SQLITE_BUSY_SNAPSHOT

The SQLITE_BUSY_SNAPSHOT error code is an extended error code for SQLITE_BUSY that occurs on WAL mode databases when a database connection tries to promote a read transaction into a write transaction but finds that another database connection has already written to the database and thus invalidated prior reads.

The following scenario illustrates how an SQLITE_BUSY_SNAPSHOT error might arise: Process A starts a read transaction on the database and does one or more SELECT statements. Process A keeps the transaction open. Process B updates the database, changing values previous read by process A. Process A now tries to write to the database. But process A's view of the database content is now obsolete because process B has modified the database file after process A read from it. Hence process A gets an SQLITE_BUSY_SNAPSHOT error.