What do you mean by multi granularity?

Now Multiple Granularity means hierarchically breaking up the database into blocks that can be locked and can be tracked needs what needs to lock and in what fashion. Such a hierarchy can be represented graphically as a tree.

What is multiple granularity locking in DBMS?

In computer science, multiple granularity locking (MGL) is a locking method used in database management systems (DBMS) and relational databases. In multiple granularity locking, locks are set on objects that contain other objects. This can be thought of as a tree of objects, where each node contains its children.

What is database granularity?

Granularity is the level of detail at which data are stored in a database. When the same data are represented in multiple databases, the granularity may differ.

What are the different levels of lock granularity?

Each MySQL storage engine supports different levels of granularity for their locks. MySQL has three lock levels: row-level locking, page-level locking and table-level locking.

How is concurrency performed?

It uses system time to determine the time stamp of the transaction. This is the most commonly used concurrency protocol. Lock-based protocols help you to manage the order between the conflicting transactions when they will execute. Timestamp-based protocols manage conflicts as soon as an operation is created.

What is data granularity in data warehouse?

In a data warehouse, data granularity is the level of detail in a model or decision making process. It tells you how detailed your data is: Lower levels of detail equal finer, more detailed, data granularity (Ponniah, 2004; Bellahsène, 2008).

What is lock granularity in DBMS?

The granularity of locks in a database refers to how much of the data is locked at one time. Such extremes affect the concurrency (number of users that can access the data) and locking overhead (amount of work to process lock requests) in the server. Adaptive Server supports locking at the table, page, and row level.

What is granularity with example?

The granularity of data refers to the size in which data fields are sub-divided. For example, a postal address can be recorded, with coarse granularity, as a single field: address = 200 2nd Ave.

What are the levels of granularity?

Granularity refers to “the level of detail or summarisation of the units of data in the data warehouse”. The low level of granularity contains high level of detail and the high level of granularity contains low level of detail.

Why lock granularity is required?

Here, space refers to data structure in DBMS for each lock and time refers to handling of lock request and release. If a transaction typically accesses many records of the same file it is better to have block or file granularity so that the transaction will consider all those records as one data item.

How many levels of locking are available?

Levels of Locks: Oracle provides the following three levels of Locking.