is determined. If the condition is satisfied, then the default operation that is appropriate for a given source record is performed. If the condition is not satisfied, then the given source record is processed without performing the appropriate default operation. In one aspect, the UPDATE clause of the MERGE statement is extended to include a conditional DELETE clause. Hence, records are deleted as appropriate based on a temporary updated state, as part of the same process as the update operation, without an additional table scan and without having to first update the record in shared memory or in persistent storage.

Growing community of inventors

Mountain View, CA, United States of America

Richard Yu Gu