The initial step in optimizing segment metadata was to centralize the construction of datasource schema in the Coordinator (#14985). Subsequently, our goal is to eliminate the requirement for regularly executing queries to obtain segment schema information. This task encompasses addressing both realtime and finalized segments.
This modification specifically addresses the issue with realtime segments. Tasks will now routinely communicate the schema for realtime segments during the segment announcement process. The Coordinator will identify the schema alongside the segment announcement and subsequently update the schema for realtime segments in the metadata cache.
Database slowness while doing audits seems to be causing flakiness in auth ITs.
The failing test is almost always
`ITBasicAuthConfigurationTest.test_avaticaQuery_datasourceAndContextParamsUser`
but in some rare cases, other tests fail too. Alternately, this failing test has been seen to pass too.
It is most likely because the auth changes are not able to propagate in time from
the coordinator to other services.
Fix: Just log the audits rather than persisting them to database.
Most audits have been newly added and it is okay to not have them persisted.
Moreover, logging audits can also be more beneficial while debugging an IT.
Changes
- Add `log` implementation for `AuditManager` alongwith `SQLAuditManager`
- `LoggingAuditManager` simply logs the audit event. Thus, it returns empty for
all `fetchAuditHistory` calls.
- Add new config `druid.audit.manager.type` which can take values `log`, `sql` (default)
- Add new config `druid.audit.manager.logLevel` which can take values `DEBUG`, `INFO`, `WARN`.
This gets activated only if `type` is `log`.
- Remove usage of `ConfigSerde` from `AuditManager` as audit is not just limited to configs
- Add `AuditSerdeHelper` for a single implementation of serialization/deserialization of
audit payload and other utility methods.
* unpin snakeyaml globally, add suppressions and licenses
* pin snakeyaml in the specific modules that require version 1.x, update licenses and owasp suppression
This removes the pin of the Snakeyaml introduced in: https://github.com/apache/druid/pull/14519
After the updates of io.kubernetes.java-client and io.confluent.kafka-clients, the only uses of the Snakeyaml 1.x are:
- in test scope, transitive dependency of jackson-dataformat-yaml🫙2.12.7
- in compile scope in contrib extension druid-cassandra-storage
- in compile scope in it-tests.
With the dependency version un-pinned, io.kubernetes.java-client and io.confluent.kafka-clients bring Snakeyaml versions 2.0 and 2.2, consequently allowing to build a Druid distribution without the contrib-extension and free of vulnerable Snakeyaml versions.
* Add initial draft of MarkDanglingTombstonesAsUnused duty.
* Use overshadowed segments instead of all used segments.
* Add unit test for MarkDanglingSegmentsAsUnused duty.
* Add mock call
* Simplify code.
* Docs
* shorter lines formatting
* metric doc
* More tests, refactor and fix up some logic.
* update javadocs; other review comments.
* Make numCorePartitions as 0 in the TombstoneShardSpec.
* fix up test
* Add tombstone core partition tests
* Update docs/design/coordinator.md
Co-authored-by: 317brian <53799971+317brian@users.noreply.github.com>
* review comment
* Minor cleanup
* Only consider tombstones with 0 core partitions
* Need to register the test shard type to make jackson happy
* test comments
* checkstyle
* fixup misc typos in comments
* Update logic to use overshadowed segments
* minor cleanup
* Rename duty to eternity tombstone instead of dangling. Add test for full eternity tombstone.
* Address review feedback.
---------
Co-authored-by: 317brian <53799971+317brian@users.noreply.github.com>
* update confluent's dependencies to common, supported version
Update io.confluent.* dependencies to common, updated version 6.2.12
currently used versions are EOL
* move version definition to the top level pom
Lately, Query IT has been failing due to historical server running out of memory (OOM).
We are investigating the historical heap dump from the test. Until the issue is resolved, we are increasing the heap size of historical server.
Historical OOMs were not getting dumped into /shared/logs because common JVM flags will override service-specific JVM flags. This PR fixes that and also removes unnecessary overrides in historical.
In the current design, brokers query both data nodes and tasks to fetch the schema of the segments they serve. The table schema is then constructed by combining the schemas of all segments within a datasource. However, this approach leads to a high number of segment metadata queries during broker startup, resulting in slow startup times and various issues outlined in the design proposal.
To address these challenges, we propose centralizing the table schema management process within the coordinator. This change is the first step in that direction. In the new arrangement, the coordinator will take on the responsibility of querying both data nodes and tasks to fetch segment schema and subsequently building the table schema. Brokers will now simply query the Coordinator to fetch table schema. Importantly, brokers will still retain the capability to build table schemas if the need arises, ensuring both flexibility and resilience.
* disable parallel builds; enable batch mode to get rid of transfer progress
* restore .m2 from setup-java if not found
* some change to sql
* add ws
* fix quote
* fix quote
* undo querytest change
* nullhandling in mvtest
* init more
* skip commitid plugin
* add-back 1.0C to build ; remove redundant skip-s from copy-resources; add comment
* Vectorizing earliest for numeric
* Vectorizing earliest string aggregator
* checkstyle fix
* Removing unnecessary exceptions
* Ignoring tests in MSQ as earliest is not supported for numeric there
* Fixing benchmarks
* Updating tests as MSQ does not support earliest for some cases
* Addressing review comments by adding the following:
1. Checking capabilities first before creating selectors
2. Removing mockito in tests for numeric first aggs
3. Removing unnecessary tests
* Addressing issues for dictionary encoded single string columns where we can use the dictionary ids instead of the entire string
* Adding a flag for multi value dimension selector
* Addressing comments
* 1 more change
* Handling review comments part 1
* Handling review comments and correctness fix for latest_by when the time expression need not be in sorted order
* Updating numeric first vector agg
* Revert "Updating numeric first vector agg"
This reverts commit 4291709901.
* Updating code for correctness issues
* fixing an issue with latest agg
* Adding more comments and removing an unnecessary check
* Addressing null checks for tie selector and only vectorize false for quantile sketches
Follow up changes to #12599
Changes:
- Rename column `used_flag_last_updated` to `used_status_last_updated`
- Remove new CLI tool `UpdateTables`.
- We already have a `CreateTables` with similar functionality, which should be able to
handle update cases too.
- Any user running the cluster for the first time should either just have `connector.createTables`
enabled or run `CreateTables` which should create tables at the latest version.
- For instance, the `UpdateTables` tool would be inadequate when a new metadata table has
been added to Druid, and users would have to run `CreateTables` anyway.
- Remove `upgrade-prep.md` and include that info in `metadata-init.md`.
- Fix log messages to adhere to Druid style
- Use lambdas
* Add new configurable buffer period to create gap between mark unused and kill of segment
* Changes after testing
* fixes and improvements
* changes after initial self review
* self review changes
* update sql statement that was lacking last_used
* shore up some code in SqlMetadataConnector after self review
* fix derby compatibility and improve testing/docs
* fix checkstyle violations
* Fixes post merge with master
* add some unit tests to improve coverage
* ignore test coverage on new UpdateTools cli tool
* another attempt to ignore UpdateTables in coverage check
* change column name to used_flag_last_updated
* fix a method signature after column name switch
* update docs spelling
* Update spelling dictionary
* Fixing up docs/spelling and integrating altering tasks table with my alteration code
* Update NULL values for used_flag_last_updated in the background
* Remove logic to allow segs with null used_flag_last_updated to be killed regardless of bufferPeriod
* remove unneeded things now that the new column is automatically updated
* Test new background row updater method
* fix broken tests
* fix create table statement
* cleanup DDL formatting
* Revert adding columns to entry table by default
* fix compilation issues after merge with master
* discovered and fixed metastore inserts that were breaking integration tests
* fixup forgotten insert by using pattern of sharing now timestamp across columns
* fix issue introduced by merge
* fixup after merge with master
* add some directions to docs in the case of segment table validation issues
* Merge core CoordinatorClient with MSQ CoordinatorServiceClient.
Continuing the work from #12696, this patch merges the MSQ
CoordinatorServiceClient into the core CoordinatorClient, yielding a single
interface that serves both needs and is based on the ServiceClient RPC
system rather than DruidLeaderClient.
Also removes the backwards-compatibility code for the handoff API in
CoordinatorBasedSegmentHandoffNotifier, because the new API was added
in 0.14.0. That's long enough ago that we don't need backwards
compatibility for rolling updates.
* Fixups.
* Trigger GHA.
* Remove unnecessary retrying in DruidInputSource. Add "about an hour"
retry policy and h
* EasyMock
* Claim full support for Java 17.
No production code has changed, except the startup scripts.
Changes:
1) Allow Java 17 without DRUID_SKIP_JAVA_CHECK.
2) Include the full list of opens and exports on both Java 11 and 17.
3) Document that Java 17 is both supported and preferred.
4) Switch some tests from Java 11 to 17 to get better coverage on the
preferred version.
* Doc update.
* Update errorprone.
* Update docker_build_containers.sh.
* Update errorprone in licenses.yaml.
* Add some more run-javas.
* Additional run-javas.
* Update errorprone.
* Suppress new errorprone error.
* Add exports and opens in ForkingTaskRunner for Java 11+.
Test, doc changes.
* Additional errorprone updates.
* Update for errorprone.
* Restore old fomatting in LdapCredentialsValidator.
* Copy bin/ too.
* Fix Java 15, 17 build line in docker_build_containers.sh.
* Update busybox image.
* One more java command.
* Fix interpolation.
* IT commandline refinements.
* Switch to busybox 1.34.1-glibc.
* POM adjustments, build and test one IT on 17.
* Additional debugging.
* Fix silly thing.
* Adjust command line.
* Add exports and opens one more place.
* Additional harmonization of strong encapsulation parameters.
Apache Druid brings multiple direct and transitive dependencies that are affected by plethora of CVEs.
This PR attempts to update all the dependencies that did not require code refactoring.
This PR modifies pom files, license file and OWASP Dependency Check suppression file.
* Add "stringEncoding" parameter to DataSketches HLL.
Builds on the concept from #11172 and adds a way to feed HLL sketches
with UTF-8 bytes.
This must be an option rather than always-on, because prior to this
patch, HLL sketches used UTF-16LE encoding when hashing strings. To
remain compatible with sketch images created prior to this patch -- which
matters during rolling updates and when reading sketches that have been
written to segments -- we must keep UTF-16LE as the default.
Not currently documented, because I'm not yet sure how best to expose
this functionality to users. I think the first place would be in the SQL
layer: we could have it automatically select UTF-8 or UTF-16LE when
building sketches at query time. We need to be careful about this, though,
because UTF-8 isn't always faster. Sometimes, like for the results of
expressions, UTF-16LE is faster. I expect we will sort this out in
future patches.
* Fix benchmark.
* Fix style issues, improve test coverage.
* Put round back, to make IT updates easier.
* Fix test.
* Fix issue with filtered aggregators and add test.
* Use DS native update(ByteBuffer) method. Improve test coverage.
* Add another suppression.
* Fix ITAutoCompactionTest.
* Update benchmarks.
* Updates.
* Fix conflict.
* Adjustments.
Our CI system has a lot of tests. And much of this testing is really unnecessary for most of the PRs. This PR adds some checks so we can skip these expensive tests when we know they are not necessary.
This commit does a complete revamp of the coordinator to address problem areas:
- Stability: Fix several bugs, add capabilities to prioritize and cancel load queue items
- Visibility: Add new metrics, improve logs, revamp `CoordinatorRunStats`
- Configuration: Add dynamic config `smartSegmentLoading` to automatically set
optimal values for all segment loading configs such as `maxSegmentsToMove`,
`replicationThrottleLimit` and `maxSegmentsInNodeLoadingQueue`.
Changed classes:
- Add `StrategicSegmentAssigner` to make assignment decisions for load, replicate and move
- Add `SegmentAction` to distinguish between load, replicate, drop and move operations
- Add `SegmentReplicationStatus` to capture current state of replication of all used segments
- Add `SegmentLoadingConfig` to contain recomputed dynamic config values
- Simplify classes `LoadRule`, `BroadcastRule`
- Simplify the `BalancerStrategy` and `CostBalancerStrategy`
- Add several new methods to `ServerHolder` to track loaded and queued segments
- Refactor `DruidCoordinator`
Impact:
- Enable `smartSegmentLoading` by default. With this enabled, none of the following
dynamic configs need to be set: `maxSegmentsToMove`, `replicationThrottleLimit`,
`maxSegmentsInNodeLoadingQueue`, `useRoundRobinSegmentAssignment`,
`emitBalancingStats` and `replicantLifetime`.
- Coordinator reports richer metrics and produces cleaner and more informative logs
- Coordinator uses an unlimited load queue for all serves, and makes better assignment decisions
Introduce DruidException, an exception whose goal in life is to be delivered to a user.
DruidException itself has javadoc on it to describe how it should be used. This commit both introduces the Exception and adjusts some of the places that are generating exceptions to generate DruidException objects instead, as a way to show how the Exception should be used.
This work was a 3rd iteration on top of work that was started by Paul Rogers. I don't know if his name will survive the squash-and-merge, so I'm calling it out here and thanking him for starting on this.
Description:
Druid allows a configuration of load rules that may cause a used segment to not be loaded
on any historical. This status is not tracked in the sys.segments table on the broker, which
makes it difficult to determine if the unavailability of a segment is expected and if we should
not wait for it to be loaded on a server after ingestion has finished.
Changes:
- Track replication factor in `SegmentReplicantLookup` during evaluation of load rules
- Update API `/druid/coordinator/v1metadata/segments` to return replication factor
- Add column `replication_factor` to the sys.segments virtual table and populate it in
`MetadataSegmentView`
- If this column is 0, the segment is not assigned to any historical and will not be loaded.
* Limit select results in MSQ
* reduce number of files in test
* add truncated flag
* avoid materializing select results to list, use iterable instead
* javadocs
Hadoop 2 often causes red security scans on Druid distribution because of the dependencies it brings. We want to move away from Hadoop 2 and provide Hadoop 3 distribution available. Switch druid to building with Hadoop 3 by default. Druid will still be compatible with Hadoop 2 and users can build hadoop-2 compatible distribution using hadoop2 profile.
* Compaction: Block input specs not aligned with segmentGranularity.
When input intervals are not aligned with segmentGranularity, data may be
overshadowed if it lies in the space between the input intervals and the
output segmentGranularity.
In MSQ REPLACE, this is a validation error. IMO the same behavior makes
sense for compaction tasks. In case anyone was depending on the ability
to compact nonaligned intervals, a configuration parameter
allowNonAlignedInterval is provided. I don't expect it to be used much.
* Remove unused.
* ITCompactionTaskTest uses non-aligned intervals.
* MSQ: Support multiple result columns with the same name.
This is allowed in SQL, and is supported by the regular SQL endpoint.
We retain a validation that INSERT ... SELECT does not allow multiple
columns with the same name, because column names in segments must be
unique.
* 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.
Create the docker image in case of maven dependencies cache restore failure too as env.sh file is removed on maven rebuild.
Increase java heap size for security IT failing with error
* 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.
* Always return sketches from DS_HLL, DS_THETA, DS_QUANTILES_SKETCH.
These aggregation functions are documented as creating sketches. However,
they are planned into native aggregators that include finalization logic
to convert the sketch to a number of some sort. This creates an
inconsistency: the functions sometimes return sketches, and sometimes
return numbers, depending on where they lie in the native query plan.
This patch changes these SQL aggregators to _never_ finalize, by using
the "shouldFinalize" feature of the native aggregators. It already
existed for theta sketches. This patch adds the feature for hll and
quantiles sketches.
As to impact, Druid finalizes aggregators in two cases:
- When they appear in the outer level of a query (not a subquery).
- When they are used as input to an expression or finalizing-field-access
post-aggregator (not any other kind of post-aggregator).
With this patch, the functions will no longer be finalized in these cases.
The second item is not likely to matter much. The SQL functions all declare
return type OTHER, which would be usable as an input to any other function
that makes sense and that would be planned into an expression.
So, the main effect of this patch is the first item. To provide backwards
compatibility with anyone that was depending on the old behavior, the
patch adds a "sqlFinalizeOuterSketches" query context parameter that
restores the old behavior.
Other changes:
1) Move various argument-checking logic from runtime to planning time in
DoublesSketchListArgBaseOperatorConversion, by adding an OperandTypeChecker.
2) Add various JsonIgnores to the sketches to simplify their JSON representations.
3) Allow chaining of ExpressionPostAggregators and other PostAggregators
in the SQL layer.
4) Avoid unnecessary FieldAccessPostAggregator wrapping in the SQL layer,
now that expressions can operate on complex inputs.
5) Adjust return type to thetaSketch (instead of OTHER) in
ThetaSketchSetBaseOperatorConversion.
* Fix benchmark class.
* Fix compilation error.
* Fix ThetaSketchSqlAggregatorTest.
* Hopefully fix ITAutoCompactionTest.
* Adjustment to ITAutoCompactionTest.
In clusters with a large number of segments, the duty `MarkAsUnusedOvershadowedSegments`
can take a long very long time to finish. This is because of the costly invocation of
`timeline.isOvershadowed` which is done for every used segment in every coordinator run.
Changes
- Use `DataSourceSnapshot.getOvershadowedSegments` to get all overshadowed segments
- Iterate over this set instead of all used segments to identify segments that can be marked as unused
- Mark segments as unused in the DB in batches rather than one at a time
- Refactor: Add class `SegmentTimeline` for ease of use and readability while using a
`VersionedIntervalTimeline` of segments.
* Refactor Calcite test "framework" for planner tests
Refactors the current Calcite tests to make it a bit easier
to adjust the set of runtime objects used within a test.
* Move data creation out of CalciteTests into TestDataBuilder
* Move "framework" creation out of CalciteTests into
a QueryFramework
* Move injector-dependent functions from CalciteTests
into QueryFrameworkUtils
* Wrapper around the planner factory, etc. to allow
customization.
* Bulk of the "framework" created once per class rather
than once per test.
* Refactor tests to use a test builder
* Change all testQuery() methods to use the test builder.
Move test execution & verification into a test runner.
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
* Add interpolation to JsonConfigurator
* Fix checkstyle
* Fix tests by removing common-text override
* Add back commons-text without version
* Remove unused hadoopDir configs
* Move some stuff to hopefully pass coverage
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.
* Refactor SqlLifecycle into statement classes
Create direct & prepared statements
Remove redundant exceptions from tests
Tidy up Calcite query tests
Make PlannerConfig more testable
* Build fixes
* Added builder to SqlQueryPlus
* Moved Calcites system properties to saffron.properties
* Build fix
* Resolve merge conflict
* Fix IntelliJ inspection issue
* Revisions from reviews
Backed out a revision to Calcite tests that didn't work out as planned
* Build fix
* Fixed spelling errors
* Fixed failed test
Prepare now enforces security; before it did not.
* Rebase and fix IntelliJ inspections issue
* Clean up exception handling
* Fix handling of JDBC auth errors
* Build fix
* More tweaks to security messages
Kinesis ingestion requires all shards to have at least 1 record at the required position in druid.
Even if this is satisified initially, resharding the stream can lead to empty intermediate shards. A significant delay in writing to newly created shards was also problematic.
Kinesis shard sequence numbers are big integers. Introduce two more custom sequence tokens UNREAD_TRIM_HORIZON and UNREAD_LATEST to indicate that a shard has not been read from and that it needs to be read from the start or the end respectively.
These values can be used to avoid the need to read at least one record to obtain a sequence number for ingesting a newly discovered shard.
If a record cannot be obtained immediately, use a marker to obtain the relevant shardIterator and use this shardIterator to obtain a valid sequence number. As long as a valid sequence number is not obtained, continue storing the token as the offset.
These tokens (UNREAD_TRIM_HORIZON and UNREAD_LATEST) are logically ordered to be earlier than any valid sequence number.
However, the ordering requires a few subtle changes to the existing mechanism for record sequence validation:
The sequence availability check ensures that the current offset is before the earliest available sequence in the shard. However, current token being an UNREAD token indicates that any sequence number in the shard is valid (despite the ordering)
Kinesis sequence numbers are inclusive i.e if current sequence == end sequence, there are more records left to read.
However, the equality check is exclusive when dealing with UNREAD tokens.
* 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
* Druid planner now makes only one pass through Calcite planner
Resolves the issue that required two parse/plan cycles: one
for validate, another for plan. Creates a clone of the Calcite
planner and validator to resolve the conflict that prevented
the merger.
* Fixes for the Avatica JDBC driver
Correctly implement regular and prepared statements
Correctly implement result sets
Fix race condition with contexts
Clarify when parameters are used
Prepare for single-pass through the planner
* Addressed review comments
* Addressed review comment
This commit contains changes made to the existing ITs to support the new ITs.
Changes:
- Make the "custom node role" code usable by the new ITs.
- Use flag `-DskipITs` to skips the integration tests but runs unit tests.
- Use flag `-DskipUTs` skips unit tests but runs the "new" integration tests.
- Expand the existing Druid profile, `-P skip-tests` to skip both ITs and UTs.
* Remove null and empty fields from native queries
* Test fixes
* Attempted IT fix.
* Revisions from review comments
* Build fixes resulting from changes suggested by reviews
* IT fix for changed segment size
The web-console (indirectly) calls the Overlord’s GET tasks API to fetch the tasks' summary which in turn queries the metadata tasks table. This query tries to fetch several columns, including payload, of all the rows at once. This introduces a significant memory overhead and can cause unresponsiveness or overlord failure when the ingestion tab is opened multiple times (due to several parallel calls to this API)
Another thing to note is that the task table (the payload column in particular) can be very large. Extracting large payloads from such tables can be very slow, leading to slow UI. While we are fixing the memory pressure in the overlord, we can also fix the slowness in UI caused by fetching large payloads from the table. Fetching large payloads also puts pressure on the metadata store as reported in the community (Metadata store query performance degrades as the tasks in druid_tasks table grows · Issue #12318 · apache/druid )
The task summaries returned as a response for the API are several times smaller and can fit comfortably in memory. So, there is an opportunity here to fix the memory usage, slow ingestion, and under-pressure metadata store by removing the need to handle large payloads in every layer we can. Of course, the solution becomes complex as we try to fix more layers. With that in mind, this page captures two approaches. They vary in complexity and also in the degree to which they fix the aforementioned problems.
Issue:
Even though `CompactionTuningConfig` allows a `maxColumnsToMerge` config
(to optimize memory usage, particulary for datasources with many dimensions),
the corresponding client object `ClientCompactionTaskQueryTuningConfig`
(used by the coordinator duty `CompactSegments` to trigger auto-compaction)
does not contain this field. Thus, the value of `maxColumnsToMerge` specified
in any datasource compaction config is ignored.
Changes:
- Add field `maxColumnsToMerge` in `ClientCompactionTaskQueryTuningConfig`
and `UserCompactionTaskQueryTuningConfig`
- Fix tests
* SQL: Add is_active to sys.segments, update examples and docs.
is_active is short for:
(is_published = 1 AND is_overshadowed = 0) OR is_realtime = 1
It's important because this represents "all the segments that should
be queryable, whether or not they actually are right now". Most of the
time, this is the set of segments that people will want to look at.
The web console already adds this filter to a lot of its queries,
proving its usefulness.
This patch also reworks the caveat at the bottom of the sys.segments
section, so its information is mixed into the description of each result
field. This should make it more likely for people to see the information.
* Wording updates.
* Adjustments for spellcheck.
* Adjust IT.
Karan Kumar
Kashif Faraz
Rishabh Singh
Jan Werner
Ankit Kothari
Abhishek Radhakrishnan
Abhishek Agarwal
Xavier Léauté
Laksh Singla
Zoltan Haindrich
Soumyava
Clint Wylie
Lucas Capistrant
Tejaswini Bandlamudi
AmatyaAvadhanula
Gian Merlino
Adarsh Sanjeev
imply-cheddar
Atul Mohan
AdheipSingh
hqx871
Paul Rogers
Maytas Monsereenusorn
abhagraw
Rohan Garg
Frank Chen
Vadim Ogievetsky
Adam Peck
Jihoon Son
superivaj