International Business Machines Corporation

Paul C Huffman

Sam Sampson Lightstone

David C Kalmuk

David C Sharpe

Daniel Costante Zilio

Shaorong Liu

Xing Yi Chen

Kathy A McKnight

Douglas James Doole

John E Lumby

A computer-implemented method includes receiving a request to transmit column group data to a target node, the column group data comprising C columns within a column-oriented data table and determining a transmission row count R for transmitting the column group data to the target node. The method may also include transmitting a transmission packet comprising R sequentially-ordered data elements for each of the C columns to the target node. The R data elements for each column may be sequentially retrieved from memory. A corresponding method includes receiving, at a target node, a request to receive the column group data, determining the transmission row count R for receiving the column group data, and receiving a transmission packet comprising R sequentially-ordered data elements for each of the C columns and storing the sequentially-ordered data elements within memory. A corresponding computer system and corresponding computer program products are also disclosed herein.

Data transfers in columnar data systems

A query processing system has a query processor and a data manager. The query processor calls the data manager to carry out data access for a query including a filtering operation. The data manager accesses the data in a set of data and before returning the data, initiates a callback to the query processor to determine if the located data meets the filtering criteria. Where the data does not satisfy the filtering criteria, the data manager seeks additional data in the set of data, without having to return the first located data to the query processor.

Execution of database queries including filtering

The invention provides a method and apparatus including a programming product for a parallel data processing system having a plurality of nodes interconnected by communication paths, in which one or more sets of data present at one or more source nodes of the system is required to be sent on a plurality of communication paths having communication buffers to selected nodes of the database system for processing, a system of communicating the data over the paths between the nodes to avoid deadlocking the processing system, including: accessing data from the one or more source nodes in subsets of the data; sending the subsets of data on a plurality of paths to the selected nodes of the processing system; if a path of the paths intended for the sending of one or more of the subsets of data becomes blocked, suspending the sending of subsets of the data on the path for a predetermined time period; if the blocked path becomes capable of accepting additional data before the predetermined time period has expired, resuming the sending of subsets of data on the path; however, if the predetermined time period expires without the path becoming available, placing one or more subsequent subsets of data intended for the path into an overflow buffer; when the blocked path again becomes free, sending the subsets of data from the overflow buffer on the path to the intended recipient node for processing.

System for internode deadlock avoidance in parallel database system using as overflow buffer a temporary table storage allocated to the parallel database application program being executed

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Lively, Canada

Paul C Huffman