* allow JsonConfigTesterBase to treat the fields of collections
* [Feature] Exhibitor Support (#3664)
This patch provides the integration of Druid & Netflix Exhibitor. Druid
currently use Apache Curator as ZooKeeper client. Curator can be
integrated with Exhibitor to achieve a live/updating list of the
ZooKeeper ensemble. This patch enables Druid to use this features.
* Fix#3795 (Java 7 compatibility).
Also introduce Animal Sniffer checks during build, which would
have caught the original problems.
* Add Animal Sniffer on caffeine-cache for JDK8.
* Add metrics for Query Count statistics
This PR adds a new metrics monitor “QueryCountStatsMonitor” which emits
three new metrics -
1) query/success/count - number of successful queries
2) query/failed/count - number of failed queries
3) query/interrupted/count - number of interrupted/timedout queries
fix bindings
* make fields final
* fix imports
* AsyncQueryForwardingServlet implement QueryStatsProvider
* remove unused import
* Enable parallel test
* Remove unnecessary NotThreadSafe annocation
* Randomize the start port when finding available ports
* Fix test failure
* Change to handle all negatives
* report message gap, source gap and sink count in RealtimePlumber
* report message gap, sink count in Appenderator
* add ingest/events/sourceGap in metrics.md
* remove source gap
* Fix PathChildrenCache's executorService leak in Announcer, CuratorInventoryManager and RemoteTaskRunner
* Use a single ExecutorService for all workerStatusPathChildrenCaches in RemoteTaskRunner
* make sure CliCoordinator initializes and starts DerbyMetadataStorage first if configured
* Revert "make sure CliCoordinator initializes and starts DerbyMetadataStorage first if configured"
This reverts commit 54f5644054626d4a9e2448bb4bd5e6ce9a9fca1d.
* make sure CliCoordinator initializes and starts DerbyMetadataStorage first if configured
* Normalized Cost Balancer
* Adding documentation and renaming to use diskNormalizedCostBalancer
* Remove balancer from the strings
* Update docs and include random cost balancer
* Fix checkstyle issues
This retries when the start condition is met but SELECT -> INSERT/UPDATE
fails, which indicates a race. If the start condition isn't met, there
won't be any retrying.
* Update emitter dependency to 0.4.0 and emit "version" dimension for all druid metrics, not only query metrics
* Remove unused imports
* Use empty string instead of "testing-version" as a version placeholder
Excludes tests from AvoidStaticImport, since those are used often there and
I didn't want to make this changeset too large. Production code use was minimal
and I switched those to non-static imports.
This is useful for the insert-segment-to-db tool, which would otherwise
potentially insert a lot of overshadowed segments as "used", causing
load and drop churn in the cluster.
* print exception details from QueryInterruptedException
* in QueryResource.java, set thread name to include dataSource names and not whole query string e.g. from QueryDataSource
* Add support for timezone in segment granularity
* CR feedback. Handle null timezone during equals check.
* Include timezone in docs.
Add timezone for ArbitraryGranularitySpec.
* Show candidate hosts for the given query
* Added test cases & minor changes to address comments
* Changed path-param to query-pram for intervals/numCandidates
* support renaming of outputName for cached select and search queries
* rebase and resolve conflicts
* rollback CacheStrategy interface change
* updated based on review comments
* introducing lists of existing columns in the fields of select queries' output
* rebase master
* address the comment. add test code for select query caching
* change the cache code in SelectQueryQueryToolChest to 0x16
Follow-up to #1773, which meant to add more useful query errors but
did not actually do so. Since that patch, any error other than
interrupt/cancel/timeout was reported as `{"error":"Unknown exception"}`.
With this patch, the error fields are:
- error, one of the specific strings "Query interrupted", "Query timeout",
"Query cancelled", or "Unknown exception" (same behavior as before).
- errorMessage, the message of the topmost non-QueryInterruptedException
in the causality chain.
- errorClass, the class of the topmost non-QueryInterruptedException
in the causality chain.
- host, the host that failed the query.
* ability to not rollup at index time, make pre aggregation an option
* rename getRowIndexForRollup to getPriorIndex
* fix doc misspelling
* test query using no-rollup indexes
* fix benchmark fail due to jmh bug
* Add numeric StringComparator
* Only use direct long comparison for numeric ordering in BoundFilter, add time filtering benchmark query
* Address PR comments, add multithreaded BoundDimFilter test
* Add comment on strlen tie handling
* Add timeseries interval filter benchmark
* Adjust docs
* Use jackson for StringComparator, address PR comments
* Add new TopNMetricSpec and SearchSortSpec with tests (WIP)
* More TopNMetricSpec and SearchSortSpec tests
* Fix NewSearchSortSpec serde
* Update docs for new DimensionTopNMetricSpec
* Delete NumericDimensionTopNMetricSpec
* Delete old SearchSortSpec
* Rename NewSearchSortSpec to SearchSortSpec
* Add TopN numeric comparator benchmark, address PR comments
* Refactor OrderByColumnSpec
* Add null checks to NumericComparator and String->BigDecimal conversion function
* Add more OrderByColumnSpec serde tests
This reverts commit a931debf79.
Fixes#3283
The core issue here is that realtime nodes announce their size as 0, so a coordinator which interns the realtime version of the data segment will not be able to see the new sized announcement when handoff occurs.
This is caused by the `eauals` method on a `DataSegment` only evaluating the identifier. the `eauals` method *should* be correct for object equivalence, and things which need to check equivalence of some sub-portion of the object should do so explicitly.
Fixes inconsistent metric handling between the two implementations. Formerly,
RealtimePlumber only emitted query/segmentAndCache/time and query/wait and
Appenderator only emitted query/partial/time and query/wait (all per sink).
Now they both do the same thing:
- query/segmentAndCache/time, query/segment/time are the time spent per sink.
- query/cpu/time is the CPU time spent per query.
- query/wait/time is the executor waiting time per sink.
These generally match historical metrics, except segmentAndCache & segment
mean the same thing here, because one Sink may be partially cached and
partially uncached and we aren't splitting that out.
All query metrics now start with toolChest.makeMetricBuilder, and all of
*those* now start with DruidMetrics.makePartialQueryTimeMetric. Also, "id"
moved to common code, since all query metrics added it anyway.
In particular this will add query-type specific dimensions like "threshold"
and "numDimensions" to servlet-originated metrics like query/time.
* Migrate IndexerSQLMetadataStorageCoordinator.getUnusedSegmentsForInterval to streaming
* Missed query from #2859
* Make inReadOnlyTransaction part of SQLMetadataConnector
This patch introduces a GroupByStrategy concept and two strategies: "v1"
is the current groupBy strategy and "v2" is a new one. It also introduces
a merge buffers concept in DruidProcessingModule, to try to better
manage memory used for merging.
Both of these are described in more detail in #2987.
There are two goals of this patch:
1. Make it possible for historical/realtime nodes to return larger groupBy
result sets, faster, with better memory management.
2. Make it possible for brokers to merge streams when there are no order-by
columns, avoiding materialization.
This patch does not do anything to help with memory management on the broker
when there are order-by columns or when there are nested queries. That could
potentially be done in a future patch.
* add get dimension rangeset to filters
* add get domain to ShardSpec and added chunk filter in caching clustered client
* add null check and modified not filter, started with unit test
* add filter test with caching
* refactor and some comments
* extract filtershard to helper function
* fixup
* minor changes
* update javadoc
* fix caching for search results
properly read count when reading from cache.
* fix NPE during merging search count and add test
* Update cache key to invalidate prev results
* validate X-Druid-Task-Id header in request and add header to response
* modify KafkaIndexTaskClient to take a TaskLocationProvider as the TaskLocation may not remain constant
* Allow dynamically setting of shutoffTime for EventReceiverFirehose
Allow dynamically setting shutoffTime for EventReceiverFirehose
review comments and tests
* shut down exec on close
* Datasource as lookup tier
* Adds an option to let indexing service tasks pull their lookup tier from the datasource they are working for.
* Fix bad docs for lookups lookupTier
* Add Datasource name holder
* Move task and datasource to be pulled from Task file
* Make LookupModule pull from bound dataSource
* Fix test
* Fix code style on imports
* Fix formatting
* Make naming better
* Address code comments about naming
* new interval based cost function
Addresses issues with balancing of segments in the existing cost function
- `gapPenalty` led to clusters of segments ~30 days apart
- `recencyPenalty` caused imbalance among recent segments
- size-based cost could be skewed by compression
New cost function is purely based on segment intervals:
- assumes each time-slice of a partition is a constant cost
- cost is additive, i.e. cost(A, B union C) = cost(A, B) + cost(A, C)
- cost decays exponentially based on distance between time-slices
* comments and formatting
* add more comments to explain the calculation
* Allow user to set cost balancer threads more than the number of cores.
Allow user to set cost balancer threads more than the number of cores.
* modify test
* Optimize CostBalancerStrategy
Ignore benchmark test in normal run
fix test
review comments
fix compilation
fix test
* review comments
* review comment
* Make URI Exctraction Namespace take more sane arguments
* Fixes https://github.com/druid-io/druid/issues/2669
* Update docs
* Rename error message
* Undo overzealous deletion of docs
* Explain caching mechanism a bit more in docs
- Introduce `AuthorizationInfo` interface, specific implementations of which would be provided by extensions
- If the `druid.auth.enabled` is set to `true` then the `isAuthorized` method of `AuthorizationInfo` will be called to perform authorization checks
- `AuthorizationInfo` object will be created in the servlet filters of specific extension and will be passed as a request attribute with attribute name as `AuthConfig.DRUID_AUTH_TOKEN`
- As per the scope of this PR, all resources that needs to be secured are divided into 3 types - `DATASOURCE`, `CONFIG` and `STATE`. For any type of resource, possible actions are - `READ` or `WRITE`
- Specific ResourceFilters are used to perform auth checks for all endpoints that corresponds to a specific resource type. This prevents duplication of logic and need to inject HttpServletRequest inside each endpoint. For example
- `DatasourceResourceFilter` is used for endpoints where the datasource information is present after "datasources" segment in the request Path such as `/druid/coordinator/v1/datasources/`, `/druid/coordinator/v1/metadata/datasources/`, `/druid/v2/datasources/`
- `RulesResourceFilter` is used where the datasource information is present after "rules" segment in the request Path such as `/druid/coordinator/v1/rules/`
- `TaskResourceFilter` is used for endpoints is used where the datasource information is present after "task" segment in the request Path such as `druid/indexer/v1/task`
- `ConfigResourceFilter` is used for endpoints like `/druid/coordinator/v1/config`, `/druid/indexer/v1/worker`, `/druid/worker/v1` etc
- `StateResourceFilter` is used for endpoints like `/druid/broker/v1/loadstatus`, `/druid/coordinator/v1/leader`, `/druid/coordinator/v1/loadqueue`, `/druid/coordinator/v1/rules` etc
- For endpoints where a list of resources is returned like `/druid/coordinator/v1/datasources`, `/druid/indexer/v1/completeTasks` etc. the list is filtered to return only the resources to which the requested user has access. In these cases, `HttpServletRequest` instance needs to be injected in the endpoint method.
Note -
JAX-RS specification provides an interface called `SecurityContext`. However, we did not use this but provided our own interface `AuthorizationInfo` mainly because it provides more flexibility. For example, `SecurityContext` has a method called `isUserInRole(String role)` which would be used for auth checks and if used then the mapping of what roles can access what resource needs to be modeled inside Druid either using some convention or some other means which is not very flexible as Druid has dynamic resources like datasources. Fixes#2355 with PR #2424
* Avoids fetching all segment records into heap by JDBC driver
* Set connection to read-only to help database optimize queries
* Update JDBC drivers (MySQL has fixes for streaming results)
* Add back FilteredServerView removed in a32906c7fd to reduce memory usage using watched tiers.
* Add functionality to specify "druid.broker.segment.watchedDataSources"
segment creation deterministic.
This means that each segment will contain data from just one Kafka
partition. So, users will probably not want to have a super high number
of Kafka partitions...
Fixes#2703.
Reverts "Update com.maxmind.geoip2 to 2.6.0" and exclude the google http client
from com.maxmind.geoip2. This should satisfy the original need from #2646 (wanting
to run Druid along with an upgraded com.google.http-client) while preventing
Jackson conflicts pointed out in #2717.
Fixes#2717.
This reverts commit 21b7572533.
Fixes#2682
IndexingService helpers are added according to the settings in runtime.properties.
Rather than having all the config.isXXX checks there, it makes sense to have a pluggable
approach for allowing the dynamic configuration to bring in implementations for helpers
without having to have hard-coded sets of available helpers. Plus, it will also make it possible for extensions to plug helpers in.
With https://github.com/druid-io/druid-api/pull/76, we could conditionally bind a helper to Coordinator's runlist.
The condition is driven by the value set in the runtime.properties.
I believe that the instanceof chain in Filters exists because in the past, Filter
and DimFilter were in different packages (DimFilter was in druid-client and Filter
was in druid-processing). And since druid-client didn't depend on druid-processing,
DimFilter couldn't have a toFilter method. But now it can.
com.maxmind.geoip2 2.6.0 depends on com.google.http-client 1.15.0-rc (3 years old).
When trying to include other libraries in Druid that require an up to date version of com.google.http-client this causes a problem.
Geared towards supporting transactional inserts of new segments. This involves an
interface "DataSourceMetadata" that allows combining of partially specified metadata
(useful for partitioned ingestion).
DataSource metadata is stored in a new "dataSource" table.
Appenderators are a way of getting more control over the ingestion process
than a Plumber allows. The idea is that existing Plumbers could be implemented
using Appenderators, but you could also implement things that Plumbers can't do.
FiniteAppenderatorDrivers help simplify indexing a finite stream of data.
Also:
- Sink: Ability to consider itself "finished" vs "still writable".
- Sink: Ability to return the number of rows contained within the sink.
The incremental indexes handle that now so it's not necessary.
Also, add debug logging and more detailed exceptions to the incremental
indexes for the case where there are parse exceptions during aggregation.
After finding the FireChief for a specific partition, Druid will need to find the specific queryRunner for each segment being queried by passing the query to FireChief. Currently Druid is passing the original query that contains all the segments need to be queried, it's possible that fireChief.getQueryRunner(query) returns more than 1 queryRunner because query.getIntervals() is not specific to a single segment.
In this patch, for each segment being queried, Druid will update the query with its corresponding SpecificSegmentSpec.
See stack traces here, from current master: https://gist.github.com/gianm/bd9a66c826995f97fc8f
1. The thread "qtp925672150-62" holds the lock on InternalInjectorCreator.class,
used by Scopes.SINGLETON, and wants the lock on "handlers" in Lifecycle.addMaybeStartHandler
called by DiscoveryModule.getServiceAnnouncer.
2. The main thread holds the lock on "handlers" in Lifecycle.addMaybeStartHandler, which it
took because it's trying to add the ExecutorLifecycle to the lifecycle. main is trying
to get the InternalInjectorCreator.class lock because it's running ExecutorLifecycle.start,
which does some Jackson deserialization, and Jackson needs that lock in order to inject
stuff into the Task it's deserializing.
This patch eagerly instantiates ChatHandlerResource (which I believe is what's trying to
create the ServiceAnnouncer in the qtp925672150-62 jetty thread) and the ExecutorLifecycle.
To bring consistency to docs and source this commit changes the default
values for maxRowsInMemory and rowFlushBoundary to 75000 after
discussion in PR https://github.com/druid-io/druid/pull/2457.
The previous default was 500000 and it's lower now on the grounds that
it's better for a default to be somewhat less efficient, and work,
than to reach for the stars and possibly result in
"OutOfMemoryError: java heap space" errors.
Add tests that verify whether RealtimeManager is querying the correct FireChief for a specific partition
make FireChief static and package private, add latches in the UT
Two changes:
- Allow IncrementalIndex to suppress ParseExceptions on "aggregate".
- Add "reportParseExceptions" option to realtime tuning configs. By default this is "false".
Behavior of the counters should now be:
- processed: Number of rows indexed, including rows where some fields could be parsed and some could not.
- thrownAway: Number of rows thrown away due to rejection policy.
- unparseable: Number of rows thrown away due to being completely unparseable (no fields salvageable at all).
If "reportParseExceptions" is true then "unparseable" will always be zero (because a parse error would
cause an exception to be thrown). In addition, "processed" will only include fully parseable rows
(because even partial parse failures will cause exceptions to be thrown).
Fixes#2510.
- Add druid.indexer.server.maxChatRequests, which sets up a QoSFilter on the main Jetty server.
- Deprecate druid.indexer.runner.separateIngestionEndpoint
- Deprecate druid.indexer.server.chathandler.*
- Throw most exceptions rather than suppressing them, which should help
detect problems. Continue suppressing exceptions that make sense to
suppress.
- Handle payload length checks consistently, and improve error message.
- Remove unused WorkerCuratorCoordinator.announceTaskAnnouncement method.
- Max znode length should be int, not long.
- Add tests.
* Defaults the thread priority to java.util.Thread.NORM_PRIORITY in io.druid.indexing.common.task.AbstractTask
* Each exec service has its own Task Factory which is assigned a priority for spawned task. Therefore each priority class has a unique exec service
* Added priority to tasks as taskPriority in the task context. <0 means low, 0 means take default, >0 means high. It is up to any particular implementation to determine how to handle these numbers
* Add options to ForkingTaskRunner
* Add "-XX:+UseThreadPriorities" default option
* Add "-XX:ThreadPriorityPolicy=42" default option
* AbstractTask - Removed unneded @JsonIgnore on priority
* Added priority to RealtimePlumber executors. All sub-executors (non query runners) get Thread.MIN_PRIORITY
* Add persistThreadPriority and mergeThreadPriority to realtime tuning config
Historical will drop a segment that shouldn't be dropped in the following scenario:
Historical node tried to load segmentA, but failed with SegmentLoadingException,
then ZkCoordinator called removeSegment(segmentA, blah) to schedule a runnable that would drop segmentA by deleting its files. Now, before that runnable executed, another LOAD request was sent to this historical, this time historical actually succeeded on loading segmentA and announced it. But later on, the scheduled drop-of-segment runnable started executing and removed the segment files, while historical is still announcing segmentA.
When one of the tiers have no servers, LoadRule should ignore that tier
and continue to load/drop segments in other available tiers.
the bug also causes whacky behavior with LoadRule with non existent
tier where the segment balancer keeps on moving segments to other nodes
in existing tiers but the extra segment copies are never dropped
eventually leading to all the tiers getting full .
`insert-segment-to-db` is a tool that can insert segments into Druid metadata storage. It is intended to be used
to update the segment table in metadata storage after people manually migrate segments from one place to another.
It can also be used to insert missing segment into Druid, or even recover metadata storage by telling it where the
segments are stored.
Note: This tool expects users to have Druid cluster running in a "safe" mode, where there are no active tasks to interfere
the segments being inserted. Users can optionally bring down the cluster to make 100% sure nothing is interfering.
- fixes#1970
- extracted out segment handoff callbacks in SegmentHandoffNotifier
which is responsible for tracking segment handoffs and doing callbacks
when handoff is complete.
- Coordinator now maintains a view of segments in the cluster, this
will affect the jam heap requirements for the overlord for large
clusters.
realtime index task and nodes now use HTTP end points exposed by the
coordinator to get serverView
review comment
fix realtime node guide injection
review comments
make test not rely on scheduled exec
fix compilation
fix import
review comment
introduce immutableSegmentLoadInfo
fix son reading
remove unnecessary logging
This change will cause the CachingClusteredClient to populate the "uncoveredIntervals"
key in the responseContext map. The value will be any intervals that were requested in
the query but are not actually covered by the segments underlying the data source.
For unit testing, CachingClisteredClientTest is testing the caching behavior of the
object and it is pretty hard to adjust it to only test this new behavior, so I created
a new, parallel "CachingClusteredClientFunctionalityTest" to simplify testing just
basic functionality.
This is done by killing and respawning the jvms rather than reconnecting to existing
jvms, for a couple reasons. One is that it lets you restore tasks after server reboots
too, and another is that it lets you upgrade all the software on a box at once by just
restarting everything.
The main changes are,
1) Add "canRestore" and "stopGracefully" methods to Tasks that say if a task can
stop gracefully, and actually do a graceful stop. RealtimeIndexTask is the only
one that currently implements this.
2) Add "stop" method to TaskRunners that attempts to do an orderly shutdown.
ThreadPoolTaskRunner- call stopGracefully on restorable tasks, wait for exit
ForkingTaskRunner- close output stream to restorable tasks, wait for exit
RemoteTaskRunner- do nothing special, we actually don't want to shutdown
3) Add "restore" method to TaskRunners that attempts to bootstrap tasks from last run.
Only ForkingTaskRunner does anything here. It maintains a "restore.json" file with
a list of restorable tasks.
4) Have the CliPeon's ExecutorLifecycle lock the task base directory to avoid a restored
task and a zombie old task from stomping on each other.
This PR adds adds the ability to skip incremental index when querying
results from realtime nodes. default behaviour is to include
incrementalIndex in queries.
review comment
This is a feature meant to allow realtime tasks to work without being told upfront
what shardSpec they should use (so we can potentially publish a variable number
of segments per interval).
The idea is that there is a "pendingSegments" table in the metadata store that
tracks allocated segments. Each one has a segment id (the same segment id we know
and love) and is also part of a sequence.
The sequences are an idea from @cheddar that offers a way of doing replication.
If there are N tasks reading exactly the same data with exactly the same logic
(think Kafka tasks reading a fixed range of offsets) then you can place them
in the same sequence, and they will generate the same sequence of segments.
add an EventReceiverFirehoseMonitor so that we can monitor how many
events have been queued in the EventReceiverFirehose and get a sense
about whether the firehose is under too much pressure.
1) Remove maven client from downloading extensions at runtime.
2) Provide a way to load Druid extensions and hadoop dependencies through file system.
3) Refactor pull-deps so that it can download extensions into extension directories.
4) Add documents on how to use this new extension loading mechanism.
5) Change the way how Druid tarball is generated. Now all the extensions + hadoop-client 2.3.0
are packaged within the Druid tarball.
Fixes#1727.
revert to doing merging for results for union queries on broker.
revert unrelated changes
Add test for union query runner
Add test
remove unused imports
fix imports
fix renamed file
fix test
update docs.
so that user hadoop related InputRowParsers are created only when needed
this allows overlord to accept a HadoopIndexTask with a hadoopy InputRowParser
and not fail because hadoopy InputRowParser might need hadoop libraries
1) Persist using Committer instead of Runnable. (Although the metadata object
is ignored in this patch)
2) Remove the getSink method.
3) Plumbers are now responsible for time-based and hydrant-full-based periodic
committing. (FireChief, RealtimeIndexTask, and IndexTask used to do this)
Support for Smile format for EventReceiverFireshoseFactory.
would help in decreasing network load on middle managers ingesting high
data volumes.
review comments
* Adds kafka, URI, and JDBC namespace defintions
* Add ability to explicitly rename using a "namespace" which is a particular data collection that is loaded on all realtime, historic nodes, and brokers. If any of these nodes has the namespace extension, ALL nodes have the namespace extension.
* Add namespace caching and populating (can be on heap or off heap)
* Add NamespaceExtractionCacheManager for handling caches
* Added ExtractionNamespace for handling metadata on the extraction namespaces
* Added ExtractionNamespaceUpdate for handling metadata related to updates
* Add extension which caches renames from a kafka stream (requires kafka8)
* Added README.md for the namespace kafka extension
* Added docs
* Added namespace/size, namespace/count, namespace/deltaTasksStarted metrics
Add static config for namespaces via `druid.query.extraction.namespace`
* This is a rebase of https://github.com/b-slim/druid/tree/static_config_only
Also, harmonize exception handling between the RealtimeIndexTask and the RealtimeManager.
Conditions other than null inputRows and parse errors bubble up in both.
Issue - while storing results in cache we store the event map which
contains aggregator names mapped to values. Now when someone fire same
query after renaming aggs, the cache key will be same but the event
will contain metric values mapped to older names which leads to wrong
results.
Fix - modify cache to not store raw event but the actual list of values
only.
review comments + fix dimension renaming
review comment
With the existing hash function some nodes could end up with 3 times the
number of keys as others. The following changes improve that to roughly
less than 5% differences across nodes.
- switch from fnv-1a to murmur3_128 hash
- increase repetitions for ketama algorithm
- test to analyze distribution
Also updates spymemcached for recent bugfixes
It is highly recommended to keep loading threads single threaded. There can be benefits to having multiple bootstrapping threads, though. Those bootstrapping threads shouldn't be kept alive for the whole life of the process, however.
Also, adjust some logging and do some code cleanup.
which could cause Guice duplicate binding errors.
Add unit test to replicate duplicate extension issue. Update documents. Add an package accessible getter for loadersMap for testing only.
Notice that extensions explicitly specified in druid.extensions.coordinates have a higher priority than ones included in the classpath.
Extension modules that don't have a canonical class name will be ignored.
Anyways, @guobingkun , if possible, can you please test proposed change and send another PR to fix#1016 . but that doesn't necessarily hold this PR, so I'm merging this.
renamed all [Max/Min]*.java to [DoubleMax/DoubleMin]*.java and created [Max/Min]AggregatorFactory.java which can be removed when we dont need the min/max aggregator type backward compatibility