2.3.2. Operations that require locks and which locks those operations use  ... Transitioning into WAL mode is, therefore, just like any other write transaction, since every write transaction in rollback mode requires the SQLITE_LOCK_EXCLUSIVE lock. If the database file is already in WAL mode (hence if the desire is to change it ... 

1. Usage  ... changes --table TABLE Show only the differences in content for TABLE, not for the entire database --transaction Wrap SQL output in a single large transaction --vtab Add support for handling FTS3, FTS5 and rtree virtual tables. See below for details.

 ... WAL mode with PRAGMA synchronous set to NORMAL avoids calls to fsync() during transaction commit and only invokes fsync() during a checkpoint operation. The use of WAL mode largely obviates the need for this asynchronous I/O module. Hence, this ... 

 ... The commit does not occur until the statement finishes, and maybe not even then if the statement is part of a larger transaction. Changes to the database are still atomic, consistent, isolated, and durable (ACID). When the previous section says ... 

sqlite3_backup_init(), sqlite3_backup_step(), sqlite3_backup_finish(), sqlite3_backup_remaining(), sqlite3_backup_pagecount()

 ... Using the SQLite Online Backup API SQLite holds a write transaction open on the destination database file for the duration of the backup operation. The source database is read-locked only while it is being read; it is not locked ... 

1. Background  ... SQL and SQLite are transactional. The use of a transactional storage system makes it much easier to reason about the behavior of the application, and to write applications that are robust, even in the face of software bugs, hardware faults ... 

sqlite3_stmt_readonly()

 ... side-effects: But because the SELECT statement does not change the database file directly, sqlite3_stmt_readonly() would still return true. Transaction control statements such as BEGIN, COMMIT, ROLLBACK, SAVEPOINT, and RELEASE cause sqlite3_stmt_readonly() to return true, since the statements themselves do ... 

4.3. Checkpoint Algorithm  ... It might be that some readers are still using older transactions with data that is contained in the database file. In that case, transferring content for newer transactions from the WAL file into the database would delete the content out ... 

sqlite3_deserialize()

 ... The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the database is currently in a read transaction or is involved in a backup operation. It is not possible to deserialized into the TEMP database. If the S argument to sqlite3_deserialize(D ... 

 ... But if the Client Application has bothered to use SQL/SQLite transactions properly, such failures will only cause a transaction to fail and be rolled back, without compromising the integrity of the data. In contrast, if the network link is ...