Using SQLite

Name

locking_mode — Control how a database releases read/write locks

Common Usage

PRAGMA locking_mode;
PRAGMA locking_mode = mode;
PRAGMA database.locking_mode;
PRAGMA database.locking_mode = mode;

Description

The locking_mode pragma controls how database file locks are managed. The mode can either be NORMAL or EXCLUSIVE. In normal mode, the database connection acquires and releases the appropriate locks with each transaction. In exclusive mode, the locks are acquired in the normal fashion, but are not released when a transaction finishes.

Although exclusive locking mode prevents any other database connections from accessing the database, it also provides better performance. This may be an easy trade-off in situations such as some embedded environments, where it is very unlikely that multiple processes will ever attempt to access the same database.

Exclusive locking reduces the start-up cost of a transaction by eliminating the need to acquire the appropriate locks. It also allows SQLite to skip several file reads at the start of each transaction. For example, when SQLite starts a new transaction, it will normally reread the database header to verify that the database schema has not changed. This is not required if the database is in exclusive mode.

Since temporary and in-memory databases cannot be accessed by more than one database connection, they are always in exclusive mode. Any attempt to set these database types to normal mode will silently fail.

The behavior of the locking_mode pragma ...