NetXMS Support Forum

Please login or register.

Login with username, password and session length

Author Topic: TimeScale and drop_chunks, DCI disk usage  (Read 60 times)

jermudgeon

  • Newbie
  • *
  • Posts: 19
    • View Profile
TimeScale and drop_chunks, DCI disk usage
« on: August 14, 2019, 07:40:43 pm »

Anyone else using timescaledb with postgres?

When I look at timescaledb maintenance, typically the drop_chunks function would be used to reclaim disk space. However, drop_chunks requires TIMESTAMP, TIMESTAMPTZ, or DATE column types. For 'idata' and 'tdata', for example, the timestamp column is actually an int4.

Any pointers on how to determine whether NetXMS is actually pruning old entries to reclaim disk space? It's certainly dropping DCIs correctly from an access standpoint -- queries only return the expected time ranges.


Logged

Tursiops

  • Sr. Member
  • ****
  • Posts: 444
    • View Profile
Re: TimeScale and drop_chunks, DCI disk usage
« Reply #1 on: August 15, 2019, 01:42:54 am »

drop_chunks requires TIMESTAMP, TIMESTAMPTZ or DATE if the cut-off point is set as an interval.
If the cut-off point is given explicitly, you can use integers, see https://docs.timescale.com/latest/api#drop_chunks
As NetXMS uses integers in its current cleanup queries, I would assume it will use explicit cut-off points for drop_chunks as well.
Note that I'm not a dev and haven't looked at the code...
Logged

Victor Kirhenshtein

  • Lead Developer
  • Administrator
  • Hero Member
  • *****
  • Posts: 6654
    • View Profile
Re: TimeScale and drop_chunks, DCI disk usage
« Reply #2 on: August 20, 2019, 03:57:32 pm »

Yes, NetXMS uses explicit cutoff points for dropping chunks. But please note that TimescaleDB support in 2.2.16 is quite immature - we have improved it significantly in 3.0 branch.

Best regards,
Victor
Logged