perf: speed up dense count agg with array counting

[cheb0]

Description

• Aggregator now accepts batches of lids, SourceNodeIterator rerturns a batch of sources
• MIDs are extracted for a batch of lids
• SingleSourceCountAggregator now delegates aggregation logic to sourceCounter interface, which has two implementations: plainSourceCounter handles ordinary aggs, uses a chunked array for counting. tsSourceCounter handles timeseries aggs, uses map

Array is better than map when we have many many lids processed in agg, but can be slower when the number of lids is low and agg is high cardinality (we need to allocate an array). This is partially handled by "chunking" the array.

Query	env	Total	cold, ms		hot, ms		cold (branch), ms		hot (branch), ms		cold diff	hot diff
service:large | by k8s_pod	prod	112107	57.6	±3.80	18	±1.33	52.57	±2.72	13.36	±0.78	-8.7%	-25.8%
service:small | by k8s_pod	prod	3211	48.1	±2.76	7.3	±1.66	47.89	±1.66	6.15	±0.37	-0.4%	-15.8%
service:micro | by k8s_pod	prod	99	67.64	±1.60	6.41	±0.45	66.73	±1.04	6.66	±0.53	-1.3%	3.9%
service:large | by (k8s_pod, 60s)	prod	112107	122.21	±2.95	23.04	±1.86	119.04	±2.93	21.99	±0.61	-2.6%	-4.6%
service:large | by (level, 60s)	prod	112107	106.44	±1.95	22.83	±0.20	103.82	±1.30	21.42	±0.28	-2.5%	-6.2%
request_host:huge | by response_status	lb	1065220	84.05	±3.89	53.89	±1.09	56.52	±2.55	29.26	±0.94	-32.8%	-45.7%
request_host:huge | by request_method	lb	1065220	78.11	±2.80	47.77	±0.72	55.14	±1.53	28.18	±0.72	-29.4%	-41%
response_status:500 | by remote_addr	lb	172	92.18	±2.95	16.51	±0.72	90.06	±3.16	16.53	±1.02	-2.3%	0.1%
exists:remote_addr | by remote_addr	lb	2844073	2027.1	±47.77	1860.21	±25.41	1745.57	±85.87	1538.06	±90.97	-13.9%	-17.3%
request_host:huge | request_uri	lb	1065220	100.97	±3.68	59.22	±1.42	78.79	±10.05	34.73	±3.04	-22%	-41.4%
request_host:huge | k8s_service_name	lb	1065220	84.42	±2.12	49.34	±0.90	64.24	±1.97	28.53	±0.63	-23.9%	-42.2%
request_host:huge | by x_o3_app_name	lb	1065220	88.51	±1.84	57.45	±0.72	63.36	±1.57	31.02	±0.74	-28.4%	-46%

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.36111% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.10%. Comparing base (02f1355) to head (8a910ee).

Files with missing lines	Patch %	Lines
frac/processor/aggregator.go	92.90%	10 Missing ⚠️
frac/processor/search.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@                         Coverage Diff                          @@
##           0-materialized-column-field-iter     #559      +/-   ##
====================================================================
+ Coverage                             77.03%   77.10%   +0.06%     
====================================================================
  Files                                   251      251              
  Lines                                 19104    19162      +58     
====================================================================
+ Hits                                  14716    14774      +58     
  Misses                                 4388     4388              

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[github-actions]

🔴 Performance Degradation

Some benchmarks have degraded compared to the previous run.
Click on Show table button to see full list of degraded benchmarks.

Show table

Name	Previous	Current	Ratio	Verdict
AggDeep/size=10000-4	70af15	1faa84
	0.00 B/op	3.00 B/op	NaN	🔴
AggDeep/size=1000000-4	70af15	1faa84
	0.00 B/op	30902.00 B/op	NaN	🔴
AggWide/size=10000-4	70af15	1faa84
	0.00 B/op	3.00 B/op	NaN	🔴
AggWide/size=1000000-4	70af15	1faa84
	842.00 B/op	34521.00 B/op	41.00	🔴