What is SQLite Wal?

What is WAL file in SQLite?

Write-Ahead Log (WAL) Files. 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.

What is SQLite SHM and WAL files?

The WAL-Index File Format. The WAL-index or "shm" file is used to coordinate access to the database by multiple clients, and as a cache to help clients quickly locate frames within the wal file. Because the shm file is not involved in recovery, the shm file does not need to be machine byte-order independent.

What is a WAL file?

WAL is short for Write Ahead Log. WALs are used in nearly all modern RDBMS systems to provide durable and atomic transactions. Simply put, any transaction performed on the database is first written out as a WAL file, then applied to the actual on-disk table data files. WAL files are strictly sequential.

What is the WAL property?

In computer science, write-ahead logging (WAL) is a family of techniques for providing atomicity and durability (two of the ACID properties) in database systems. The changes are first recorded in the log, which must be written to stable storage, before the changes are written to the database.