Sap Se

Sybase, Inc.

Other

Amarnadh Sai Eluri

Mihnea Andrei

Vimal Chandran Satheesh

Ivan Schreter

Yanhong Wang

Anupam Mukherjee

Andreas Tonder

Panfeng Zhou

Colin Florendo

Robert Schulze

Vivek Kandiyanallur

Zheng-Wei She

Thorsten Glebe

Aditya Gurajada

Eunsang Kim

Sarika Iyer

Nikhil Jamadagni

Xu-Dong Qian

Daniel Alan Wood

Vaibhav A Nalawade

Shyam Sunder Reddy Avula

Sasikanth Simhachala Gottapu

Jian Wu

Chirag Samtani

Prateek Basavapur Swamy

System, method, and various embodiments for providing a data access and recommendation system are described herein. An embodiment operates by identifying a column access of one or more data values of a first column of a plurality of columns of a table of a database during a sampling period. A count of how many of the one or more data values are accessed during the column access are recorded. A first counter is incremented by the count. The sampling period is determined to have expired. A load recommendation on how to load data values into the first column based on the first counter is computed. The load recommendation for implementation into the database for one or more subsequent column accesses is provided.

Data access and recommendation system

Disclosed herein are system, method, and computer program product embodiments for managing timestamp information in memory systems. In an embodiment, an infrastructure may utilize a controller to manage sparse timestamp blocks. These sparse timestamp blocks may manage timestamp information in a persistent memory structure. Controllermay utilize a transient timestamp accessor to map the timestamp information for faster hash lookups. Controllermay also utilize a garbage collection map as a bitmap to further save processing steps. Controllermay utilize the sparse timestamp blocks, transient timestamp accessor, and garbage collection map to efficiently store timestamp data and to quickly retrieve the stored timestamp data.

Sparse infrastructure for tracking ad-hoc operation timestamps

System, method, and various embodiments for providing a data access and recommendation system are described herein. An embodiment operates by identifying a column access of one or more data values of a first column of a plurality of columns of a table of a database during a sampling period. A count of how many of the one or more data values are accessed during the column access are recorded. A first counter, corresponding to the first column and stored in a distributed hash table, is incremented by the count. The sampling period is determined to have expired. A load recommendation on how to load data values into the first column based on the first counter is computed. The load recommendation for implementation into the database for one or more subsequent column accesses is provided.

Disclosed herein are systems, methods, and devices for providing load unit recommendations. An example method includes monitoring queries executed by a database management system including a database object, determining an access frequency of the database object based upon the monitoring, and determining relative access counter information for the database object based on the access frequency. Subsequently, the method includes generating a sorted element based on the relative access counter information, determining threshold values based on threshold information and the sorted element, and determining a load unit for the database object based on the sorted element and the threshold values. The load unit indicates whether to load the whole database object, or only a portion thereof, into a main memory of the DBMS while accessing the database object.

Column loadable and page loadable load unit recommendation system

In one aspect, there is provided a method. The method may include accessing a multi-version concurrency control block providing row state for a block of rows in a table of a database, the multi-version concurrency control block including a header portion and a data portion, the header portion including a type indicator indicating whether all of the rows of the block are visible to a plurality of threads at a database management system or invisible to the plurality of threads at the database management system. Related systems, methods, and articles of manufacture are also disclosed.

Compressed row state information

A method may include iterating through at least a portion of a table stored in a database by identifying a timestamp block associated with a range of rows forming the portion of the table. In response to determining that the timestamp block is a sparse timestamp block storing timestamps associated with only some of the rows in the first range of rows, generating a bitmap. Each of the binary values in the bitmap may correspond one of the rows in the range of rows. Moreover, each of the binary values in the bitmap may indicate whether the timestamp block includes a timestamp associated with a corresponding row from the range of rows. Iterating through the range of rows may include accessing, based on the bitmap, the timestamp block to read or write timestamps of transaction affecting the rows in the range of rows.

Timestamp block iterator

A method may include performing a transaction on a row in a table stored in a database. In response to performing the transaction, a first timestamp block associated with a range of rows including the row may be retrieved. In response to determining that the first timestamp block is a sparse timestamp block that has reached maximum capacity, a second timestamp block may be allocated for storing the timestamp associated with the transaction. The sparse timestamp block may be allocated with sufficient storage space for storing some but not all of the timestamps associated with the range of rows. By contrast, the second timestamp block may be a dense timestamp block allocated with sufficient storage space for storing all of the timestamps associated with the range of rows. The timestamp associated with the transaction may be stored in the second timestamp block.

Adaptive timestamp access controller

Embodiments include a method, apparatus and computer program product for providing access to a database data source during database maintenance. The method includes initiating maintenance of the database data source and managing the database maintenance to allow concurrent access to the database data source.

Multiphase approach to data availability

An operation on a row of a table of a database is initiated. Thereafter, a multi-version concurrency control (MVCC) object is accessed to identify blocks associated with the row position of the row using bitwise operations. Subsequently, a row state block computed based on the row position of the row is accessed to determine a row state for the row. At least one other block is accessed, based in part on the row state, to obtain at least one timestamp from the computed offset based on the row. Next, the at least one timestamp is stored or retrieved. Related apparatus, systems, techniques and articles are also described.

Database lockless index for accessing multi-version concurrency control data

Disclosed herein are system, method, and computer program product embodiments for performing garbage collection on a multi-version concurrency control information in the database management system. An embodiment operates by determining, using multi-version concurrency control (MVCC) information, when a row manipulated by a write transaction is visible to a plurality of readers accessing a table that includes the row. The MVCC information for the row includes at least a creation timestamp, a destruction timestamp and a row state. Once the row is visible to the plurality of readers, garbage collecting at least the creation timestamp or the destruction timestamp in the MVCC information. After the creation timestamp or destruction timestamp have been garbage collected, the plurality of readers use the row state to determine accessibility of the row in the table.

Garbage collection of versions driving the garbage collection of multi-version concurrency control timestamps

Lockless allocation of a block from a page is initiated by computing a needed block size from an original block header value. Thereafter, a currently used block size and a capacity of the page are determined. A new block size is then computed based on the currently used block size and the needed block size and a remaining capacity of the page. A new block header value is subsequently generated that includes the determined new block size and the determined remaining capacity of the page The original block header value is then replaced with the new block header value. Related apparatus, systems, techniques and articles are also described.

Efficient block-level space allocation for multi-version concurrency control data

In some example embodiments, a method comprises: receiving, by a first node of a plurality of nodes in a distributed database system on a shared disk cluster infrastructure, a transaction request to perform a user database transaction a data item in a user database on a shared disk; acquiring, by the first node, a transaction lock for the data item; storing a lock file for the user database transaction in a lock information database on the shared disk, the lock file comprising lock information for the transaction lock and an indication of a status of the user database transaction, and the lock information comprising an identification of a location of the data item; and storing a transaction record of the user database transaction in the user database on the shared disk subsequent to the storing of the lock file in the lock information database on the shared disk.

System and method of failover recovery

Disclosed herein are system, method, and computer program product embodiments for performing garbage collection in a database management system with a multi-version concurrency control. An embodiment operate by qualifying a multi-version concurrency control (MVCC) block for garbage collection, where the MVCC block includes multiple cells, each cell corresponding to a row of a table that was acted on by a transaction. Determining that the MVCC block can be garbage collected based on MVCC information in the MVCC block, where the MVCC information includes information that determines whether changes made to rows in the multiple cells are visible in a database management system. Based on the determining, garbage collecting the MVCC block.

Garbage collection of multi-version concurrency control (MVCC) data blocks

System, method, computer program product embodiments and combinations and sub-combinations thereof for managing data storage as an in-memory database in a database management system (DBMS) are provided. In an embodiment, a specialized database type is provided as a parameter of a native DBMS command. A database hosted entirely in-memory of the DBMS is formed when the specialized database type is specified.

Growing community of inventors

Pleasanton, CA, United States of America

Amarnadh Sai Eluri