* array_concat_agg and array_agg support for array inputs
changes:
* added array_concat_agg to aggregate arrays into a single array
* added array_agg support for array inputs to make nested array
* added 'shouldAggregateNullInputs' and 'shouldCombineAggregateNullInputs' to fix a correctness issue with STRING_AGG and ARRAY_AGG when merging results, with dual purpose of being an optimization for aggregating
* fix test
* tie capabilities type to legacy mode flag about coercing arrays to strings
* oops
* better javadoc
* fix bug where queries fail immediately when timeout is 0 instead of using default timeout
* fix to use serverside max
* more better
* less flaky test
* oops
Add the ability to pass time column in first/last aggregator (and latest/earliest SQL functions). It is to support cases where the time to query upon is stored as a part of a column different than __time. Also, some other logical time column can be specified.
* IMPLY-4344: Adding safe divide function along with testcases and documentation updates
* Changing based on review comments
* Addressing review comments, fixing coding style, docs and spelling
* Checkstyle passes for all code
* Fixing expected results for infinity
* Revert "Fixing expected results for infinity"
This reverts commit 5fd5cd480d.
* Updating test result and a space in docs
* revert ColumnAnalysis type, add typeSignature and use it for DruidSchema
* review stuffs
* maybe null
* better maybe null
* Update docs/querying/segmentmetadataquery.md
* Update docs/querying/segmentmetadataquery.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* fix null right
* sad
* oops
* Update batch_hadoop_queries.json
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Remove OffheapIncrementalIndex and clarify aggregator thread-safety needs.
This patch does the following:
- Removes OffheapIncrementalIndex.
- Clarifies that Aggregators are required to be thread safe.
- Clarifies that BufferAggregators and VectorAggregators are not
required to be thread safe.
- Removes thread safety code from some DataSketches aggregators that
had it. (Not all of them did, and that's OK, because it wasn't necessary
anyway.)
- Makes enabling "useOffheap" with groupBy v1 an error.
Rationale for removing the offheap incremental index:
- It is only used in one rare scenario: groupBy v1 (which is non-default)
in "useOffheap" mode (also non-default). So you have to go pretty deep
into the wilderness to get this code to activate in production. It is
never used during ingestion.
- Its existence complicates developer efforts to reason about how
aggregators get used, because the way it uses buffer aggregators is so
different from how every other query engine uses them.
- It doesn't have meaningful testing.
By the way, I do believe that the given way the offheap incremental index
works, it actually didn't require buffer aggregators to be thread-safe.
It synchronizes on "aggregate" and doesn't call "get" until it has
stopped calling "aggregate". Nevertheless, this is a bother to think about,
and for the above reasons I think it makes sense to remove the code anyway.
* Remove things that are now unused.
* Revert removal of getFloat, getLong, getDouble from BufferAggregator.
* OAK-related warnings, suppressions.
* Unused item suppressions.
* Add druid.sql.approxCountDistinct.function property.
The new property allows admins to configure the implementation for
APPROX_COUNT_DISTINCT and COUNT(DISTINCT expr) in approximate mode.
The motivation for adding this setting is to enable site admins to
switch the default HLL implementation to DataSketches.
For example, an admin can set:
druid.sql.approxCountDistinct.function = APPROX_COUNT_DISTINCT_DS_HLL
* Fixes
* Fix tests.
* Remove erroneous cannotVectorize.
* Remove unused import.
* Remove unused test imports.
* update docs with X-Druid-SQL-Query-Id
* review comments
* update header description
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update sql.md
Added two example queries and adjusted formatting of one that was already there
* Update docs/querying/sql.md
Co-authored-by: Frank Chen <frankchen@apache.org>
* Update docs/querying/sql.md
Co-authored-by: Frank Chen <frankchen@apache.org>
* Update docs/querying/sql.md
Co-authored-by: Frank Chen <frankchen@apache.org>
* Update docs/querying/sql.md
Co-authored-by: Frank Chen <frankchen@apache.org>
* Update sql.md
Co-authored-by: Frank Chen <frankchen@apache.org>
* add MV_FILTER_ONLY SQL function, and list filter virtual column
* MV_FILTER_NONE and more tests
* formatting
* o yeah, forgot can do easy thing
* style
* hmm why was that there
* test filtering on virtual column
* style
* meh
* do it right
* good bot
* Update granularities.md
Link-back to the ingestion spec as well as Native queries plus examples.
* Update docs/querying/granularities.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/granularities.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Configurable maxStreamLength for doubles sketches
* fix equals/hashcode and it test failure
* fix test
* fix it test
* benchmark
* doc
* grouping key
* fix comment
* dependency check
* Update docs/development/extensions-core/datasketches-quantiles.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* Update docs/querying/sql.md
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
* add binary_byte_format/decimal_byte_format/decimal_format
* clean code
* fix doc
* fix review comments
* add spelling check rules
* remove extra param
* improve type handling and null handling
* remove extra zeros
* fix tests and add space between unit suffix and number as most size-format functions do
* fix tests
* add examples
* change function names according to review comments
* fix merge
Signed-off-by: frank chen <frank.chen021@outlook.com>
* no need to configure NullHandling explicitly for tests
Signed-off-by: frank chen <frank.chen021@outlook.com>
* fix tests in SQL-Compatible mode
Signed-off-by: frank chen <frank.chen021@outlook.com>
* Resolve review comments
* Update SQL test case to check null handling
* Fix intellij inspections
* Add more examples
* Fix example
This change allows the selection of a specific broker service (or broker tier) by the Router.
The newly added ManualTieredBrokerSelectorStrategy works as follows:
Check for the parameter brokerService in the query context. If this is a valid broker service, use it.
Check if the field defaultManualBrokerService has been set in the strategy. If this is a valid broker service, use it.
Move on to the next strategy
* HLL lgK and a tip
Knowledge transfer from https://the-asf.slack.com/archives/CJ8D1JTB8/p1600699967024200. Attempted to make a connection between the SQL HLL function and the HLL underneath without getting too complicated. Also added a note about using K over 16 being pretty much pointless.
* Corrected spelling
* Create datasketches-hll.md
Put roll-up back to rollup
* Update docs/development/extensions-core/datasketches-hll.md
Co-authored-by: Abhishek Agarwal <1477457+abhishekagarwal87@users.noreply.github.com>
Co-authored-by: Abhishek Agarwal <1477457+abhishekagarwal87@users.noreply.github.com>
* add single input string expression dimension vector selector and better expression planning
* better
* fixes
* oops
* rework how vector processor factories choose string processors, fix to be less aggressive about vectorizing
* oops
* javadocs, renaming
* more javadocs
* benchmarks
* use string expression vector processor with vector size 1 instead of expr.eval
* better logging
* javadocs, surprising number of the the
* more
* simplify
* SQL timeseries no longer skip empty buckets with all granularity
* add comment, fix tests
* the ol switcheroo
* revert unintended change
* docs and more tests
* style
* make checkstyle happy
* docs fixes and more tests
* add docs, tests for array_agg
* fixes
* oops
* doc stuffs
* fix compile, match doc style
* Update datasource.md
Change "table" to "datasource" in join discussion: This means that all datasources
other than the leftmost "base" table must fit in memory.
According to docs on datasources, "datasource" is the more general term, and a table is a kind of datasource. In the context here, then, "datasource" is applicable.
* left-hand table -> left-hand datasource
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
Co-authored-by: sthetland <steve.hetland@imply.io>
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
* ARRAY_AGG sql aggregator function
* add javadoc
* spelling
* review stuff, return null instead of empty when nil input
* review stuff
* Update sql.md
* use type inference for finalize, refactor some things
The main one is updating datasources.md to talk about SQL. (It still said
that table unions are not supported in SQL.) Also, this doc update adds
some clarifying details on limitations.
* Clarify docs
* Apply suggestions from code review
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
Co-authored-by: Charles Smith <38529548+techdocsmith@users.noreply.github.com>
* integration test for coordinator and overlord leadership, added sys.servers is_leader column
* docs
* remove not needed
* fix comments
* fix compile heh
* oof
* revert unintended
* fix tests, split out docker-compose file selection from starting cluster, use docker-compose down to stop cluster
* fixes
* style
* dang
* heh
* scripts are hard
* fix spelling
* fix thing that must not matter since was already wrong ip, log when test fails
* needs more heap
* fix merge
* less aggro
* First draft of grouping_id function
* Add more tests and documentation
* Add calcite tests
* Fix travis failures
* bit of a change
* Add documentation
* Fix typos
* typo fix
* Add documentation for when caching is unsupported
* Minor changes
* Minor doc fix
* Review comments
* Add more details
* Fix spelling check
* Fix doc for union query
* Trailing dot
* fix JSON format
* Change all columns in sys segments to be JSON
* Change all columns in sys segments to be JSON
* add tests
* fix failing tests
* fix failing tests
* Store hash partition function in dataSegment and allow segment pruning only when hash partition function is provided
* query context
* fix tests; add more test
* javadoc
* docs and more tests
* remove default and hadoop tests
* consistent name and fix javadoc
* spelling and field name
* default function for partitionsSpec
* other comments
* address comments
* fix tests and spelling
* test
* doc
* subtotalsSpec results with null values
Document the format change in results of a groupBy query with a subtotalsSpec. This update applies to 0.18 and later.
* Review catches
* SQL support for union datasources.
Exposed via the "UNION ALL" operator. This means that there are now two
different implementations of UNION ALL: one at the top level of a query
that works by concatenating subquery results, and one at the table level
that works by creating a UnionDataSource.
The SQL documentation is updated to discuss these two use cases and how
they behave.
Future work could unify these by building support for a native datasource
that represents the union of multiple subqueries. (Today, UnionDataSource
can only represent the union of tables, not subqueries.)
* Fixes.
* Error message for sanity check.
* Additional test fixes.
* Add some error messages.
* Fix handling of 'join' on top of 'union' datasources.
The problem is that unions are typically rewritten into a series of
individual queries on the underlying tables, but this isn't done when
the union is wrapped in a join.
The main changes are in UnionQueryRunner:
1) Replace an instanceof UnionQueryRunner check with DataSourceAnalysis.
2) Replace a "query.withDataSource" call with a new function, "Queries.withBaseDataSource".
Together, these enable UnionQueryRunner to "see through" a join.
* Tests.
* Adjust heap sizes for integration tests.
* Different approach, more tests.
* Tweak.
* Styling.
* Add SQL "OFFSET" clause.
Under the hood, this uses the new offset features from #10233 (Scan)
and #10235 (GroupBy). Since Timeseries and TopN queries do not currently
have an offset feature, SQL planning will switch from one of those to
Scan or GroupBy if users add an OFFSET.
Includes a refactoring to harmonize offset and limit planning using an
OffsetLimit wrapper class. This is useful because it ensures that the
various places that need to deal with offset and limit collapsing all
behave the same way, using its "andThen" method.
* Fix test and add another test.
* Add note about aggreations on floats
Floating point math is known to be unstable. Due to the way aggregators work
across segments it's possible for the same query operating on the same data to
produce slightly different results.
The same problem exists with any aggregators that are not commutative since
the merge order across segments is not guaranteed.
* Also talk about doubles
* Apply suggestions from code review
* Add "offset" parameter to the Scan query.
It works by doing the query as normal and then throwing away the first
"offset" number of rows on the broker.
* Fix constructor call.
* Fix up JSONs.
* Fix call to ScanQuery.
* Doc update.
* Fix javadocs.
* Spotbugs, LGTM suppressions.
* Javadocs.
* Fix suppression.
* Stabilize Scan query result order, add tests.
* Update LGTM comment.
* Fixup.
* Test different batch sizes too.
* Nicer tests.
* Fix comment.
* LongMaxVectorAggregator support and test case.
* DoubleMinVectorAggregator and test cases.
* DoubleMaxVectorAggregator and unit test.
* FloatMinVectorAggregator and FloatMaxVectorAggregator.
* Documentation update to include the other vector aggregators.
* Bug fix.
* checkstyle formatting fixes.
* CalciteQueryTest cases update.
* Separate test classes for FloatMaxAggregation and FloatMniAggregation.
* remove the cannotVectorize for float max/min aggregator in test.
* Tests in GroupByQueryRunner, GroupByTimeseriesQueryRunner and TimeseriesQueryRunner.
* Add "offset" parameter to GroupBy query.
It works by doing the query as normal and then throwing away the first
"offset" number of rows on the broker.
* Stabilize GroupBy sorts.
* Fix inspections.
* Fix suppression.
* Fixups.
* Move TopNSequence to druid-core.
* Addl comments.
* NumberedElement equals verification.
* Changes from review.
* Fix minor formatting in docs.
* Add Nullhandling initialization for test to run from IDE.
* Vectorize longMin aggregator.
- A new vectorized class for the vectorized long min aggregator.
- Changes to AggregatorFactory to support vectorize functionality.
- Few changes to schema evolution test to add LongMinAggregatorFactory.
* Add longSum to the supported vectorized aggregator implementations.
* Add MIN() long min to calcite query test that can vectorize.
* Add simple long aggregations test.
* Fixup formatting per checkstyle guide.
* fixup and add more tests for long min aggregator.
* Override test for groupBy since timestamps are handled differently.
* Null compatibility check in test.
* Review comment: Add a test case to LongMinAggregationTest.
* ROUND and having comparators correctly handle doubles
Double.NaN, Double.POSITIVE_INFINITY and Double.NEGATIVE_INFINITY are not real
numbers. Because of this, they can not be converted to BigDecimal and instead
throw a NumberFormatException.
This change adds support for calculations that produce these numbers either
for use in the `ROUND` function or the HavingSpecMetricComparator by not
attempting to convert the number to a BigDecimal.
The bug in ROUND was first introduced in #7224 where we added the ability to
round to any decimal place. This PR changes the behavior back to using
`Math.round` if we recognize a number that can not be converted to a
BigDecimal.
* Add tests and fix spellcheck
* update error message in ExpressionsTest
* Address comments
* fix up round for infinity
* round non numeric doubles returns a double
* fix spotbugs
* Update docs/misc/math-expr.md
* Update docs/querying/sql.md
* lpad and rpad functions deal with empty pad
Return null if the pad string used by the `lpad` and `rpad` functions is
an empty string
* Fix rpad
* Match PostgreSQL behavior in SQL compliant null handling mode
* Match PostgreSQL behavior for pad -ve len
* address review comments
* Add REGEXP_LIKE, fix empty-pattern bug in REGEXP_EXTRACT.
- Add REGEXP_LIKE function that returns a boolean, and is useful in
WHERE clauses.
- Fix REGEXP_EXTRACT return type (should be nullable; causes incorrect
filter elision).
- Fix REGEXP_EXTRACT behavior for empty patterns: should always match
(previously, they threw errors).
- Improve error behavior when REGEXP_EXTRACT and REGEXP_LIKE are passed
non-literal patterns.
- Improve documentation of REGEXP_EXTRACT.
* Changes based on PR review.
* Fix arg check.
* Important fixes!
* Add speller.
* wip
* Additional tests.
* Fix up tests.
* Add validation error tests.
* Additional tests.
* Remove useless call.
* Update tutorial-query.md
* First full pass complete
* Smoothing over, a bit
* link and spell checking
* Update querying.md
* Review comments; screenshot fixes
* Making ports consistent, pending confirmation
Switching to the Router port, to make this be consistent with the tutorial ports, but can switch back here and there if it should be 8082 instead.
* Resizing screenshot
* Update querying.md
* Review feedback incorporated.
* Bad plan for table-lookup-lookup join with filter on first lookup and outer limit
* Bad plan for table-lookup-lookup join with filter on first lookup and outer limit
* Bad plan for table-lookup-lookup join with filter on first lookup and outer limit
* Bad plan for table-lookup-lookup join with filter on first lookup and outer limit
* Bad plan for table-lookup-lookup join with filter on first lookup and outer limit
* Bad plan for table-lookup-lookup join with filter on first lookup and outer limit
* address comments
* address comments
* fix checkstyle
* address comments
* address comments
- Reorder both the datasource and query-execution page orderings to
table, lookup, union, inline, query, join. (Roughly increasing order
of conceptual "fanciness".)
- Add more crosslinks from datasource page to query-execution page:
one per datasource type.
* Refresh query docs.
Larger changes:
- New doc: querying/datasource.md describes the various kinds of
datasources you can use, and has examples for both SQL and native.
- New doc: querying/query-execution.md describes how native queries
are executed at a high level. It doesn't go into the details of specific
query engines or how queries run at a per-segment level. But I think it
would be good to add or link that content here in the future.
- Refreshed doc: querying/sql.md updated to refer to joins, reformatted
a bit, added a new "Query translation" section that explains how
queries are translated from SQL to native, and removed configuration
details (moved to configuration/index.md).
- Refreshed doc: querying/joins.md updated to refer to join datasources.
Smaller changes:
- Add helpful banners to the top of query documentation pages telling
people whether a given page describes SQL, native, or both.
- Add SQL metrics to operations/metrics.md.
- Add some color and cross-links in various places.
- Add native query component docs to the sidebar, and renamed them so
they look nicer.
- Remove Select query from the sidebar.
- Fix Broker SQL configs in configuration/index.md. Remove them from
querying/sql.md.
- Combined querying/searchquery.md and querying/searchqueryspec.md.
* Updates.
* Fix numbering.
* Fix glitches.
* Add new words to spellcheck file.
* Assorted changes.
* Further adjustments.
* Add missing punctuation.
* SQL support for joins on subqueries.
Changes to SQL module:
- DruidJoinRule: Allow joins on subqueries (left/right are no longer
required to be scans or mappings).
- DruidJoinRel: Add cost estimation code for joins on subqueries.
- DruidSemiJoinRule, DruidSemiJoinRel: Removed, since DruidJoinRule can
handle this case now.
- DruidRel: Remove Nullable annotation from toDruidQuery, because
it is no longer needed (it was used by DruidSemiJoinRel).
- Update Rules constants to reflect new rules available in our current
version of Calcite. Some of these are useful for optimizing joins on
subqueries.
- Rework cost estimation to be in terms of cost per row, and place all
relevant constants in CostEstimates.
Other changes:
- RowBasedColumnSelectorFactory: Don't set hasMultipleValues. The lack
of isComplete is enough to let callers know that columns might have
multiple values, and explicitly setting it to true causes
ExpressionSelectors to think it definitely has multiple values, and
treat the inputs as arrays. This behavior interfered with some of the
new tests that involved queries on lookups.
- QueryContexts: Add maxSubqueryRows parameter, and use it in druid-sql
tests.
* Fixes for tests.
* Adjustments.
* Match GREATEST/LEAST function behavior
Change the behavior of the GREATEST / LEAST functions to be similar to
how it is implemented in other databases (as functions instead of
aggregators). The GREATEST/LEAST functions are not in the SQL standard,
but users will expect behavior similar to what other databases provide.
* Match postgres behavior & handle more SQL types
* Fix imports
* Add SQL GROUPING SETS support.
Built on top of the subtotalsSpec feature in the groupBy query. This also involves
two changes to subtotalsSpec:
- Alter behavior so limitSpec is applied after subtotalsSpec, rather than applied to
each grouping set. This is more in line with SQL standard behavior. I think it is okay
to make this change, since the old behavior was not documented, so users should
hopefully not be depending on it.
- Fix a bug where virtual columns were included in the subtotal queries, but they
should not have been.
Also fixes two bugs in query equality checking:
- BaseQuery: Use getDuration() instead of "duration" in equals and hashCode, since the
latter is lazily initialized and might be null in one query but not the other.
- GroupByQuery: Include subtotalsSpec in equals and hashCode.
* Fix bugs.
* Fix tests.
* PR updates.
* Grouping class hygiene.
* implement shell for greatest sql aggregator with hardcoded long values
* implement functional long greatest aggregator for direct access columns
* implement greatest & least sql aggregators for long & double types using abstract base class
* add javadocs, unit tests & handling for floats for greatest/least postaggregations
* minor checkstyle fix
* improve naming for the test cases
* make inner class static
* remove blank lines to retest travis build
* change trivial text to rerun travis build
* implement suggested updates for greatest/least sql aggs & fix checkstyle issues
* fix stale comments in greatest/least sql aggs abstract base
* Update sql.md
* improve sql function definitions for greatest/least sql aggs
* add more tests for greatest/least sql aggs
* add tests to cover invalid greatest/least sql expressions
* rename & reorder greatest least sql tests
* null handling for numeric first/last aggregators, refactor to not extend nullable numeric agg since they are complex typed aggs
* initially null or not based on config
* review stuff, make string first/last consistent with null handling of numeric columns, more tests
* docs
* handle nil selectors, revert to primitive first/last types so groupby v1 works...
* SQL: EARLIEST, LATEST aggregators.
I chose these names instead of FIRST, LAST because those are already
reserved functions in Calcite that mean something different. I think
these are also better names anyway.
* Finalify.
* SQL updates.
* Adjust aggregator calls.
* Validations, test updates.
* Review docs.
* sketch of broker parallel merges done in small batches on fork join pool
* fix non-terminating sequences, auto compute parallelism
* adjust benches
* adjust benchmarks
* now hella more faster, fixed dumb
* fix
* remove comments
* log.info for debug
* javadoc
* safer block for sequence to yielder conversion
* refactor LifecycleForkJoinPool into LifecycleForkJoinPoolProvider which wraps a ForkJoinPool
* smooth yield rate adjustment, more logs to help tune
* cleanup, less logs
* error handling, bug fixes, on by default, more parallel, more tests
* remove unused var
* comments
* timeboundary mergeFn
* simplify, more javadoc
* formatting
* pushdown config
* use nanos consistently, move logs back to debug level, bit more javadoc
* static terminal result batch
* javadoc for nullability of createMergeFn
* cleanup
* oops
* fix race, add docs
* spelling, remove todo, add unhandled exception log
* cleanup, revert unintended change
* another unintended change
* review stuff
* add ParallelMergeCombiningSequenceBenchmark, fixes
* hyper-threading is the enemy
* fix initial start delay, lol
* parallelism computer now balances partition sizes to partition counts using sqrt of sequence count instead of sequence count by 2
* fix those important style issues with the benchmarks code
* lazy sequence creation for benchmarks
* more benchmark comments
* stable sequence generation time
* update defaults to use 100ms target time, 4096 batch size, 16384 initial yield, also update user docs
* add jmh thread based benchmarks, cleanup some stuff
* oops
* style
* add spread to jmh thread benchmark start range, more comments to benchmarks parameters and purpose
* retool benchmark to allow modeling more typical heterogenous heavy workloads
* spelling
* fix
* refactor benchmarks
* formatting
* docs
* add maxThreadStartDelay parameter to threaded benchmark
* why does catch need to be on its own line but else doesnt
* remove select query
* thanks teamcity
* oops
* oops
* add back a SelectQuery class that throws RuntimeExceptions linking to docs
* adjust text
* update docs per review
* deprecated
Since it hasn't received updates or community interest in a while, it makes sense
to de-emphasize it in the distribution and most documentation (outside of simple
mentions of its existence).
* groupBy query: optional limit push down to segment scan
* make segment level limit push down configurable
* fix teamcity errors
* fix segment limit pushdown flag handling on query level config override
* use equals for comparator check
* fix sql and null handling
* fix unused imports
* handle null offset in NullableValueGroupByColumnSelectorStrategy for buffer comparator similar to RowBasedGrouperHelper.NullableRowBasedKeySerdeHelper
* Add group_id to overlord tasks API and sys.tasks table
* adjust test
* modify docs
* Make groupId nullable
* fix integration test
* fix toString
* Remove groupId from TaskInfo
* Modify docs and tests
* modify TaskMonitorTest
Clint Wylie
Vadim Ogievetsky
Victoria Lim
Rohan Garg
somu-imply
sthetland
Gian Merlino
Charles Smith
Peter Marshall
Jihoon Son
frank chen
Maytas Monsereenusorn
Yi Yuan
Kashif Faraz
Charles Smith
benkrug
Lasse Krogh Mammen
imply-jbalik
Cameron Teasdale
Abhishek Agarwal
Atul Mohan
Makdon
michaelschiff
Suneet Saldanha
Suneet Saldanha
Abhishek Radhakrishnan
Surekha
Yuanli Han
Suneet Saldanha
Maytas Monsereenusorn
James Dalton
Chi Cao Minh
Himanshu
Maytas Monsereenusorn
Aditya
Jonathan Wei
Vadim Ogievetsky