摘要:
An end transaction procedure is optimized for certain database operations. Where a transaction preceding the end transaction procedure includes a step that employs all the access modules in the transaction, a flush of the transaction log is performed during execution of the last step of the transaction. The need to flush the transaction log during the subsequent end transaction procedure is obviated. The end transaction procedure further may check to determine whether the transaction log was previously flushed, rather than always flushing the transaction log. Also, where the access modules involved in a transaction are part of the same cluster, certain broadcast operations of the end transaction procedure may be avoided.
摘要:
A method and apparatus enables remote access of data of a database system. Such access may be performed by a remote device, such as a client computer system. A custom defined data type is assigned to data stored in the database system, the custom data type associates an access restriction to the data. A request for the data may be received over a communication network, such as the Internet or a local area network (LAN). In response to the request, the database system prepares the data for transmission and provides the requested information back over the communication network. The data is accessed using a security restriction defined by the custom data type.
摘要:
A parallel processing architecture for a relational database management system (RDBMS) that supports both a process model operating system and a thread model operating system. The RDBMS is implemented as a shared nothing, single database image utilizing Parallel Database Extensions (PDEs) that insulate the RDBMS from the specifics of the operating system and that provide the necessary techniques for accessing common memory segments.
摘要:
Techniques for extending horizontal partitioning to column partitioning are provided. A database table is partitioned into custom groups of rows and custom groups of columns. Each partitioned column is managed as a series of containers representing all values appearing under the partitioned column. A logical row represents a row of the table logically indicating each column value of a row. Compression, deletion, and insertion within the containers are managed via a control header maintained with each container.
摘要:
A computer-implemented method, apparatus and article of manufacture for performing an automatic error recovery in a database system. Automatic error recovery is performed for a query execution plan, following errors, problems or failures that occur during execution, by automatically or manually deactivating and/or activating components, features or code paths, and then re-submitting the query execution plan for execution in the computer system.
摘要:
A method, apparatus, and article of manufacture for accessing data in a computer system. Compression and decompression functions are associated with a column of the table, in order to perform compression of decimal, numeric or date data stored in the column when the data is inserted or updated in the table, and in order to perform decompression of the data stored in the column when the data is retrieved from the table. The compression function compresses and stores the data in a fixed-length compressed field in the column without a length value, and the fixed-length compressed field has a size that is determined by a range of values for the data stored in the fixed-length compressed field. The decompression function retrieves and decompresses the data from the fixed-length compressed field.
摘要:
A computer-implemented method, apparatus and article of manufacture for performing an automatic error recovery in a database system. Automatic error recovery is performed for a query execution plan, following errors, problems or failures that occur during execution, by automatically or manually deactivating and/or activating components, features or code paths, and then re-submitting the query execution plan for execution in the computer system.
摘要:
A method, apparatus, and article of manufacture for accessing data in a computer system. Compression and decompression functions are associated with a column of the table, in order to perform compression of decimal, numeric or date data stored in the column when the data is inserted or updated in the table, and in order to perform decompression of the data stored in the column when the data is retrieved from the table. The compression function compresses and stores the data in a fixed-length compressed field in the column without a length value, and the fixed-length compressed field has a size that is determined by a range of values for the data stored in the fixed-length compressed field. The decompression function retrieves and decompresses the data from the fixed-length compressed field.
摘要:
Techniques for finding a column with column partitioning are provided. Metadata for a container row is expanded to include information for searching ranges of partitioned column values. The metadata identifies offsets to specific ranges and specific columns within a specific range. The offsets also identify where compressed data for a desired column resides. Thereby, permitting partitioned columns having compressed data to be located without being decompressed and decompressed on demand as needed.
摘要:
Techniques for processing operations on column partitions of a table in a database are provided. A table includes a control column partition. Each delete container of the control column partition representing multiple rows in the table (or a row partition, if any), and each row represented by a bit flag within a bit string. Rows of the table set for deletion have their corresponding bits within a particular delete container set to indicate those rows are deleted.