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Asked: 2026-05-26T02:16:07+00:00

I have a sqlite3 database on some system which I need to download during

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I have a sqlite3 database on some system which I need to download during ongoing operation. Stopping or pausing the accessing processes is not an option. So as far as I understand this I need to hold a SHARED lock (as described in http://www.sqlite.org/lockingv3.html) to the db during download to avoid db changes and corruption during download. How do I explicitly get such a lock? The download is controlled from a C++-program, so I would need to get the lock there.

EDIT: thkala suggested to make a db dump. But I would prefer to find a solution with locking because I’m not sure if there will be sufficient memory available for a complete copy of the db.

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  1. Editorial Team

    No, no. no and no!

    Messing with locks and copying files by hand is the old way to do things. SQLite now has a proper backup API that you can use. It is the recommended way to perform on-line copies of an SQLite database – you can use it to create a copy of the database, which can be then downloaded at your convenience.

    EDIT:

    If you absolutely have to use locking, you can use the method outlined here – possibly after translating into C:

    • Open the database

    • Use the BEGIN IMMEDIATE statement to acquire a shared lock.

    • Copy/download the files manually – make sure that you don’t miss any. There are at least the DB file, the journal file and possibly the WAL file. You might want to place the DB in a separate directory to make things simpler.

    • ROLLBACK the transaction you just started.

    I understand how this method could be useful in some cases, but I have to repeat that this is not the recommended method any more.

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