Tracking issue for dataflow framework

[discord9]

What problem does the new feature solve?

Being able to do simple continuous aggregation.

What does the feature do?

• not a complete streaming-processing system. Only a must subset functionalities are provided.
• can handle most aggregate operators within one table(i.e. Sum, avg, min, max and comparison operators). But others (join, trigger, txn etc.) are not the target feature. Framework

Implementation challenges

• [ ] Persisent intermediate state for operator
• [ ] Write more operator suitable for stream computation
• [ ] Limit the scope of system boundary to simple aggregation.

Implementation Progress

• [x] RFC #3185
• [x] Basic Types, Expressions&Functions:
  • [x] #3186
  • [x] #3267
  • [x] #3283
  • [x] #3359
  • [x] #3396
• [ ] Dataflow Logical Plan Defination & Execution
  • [x] #3490
  • [x] #3508 and #3552
  • [x] #3581
  • [ ] #3736
• [ ] SQL/substrait to Dataflow Logical Plan translator
  • [x] #3657
  • [x] #3690
• [ ] register tasks to metasrc, and coordinate everything to make flow useable https://github.com/GreptimeTeam/greptimedb/issues/3664

[tisonkun]

@discord9 I read the RFC now and wonder what's a completed sample for this feature.

I can see how to create a task (continuous query/materialize view):

CREATE TASK avg_over_5m WINDOW_SIZE = "5m" AS SELECT avg(value) FROM table WHERE time > now() - 5m GROUP BY time(1m)

Then we can use avg_over_5m as a normal table reference in query?

[discord9]

@discord9 I read the RFC now and wonder what's a completed sample for this feature.

I can see how to create a task (continuous query/materialize view):

CREATE TASK avg_over_5m WINDOW_SIZE = "5m" AS SELECT avg(value) FROM table WHERE time > now() - 5m GROUP BY time(1m)

Then we can use avg_over_5m as a normal table reference in query?

Yes, sorry for the late reply, github's layout for issues is really terrible, this task also create a result table avg_over_5m and write to it with negligible delay, so naturally one can use avg_over_5m in normal query

[killme2008]

@discord9 I think we can close this issue right now. The next iteration could start with a new issue. What do you think?

[discord9]

Close this issue as now have a basic dataflow framework, and can start a new issue to track it's next iteration