docs: document configurable future_partitions buffer

postgresql/procedures/README.md

@@ -54,7 +54,13 @@ DB_USER="zbxpart_admin"
 
 for script in 00_schema_create.sql 01_maintenance.sql 02_enable_partitioning.sql 03_monitoring_view.sql; do
     echo "Applying $script..."
-    psql -h $DB_HOST -U $DB_USER -d $DB_NAME -f "$script"
+    # -v ON_ERROR_STOP=1 forces psql to exit immediately with an error code if any statement fails
+    if ! psql -v ON_ERROR_STOP=1 -h $DB_HOST -U $DB_USER -d $DB_NAME -f "$script"; then
+        echo -e "\nERROR: Failed to apply $script."
+        read -p "Press [Enter] to forcefully continue anyway, or Ctrl+C to abort... "
+    else
+        echo -e "Successfully applied $script.\n----------------------------------------"
+    fi
 done
 ```
 
@@ -213,6 +219,24 @@ System state can be monitored via the `partitions.monitoring` view. It includes
 SELECT * FROM partitions.monitoring;
 ```
 
+### Zabbix Agent Integration
+To monitor the state of the partitions directly from Zabbix, you need to provide the Zabbix Agent with the SQL query used to fetch this data. You can automatically generate the required `partitions.get_all.sql` file on your agent using this one-liner:
+
+```bash
+cat << 'EOF' | sudo tee /etc/zabbix/zabbix_agent2.d/partitions.get_all.sql > /dev/null
+SELECT 
+    table_name,
+    period,
+    keep_history::text AS keep_history,
+    configured_future_partitions,
+    actual_future_partitions,
+    total_size_bytes,
+    EXTRACT(EPOCH FROM (now() - last_updated)) AS age_seconds
+FROM partitions.monitoring;
+EOF
+```
+*(Make sure to adjust the destination path according to your Zabbix Agent template directory)*
+
 ### Versioning
 To check the installed version of the partitioning solution:
 ```sql