[Xapian-discuss] backing up a database by locking while backup program runs

[Ronan]

Hi.

I want to back up a Xapian database.  If I copy the database directory
and its contents using (for instance) rsync, and I know that throughout
the duration of the rsync process another process has had the database
open for writing, but has not actually made any modifications, can I
be sure that, on completion of the rsync process, I have a copy of the
database which is consistent and fully up-to-date?

The document at [1] makes it fairly clear that the answer is "Yes",
but I'm a little doubtful about the status of that document, since there
seem to be no links to it from the Xapian website.  (The following Google
query finds nothing: "link:www.xapian.org/docs/admin_notes.html".)

[1] http://www.xapian.org/docs/admin_notes.html

I propose to use a simple PHP script like the following in order to
obtain the write lock:

  <?php 
  $h = new XapianWritableDatabase("/my/Xapian/database", DB_OPEN);
  sleep(99999);

Regards,

Ronan.