Concurrency management

Informix® is a multiuser database engine, while SQLite is typically used for a single-user application. SQLite 3 supports multiuser access to the same database file, but it is not designed for large multiuser applications.

SQLite 3 supports two isolation levels: SERIALIZABLE (the default), and READ UNCOMMITTED. The isolation level can be changed with the PRAGMA command.

By default in the SERIALIZABLE isolation level, SQLite will raise an SQL error if a program tries to access a database resource in use by another program. To avoid the SQL error and force programs to wait for each other, programs define the behavior when the SQLite database is busy (SQLITE_BUSY), with a specific API call. No SQL command exists for this.


We recommend that you use SQLite for single-user DB applications. If several programs must access the same SQLite database, each program must perform a SET LOCK MODE TO WAIT instruction after the connection: SET LOCK MODE will be mapped to a call to the sqlite3_busy_timeout() SQLite API function to get the same behavior as Informix, while SET ISOLATION instructions will be ignored.