16 Nov 2015
Architecture of a Database System
http://db.cs.berkeley.edu/papers/fntdb07-architecture.pdf
Today’s DBMSs embody decades of academic and industrial research and
intense corporate software development. Database systems were among
the earliest widely deployed online server systems and, as such, have
pioneered design solutions spanning not only data management …
Relational systems serve as the repositories of record behind
nearly all online transactions and most online content management
systems (blogs, wikis, social networks, and the like). In addition to
being important software infrastructure, relational database
systems serve as a well-understood point of reference for new
extensions and revolutions in database systems that may arise in the
future.
2 Process Models
When designing any multi-user server, early decisions need to be made
regarding the execution of concurrent user requests and how these are
mapped to operating system processes or threads.
4.2 Query Rewrite
- View expansion (The rewriter’s main responsibilities)
- Handling views is the rewriter’s main traditional role. For each
view reference that appears in the FROM clause, the rewriter retrieves
the view definition from the catalog manager. It then rewrites the
query to (1) replace that view with the tables and predicates
referenced by the view and (2) substitute any references to that view
with column references to tables in the view. This process is applied
recursively until the query is expressed exclusively over tables and
includes no views. … requires some care in SQL to correctly handle
duplicate elimination, nested queries, NULLs, and other tricky details [68].
reference
- [68] H. Pirahesh, J. M. Hellerstein, and W. Hasan, “Extensible/rule-
based query rewrite optimization in starburst,” in Proceedings of
ACM-SIGMOD International Conference on Management of Data,
pp. 39–48, San Diego, June 1992.