Read/write concurrency can now be enabled in the SQL API by using
PRAGMA multiversion=on before accessing any
tables in the database. After multiversion has been enabled, it
can be temporarily disabled using the
PRAGMA transaction_snapshots=on/off.
For more details on pragmas concerning Transaction Snapshots read Using Multiversion Concurrency Control in the Berkeley DB Getting Started with the SQL APIs guide.
PRAGMA multiversion=ON|OFF;
PRAGMA snapshot_isolation=ON|OFF