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3 months ago Generate changelog in changelog-dir>`changelog/@unreleased`</changelog-dir
What do the change types mean?
- `feature`: A new feature of the service. - `improvement`: An incremental improvement in the functionality or operation of the service. - `fix`: Remedies the incorrect behaviour of a component of the service in a backwards-compatible way. - `break`: Has the potential to break consumers of this service's API, inclusive of both Palantir services and external consumers of the service's API (e.g. customer-written software or integrations). - `deprecation`: Advertises the intention to remove service functionality without any change to the operation of the service itself. - `manualTask`: Requires the possibility of manual intervention (running a script, eyeballing configuration, performing database surgery, ...) at the time of upgrade for it to succeed. - `migration`: A fully automatic upgrade migration task with no engineer input required. _Note: only one type should be chosen._How are new versions calculated?
- ❗The `break` and `manual task` changelog types will result in a major release! - 🐛 The `fix` changelog type will result in a minor release in most cases, and a patch release version for patch branches. This behaviour is configurable in autorelease. - ✨ All others will result in a minor version release.Type
Description
schlosna
svc-autorelease
General
Before this PR:
Follow up to https://github.com/palantir/atlasdb/pull/7073 as we encountered an AtlasDB service that hit JDK classloader deadlock bug JDK-8266350 / JDK-8266310 on JDK 17 that was outside of #7073 changes.
The problematic class loading was the service loader traversal in
org.eclipse.collections.api.factory.Setslooking fororg.eclipse.collections.api.factory.set.ImmutableSetFactoryinstances triggered fromorg.eclipse.collections.impl.set.immutable.primitive.ImmutableLongEmptySet#collectviaCommitTimestampLoader.waitForCommitToComplete(LongIterable). This ends uporg.eclipse.collections.impl.set.immutable.primitive.ImmutableLongEmptySet#collect:https://github.com/palantir/atlasdb/blob/59ba3ee8fcbcaa4b1c1985f34f32f6481a3e5914/atlasdb-impl-shared/src/main/java/com/palantir/atlasdb/transaction/impl/CommitTimestampLoader.java#L174-L181
Note that this code was recently refactored and moved to
DefaultCommitTimestampLoader, but the same issue may still occur with some probability depending on JNI & class loading ordering.https://github.com/palantir/atlasdb/blob/29d98957a65265a83bb525af79ce637a84fb9885/atlasdb-impl-shared/src/main/java/com/palantir/atlasdb/transaction/impl/DefaultCommitTimestampLoader.java#L183-L190
After this PR:
As a temporary workaround for services that are not yet running with JDK-8266310 fix in JDK 18+, we can pre-load the
eclipse-collectionsclasses that traverseServiceLoaderas those are the ones most likely to encounter deadlock with concurrent JNIloadLibrarycalls.==COMMIT_MSG== Eagerly initialize Eclipse collections classes to avoid potential JDK classloader deadlock bug JDK-8266350 / JDK-8266310 when one thread is attempting to load a native library (e.g. netty which is used by grpc) while another thread is attempting to load classes from a cryptographically signed JAR (e.g. eclipse-collections). This has been seen by some folks using netty & eclipse-collections in netty issue 11209](https://github.com/netty/netty/issues/11209#issuecomment-829468638)
JDK-8266310 fixed this deadlock in JDK 18+.
==COMMIT_MSG==
Priority:
Concerns / possible downsides (what feedback would you like?):
This could add significant time to initial transaction manager startup (e.g. unit test in CI took 18.4 seconds to initialize these
eclipse-collectionsclasses, with a relatively small set of libraries inatlasdb-commonscompared to full services & the classes in their application classloader context )Is documentation needed?:
Compatibility
Does this PR create any API breaks (e.g. at the Java or HTTP layers) - if so, do we have compatibility?:
Does this PR change the persisted format of any data - if so, do we have forward and backward compatibility?:
The code in this PR may be part of a blue-green deploy. Can upgrades from previous versions safely coexist? (Consider restarts of blue or green nodes.):
Does this PR rely on statements being true about other products at a deployment - if so, do we have correct product dependencies on these products (or other ways of verifying that these statements are true)?:
Does this PR need a schema migration?
Testing and Correctness
What, if any, assumptions are made about the current state of the world? If they change over time, how will we find out?:
What was existing testing like? What have you done to improve it?:
If this PR contains complex concurrent or asynchronous code, is it correct? The onus is on the PR writer to demonstrate this.:
If this PR involves acquiring locks or other shared resources, how do we ensure that these are always released?:
Execution
How would I tell this PR works in production? (Metrics, logs, etc.):
Has the safety of all log arguments been decided correctly?:
Will this change significantly affect our spending on metrics or logs?:
How would I tell that this PR does not work in production? (monitors, etc.):
If this PR does not work as expected, how do I fix that state? Would rollback be straightforward?:
If the above plan is more complex than “recall and rollback”, please tag the support PoC here (if it is the end of the week, tag both the current and next PoC):
Scale
Would this PR be expected to pose a risk at scale? Think of the shopping product at our largest stack.:
Would this PR be expected to perform a large number of database calls, and/or expensive database calls (e.g., row range scans, concurrent CAS)?:
Would this PR ever, with time and scale, become the wrong thing to do - and if so, how would we know that we need to do something differently?:
Development Process
Where should we start reviewing?:
If this PR is in excess of 500 lines excluding versions lock-files, why does it not make sense to split it?:
Please tag any other people who should be aware of this PR: @jeremyk-91 @sverma30 @raiju