From 50686ae19161261f38bab53b0a288660bb48e7a3 Mon Sep 17 00:00:00 2001
From: croneter <kathriner.thomas@gmail.com>
Date: Tue, 25 Dec 2018 19:12:49 +0100
Subject: [PATCH] Fix database is locked

- Fixes #580
---
 resources/lib/library_sync/fanart.py | 51 ++++++++++++++++------------
 resources/lib/plex_db/common.py      | 18 +++++++---
 2 files changed, 43 insertions(+), 26 deletions(-)

diff --git a/resources/lib/library_sync/fanart.py b/resources/lib/library_sync/fanart.py
index e32b33ef..77af7634 100644
--- a/resources/lib/library_sync/fanart.py
+++ b/resources/lib/library_sync/fanart.py
@@ -15,6 +15,7 @@ LOG = getLogger('PLEX.sync.fanart')
 SUPPORTED_TYPES = (v.PLEX_TYPE_MOVIE, v.PLEX_TYPE_SHOW)
 SYNC_FANART = utils.settings('FanartTV') == 'true'
 PREFER_KODI_COLLECTION_ART = utils.settings('PreferKodiCollectionArt') == 'false'
+BATCH_SIZE = 500
 
 
 def suspends():
@@ -45,29 +46,37 @@ class FanartThread(backgroundthread.KillableThread):
     def _run_internal(self):
         LOG.info('Starting FanartThread')
         finished = False
-        while True:
-            with PlexDB() as plexdb:
-                func = plexdb.every_plex_id if self.refresh else plexdb.missing_fanart
-                for typus in SUPPORTED_TYPES:
-                    for plex_id in func(typus):
-                        if self.isCanceled() or self.isSuspended():
-                            break
+        try:
+            for typus in SUPPORTED_TYPES:
+                offset = 0
+                while True:
+                    with PlexDB() as plexdb:
+                        # Keep DB connection open only for a short period of time!
+                        if self.refresh:
+                            batch = list(plexdb.every_plex_id(typus,
+                                                              offset,
+                                                              BATCH_SIZE))
+                        else:
+                            batch = list(plexdb.missing_fanart(typus,
+                                                               offset,
+                                                               BATCH_SIZE))
+                    for plex_id in batch:
+                        # Do the actual, time-consuming processing
+                        if self.isCanceled():
+                            return
+                        if self.isSuspended():
+                            if self.isCanceled():
+                                return
+                            app.APP.monitor.waitForAbort(1)
                         process_fanart(plex_id, typus, self.refresh)
-                    if self.isCanceled() or self.isSuspended():
+                    if len(batch) < BATCH_SIZE:
                         break
-                else:
-                    # Done processing!
-                    finished = True
-                    break
-            # Need to have these outside our DB context to close the connection
-            if self.isCanceled():
-                return
-            if self.isSuspended():
-                if self.isCanceled():
-                    return
-                app.APP.monitor.waitForAbort(1)
-        LOG.info('FanartThread finished')
-        self.callback(finished)
+                    offset += BATCH_SIZE
+            else:
+                finished = True
+        finally:
+            LOG.info('FanartThread finished: %s', finished)
+            self.callback(finished)
 
 
 class FanartTask(common.libsync_mixin, backgroundthread.Task):
diff --git a/resources/lib/plex_db/common.py b/resources/lib/plex_db/common.py
index 4e9e50c0..981db266 100644
--- a/resources/lib/plex_db/common.py
+++ b/resources/lib/plex_db/common.py
@@ -121,20 +121,28 @@ class PlexDBBase(object):
         """
         self.cursor.execute('DELETE FROM %s WHERE plex_id = ?' % plex_type, (plex_id, ))
 
-    def every_plex_id(self, plex_type):
+    def every_plex_id(self, plex_type, offset, limit):
         """
         Returns an iterator for plex_type for every single plex_id
+        Will start with records at DB position offset [int] and return limit
+        [int] number of items
         """
         return (x[0] for x in
-                self.cursor.execute('SELECT plex_id from %s' % plex_type))
+                self.cursor.execute('SELECT plex_id FROM %s LIMIT %s OFFSET %s'
+                                    % (plex_type, limit, offset)))
 
-    def missing_fanart(self, plex_type):
+    def missing_fanart(self, plex_type, offset, limit):
         """
         Returns an iterator for plex_type for all plex_id, where fanart_synced
         has not yet been set to 1
+        Will start with records at DB position offset [int] and return limit
+        [int] number of items
         """
-        return (x[0] for x in
-                self.cursor.execute('SELECT plex_id from %s WHERE fanart_synced = 0' % plex_type))
+        query = '''
+            SELECT plex_id FROM %s WHERE fanart_synced = 0
+            LIMIT %s OFFSET %s
+        ''' % (plex_type, limit, offset)
+        return (x[0] for x in self.cursor.execute(query))
 
     def set_fanart_synced(self, plex_id, plex_type):
         """