Continued:

- how to maintain (check for bad entries in `instances`) added

diff --git a/README.md b/README.md
index f0fb65c5d8d12fb957e41d1a6cb9da8493eceef9..db37a0e0881fac22fa75b0958491ace86daed4c8 100644 (file)
--- a/README.md
+++ b/README.md
@@ -58,6 +58,14 @@ systemctl enable --now fedi_block_api
 
 https://fba.ryona.agency/ uses an older code than this one. So it doesn't reflect this code here. My FBA sub-domain is currently password-protected as I still need to fix some performance issues with large blocking lists.
 
+## Maintenance
+
+Run these SQL queries from time to time. They always should return zero.
+
+```sql
+SELECT COUNT(blocked) AS cnt FROM blocks LEFT JOIN instances ON blocks.blocked = instances.domain OR blocks.blocker = instances.domain WHERE domain IS NULL LIMIT 1;
+SELECT COUNT(domain) AS cnt FROM instances WHERE nodeinfo_url IS NOT NULL AND software IS NULL LIMIT 1;
+```
 ## License
 
 [AGPLv3](https://gnu.org)