Mar 3, 2025 · The only safe way to remove a WAL file is to open the database file using one of the sqlite3_open() interfaces then immediately close the database using sqlite3_close(). The WAL file format is precisely defined and is cross-platform.

This leaves the database in a state that allows other processes without write permission on the database, WAL, or WAL-index files to open the database read-only.

Aug 10, 2023 · Modern emcc builds ours with WAL now, and that's what will be delivered with 3.43, but it fails to open any WAL-mode db (with SQLITE_CANTOPEN). Figuring out what needs to change to make that work near the top of my TODO list.

A write-ahead log or WAL file is used in place of a rollback journal when SQLite is operating in WAL mode. As with the rollback journal, the purpose of the WAL file is to implement atomic commit and rollback.

3 days ago · In wal2 mode, the system uses two wal files instead of one. The files are named "<database>-wal" and "<database>-wal2", where "<database>" is of course the name of the database file. When data is written to the database, the writer begins by appending the new data to the first wal file.

This function attempts to scan the WAL file associated with database zDb of database handle db and make all valid snapshots available to sqlite3_snapshot_open(). It is an error if there is already a read transaction open on the database, or if the database is not a WAL mode database.

When a database is in WAL mode, all connections to that database must use the WAL. A particular database will use either a rollback journal or a WAL, but not both at the same time. The WAL is always located in the same directory as the database file and has the same name as the database file but with the string "-wal" appended. 4.1. WAL File Format

Jan 18, 2022 · If you really have a use-case for a read-only DB, then store the DB file in a read-only location, and before using it from a new connection, first copy the DB file to a temp folder (with read-access), OR serialize it into memory then open that temporary/memory DB and read it to your heart's content.

The opening process must have write privileges for "-shm" [wal-index] shared memory file associated with the database, if that file exists, or else write access on the directory containing the database file if the "-shm" file does not exist.

Sep 1, 2022 · It's enough to open and close that database, this will incorporate the WAL files. I always do sqlite db.sqlite3 .schema, which is sufficient.