[Backport] IncrementalIndex#add is no longer thread-safe. #15793
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* IncrementalIndex#add is no longer thread-safe. Following apache#14866, there is no longer a reason for IncrementalIndex#add to be thread-safe. It turns out it already was not using its selectors in a thread-safe way, as exposed by apache#15615 making `testMultithreadAddFactsUsingExpressionAndJavaScript` in `IncrementalIndexIngestionTest` flaky. Note that this problem isn't new: Strings have been stored in the dimension selectors for some time, but we didn't have a test that checked for that case; we only have this test that checks for concurrent adds involving numeric selectors. At any rate, this patch changes OnheapIncrementalIndex to no longer try to offer a thread-safe "add" method. It also improves performance a bit by adding a row ID supplier to the selectors it uses to read InputRows, meaning that it can get the benefit of caching values inside the selectors. This patch also: 1) Adds synchronization to HyperUniquesAggregator and CardinalityAggregator, which the similar datasketches versions already have. This is done to help them adhere to the contract of Aggregator: concurrent calls to "aggregate" and "get" must be thread-safe. 2) Updates OnHeapIncrementalIndexBenchmark to use JMH and moves it to the druid-benchmarks module. * Spelling. * Changes from static analysis. * Fix javadoc.
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abhishekagarwal87
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Jan 30, 2024
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Backport of #15697 to 29.0.0.