DeWitt, D.J., "DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems," IEEE Transactions on Computers, June, 1979.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... disk processing in the database machines fell into roughly four categories: processor per head (e.g. OSU s DBC [10] SURE [56] processor per track (e.g. CASSM [97] RAP [72] RARES [59] and CAFS [9] processor per disk (e.g. SURE [56] and multi processor cache (e.g. RAP.2 [88] DIRECT [31], INFOPLEX [62] RDBM [42] and DBMAC [68] In each architecture, a central processor(s) acted as the front end of the system. For the most part, these machines were exceptionally good at pushing simple processing, such as scan operations, closer to the disk, achieving great performance ....

D. J. DeWitt. "DIRECT - A multiprocessor organization for supporting relational database management systems," IEEE Transactions on Computers, pages 395-406, June 1979.

....database. 6 A partition, as defined in [39] is the unit of memory allocation for a system s underlying memory 20 log of activity. Agrawal [1, 2] investigates some alternative solutions to the recovery problem for the multiprocessor cache class of database machines, of which the DIRECT system [14, 8] is an example. He investigates four different distribution policies for determining the log disk to which to send a log record: cyclic, random, Query Processor Number mod Total Log Processors (QPNmTLP) and Transaction Number mod Total Log Processors (TNmTLP) Agrawal concluded that the TNmTLP ....

David J. DeWitt. DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems. IEEE Trans on Computers, C-28(6):395-- 406, June 1979.

....transistors 100 MB s proposed system Table 2 2 Sizes and functionalities of various database machine architectures. The chart shows the size and functionality of several database machine architectures from the original RAP in 1977 to Active Disks today. Data from [Schuster79] Su79] [DeWitt79], DeWitt90] and [Illman96] 11 . that the specialized database machine hardware elements were difficult to program, requiring specialized microcode which was difficult to develop, and . that the simplest database machines, while good for simple scans, did not efficiently support the more ....

....in core sort. This means that a sort operation will require n m 1 revolutions where n is the number of records and m is the size of the front end memory. 8.1. 5 DIRECT The DIRECT machine uses a set of processing elements that are not directly associated with the heads or tracks on the disk [DeWitt79]. Instead, it depends on a full crossbar switch which allows any of the processing elements to process data from any of the storage units. Storage consists of both CCD associative memory and mass storage (disk) elements. The processing elements operate in a MIMD (multiple instruction, multiple ....

DeWitt, D.J. "DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems" IEEE Transactions on Computers 28 (6), June 1979.

....modeled this way if one assumes that the networks they use have sufficient bandwidth for the number of processing nodes they have. 4 Our work therefore builds on the join algorithms already proposed for those machines. See [BR85, H83] for a modern review of database machines and original papers [B79, BDFW83, BO79, D79, GS81, MH81, S79, Schm79, SG75]. For the purposes of this paper any data distribution strategy that partitions a relation roughly evenly based on some subset of its attributes will be satisfactory. The one we use is hash partitioning. To partition a relation R based on attribute A, we use a function h whose domain is the ....

D. J. DeWitt, "DIRECT -- a multiprocessor organization for supporting relational database management systems," IEEE Transactions on Computers, C-28, 6, 1979. Ultracomputer Note 95

....to the above problem is parallel processing. With the advent of multiprocessor machines, there have been several parallel algorithms designed to efficiently utilize this environment in order to achieve enhanced performance. Database machines such as VOLCANO [GT92, Gra94] GAMMA [SD89] DIRECT [DeW79], etc. and general purpose machines such as the hypercube [TOY94] are all very popular choices for database processing. The mesh architecture presents a viable alternative due to its low cost. 1.1 RELATIONAL ALGEBRA DEFINITIONS There are various different data models such as relational data ....

....Bitton in [BBDW83] presents the Nested Join algorithm and the Sort Merge Algorithm. Both these algorithms are analyzed under similar conditions such as size of the relations and the number of processors used for the join. An implementation of the above parallel algorithms was conducted by DeWitt [DeW79]. The results obtained on the database machine DIRECT [DeW79] were very similar to the results obtained in this thesis. A Hash Based Join algorithm is presented by Tien in [OT89] and implemented on a hypercube. The superiority of this algorithm over the more conventional algorithms such as the ....

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D. J. DeWitt. DIRECT - A multiprocessor organization for supporting relational database management systems. IEEE Transaction on Computing, 6:C-28, June 1979.

.... Database machines [46] in the late 1970s proposed various levels of processor integration 4 http: www.emulex.com into disk: processor per track [30, 35, 47, 49] processor per head [10, 29] and off the disk designs that used a shared disk cache with multiple processors and multiple disks [16, 44]. There are several differences between the database machines of late 1970 s and today s Active Disks. Unlike the database machine processors, the processors proposed for Active Disks are general purpose commodity components and are likely to evolve as the disks evolve. Unlike the low bandwidth ....

D. DeWitt. DIRECT - a multiprocessor organization for supporting relational database management systems. IEEE Trans. on Computers, 28(6):395--406, Jun 1979. 5 http://cnls.lanl.gov/avalon/FAQ.html

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DeWitt, D.J., "DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems," IEEE Transactions on Computers, June, 1979.

....to initiate each operator of a query tree and 1 message when the operator terminates, the execution of a query is entirely self scheduling. 1. Introduction While the database machine field has been a very active area of research for the last 10 years, only a handful of research prototypes [OZKA75, LEIL78, DEWI79a, STON79 HELL81, SU82, GARD83, FISH84, KAKU85, DEMU86] and three commercial products [TERA83, UBEL85, IDM85] have ever been built. None have demonstrated that a highly parallel relational database machine can actually be constructed. Of the commercial products the most successful one (the IDM500) does not exploit parallelism in any form. Why is this ....

DeWitt, D.J., "DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems," IEEE Transactions on Computers, June, 1979.

....1 1. Introduction For the last 5 years, the Gamma database machine project has focused on issues associated with the design and implementation of highly parallel database machines. In a number of ways, the design of Gamma is based on what we learned from our earlier database machine DIRECT [DEWI79]. While DIRECT demonstrated that parallelism could be successfully applied to processing database operations, it had a number of serious design deficiencies that made scaling of the architecture to 100s of processors impossible; primarily the use of shared memory and centralized control for the ....

DeWitt, D.J., "DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems," IEEE Transactions on Computers, June, 1979.

....computers. 1 This paper is a first attempt to provide an answer to this question by presenting the results of benchmarks run on three conventional database management systems and two database machines. More specifically we have measured and compared the performance of the database machine DIRECT [DEWI79, BORA82], the Britton Lee IDM 500 database machine with and without a database accelerator (DAC) IDM500, EPST80, UBEL81] the commercial and university versions of the INGRES database system [STON76, STON80] and the ORACLE database system. Since database machines have already been an active field of ....

....have now been implemented, we feel that the time has come for measuring the actual performance enhancement that can be expected from using special purpose hardware and software for database management. When database machines designs such as CASSM [SU75] RAP [OZKA75, OZKA77] DBC [BANE78] DIRECT [DEWI79] were proposed, the future of database machines looked bright. It seemed that both successful research efforts and advances in hardware technology would lead to the widespread use of commercial database machines. However, while most projects appeared promising initially, it is only very recently ....

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DeWitt, D.J., "DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems," IEEE Transactions on Computers, June 1979, pp. 395-406.

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D. J. DeWitt, "DIRECT - A Multiprocessor Organization for Supporting Relational Database Management Systems," IEEE Trans. Computers, C-28(6), June 1979, pp. 395-406.

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