Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

Locking Granularity and Lock Types

  • Ralf Schenkel
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_834

Synonyms

Locking granularity and lock types

Definition

Databases are usually organized hierarchically, with tablespaces containing tables, which in turn contain records. In multigranularity locking, this organization is exploited for a more efficient lock management by allowing transactions to lock objects of different granularities like tables or records. Thus, instead of locking each record of a table separately, a transaction can lock the complete table. To ensure a correct execution when transactions use different granularities for locking, additional lock modes are introduced to avoid non-serializable executions.

Key Points

Transactions that acquire many locks on small items like records or pages incur a non-negligible performance and memory overhead for managing these locks. Such transactions can benefit from acquiring locks on coarser granules like tables or complete tablespaces, avoiding many fine-grained locks. However, concurrency may be lower due to an increased number of...

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Recommended Reading

  1. 1.
    Gray J, Lorie RA, Putzolu GR, Traiger IL. Granularity of locks in a large shared data base. In: Proceedings of the 1st International Conference on Very Large Data Bases; 1975. p. 428–51.Google Scholar
  2. 2.
    Weikum G, Vossen G. Transactional information systems. San Francisco: Morgan Kaufman; 2002.Google Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Campus II Department IV – Computer Science, Professorship for databases and information systemsUniversity of TrierTrierGermany

Section editors and affiliations

  • Gottfried Vossen
    • 1
  1. 1.Dep. of Inf. SystemsWestf. Wilhelms-UniveristätMünsterGermany