database disk image is malformed & Unhandled exception: MemoryError

### Step 1: Please describe your environment

* ZeroNet version: 4486
* Operating system: Raspbian

### Step 2: Describe the problem:

@HelloZeroNet
Zeronet pages fails to load dynamic content (from DB) so i extracted ERROR lines from the debug.log and sorted removing duplicates, this is result:

```
ERROR Site:1ADQAH..g6aA WebSocket receive error: OSError: [Errno 113] No route to host in UiWebsocket.py line 71 > __init__.py line 80 > 86 > 48 > 105 > 125 > 156 > _socket3.py line 378
ERROR Site:1HeLLo..Tf3D WebSocket receive error: OSError: [Errno 113] No route to host in UiWebsocket.py line 71 > __init__.py line 80 > 86 > 48 > 105 > 125 > 156 > _socket3.py line 378
ERROR Site:1MWkQT..72fR Announce to 5 trackers in 130.400s, failed
ERROR Site:1uPDaT..NACf WebSocket handleRequest error: MemoryError: in UiWebsocket.py line 79 > 215 > 341 > 1133 > SiteManager.py line 124 > helper.py line 52 > re.py line 192
ERROR - Unhandled exception: DatabaseError: database disk image is malformed in greenlet.py line 766 > helper.py line 234 > Chart/ChartDb.py line 130 > Db.py line 150 > DbCursor.py line 105
ERROR - Unhandled exception: KeyError: 'data/users/19ZYUMmjE6hvT25iPzre4LMmx55aAZ5C3y/content.json' in greenlet.py line 766 > Pooled.py line 12 > Bigfile/BigfilePlugin.py line 804 > 833 > Site.py line 803 > 767 > Bigfile/BigfilePlugin.py line 258 > ContentManager.py line 408 > ContentDbDict.py line 116
ERROR - Unhandled exception: KeyError: 'data/users/1Cz94uug7y5gXzxKUzSpT5Cm2k8dM5KPDT/content.json' in greenlet.py line 766 > Pooled.py line 12 > Bigfile/BigfilePlugin.py line 804 > 833 > Site.py line 803 > 767 > Bigfile/BigfilePlugin.py line 258 > ContentManager.py line 408 > ContentDbDict.py line 116
ERROR - Unhandled exception: MemoryError: in greenlet.py line 766 > FileServer.py line 228 > Noparallel.py line 62 > 55 > Site.py line 509
ERROR - Unhandled exception: MemoryError: in greenlet.py line 766 > OptionalManager/UiWebsocketPlugin.py line 46 > OptionalManager/ContentDbPlugin.py line 243 > collections/__init__.py line 566 > 653
ERROR - Unhandled exception: MemoryError: in greenlet.py line 766 > OptionalManager/UiWebsocketPlugin.py line 46 > OptionalManager/ContentDbPlugin.py line 256
ERROR - Unhandled exception: MemoryError: in greenlet.py line 766 > SiteManager.py line 124 > helper.py line 52 > re.py line 192
ERROR - Unhandled exception: MemoryError: in greenlet.py line 766 > SiteManager.py line 138 > 124 > helper.py line 43 > json/__init__.py line 238 > json/encoder.py line 202
ERROR - Unhandled exception: UnicodeEncodeError: 'latin-1' codec can't encode characters in position 99-109: ordinal not in range(256) in greenlet.py line 766 > Bigfile/BigfilePlugin.py line 833 > Site.py line 785 > FilePack/FilePackPlugin.py line 106 > SiteStorage.py line 390 > genericpath.py line 30
```

Please do you see any helpful information that can fix something or what do you suggest to try?
Should i "just" quit ZN, delete content.db file and start it? Or something else i can try in order to prevent this issue in future?

Commencez par les entrées de traceback liées à la base de données dans Chart/ChartDb.py, Db.py et DbCursor.py, puis examinez les erreurs environnantes dans debug.log afin d’identifier un échec reproductible. Déterminez quelle exception signalée constitue le problème principal de la base de données et définissez un résultat de récupération ou de prévention testable avant de modifier le code.

Rédigé par le modèle d'indexation à partir du texte de l'issue.