feat: table view support for cumulative & delta metrics

[srikanthccv]

Part of #2842

Attempts at showing what happens with an example. I will be happy to answer any questions or explain in more detail.

signoz_metrics.samples_v2

id	t	v(cumulative)	v(delta)
S1	12.00	0	0
S1	12.05	12	12
S1	12.10	14	2
S1	12.15	16	2
S1	12.20	22	6
S1	12.25	25	3
S1	12.30	32	7
S1	12.35	37	5
S1	12.40	45	8
S1	12.45	49	4
S1	12.50	59	10
S1	12.55	66	7
S2	12.00	0	0
S2	12.05	15	15
S2	12.10	17	2
S2	12.15	21	4
S2	12.20	34	13
S2	12.25	36	2
S2	12.30	45	9
S2	12.35	47	2
S2	12.40	49	2
S2	12.45	51	2
S2	12.50	62	11
S2	12.55	71	9

signoz_metrics.time_series_v2

id	labels
S1	{service_name:frontend, operation:GET}
S2	{service_name:frontend, operation:POST}

Assume you wanted a request rate for the service frontend.

Here is what we would do for the delta. We join the both the table on the id and then on the result we use sum(value)/duration to get the rate.

Here is the intermediary result of the join.

id	t	v(cumulative)	v(delta)	labels
S1	12.00	0	0	{service_name:frontend, operation:GET}
S1	12.05	12	12	{service_name:frontend, operation:GET}
S1	12.10	14	2	{service_name:frontend, operation:GET}
S1	12.15	16	2	{service_name:frontend, operation:GET}
S1	12.20	22	6	{service_name:frontend, operation:GET}
S1	12.25	25	3	{service_name:frontend, operation:GET}
S1	12.30	32	7	{service_name:frontend, operation:GET}
S1	12.35	37	5	{service_name:frontend, operation:GET}
S1	12.40	45	8	{service_name:frontend, operation:GET}
S1	12.45	49	4	{service_name:frontend, operation:GET}
S1	12.50	59	10	{service_name:frontend, operation:GET}
S1	12.55	66	7	{service_name:frontend, operation:GET}
S2	12.00	0	0	{service_name:frontend, operation:POST}
S2	12.05	15	15	{service_name:frontend, operation:POST}
S2	12.10	17	2	{service_name:frontend, operation:POST}
S2	12.15	21	4	{service_name:frontend, operation:POST}
S2	12.20	34	13	{service_name:frontend, operation:POST}
S2	12.25	36	2	{service_name:frontend, operation:POST}
S2	12.30	45	9	{service_name:frontend, operation:POST}
S2	12.35	47	2	{service_name:frontend, operation:POST}
S2	12.40	49	2	{service_name:frontend, operation:POST}
S2	12.45	51	2	{service_name:frontend, operation:POST}
S2	12.50	62	11	{service_name:frontend, operation:POST}
S2	12.55	71	9	{service_name:frontend, operation:POST}

For delta we would sum the value column group by the service_name:

service_name	sum(v)/ duration
frontend	(12 + 2 + 2 + 6 + 3 + 7 + 5 + 8 + 4 + 10 + 7 + 15 + 2 + 4 + 13 + 2 + 9 + 2 + 2 + 2 + 11 + 9)/ 60

For cumulative we would would first need to calculate the rate of change for each series and then sum them up.

service_name	t	runningRate
frontend	12.05	(12-0)/0.5
frontend	12.10	(14-12)/0.5
frontend	12.15	(16-14)/0.5
frontend	12.20	(22-16)/0.5
frontend	12.25	(25-22)/0.5
frontend	12.30	(32-25)/0.5
frontend	12.35	(37-32)/0.5
frontend	12.40	(45-37)/0.5
frontend	12.45	(49-45)/0.5
frontend	12.50	(59-49)/0.5
frontend	12.55	(66-59)/0.5
frontend	12.05	(15-0)/0.5
frontend	12.10	(17-15)/0.5
frontend	12.15	(21-17)/0.5
frontend	12.20	(34-21)/0.5
frontend	12.25	(36-34)/0.5
frontend	12.30	(45-36)/0.5
frontend	12.35	(47-45)/0.5
frontend	12.40	(49-47)/0.5
frontend	12.45	(51-49)/0.5
frontend	12.50	(62-51)/0.5
frontend	12.55	(71-62)/0.5

Now we sum the runningRate column and divide by the duration.

service_name	sum(runningRate)/ duration
frontend	(12 + 2 + 2 + 6 + 3 + 7 + 5 + 8 + 4 + 10 + 7 + 15 + 2 + 4 + 13 + 2 + 9 + 2 + 2 + 2 + 11 + 9)/ (5minutes * 10points)

[nityanandagohain]

Will take some time to read about cumulative and delta metrics and then review this.

[srikanthccv]

Appreciate it. I have written a descriptive comment here to explain the difference #2505. I will do the same with little more details and queries to help understand changes better.

[srikanthccv]

I updated the PR description with an example to show what is the underlying table structure and how is a final value calculated and how does it relate to the query written.

[srikanthccv]

Please find some time to review. Let me know if there is something I can help understand any part better or could improve.

[nityanandagohain]

Will review today

[nityanandagohain]

Thanks for explaining the concept, looks good to me.