On Sat, Mar 28, 2026 at 3:07 AM Hua W Peng <[email protected]> wrote:

> Hello,
>
> I have a common table for telemetry data. the stru is:
>
>          Column         |           Type           | Collation | Nullable
> | Default
>
>
> ------------------------+--------------------------+-----------+----------+---------
>
>  record_time            | timestamp with time zone |           | not null
> |
>
>  station_name           | text                     |           |
> |
>
>  feeder_gis_id          | text                     |           |
> |
>
>  switch_name            | text                     |           |
> |
>
>  switch_oid             | text                     |           | not null
> |
>
>  switch_gis_id          | text                     |           |
> |
>
>  switch_status          | integer                  |           |
> |
>
>  switch_status_quality  | integer                  |           |
> |
>
>  active_power           | numeric(18,6)            |           |
> |
>
>  active_power_quality   | integer                  |           |
> |
>
>  reactive_power         | numeric(18,6)            |           |
> |
>
>  reactive_power_quality | integer                  |           |
> |
>
>  current_a              | numeric(18,6)            |           |
> |
>
>  current_a_quality      | integer                  |           |
> |
>
>  current_b              | numeric(18,6)            |           |
> |
>
>  current_b_quality      | integer                  |           |
> |
>
>  current_c              | numeric(18,6)            |           |
> |
>
>  current_c_quality      | integer                  |           |
> |
>
>  voltage_uab            | numeric(18,6)            |           |
> |
>
>  voltage_uab_quality    | integer                  |           |
> |
>
>  voltage_ubc            | numeric(18,6)            |           |
> |
>
>  voltage_ubc_quality    | integer                  |           |
> |
>
>  voltage_uca            | numeric(18,6)            |           |
> |
>
>  voltage_uca_quality    | integer                  |           |
> |
>
>  created_at             | timestamp with time zone |           |          |
> now()
>
> Indexes:
>
>     "dms_data_gzdy_pkey" PRIMARY KEY, btree (record_time, switch_oid)
>
>     "dms_data_gzdy_record_time_idx" btree (record_time DESC)
>
>     "idx_dms_feeder_gis_id" btree (feeder_gis_id, record_time)
>
>     "idx_dms_station_name" btree (station_name, record_time)
>
>     "idx_dms_switch_oid" btree (switch_oid, record_time)
>
>
> Data records are growing by about *10 million* every day, reaching *300
> million* per month.
>
How many months of data?

Is the production table partitioned?  If so, by what date range?

> In this case, even a simple COUNT(*) query becomes extremely slow, taking
> about 7-8 minutes to finish.
>
> I am running PostgreSQL 14
>
What minor version?

> on Ubuntu 22.04 with a 24GB shared buffer.
>
Is that 25% of total RAM?

What's the effective_cache_size?

And, though in our test env we have timescaledb enabled:
>
>
> Triggers:
>
>     ts_insert_blocker BEFORE INSERT ON dms_data_gzdy FOR EACH ROW EXECUTE
> FUNCTION _timescaledb_functions.insert_blocker()
>
> Number of child tables: 9 (Use \d+ to list them.)
>
>
> But in production env there is no timescaledb which can't be installed as
> well.
>

Laurenz is right: installing and using timescale in your *test* system *tests
timescale*. Why are you testing timescale when you can't install it in prod?

-- 
Death to <Redacted>, and butter sauce.
Don't boil me, I'm still alive.
<Redacted> lobster!

Reply via email to