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Field | Value |
Title | On efficiently implementing SchemaSQL on a SQL database system |
Names |
LAKSHMANAN, LVS
SADRI, F SUBRAMANIAN, SN |
Date Issued | 1999 (iso8601) |
Abstract | SchemaSQL is a recently proposed extension to SQL for enabling multi-database interoperability. Several recently identified applications for SchemaSQL, however, mainly rely on its ability to treat data and schema labels in a uniform manner, and call for an efficient implementation of it on a single RDBMS. We first develop a logical algebra for SchemaSQL by combining classical relational algebra with four restructuring operators - unfold, fold, split, and unite - originally introduced in the context of the tabular data model by Gyssens et al. [GLS96], and suitably adapted to fit the needs of SchemaSQL. We give an algorithm for translating SchemaSQL queries/views involving restructuring, into the logical algebra above. We also provide physical algebraic operators which are useful for query optimization. Using the various operators as a vehicle, we give several alternate implementation strategies for SchemaSQL queries/views. All the proposed strategies can be implemented non-intrusively on top of existing relational DBMS, in that they do not require any additions to the existing set of plan operators. We conducted a series of performance experiments based on TPC-D benchmark data, using the IBM DB2 DBMS running on Windows/NT. In addition to showing the relative tradeoffs between Various alternate strategies, our experiments show the feasibility of implementing SchemaSQL on top of traditional RDBMS in a non-intrusive manner. Further more, they also suggest new plan operators which might profitably be added to the existing set available to relational query optimizers, to further boost their performance. |
Genre | Proceedings Paper |
Topic | Logic |
Identifier | PROCEEDINGS OF THE TWENTY-FIFTH INTERNATIONAL CONFERENCE ON VERY LARGE DATA BASES,471-482 |