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SQLite's VACUUM command copies the contents of the master database to a tempdb file, then empties the master database, and reloads the original database file from the replica. This eliminates free pages, arranges the data in the table as contiguous, and cleans up the database file structure.

Manual VACUUM

Here is the syntax for issuing the VACUUM command against the entire database from a command prompt:

$sqlite3 database_name "VACUUM;"

You can also run VACUUM from the SQLite prompt, as follows:

Sqlite > VACUUM

You can also run VACUUM on a specific table, as follows:

Sqlite > VACUUM table_name; automatic VACUUM (Auto-VACUUM)

SQLite's Auto-VACUUM is different from VACUUM in that it simply moves free pages to the end of the database, thereby reducing the database size. By doing so, it can obviously fragment the database, while VACUUM is anti-fragmented. So Auto-VACUUM will only make the database smaller.

In the SQLite prompt, you can enable / disable Auto-VACUUM for SQLite by running the following compilation:

Sqlite > PRAGMA auto_vacuum = NONE;-- 0 means disable auto vacuumsqlite > PRAGMA auto_vacuum = INCREMENTAL;-- 1 means enable incremental vacuumsqlite > PRAGMA auto_vacuum = FULL;-- 2 means enable full auto vacuum

You can check the auto-vacuum settings by running the following command from a command prompt:

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