From 86dab6d6cc89e536a99300f7e1dcbf1052317ff5 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 2 Jul 2018 18:01:13 +0530
Subject: [PATCH] When exporting very large libraries fix failures due to busy
 errors.  Fixes #1779664 [Error-message when exporting library for
 Backup](https://bugs.launchpad.net/calibre/+bug/1779664)

---
 src/calibre/db/backend.py | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/calibre/db/backend.py b/src/calibre/db/backend.py
index e4c2e9d7af..d68370ccbe 100644
--- a/src/calibre/db/backend.py
+++ b/src/calibre/db/backend.py
@@ -1788,14 +1788,13 @@ class DB(object):
         self.executemany('INSERT INTO data (book,format,uncompressed_size,name) VALUES (?,?,?,?)', vals)
 
     def backup_database(self, path):
-        # We have to open a new connection to self.dbpath, until this issue is fixed:
-        # https://github.com/rogerbinns/apsw/issues/199
         dest_db = apsw.Connection(path)
-        source = apsw.Connection(self.dbpath)
-        with dest_db.backup('main', source, 'main') as b:
+        with dest_db.backup('main', self.conn, 'main') as b:
             while not b.done:
-                b.step(100)
-        source.close()
+                try:
+                    b.step(100)
+                except apsw.BusyError:
+                    pass
         dest_db.cursor().execute('DELETE FROM metadata_dirtied; VACUUM;')
         dest_db.close()