sqlite3_initialize(), sqlite3_shutdown(), sqlite3_os_init(), sqlite3_os_end()

 ... The sqlite3_shutdown() interface must only be called from a single thread. All open database connections must be closed and all other SQLite resources must be deallocated prior to invoking sqlite3_shutdown(). Among other things, sqlite3_initialize() will invoke sqlite3_os_init(). Similarly, sqlite3_shutdown() will ... 

sqlite3_syscall_ptr(), struct sqlite3_vfs

 ... The sqlite3_vfs_register() and sqlite3_vfs_unregister() interfaces manage this list in a thread-safe way. The sqlite3_vfs_find() interface searches the list. Neither the application code nor the VFS implementation should use the pNext pointer. The pNext field is the only field in ... 

4. Typical Usage Of Core Routines And Objects  ... Sometimes a multi-threaded application will create separate database connections for each thread. Note that a single database connection can access two or more databases using the ATTACH SQL command, so it is not necessary to have a separate database ... 

2.3. Performance Considerations  ... If an application therefore runs checkpoint in a separate thread or process, the main thread or process that is doing database queries and updates will never block on a sync operation. This helps to prevent "latch-up" in applications running ... 

 ... Or it could be the case that the same database connection is being used by two or more threads at the same moment in time. For all versions of SQLite up to and including 3.6.23.1, a call ... 

sqlite3_value_blob(), sqlite3_value_double(), sqlite3_value_int(), sqlite3_value_int64(), sqlite3_value_pointer(), sqlite3_value_text ... 

 ... These routines must be called from the same thread as the SQL function that supplied the sqlite3_value* parameters. As long as the input parameter is correct, these routines can only fail if an out-of-memory error occurs during a ... 

3. Recovery  ... Recovery is run by the first thread to connect to a WAL-mode database. Recovery restores the WAL-index so that it accurately describes the WAL file. If there is no WAL file present when the first thread connects to ... 

 ... This is true regardless of whether the two database connections are in the same thread, in different threads of the same process, or in different processes. This is the usual and expected behavior for SQL database systems. The previous paragraph ... 

sqlite3_unlock_notify()

 ... If sqlite3_unlock_notify() is called in a multi-threaded application, there is a chance that the blocking connection will have already concluded its transaction by the time sqlite3_unlock_notify() is invoked. If this happens, then the specified callback is invoked immediately, from ... 

PRAGMA threads PRAGMA threads; PRAGMA threads = N; Query or change the value of the sqlite3_limit(db,SQLITE_LIMIT_WORKER_THREADS,...) limit for the current database connection. This limit sets an upper bound on the number of auxiliary threads that a prepared statement is allowed to ...