Attack on NoSQL

The "NoSQL" Discussion has Nothing to Do With SQL

Философия SQL или причина популярности NoSQL.

Concurrency Control, Transaction Isolation and Serializability in SQL92 and Oracle

Concurrency Control, Transaction Isolation and Serializability in SQL92 and Oracle7 - possibly the main document for citation about Oracle-specific levels of tx-isolation:
+ Oracle Consistent Read
+ Snapshot Isolation

P.S. I found it from this post - Generalized Isolation Level Definitions.
"... and Gemstone [22] and Oracle [24] provide serializability and Snapshot Isolation, respectively, using multi-version optimistic implementations."
"...
[24] Oracle Corporation. Concurrency Control, Transaction Isolation and Serializability in SQL92 and Oracle7, July 1995.
..."

Generalized Isolation Level Definitions

Generalized Isolation Level Definitions.
More recent, more complete, more difficult to follow.

Atul Adya - Microsoft Research
Barbara Liskov - Laboratory for Computer Science, MIT, Cambridge
Patrick O’Neil - Univ. of Massachusetts, Boston

Abstract
Commercial databases support different isolation levels to allow programmers to trade off consistency for a poten tial gain in performance. The isolation levels are defined in the current ANSI standard, but the definitions are ambigu ous and revised definitions proposed to correct the problem are too constrained since they allow only pessimistic (locking) implementations. This paper presents new specifications for the ANSI levels. Our specifications are portable; they apply not only to locking implementations, but also to optimistic and multi-version concurrency control schemes. Furthermore, unlike earlier definitions, our new specifications handle predicates in a correct and flexible manner at all levels.

A Critique of ANSI SQL Isolation Levels

Классика цитирования:
A Critique of ANSI SQL Isolation Levels.
Good, fairly readable discussion of transaction isolation.

Hal Berenson Microsoft Corp.
Phil Bernstein Microsoft Corp.
Jim Gray U.C. Berkeley
Jim Melton Sybase Corp.
Elizabeth O’Neil UMass/Boston
Patrick O'Neil UMass/Boston

Abstract:
ANSI SQL-92 [MS, ANSI] defines Isolation Levels in terms of phenomena: Dirty Reads, Non-Repeatable Reads, and Phantoms. This paper shows that these phenomena and the ANSI SQL definitions fail to properly characterize several popular isolation levels, including the standard locking implementations of the levels covered. Ambiguity in the statement of the phenomena is investigated and a more formal statement is arrived at; in addition new phenomena that better characterize isolation types are introduced. Finally, an important multiversion isolation type, called Snapshot Isolation, is defined.

1 . Introduction
"...which defined Degrees of Consistency in three ways: locking, data-flow graphs, and anomalies."
"The three ANSI phenomena are ambiguous, and even in their loosest interpretations do not exclude some anomalous behavior that may arise in execution histories."
"...lock-based isolation levels have different characteristics than their ANSI equivalents."
"...degrees of consistency defined in 1977 in [GLPT]."
"...Chris Date’s definitions of Cursor Stability..."

devx.com: Go Parallel: Parallel and Multi-Core Articles

    Тут подборка из 9 статей с сайта devx.com в рубрике Go Parallel:
- Writing Parallel Programs with Erlang
- A Developer's Guide to Python 3.0: Standard Library
- Forking and Joining Java to Maximize Multicore Power
- Automatic Full Parallel Processing of Hierarchical SQL Queries
- Parallel and Concurrency Futures for Microsoft Developers
- Lots about Locks
- Plan for the Future: Express Parallelism, Don't Manage It
- Getting Started with the .NET Task Parallel Library: Multi-Core Case Studies
- Getting Started with the .NET Task Parallel Library