My understanding was that:
last_updated_ts
changes whenever either the state
or an attribute
changes but last_changed_ts
changes only when a new state
is recorded.
However in my states
table, the last_changed_ts
column is present (i.e., NOT NULL) only about 2% of the time.
Indeed for 2/3 of my active sensors all rows have that column blank.
Even for sensors when it does appear, it seems to appear irregularly and erratically
The following seems to be true:
- If the state itself CHANGES, then no
last_changed_ts
entry - For the rows where the state is UNCHANGED, then
last_changed_ts
is recorded about 60% of the time but it doesn’t seem to be related to whetherattributes_id
changes – and I can’t figure out what causes it to be NULL vs non-NULL
Can someone please explain when last_changed_ts
is entered and what it really signifies?
NOTE: the last_reported_ts
column seems to be NOT NULL about 99.6% of the time – but again not clear what conditions cause it be NULL…
I could not find a clear explanation of this anywhere.
Any help appreciated…