Implements threshold based automatic query prioritization using the time period of the actual segments scanned. This differs from the current implementation of durationThreshold which uses the duration in the user supplied query. There are some usability constraints with using durationThreshold from the user supplied query, especially when using SQL. For example, if a client does not explicitly specify both start and end timestamps then the duration is extremely large and will always exceed the configured durationThreshold. This is one example interval from a query that specifies no end timestamp:
"interval":["2024-08-30T08:05:41.944Z/146140482-04-24T15:36:27.903Z"]. This interval is generated from a query like SELECT * FROM table WHERE __time > CURRENT_TIMESTAMP - INTERVAL '15' HOUR. Using the time period of the actual segments scanned allows proper prioritization without explicitly having to specify start and end timestamps. This PR adds onto #9493
Adds a configuration clientConnectTimeout to our http client config which controls the connection timeout for our http client requests.
It was observed that on busy K8S clusters, the default connect timeout of 500ms is sometimes not enough time to complete syn/acks for a request and in these cases, the requests timeout with the error:
exceptionType=java.net.SocketTimeoutException, exceptionMessage=Connect Timeout
This behavior was mostly observed on the router while forwarding queries to the broker.
Having a slightly higher connect timeout helped resolve these issues.
Background:
ZK-based segment loading has been completely disabled in #15705 .
ZK `servedSegmentsPath` has been deprecated since Druid 0.7.1, #1182 .
This legacy path has been replaced by the `liveSegmentsPath` and is not used in the code anymore.
Changes:
- Never create ZK loadQueuePath as it is never used.
- Never create ZK servedSegmentsPath as it is never used.
- Do not create ZK liveSegmentsPath if announcement on ZK is disabled
- Fix up tests
changes:
* removes `druid.indexer.task.batchProcessingMode` in favor of always using `CLOSED_SEGMENT_SINKS` which uses `BatchAppenderator`. This was intended to become the default for native batch, but that was missed so `CLOSED_SEGMENTS` was the default (using `AppenderatorImpl`), however MSQ has been exclusively using `BatchAppenderator` with no problems so it seems safe to just roll it out as the only option for batch ingestion everywhere.
* with `batchProcessingMode` gone, there is no use for `AppenderatorImpl` so it has been removed
* implify `Appenderator` construction since there are only separate stream and batch versions now
* simplify tests since `batchProcessingMode` is gone
changes:
* removed `Firehose` and `FirehoseFactory` and remaining implementations which were mostly no longer used after #16602
* Moved `IngestSegmentFirehose` which was still used internally by Hadoop ingestion to `DatasourceRecordReader.SegmentReader`
* Rename `SQLFirehoseFactoryDatabaseConnector` to `SQLInputSourceDatabaseConnector` and similar renames for sub-classes
* Moved anything remaining in a 'firehose' package somewhere else
* Clean up docs on firehose stuff
Update default value of druid.indexer.tasklock.batchAllocationWaitTime to 0.
Thus, a segment allocation request is processed immediately unless there are already some requests queued before this one. While in queue, a segment allocation request may get clubbed together with other similar requests into a batch to reduce load on the metadata store.
Follow up to #15705
Changes:
- Remove references to ZK-based segment loading in the docs
- Fix doc for existing config `druid.coordinator.loadqueuepeon.http.repeatDelay`
Issue: #14989
The initial step in optimizing segment metadata was to centralize the construction of datasource schema in the Coordinator (#14985). Thereafter, we addressed the problem of publishing schema for realtime segments (#15475). Subsequently, our goal is to eliminate the requirement for regularly executing queries to obtain segment schema information.
This is the final change which involves publishing segment schema for finalized segments from task and periodically polling them in the Coordinator.
The default value for druid.coordinator.kill.period (if unspecified) has changed from P1D to the value of druid.coordinator.period.indexingPeriod. Operators can choose to override druid.coordinator.kill.period and that will take precedence over the default behavior.
The default value for the coordinator dynamic config killTaskSlotRatio is updated from 1.0 to 0.1. This ensures that that kill tasks take up only 1 task slot right out-of-the-box instead of taking up all the task slots.
* Remove stale comment and inline canDutyRun()
* druid.coordinator.kill.period defaults to druid.coordinator.period.indexingPeriod if not set.
- Remove the default P1D value for druid.coordinator.kill.period. Instead default
druid.coordinator.kill.period to whatever value druid.coordinator.period.indexingPeriod is set
to if the former config isn't specified.
- If druid.coordinator.kill.period is set, the value will take precedence over
druid.coordinator.period.indexingPeriod
* Update server/src/test/java/org/apache/druid/server/coordinator/DruidCoordinatorConfigTest.java
* Fix checkstyle error
* Clarify comment
* Update server/src/main/java/org/apache/druid/server/coordinator/DruidCoordinatorConfig.java
* Put back canDutyRun()
* Default killTaskSlotsRatio to 0.1 instead of 1.0 (all slots)
* Fix typo DEFAULT_MAX_COMPACTION_TASK_SLOTS
* Remove unused test method.
* Update default value of killTaskSlotsRatio in docs and web-console default mock
* Move initDuty() after params and config setup.
Starting the process to officially deprecate non SQL compatible modes by updating docs to aggressively call out that Druids non SQL compliant modes are deprecated and will go away someday. There are no code or behavior changes at this PR.
Merging the work so far. @ektravel , @vogievetsky if there are additional improvements, let's track them & make another pr.
* Refactor streaming ingestion docs
* Update property definition
* Update after review
* Update known issues
* Move kinesis and kafka topics to ingestion, add redirects
* Saving changes
* Saving
* Add input format text
* Update after review
* Minor text edit
* Update example syntax
* Revert back to colon
* Fix merge conflicts
* Fix broken links
* Fix spelling error
This PR enables the flag by default to queue excess query requests in the jetty queue. Still keeping the flag so that it can be turned off if necessary. But the flag will be removed in the future.
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.
* sql compatible tri-state native logical filters when druid.expressions.useStrictBooleans=true and druid.generic.useDefaultValueForNull=false, and new druid.generic.useThreeValueLogicForNativeFilters=true
* log.warn if non-default configurations are used to guide operators towards SQL complaint behavior
This PR updates the library used for Memcached client to AWS Elasticache Client : https://github.com/awslabs/aws-elasticache-cluster-client-memcached-for-java
This enables us to use the option of encrypting data in transit:
Amazon ElastiCache for Memcached now supports encryption of data in transit
For clusters running the Memcached engine, ElastiCache supports Auto Discovery—the ability for client programs to automatically identify all of the nodes in a cache cluster, and to initiate and maintain connections to all of these nodes.
Benefits of Auto Discovery - Amazon ElastiCache
AWS has forked spymemcached 2.12.1, and has since added all the patches included in 2.12.2 and 2.12.3 as part of the 1.2.0 release. So, this can now be considered as an equivalent drop-in replacement.
GitHub - awslabs/aws-elasticache-cluster-client-memcached-for-java: Amazon ElastiCache Cluster Client for Java - enhanced library to connect to ElastiCache clusters.
https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/elasticache/AmazonElastiCacheClient.html#AmazonElastiCacheClient--
How to enable TLS with Elasticache
On server side:
https://docs.aws.amazon.com/AmazonElastiCache/latest/mem-ug/in-transit-encryption-mc.html#in-transit-encryption-enable-existing-mc
On client side:
GitHub - awslabs/aws-elasticache-cluster-client-memcached-for-java: Amazon ElastiCache Cluster Client for Java - enhanced library to connect to ElastiCache clusters.
A new monitor SubqueryCountStatsMonitor which emits the metrics corresponding to the subqueries and their execution is now introduced. Moreover, the user can now also use the auto mode to automatically set the number of bytes available per query for the inlining of its subquery's results.
Changes:
[A] Remove config `decommissioningMaxPercentOfMaxSegmentsToMove`
- It is a complicated config 😅 ,
- It is always desirable to prioritize move from decommissioning servers so that
they can be terminated quickly, so this should always be 100%
- It is already handled by `smartSegmentLoading` (enabled by default)
[B] Remove config `maxNonPrimaryReplicantsToLoad`
This was added in #11135 to address two requirements:
- Prevent coordinator runs from getting stuck assigning too many segments to historicals
- Prevent load of replicas from competing with load of unavailable segments
Both of these requirements are now already met thanks to:
- Round-robin segment assignment
- Prioritization in the new coordinator
- Modifications to `replicationThrottleLimit`
- `smartSegmentLoading` (enabled by default)
Changes
- Increase value of `replicationThrottleLimit` computed by `smartSegmentLoading` from
2% to 5% of total number of used segments.
- Assign replicas to a tier even when some replicas are already being loaded in that tier
- Limit the total number of replicas in load queue at start of run + replica assignments in
the run to the `replicationThrottleLimit`.
i.e. for every tier,
num loading replicas at start of run + num replicas assigned in run <= replicationThrottleLimit
Changes:
- Determine the default value of balancerComputeThreads based on number of
coordinator cpus rather than number of segments. Even if the number of segments
is low and we create more balancer threads, it doesn't hurt the system as threads
would mostly be idle.
- Remove unused field from SegmentLoadQueueManager
Expected values:
- Clusters with ~1M segments typically work with Coordinators having 16 cores or more.
This would give us 8 balancer threads, which is the same as the current maximum.
- On small clusters, even a single thread is enough to do the required balancing work.
### Description
This change enables the `KillUnusedSegments` coordinator duty to be scheduled continuously. Things that prevented this, or made this difficult before were the following:
1. If scheduled at fast enough rate, the duty would find the same intervals to kill for the same datasources, while kill tasks submitted for those same datasources and intervals were already underway, thus wasting task slots on duplicated work.
2. The task resources used by auto kill were previously unbounded. Each duty run period, if unused
segments were found for any datasource, a kill task would be submitted to kill them.
This pr solves for both of these issues:
1. The duty keeps track of the end time of the last interval found when killing unused segments for each datasource, in a in memory map. The end time for each datasource, if found, is used as the start time lower bound, when searching for unused intervals for that same datasource. Each duty run, we remove any datasource keys from this map that are no longer found to match datasources in the system, or in whitelist, and also remove a datasource entry, if there is found to be no unused segments for the datasource, which happens when we fail to find an interval which includes unused segments. Removing the datasource entry from the map, allows for searching for unusedSegments in the datasource from the beginning of time once again
2. The unbounded task resource usage can be mitigated with coordinator dynamic config added as part of ba957a9b97
Operators can configure continous auto kill by providing coordinator runtime properties similar to the following:
```
druid.coordinator.period.indexingPeriod=PT60S
druid.coordinator.kill.period=PT60S
```
And providing sensible limits to the killTask usage via coordinator dynamic properties.
* 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
Adithya Chakilam
Pranav
aho135
Jill Osborne
317brian
benkrug
Jakub Matyszewski
Kashif Faraz
Atul Mohan
Clint Wylie
Hugh Evans
Andreas Maechler
Charles Smith
George Shiqi Wu
Alberic Liu
Rishabh Singh
Abhishek Radhakrishnan
Gian Merlino
Katya Macedo
Abhishek Agarwal
Tts-233
David Christle
Laksh Singla
Parth Agrawal
zachjsh
Lucas Capistrant
Tejaswini Bandlamudi