The "new" IT framework provides a convenient way to package and run integration tests (ITs), but only for core modules. We have a use case to run an IT for a contrib extension: the proposed gRPC query extension. This PR provides the IT framework functionality to allow non-core ITs.
* Be able to load segments on Peons
This change introduces a new config on WorkerConfig
that indicates how many bytes of each storage
location to use for storage of a task. Said config
is divided up amongst the locations and slots
and then used to set TaskConfig.tmpStorageBytesPerTask
The Peons use their local task dir and
tmpStorageBytesPerTask as their StorageLocations for
the SegmentManager such that they can accept broadcast
segments.
Changes:
- Replace `OverlordHelper` with `OverlordDuty` to align with `CoordinatorDuty`
- Each duty has a `run()` method and defines a `Schedule` with an initial delay and period.
- Update existing duties `TaskLogAutoCleaner` and `DurableStorageCleaner`
- Add utility class `Configs`
- Update log, error messages and javadocs
- Other minor style improvements
* fix issues with filtering nulls on values coerced to numeric types
* fix issues with 'auto' type numeric columns in default value mode
* optimize variant typed columns without nested data
* more tests for 'auto' type column ingestion
We have seen that the first-time users often don't know the next steps if druid services are unresponsive for some reason. This PR makes some of those messages a bit more clear.
This PR fixes an issue when using 'auto' encoded LONG typed columns and the 'vectorized' query engine. These columns use a delta based bit-packing mechanism, and errors in the vectorized reader would cause it to incorrectly read column values for some bit sizes (1 through 32 bits). This is a regression caused by #11004, which added the optimized readers to improve performance, so impacts Druid versions 0.22.0+.
While writing the test I finally got sad enough about IndexSpec not having a "builder", so I made one, and switched all the things to use it. Apologies for the noise in this bug fix PR, the only real changes are in VSizeLongSerde, and the tests that have been modified to cover the buggy behavior, VSizeLongSerdeTest and ExpressionVectorSelectorsTest. Everything else is just cleanup of IndexSpec usage.
* MSQ: Support for querying lookup and inline data directly.
Main changes:
1) Add of LookupInputSpec and DataSourcePlan.forLookup.
2) Add InlineInputSpec, and modify of DataSourcePlan.forInline to use
this instead of an ExternalInputSpec with JSON. This allows the inline
data to act as the right-hand side of a join, if needed.
Supporting changes:
1) Modify JoinDataSource's leftFilter validation to be a little less
strict: it's now OK with leftFilter being attached to any concrete
leaf (no children) datasource, rather than requiring it be a table.
This allows MSQ to create JoinDataSource with InputNumberDataSource
as the base.
2) Add SegmentWranglerModule to CliIndexer, CliPeon. This allows them to
query lookups and inline data directly.
* Updates based on CI.
* Additional tests.
* Style fix.
* Remove unused import.
* Make the tasks run with only a single directory
There was a change that tried to get indexing to run on multiple disks
It made a bunch of changes to how tasks run, effectively hiding the
"safe" directory for tasks to write files into from the task code itself
making it extremely difficult to do anything correctly inside of a task.
This change reverts those changes inside of the tasks and makes it so that
only the task runners are the ones that make decisions about which
mount points should be used for storing task-related files.
It adds the config druid.worker.baseTaskDirs which can be used by the
task runners to know which directories they should schedule tasks inside of.
The TaskConfig remains the authoritative source of configuration for where
and how an individual task should be operating.
changes:
* introduce ColumnFormat to separate physical storage format from logical type. ColumnFormat is now used instead of ColumnCapabilities to get column handlers for segment creation
* introduce new 'auto' type indexer and merger which produces a new common nested format of columns, which is the next logical iteration of the nested column stuff. Essentially this is an automatic type column indexer that produces the most appropriate column for the given inputs, making either STRING, ARRAY<STRING>, LONG, ARRAY<LONG>, DOUBLE, ARRAY<DOUBLE>, or COMPLEX<json>.
* revert NestedDataColumnIndexer, NestedDataColumnMerger, NestedDataColumnSerializer to their version pre #13803 behavior (v4) for backwards compatibility
* fix a bug in RoaringBitmapSerdeFactory if anything actually ever wrote out an empty bitmap using toBytes and then later tried to read it (the nerve!)
array columns!
changes:
* add support for storing nested arrays of string, long, and double values as specialized nested columns instead of breaking them into separate element columns
* nested column type mimic behavior means that columns ingested with only root arrays of primitive values will be ARRAY typed columns
* neat test refactor stuff
* add v4 segment test
* add array element indexes
* add tests for unnest and array columns
* fix unnest column value selector cursor handling of null and empty arrays
* Improve memory efficiency of WrappedRoaringBitmap.
Two changes:
1) Use an int[] for sizes 4 or below.
2) Remove the boolean compressRunOnSerialization. Doesn't save much
space, but it does save a little, and it isn't adding a ton of value
to have it be configurable. It was originally configurable in case
anything broke when enabling it, but it's been a while and nothing
has broken.
* Slight adjustment.
* Adjust for inspection.
* Updates.
* Update snaps.
* Update test.
* Adjust test.
* Fix snaps.
The FiniteFirehoseFactory and InputRowParser classes were deprecated in 0.17.0 (#8823) in favor of InputSource & InputFormat. This PR removes the FiniteFirehoseFactory and all its implementations along with classes solely used by them like Fetcher (Used by PrefetchableTextFilesFirehoseFactory). Refactors classes including tests using FiniteFirehoseFactory to use InputSource instead.
Removing InputRowParser may not be as trivial as many classes that aren't deprecated depends on it (with no alternatives), like EventReceiverFirehoseFactory. Hence FirehoseFactory, EventReceiverFirehoseFactory, and Firehose are marked deprecated.
* Make CompactionSearchPolicy injectable
A small refactoring that makes the search policy for compaction injectable.
Future changes can introduce new search policies that can be configured and
injected so that operators can choose which search policy is best suited for
their cluster.
This will also allow us to de-couple the scheduling of compaction jobs from
the CompactSegments duty, allowing the co-ordinator to schedule compaction
jobs faster than the duty lifecycle.
This PR is made so that it easy to review the future changes.
* fix tests
* merge druid-core, extendedset, and druid-hll into druid-processing to simplify everything
* fix poms and license stuff
* mockito is evil
* allow reset of JvmUtils RuntimeInfo if tests used static injection to override
* Unify the handling of HTTP between SQL and Native
The SqlResource and QueryResource have been
using independent logic for things like error
handling and response context stuff. This
became abundantly clear and painful during a
change I was making for Window Functions, so
I unified them into using the same code for
walking the response and serializing it.
Things are still not perfectly unified (it would
be the absolute best if the SqlResource just
took SQL, planned it and then delegated the
query run entirely to the QueryResource), but
this refactor doesn't take that fully on.
The new code leverages async query processing
from our jetty container, the different
interaction model with the Resource means that
a lot of tests had to be adjusted to align with
the async query model. The semantics of the
tests remain the same with one exception: the
SqlResource used to not log requests that failed
authorization checks, now it does.
* Support for middle manager less druid, tasks launch as k8s jobs
* Fixing forking task runner test
* Test cleanup, dependency cleanup, intellij inspections cleanup
* Changes per PR review
Add configuration option to disable http/https proxy for the k8s client
Update the docs to provide more detail about sidecar support
* Removing un-needed log lines
* Small changes per PR review
* Upon task completion we callback to the overlord to update the status / locaiton, for slower k8s clusters, this reduces locking time significantly
* Merge conflict fix
* Fixing tests and docs
* update tiny-cluster.yaml
changed `enableTaskLevelLogPush` to `encapsulatedTask`
* Apply suggestions from code review
Co-authored-by: Abhishek Agarwal <1477457+abhishekagarwal87@users.noreply.github.com>
* Minor changes per PR request
* Cleanup, adding test to AbstractTask
* Add comment in peon.sh
* Bumping code coverage
* More tests to make code coverage happy
* Doh a duplicate dependnecy
* Integration test setup is weird for k8s, will do this in a different PR
* Reverting back all integration test changes, will do in anotbher PR
* use StringUtils.base64 instead of Base64
* Jdk is nasty, if i compress in jdk 11 in jdk 17 the decompressed result is different
Co-authored-by: Rahul Gidwani <r_gidwani@apple.com>
Co-authored-by: Abhishek Agarwal <1477457+abhishekagarwal87@users.noreply.github.com>
Async reads for JDBC:
Prevents JDBC timeouts on long queries by returning empty batches
when a batch fetch takes too long. Uses an async model to run the
result fetch concurrently with JDBC requests.
Fixed race condition in Druid's Avatica server-side handler
Fixed issue with no-user connections
We introduce two new configuration keys that refine the query context security model controlled by druid.auth.authorizeQueryContextParams. When that value is set to true then two other configuration options become available:
druid.auth.unsecuredContextKeys: The set of query context keys that do not require a security check. Use this for the "white-list" of key to allow. All other keys go through the existing context key security checks.
druid.auth.securedContextKeys: The set of query context keys that do require a security check. Use this when you want to allow all but a specific set of keys: only these keys go through the existing context key security checks.
Both are set using JSON list format:
druid.auth.securedContextKeys=["secretKey1", "secretKey2"]
You generally set one or the other values. If both are set, unsecuredContextKeys acts as exceptions to securedContextKeys.
In addition, Druid defines two query context keys which always bypass checks because Druid uses them internally:
sqlQueryId
sqlStringifyArrays
Druid currently uses Zookeeper dependent options as the default.
This commit updates the following to use HTTP as the default instead.
- task runner. `druid.indexer.runner.type=remote -> httpRemote`
- load queue peon. `druid.coordinator.loadqueuepeon.type=curator -> http`
- server inventory view. `druid.serverview.type=curator -> http`
* Fixing RACE in HTTP remote task Runner
* Changes in the interface
* Updating documentation
* Adding test cases to SwitchingTaskLogStreamer
* Adding more tests
This commit is a first draft of the revised integration test framework which provides:
- A new directory, integration-tests-ex that holds the new integration test structure. (For now, the existing integration-tests is left unchanged.)
- Maven module druid-it-tools to hold code placed into the Docker image.
- Maven module druid-it-image to build the Druid-only test image from the tarball produced in distribution. (Dependencies live in their "official" image.)
- Maven module druid-it-cases that holds the revised tests and the framework itself. The framework includes file-based test configuration, test-specific clients, test initialization and updated versions of some of the common test support classes.
The integration test setup is primarily a huge mass of details. This approach refactors many of those details: from how the image is built and configured to how the Docker Compose scripts are structured to test configuration. An extensive set of "readme" files explains those details. Rather than repeat that material here, please consult those files for explanations.
Refactors the DruidSchema and DruidTable abstractions to prepare for the Druid Catalog.
As we add the catalog, we’ll want to combine physical segment metadata information with “hints” provided by the catalog. This is best done if we tidy up the existing code to more clearly separate responsibilities.
This PR is purely a refactoring move: no functionality changed. There is no difference to user functionality or external APIs. Functionality changes will come later as we add the catalog itself.
DruidSchema
In the present code, DruidSchema does three tasks:
Holds the segment metadata cache
Interfaces with an external schema manager
Acts as a schema to Calcite
This PR splits those responsibilities.
DruidSchema holds the Calcite schema for the druid namespace, combining information fro the segment metadata cache, from the external schema manager and (later) from the catalog.
SegmentMetadataCache holds the segment metadata cache formerly in DruidSchema.
DruidTable
The present DruidTable class is a bit of a kitchen sink: it holds all the various kinds of tables which Druid supports, and uses if-statements to handle behavior that differs between types. Yet, any given DruidTable will handle only one such table type. To more clearly model the actual table types, we split DruidTable into several classes:
DruidTable becomes an abstract base class to hold Druid-specific methods.
DatasourceTable represents a datasource.
ExternalTable represents an external table, such as from EXTERN or (later) from the catalog.
InlineTable represents the internal case in which we attach data directly to a table.
LookupTable represents Druid’s lookup table mechanism.
The new subclasses are more focused: they can be selective about the data they hold and the various predicates since they represent just one table type. This will be important as the catalog information will differ depending on table type and the new structure makes adding that logic cleaner.
DatasourceMetadata
Previously, the DruidSchema segment cache would work with DruidTable objects. With the catalog, we need a layer between the segment metadata and the table as presented to Calcite. To fix this, the new SegmentMetadataCache class uses a new DatasourceMetadata class as its cache entry to hold only the “physical” segment metadata information: it is up to the DruidTable to combine this with the catalog information in a later PR.
More Efficient Table Resolution
Calcite provides a convenient base class for schema objects: AbstractSchema. However, this class is a bit too convenient: all we have to do is provide a map of tables and Calcite does the rest. This means that, to resolve any single datasource, say, foo, we need to cache segment metadata, external schema information, and catalog information for all tables. Just so Calcite can do a map lookup.
There is nothing special about AbstractSchema. We can handle table lookups ourselves. The new AbstractTableSchema does this. In fact, all the rest of Calcite wants is to resolve individual tables by name, and, for commands we don’t use, to provide a list of table names.
DruidSchema now extends AbstractTableSchema. SegmentMetadataCache resolves individual tables (and provides table names.)
DruidSchemaManager
DruidSchemaManager provides a way to specify table schemas externally. In this sense, it is similar to the catalog, but only for datasources. It originally followed the AbstractSchema pattern: it implements provide a map of tables. This PR provides new optional methods for the table lookup and table names operations. The default implementations work the same way that AbstractSchema works: we get the entire map and pick out the information we need. Extensions that use this API should be revised to support the individual operations instead. Druid code no longer calls the original getTables() method.
The PR has one breaking change: since the DruidSchemaManager map is read-only to the rest of Druid, we should return a Map, not a ConcurrentMap.
* Refactor Guice initialization
Builders for various module collections
Revise the extensions loader
Injector builders for server startup
Move Hadoop init to indexer
Clean up server node role filtering
Calcite test injector builder
* Revisions from review comments
* Build fixes
* Revisions from review comments
* Mid-level service client and updated high-level clients.
Our servers talk to each other over HTTP. We have a low-level HTTP
client (HttpClient) that is super-asynchronous and super-customizable
through its handlers. It's also proven to be quite robust: we use it
for Broker -> Historical communication over the wide variety of query
types and workloads we support.
But the low-level client has no facilities for service location or
retries, which means we have a variety of high-level clients that
implement these in their own ways. Some high-level clients do a better
job than others. This patch adds a mid-level ServiceClient that makes
it easier for high-level clients to be built correctly and harmoniously,
and migrates some of the high-level logic to use ServiceClients.
Main changes:
1) Add ServiceClient org.apache.druid.rpc package. That package also
contains supporting stuff like ServiceLocator and RetryPolicy
interfaces, and a DiscoveryServiceLocator based on
DruidNodeDiscoveryProvider.
2) Add high-level OverlordClient in org.apache.druid.rpc.indexing.
3) Indexing task client creator in TaskServiceClients. It uses
SpecificTaskServiceLocator to find the tasks. This improves on
ClientInfoTaskProvider by caching task locations for up to 30 seconds
across calls, reducing load on the Overlord.
4) Rework ParallelIndexSupervisorTaskClient to use a ServiceClient
instead of extending IndexTaskClient.
5) Rework RemoteTaskActionClient to use a ServiceClient instead of
DruidLeaderClient.
6) Rework LocalIntermediaryDataManager, TaskMonitor, and
ParallelIndexSupervisorTask. As a result, MiddleManager, Peon, and
Overlord no longer need IndexingServiceClient (which internally used
DruidLeaderClient).
There are some concrete benefits over the prior logic, namely:
- DruidLeaderClient does retries in its "go" method, but only retries
exactly 5 times, does not sleep between retries, and does not retry
retryable HTTP codes like 502, 503, 504. (It only retries IOExceptions.)
ServiceClient handles retries in a more reasonable way.
- DruidLeaderClient's methods are all synchronous, whereas ServiceClient
methods are asynchronous. This is used in one place so far: the
SpecificTaskServiceLocator, so we don't need to block a thread trying
to locate a task. It can be used in other places in the future.
- HttpIndexingServiceClient does not properly handle all server errors.
In some cases, it tries to parse a server error as a successful
response (for example: in getTaskStatus).
- IndexTaskClient currently makes an Overlord call on every task-to-task
HTTP request, as a way to find where the target task is. ServiceClient,
through SpecificTaskServiceLocator, caches these target locations
for a period of time.
* Style adjustments.
* For the coverage.
* Adjustments.
* Better behaviors.
* Fixes.
This commit contains the cleanup needed for the new integration test framework.
Changes:
- Fix log lines, misspellings, docs, etc.
- Allow the use of some of Druid's "JSON config" objects in tests
- Fix minor bug in `BaseNodeRoleWatcher`
* ForkingTaskRunner: Set ActiveProcessorCount for tasks.
This prevents various automatically-sized thread pools from being unreasonably
large (we don't want each task to size its pools as if it is the only thing on
the entire machine).
* Fix tests.
* Add missing LifecycleStart annotation.
* ForkingTaskRunner needs ManageLifecycle.
* Add QoSFilters first in the chain.
When a request is suspended and later resumed due to QoS constraints,
its filter chain is restarted. Placing QoSFilters first in the chain
avoids double-execution of other filters.
Fixes an issue where requests deferred by QoS would report 403 Forbidden
due to double-execution of SecuritySanityCheckFilter.
* Smaller changes.
* Add QoS filters in BaseJettyTest.
* Remove unused parameter.
Following up on #12315, which pushed most of the logic of building ImmutableBitmap into BitmapIndex in order to hide the details of how column indexes are implemented from the Filter implementations, this PR totally refashions how Filter consume indexes. The end result, while a rather dramatic reshuffling of the existing code, should be extraordinarily flexible, eventually allowing us to model any type of index we can imagine, and providing the machinery to build the filters that use them, while also allowing for other column implementations to implement the built-in index types to provide adapters to make use indexing in the current set filters that Druid provides.
* upgrade Airline to Airline 2
https://github.com/airlift/airline is no longer maintained, updating to
https://github.com/rvesse/airline (Airline 2) to use an actively
maintained version, while minimizing breaking changes.
Note, this is a backwards incompatible change, and extensions relying on
the CliCommandCreator extension point will also need to be updated.
* fix dependency checks where jakarta.inject is now resolved first instead
of javax.inject, due to Airline 2 using jakarta
* Thread pool for broker
* Updating two tests to improve coverage for new method added
* Updating druidProcessingConfigTest to cover coverage
* Adding missed spelling errors caused in doc
* Adding test to cover lines of new function added
* Make nodeRole available during binding; add support for dynamic registration of DruidService
* fix checkstyle and test
* fix customRole test
* address comments
* add more javadoc
Add support for hadoop 3 profiles . Most of the details are captured in #11791 .
We use a combination of maven profiles and resource filtering to achieve this. Hadoop2 is supported by default and a new maven profile with the name hadoop3 is created. This will allow the user to choose the profile which is best suited for the use case.
* Add the ability to add a context to internally generated druid broker queries
* fix docs
* changes after first CI failure
* cleanup after merge with master
* change default to empty map and improve unit tests
* add doc info and fix checkstyle
* refactor DruidSchema#runSegmentMetadataQuery and add a unit test
* Rename field, fix router documentation
* Add more lines to doc
* Apply doc suggestions from code review
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* initial work
* reduce lock in sqlLifecycle
* Integration test for sql canceling
* javadoc, cleanup, more tests
* log level to debug
* fix test
* checkstyle
* fix flaky test; address comments
* rowTransformer
* cancelled state
* use lock
* explode instead of noop
* oops
* unused import
* less aggressive with state
* fix calcite charset
* don't emit metrics when you are not authorized
Fixes#11297.
Description
Description and design in the proposal #11297
Key changed/added classes in this PR
*DataSegmentPusher
*ShuffleClient
*PartitionStat
*PartitionLocation
*IntermediaryDataManager
This PR adds a new property druid.router.sql.enable which allows the
Router to handle SQL queries when set to true.
This change does not affect Avatica JDBC requests and they are still routed
by hashing the Connection ID.
To allow parsing of the request object as a SqlQuery (contained in module druid-sql),
some classes have been moved from druid-server to druid-services with
the same package name.
This PR refactors the code for QueryRunnerFactory#mergeRunners to accept a new interface called QueryProcessingPool instead of ExecutorService for concurrent execution of query runners. This interface will let custom extensions inject their own implementation for deciding which query-runner to prioritize first. The default implementation is the same as today that takes the priority of query into account. QueryProcessingPool can also be used as a regular executor service. It has a dedicated method for accepting query execution work so implementations can differentiate between regular async tasks and query execution tasks. This dedicated method also passes the QueryRunner object as part of the task information. This hook will let custom extensions carry any state from QuerySegmentWalker to QueryProcessingPool#mergeRunners which is not possible currently.
* Do stuff
* Do more stuff
* * Do more stuff
* * Do more stuff
* * working
* * cleanup
* * more cleanup
* * more cleanup
* * add license header
* * Add unit tests
* * add java docs
* * add more unit tests
* * Cleanup test
* * Move removing of workingPath to index task rather than in hadoop job.
* * Address review comments
* * remove unused import
* * Address review comments
* Do not overwrite segment descriptor for segment if it already exists.
* * add comments to FileSystemHelper class
* * fix local hadoop integration test
* * Fix failing test failures when running with java11
* Revert "Revert "Adjust HadoopIndexTask temp segment renaming to avoid potential race conditions (#11075)" (#11151)"
This reverts commit 49a9c3ffb7.
* * remove JobHelperPowerMockTest
* * remove FileSystemHelper class
* Add feature to automatically remove rules based on retention period
* Add feature to automatically remove rules based on retention period
* address comments
* Do stuff
* Do more stuff
* * Do more stuff
* * Do more stuff
* * working
* * cleanup
* * more cleanup
* * more cleanup
* * add license header
* * Add unit tests
* * add java docs
* * add more unit tests
* * Cleanup test
* * Move removing of workingPath to index task rather than in hadoop job.
* * Address review comments
* * remove unused import
* * Address review comments
* Do not overwrite segment descriptor for segment if it already exists.
* * add comments to FileSystemHelper class
* * fix local hadoop integration test
* Add ability to wait for segment availability for batch jobs
* IT updates
* fix queries in legacy hadoop IT
* Fix broken indexing integration tests
* address an lgtm flag
* spell checker still flagging for hadoop doc. adding under that file header too
* fix compaction IT
* Updates to wait for availability method
* improve unit testing for patch
* fix bad indentation
* refactor waitForSegmentAvailability
* Fixes based off of review comments
* cleanup to get compile after merging with master
* fix failing test after previous logic update
* add back code that must have gotten deleted during conflict resolution
* update some logging code
* fixes to get compilation working after merge with master
* reset interrupt flag in catch block after code review pointed it out
* small changes following self-review
* fixup some issues brought on by merge with master
* small changes after review
* cleanup a little bit after merge with master
* Fix potential resource leak in AbstractBatchIndexTask
* syntax fix
* Add a Compcation TuningConfig type
* add docs stipulating the lack of support by Compaction tasks for the new config
* Fixup compilation errors after merge with master
* Remove erreneous newline
* add offsetFetchPeriod to kinesis ingestion doc
* Remove jackson dependencies from extensions
* Use fixed delay for lag collection
* Metrics reset after finishing processing
* comments
* Broaden the list of exceptions to retry for
* Unit tests
* Add more tests
* Refactoring
* re-order metrics
* Doc suggestions
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
* Add tests
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
* Fix byte calculation for maxBytesInMemory to take into account of Sink/Hydrant Object overhead
* Fix byte calculation for maxBytesInMemory to take into account of Sink/Hydrant Object overhead
* Fix byte calculation for maxBytesInMemory to take into account of Sink/Hydrant Object overhead
* Fix byte calculation for maxBytesInMemory to take into account of Sink/Hydrant Object overhead
* fix checkstyle
* Fix byte calculation for maxBytesInMemory to take into account of Sink/Hydrant Object overhead
* Fix byte calculation for maxBytesInMemory to take into account of Sink/Hydrant Object overhead
* fix test
* fix test
* add log
* Fix byte calculation for maxBytesInMemory to take into account of Sink/Hydrant Object overhead
* address comments
* fix checkstyle
* fix checkstyle
* add config to skip overhead memory calculation
* add test for the skipBytesInMemoryOverheadCheck config
* add docs
* fix checkstyle
* fix checkstyle
* fix spelling
* address comments
* fix travis
* address comments
Added the status/selfDiscovered endpoint to indexer. Per the api-reference doc, all services support status/selfDiscovered endpoint. So this change would fix that expected behavior.
Also added example config files for indexer process that can be used to spin up the indexer process.
* Introduce a Configurable Index Type
* Change to @UnstableApi
* Add AppendableIndexSpecTest
* Update doc
* Add spelling exception
* Add tests coverage
* Revert some of the changes to reduce diff
* Minor fixes
* Update getMaxBytesInMemoryOrDefault() comment
* Fix typo, remove redundant interface
* Remove off-heap spec (postponed to a later PR)
* Add javadocs to AppendableIndexSpec
* Describe testCreateTask()
* Add tests for AppendableIndexSpec within TuningConfig
* Modify hashCode() to conform with equals()
* Add comment where building incremental-index
* Add "EqualsVerifier" tests
* Revert some of the API back to AppenderatorConfig
* Don't use multi-line comments
* Remove knob documentation (deferred)
* Add shuffle metrics for parallel indexing
* javadoc and concurrency test
* concurrency
* fix javadoc
* Feature flag
* doc
* fix doc and add a test
* checkstyle
* add tests
* fix build and address comments
* Adding more worker metrics to Druid Overlord
* Changing the nomenclature from worker to peon as that represents the metrics that we want to monitor better
* Few more instance of worker usage replaced with peon
* Modifying the peon idle count logic to only use eligible workers available capacity
* Changing the naming to task slot count instead of peon
* Adding some unit test coverage for the new test runner apis
* Addressing Review Comments
* Modifying the TaskSlotCountStatsProvider apis so that overlords which are not leader do not emit these metrics
* Fixing the spelling issue in the docs
* Setting the annotation Nullable on the TaskSlotCountStatsProvider methods
* Move tools for indexing to TaskToolbox instead of injecting them in constructor
* oops, other changes
* fix test
* unnecessary new file
* fix test
* fix build