Closed nascentcore-eng closed 1 year ago
following promescale official docs:
Promscale uses views to provide a stable interface. The set of views is provided in the ps_trace schema.
kubectl exec -it timescaledb-0 -- sh
# Then in the shell running in the container, start psql
psql
\c postgres
postgres=# \dn
List of schemas
Name | Owner
--------------------------+----------
_prom_catalog | postgres
_prom_ext | postgres
_ps_catalog | postgres
_ps_trace | postgres
_timescaledb_cache | postgres
_timescaledb_catalog | postgres
_timescaledb_config | postgres
_timescaledb_internal | postgres
prom_api | postgres
prom_data | postgres
prom_data_exemplar | postgres
prom_data_series | postgres
prom_info | postgres
prom_metric | postgres
prom_series | postgres
ps_tag | postgres
ps_trace | postgres
public | postgres
timescaledb_experimental | postgres
timescaledb_information | postgres
(20 rows)
then query data with sql
by view
:
postgres=# SELECT * from go_gc_duration_seconds
WHERE time > now() - INTERVAL '5 minutes';
Another interesting question is if and how promscale actually deduplicate prometheus data (as prometheus metrics have a lot of labels, without deduplication it would take too much space).
@JaredTan95 found that Prometheus agent mode actually disables local compaction of metrics data, so it means some system later in the pipeline should perform compaction, or the data will explode.
The provided link is about promscale itself.
Unassign @JaredTan95 as we should focus on pre-0.1 public release
A followup question: Right now we have 3 instances of promscale pod Do we need that much? Or just 1 instance is sufficient, assuming that 3 instances are stateless replicas. If the multiple instances are coordinating, then it's a different store.
Another question/topic: https://docs.timescale.com/promscale/latest/scale-ha/high-availability/ HA configuration for promscale, which means we need to figure out the configuration for promscale to be highly-available. This is in part related to https://github.com/tricorder-observability/starship/issues/430 multi node postgres
PromScale is deprecated No need to continue this...
Goal is to better understand how promscale works, and how it can be used to support Starship open source and commercial product.
Right now when using psql connect to timescale db, and connect to postgres database
\dt+
above shows no data tables.This is confusing. As we know that prom and otel data are sent to promscale, which then writes into timescaledb, according to promscale documentation in https://docs.timescale.com/promscale/latest/about-promscale/
The goal here is to investigate and understand what's underlying mechanism used by promscale and timescale DB for storing prom and otel data, and how they serve the queries.