No, it's not empty.
If you are talking about the Web Interface Tools > Tail FTL.log page, this page doesn't show past log entries.
The page starts empty and only shows NEW log entries generated AFTER the page was loaded, but FTL doesn't generate messages too often (unless it is in debug mode), so you probably won't see many messages there.
You can read the full FTL log on the command line with cat /var/log/pihole/FTL.log
To read only the last lines on the log, you can use tail /var/log/pihole/FTL.log
There are 2 typos in your file path (Linux is case sensitive):
the file path should be /etc/pihole (all lower case).
the file name should be pihole-FTL.db (upper case "FTL").
Try again using the command:
pihole-FTL sqlite3 /etc/pihole/pihole-FTL.db "SELECT * FROM network"
This is strange.
Do you see any messages on the browser? Can you please check the browser's devtools (F12 key) and select the "Console" tab.
[2023-07-03 14:49:32.261 2576M] SQLite3 message: no such column: name in "SELECT name FROM network_addresses WHERE name IS NOT NULL AND ip = ?;" (1)
[2023-07-03 14:49:32.261 2576M] getNameFromIP("192.168.178.43") - SQL error prepare: SQL logic error
[2023-07-03 14:49:32.261 2576M] SQLite3 message: no such column: aliasclient_id in "SELECT aliasclient_id FROM network WHERE id = (SELECT network_id FROM network_addresses WHERE ip = ? AND aliasclient_id IS NOT NULL GROUP BY ip HAVING max(lastSeen));" (1)
[2023-07-03 14:49:32.261 2576M] getAliasclientIDfromIP("192.168.178.43") - SQL error prepare: SQL logic error
[2023-07-03 14:49:32.261 2576M] find_mac("192.168.178.43") returned 0 bytes of data
[2023-07-03 14:49:32.702 2576M] SQLite3 message: no such column: name in "SELECT name FROM network_addresses WHERE name IS NOT NULL AND ip = ?;" (1)
[2023-07-03 14:49:32.702 2576M] getNameFromIP("::1") - SQL error prepare: SQL logic error
[2023-07-03 14:49:32.702 2576M] SQLite3 message: no such column: aliasclient_id in "SELECT aliasclient_id FROM network WHERE id = (SELECT network_id FROM network_addresses WHERE ip = ? AND aliasclient_id IS NOT NULL GROUP BY ip HAVING max(lastSeen));" (1)
[2023-07-03 14:49:32.703 2576M] getAliasclientIDfromIP("::1") - SQL error prepare: SQL logic error
[2023-07-03 14:49:32.703 2576M] find_mac("::1") returned 0 bytes of data
[2023-07-03 14:49:32.728 2576M] SQLite3 message: no such column: name in "SELECT name FROM network_addresses WHERE name IS NOT NULL AND ip = ?;" (1)
[2023-07-03 14:49:32.728 2576M] getNameFromIP("fda2:8cfe:cbe5:e9b1:4bc3:7bff:fe67:c175") - SQL error prepare: SQL logic error
[2023-07-03 14:49:32.728 2576M] SQLite3 message: no such column: aliasclient_id in "SELECT aliasclient_id FROM network WHERE id = (SELECT network_id FROM network_addresses WHERE ip = ? AND aliasclient_id IS NOT NULL GROUP BY ip HAVING max(lastSeen));" (1)
[2023-07-03 14:49:32.728 2576M] getAliasclientIDfromIP("fda2:8cfe:cbe5:e9b1:4bc3:7bff:fe67:c175") - SQL error prepare: SQL logic error
[2023-07-03 14:49:32.728 2576M] find_mac("fda2:8cfe:cbe5:e9b1:4bc3:7bff:fe67:c175") returned 0 bytes of data
[2023-07-03 14:49:32.742 2576M] find_mac("127.0.0.1") returned 0 bytes of data
[2023-07-03 14:49:35.855 2576M] SQLite3 message: no such column: name in "SELECT name FROM network_addresses WHERE name IS NOT NULL AND ip = ?;" (1)
[2023-07-03 14:49:35.855 2576M] getNameFromIP("192.168.178.35") - SQL error prepare: SQL logic error
[2023-07-03 14:49:35.856 2576M] SQLite3 message: no such column: name in "SELECT name FROM network_addresses WHERE name IS NOT NULL AND ip = ?;" (1)
[2023-07-03 14:49:35.856 2576M] getNameFromIP("192.168.178.35") - SQL error prepare: SQL logic error
[2023-07-03 14:49:35.856 2576M] SQLite3 message: no such column: name in "SELECT name FROM network_addresses WHERE name IS NOT NULL AND ip = ?;" (1)
[2023-07-03 14:49:35.856 2576M] getNameFromIP("192.168.178.35") - SQL error prepare: SQL logic error
Versuch mal Pi-hole zu stoppen, die Datenbank umzubennen und Pi-hole neu zu starten.
Blockquote No, it's not empty.
If you are talking about the Web Interface Tools > Tail FTL.log page, this page doesn't show past log entries.
The page starts empty and only shows NEW log entries generated AFTER the page was loaded, but FTL doesn't generate messages too often (unless it is in debug mode), so you probably won't see many messages there.
You can read the full FTL log on the command line with cat /var/log/pihole/FTL.log
To read only the last lines on the log, you can use tail /var/log/pihole/FTL.log
Ah thank you for pointing that out.
root@pi-Hole:~# tail /var/log/pihole/FTL.log
[2023-07-03 19:09:00.096 6438/T6454] Network table: read interface details for interface eth0@if17 (5a:6f:40:55:7b:47) with address 192.168.178.43
[2023-07-03 19:09:00.096 6438/T6454] Network table (ip a): Client with MAC 5a:6f:40:55:7b:47 was recently be seen for network ID 25
[2023-07-03 19:09:00.100 6438/T6454] Network table: Updating existing ip a device MAC = 5a:6f:40:55:7b:47, IP = 192.168.178.43, interface = "eth0@if17"
[2023-07-03 19:09:00.100 6438/T6454] Network table: read interface details for interface eth0@if17 (5a:6f:40:55:7b:47) with address fda2:8cfe:cbe5:e9b1:4bc3:7bff:fe67:c175
[2023-07-03 19:09:00.100 6438/T6454] Network table (ip a): Client with MAC 5a:6f:40:55:7b:47 was recently be seen for network ID 25
[2023-07-03 19:09:00.104 6438/T6454] Network table: Updating existing ip a device MAC = 5a:6f:40:55:7b:47, IP = fda2:8cfe:cbe5:e9b1:4bc3:7bff:fe67:c175, interface = "eth0@if17"
[2023-07-03 19:09:00.104 6438/T6454] Network table: read interface details for interface eth0@if17 (5a:6f:40:55:7b:47) with address fe80::586f:40ff:fe55:7b47
[2023-07-03 19:09:00.104 6438/T6454] Network table (ip a): Client with MAC 5a:6f:40:55:7b:47 was recently be seen for network ID 25
[2023-07-03 19:09:00.108 6438/T6454] Network table: Updating existing ip a device MAC = 5a:6f:40:55:7b:47, IP = fe80::586f:40ff:fe55:7b47, interface = "eth0@if17"
[2023-07-03 19:09:00.113 6438/T6454] ARP table processing (38 entries from ARP, 6 from FTL's cache) took 22.5 ms
pihole-FTL sqlite3 /etc/pihole/pihole-FTL.db "SELECT * FROM network"