tailieunhanh - High-Performance Parallel Database Processing and Grid Databases- P5

High-Performance Parallel Database Processing and Grid Databases- P5: Parallel databases are database systems that are implemented on parallel computing platforms. Therefore, high-performance query processing focuses on query processing, including database queries and transactions, that makes use of parallelism techniques applied to an underlying parallel computing platform in order to achieve high performance. | 180 Chapter 7 Parallel Indexing the FRI-1 structure. Note that the global index is replicated to the three processors. In the diagram the data pointers are not shown. However one can imagine that each key in the leaf nodes has a data pointer going to the correct record and each record will have threeincoming data pointers. FRI-3 is quite similar to PRI-1 except that the table partitioning for FRI- 3 is not the same as the indexedattribuie. Forexiunple the tablepartitioningir based on the Name field and utexe raoaepertitionino iolicied tire tohexls on Ho ID fielO. However the similarity is ihattheindox toneiyrepünoted anddachoa hOeeecoods will also have n incoming data poiniees whobopttüln nemborofreplication of the index. Figure showsan exampeepp ttd ORR-3. iob aghin hXe eten pointers are not shown in tliCiliaoipni. It is clear from thetxopd iaitnnsniecdised obova . FRI-l sxdFOI-3 Orrt variation 2 is not applicable ioeFRIeteuctmei becaxeeOie indextrhuna replínated. Unlike the other variationo2 NRF2 aoI nRi-il theyesie becaoseihemdex is partitioned and poriof diagiebaiindex on o poOieater froceddat is butltujeon the records located etHor procso . iftiiemOee is fully replicated there will not be any structure like exees loceiedal a proteger camiot bebuilt purely from the recoldsiorotedatOtatprobeerdxxiona. TditeswhydRI-2 dxdstlre exist. INDEX MAINTENANCE In this section we examine the various issues and complexities related to maintaining different parallel index structures. Index maintenance covers insertion and deletion of index nodes. The general steps for index maintenance are as follows Insert delete a record toDe table carriedoutinprocessor px Insert delete anindex eodeto from theiedee ttoegcerried out in proceesor Pi and Update the datnpemierg. In the last step above i it is aninseeiion r ereetron a doiapointeriscroateg from the new index kev tothe now intertedexceed. Ifitieo deletion xpeeetion a deletion of the data pointer .