USELESS ACTIONS MAKE A DIFFERENCE: STRICT SERIALIZABILITY OF DATABASE UPDATES.

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13 Scopus citations

Abstract

When several transactions read and write items in a database, the question of consistency of the database arises. Consistency is maintained if transactions are serial: the read and write actions of a transaction execute completely before the actions of the next transaction begin. A particular history of interleaved read and write actions belonging to several transactions is correct if it is equivalent to a serial history. Since serializability of histories is known to be NP-complete, subclasses of serializable histories have been studied. One such class consists of histories serializable in a strict sense; transactions that are already in serial in a history must remain in the same relative order. When there are no useless actions in a history, it is shown that strict serializability can be determined in polynomial time. If useless actions are permitted, then strict serializability becomes NP-complete. The results apply to two-step transactions in which there is a read step followed by a write step. Each step involves some subset of the items in the database. With multistep transactions strict serializability is NP-complete even if there are no useless actions.

Original languageEnglish (US)
Pages (from-to)394-403
Number of pages10
JournalJournal of the ACM
Volume29
Issue number2
DOIs
Publication statusPublished - Apr 1982
Externally publishedYes

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ASJC Scopus subject areas

  • Computational Theory and Mathematics
  • Computer Graphics and Computer-Aided Design
  • Hardware and Architecture
  • Information Systems
  • Software
  • Theoretical Computer Science

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