Add query option to use more replica groups

[PrachiKhobragade]

In case when the routingConfig is replicaGroup, user can provide an option to
fan out a query to x replicaGroups where 1 <= x <= replicaGroups so that more
resources could be used for an expensive query
Fixes #8217

Release Notes

When the instance selection criteria for segments is based on replica groups REPLICA_GROUP_INSTANCE_SELECTOR_TYPE, the query goes to just one of the many replica groups, this helps in limiting the number of servers used to serve this query. This may sometimes have a negative effect on time consuming queries, which would get served slower. If we can somehow give an option to the user to fan their query to more replica groups, the query can be served faster.
This PR will add an option to the Sql query numReplicaGroupsToQuery which will take a positive integer, specifying the number of replica groups the query should be fanned out to.

Eg: When the replica group is set to 3, and with 3 servers S1, S2, S3. All the segments will be available on all the servers and we would choose any of S1 | S2 | S3 to serve the segments, with numReplicaGroupsToQuery set to 2 option passed with the query, we will chose two servers to serve the query with the number of segments coming equally from both the servers.
An example query should look like :

SELECT COUNT(*) FROM T GROUP BY A OPTION(numReplicaGroupsToQuery=2)

[PrachiKhobragade]

Please Review @sajjad-moradi @snleee

[sajjad-moradi]

Can you add a unit test for invalid value for numReplicas in the option?

[snleee]

Partial Review

[sajjad-moradi]

Please add a brief Release Note section to the PR description.

[kishoreg]

can we add sample docs to the description? is this specific to replica group based assignment or a generic solution where users can override routing strategy on a per query basis

[codecov-commenter]

Codecov Report

Merging #8550 (fcde57e) into master (6eff177) will decrease coverage by 41.37%.
The diff coverage is 60.00%.

@@              Coverage Diff              @@
##             master    #8550       +/-   ##
=============================================
- Coverage     70.83%   29.46%   -41.38%     
=============================================
  Files          1688     1676       -12     
  Lines         88295    87964      -331     
  Branches      13358    13327       -31     
=============================================
- Hits          62542    25916    -36626     
- Misses        21388    59666    +38278     
+ Partials       4365     2382     -1983     

Flag	Coverage Δ
integration1	27.31% <36.00%> (-0.01%)	⬇️
integration2	25.76% <60.00%> (-0.05%)	⬇️
unittests1	?
unittests2	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ing/instanceselector/BalancedInstanceSelector.java	100.00% <ø> (ø)
...va/org/apache/pinot/spi/utils/CommonConstants.java	0.00% <ø> (-21.32%)	⬇️
...roker/requesthandler/BaseBrokerRequestHandler.java	41.28% <28.57%> (-9.35%)	⬇️
.../org/apache/pinot/core/util/QueryOptionsUtils.java	72.22% <50.00%> (-2.78%)	⬇️
...instanceselector/ReplicaGroupInstanceSelector.java	73.68% <60.00%> (-26.32%)	⬇️
...routing/instanceselector/BaseInstanceSelector.java	94.69% <100.00%> (-5.31%)	⬇️
.../java/org/apache/pinot/spi/utils/BooleanUtils.java	0.00% <0.00%> (-100.00%)	⬇️
...java/org/apache/pinot/spi/trace/BaseRecording.java	0.00% <0.00%> (-100.00%)	⬇️
...java/org/apache/pinot/spi/trace/NoOpRecording.java	0.00% <0.00%> (-100.00%)	⬇️
...ava/org/apache/pinot/spi/config/table/FSTType.java	0.00% <0.00%> (-100.00%)	⬇️
... and 1174 more

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[sajjad-moradi]

can we add sample docs to the description? is this specific to replica group based assignment or a generic solution where users can override routing strategy on a per query basis

This is specific to replica group based assignment in which user can specify in each query string to use more than one replica group for query execution. @PrachiKhobragade correct me if I'm wrong.

[sajjad-moradi]

LGTM. Please update the description with a sample query and add maybe add a small release note section with summary to make life easier for the next person cutting the release.

[snleee]

@kishoreg This is for overriding # of replica groups to route per-query basis for tables with replica group feature enabled. We can use a similar approach to allow users to use different instance selecting algorithms (e.g. balanced vs replica group-based).

[PrachiKhobragade]

Can you add a unit test for invalid value for numReplicas in the option?

added an invalid option test in QueryValidationTest

[PrachiKhobragade]

can we add sample docs to the description? is this specific to replica group based assignment or a generic solution where users can override routing strategy on a per query basis

This is specific to replica group based assignment in which user can specify in each query string to use more than one replica group for query execution. @PrachiKhobragade correct me if I'm wrong.

@kishoreg This will be specific to Replica Group based based routing

[PrachiKhobragade]

Please add a brief Release Note section to the PR description.

@sajjad-moradi added

[snleee]

LGTM. Thank you for adding this feature!