pi@raspberrypi:~ $ sqlite3 /mnt/raid1/Pi-hole/pihole-FTL.db "SELECT count(domain) FROM queries
WHERE(timestamp BETWEEN strftime('%s','2020-01-01') AND strftime('%s','2020-09-30'));"
5784610
Well, now we see something!
Ok, then I suspect you'd see data up to August 13, and likely none afterwards.
Yes, PHP may run out of memory when trying to populate the UI for large amounts of queries, and 5,784,610 would be large.
Longterm-data | Graphics have a better chance of succeeding, as those will aggregate data before displaying it.
Well now when I Query data Graphic for 1 Year I can see data from March, etc where I had it set up but if I place "Last Month" I don't see anything, looks like to me more like a memory issue, anyway I think that is it, I think that at the end everything works but I am facing maybe memory issues. Any tips to increase the memory? My Raspberry Pi has 4 GB but I guess I am not allocating much for Pi-Hole.
Ok guys I finally figured out what happened.
So actually I have data until August, what happened is that because my pihole-FTL.db was mounted on my Raid 1 (External HD) something has changed on my raid config/permissions and the DB went in read-only mode. It means that by August it stopped recording. So, the DB is healthy at the end it is just the data that I was looking to the wrong place. Thanks a lot everyone that help me, I learned a lot.
Yes, I've suspected August 13th before because that's what one of the timestamps in the ftl table decoded to. I just wasn't entirely sure about that table's content semantics, apart from db version.
Glad it's sorted now. 