On Tue, 2005-09-06 at 11:09 -0400, John Duprey wrote:
> I'd like to copy a database that may or may not be in use. Doing a
> filesystem copy will not ensure a stable copy. Can I use the sqlite3 CLI and
> some SQL to do this such that I can wrap it up into a script or do I need to
> write my own program, that gets a lock and re-creates the DB in a new file?
> I'd like to avoid dumping the database and importing it into a new. My DB is
> 400M and growing so I'd like to avoid dumping such a large amount of data.
> What I'd like is a safe binary copy.
>
I suggest this approach:
1. Open the database file using sqlite3_open()
2. Run sqlite3_exec("BEGIN IMMEDIATE");
3. Make a copy of the raw database file using whatever
high-speed file copy mechanism is at hand.
4. sqlite3_close();
The BEGIN IMMEDIATE operation in step 2 will acquire a read-lock on the
database file which will insure that no other process modifies the file
during step 3. But it is also only a read-lock so other processes can
continue to read the database while you are copying it. Step 4 releases
the file lock.
--
D. Richard Hipp <[EMAIL PROTECTED]>
