Implement the overload retry policy for commands that are read/write retryable by stIncMale · Pull Request #2041 · mongodb/mongo-java-driver

stIncMale · 2026-08-18T23:54:17Z

VAKOTODO Run tests on Evergreen and self-review with Claude before asking or review:

The only new test failure is CrudProseTest.testBulkWriteHandlesCursorRequiringGetMoreWithinTransaction (both sync and async).

This PR was originally drafted as stIncMale#4.

JAVA-6248 - of the relevant spec changes, client-backpressure.md and transactions.md was implemented for commands that are read/write retryable.
JAVA-6055 - conducted the audit as per the TODO-BACKPRESSURE in the ticket. The audited logic is in SpecRetryPolicy.decideWriteProspectiveFailedResult. We are good, no code changes are needed.

JAVA-6248

Also add `UnifiedClientBackpressureTest` and enable prose tests JAVA-6248

- Removed `ClientSessionImpl.applyMajorityWriteConcernToTransactionOptions`, which was used in `withTransaction`. This is not the place for this logic, and it furthermore was useless, as `CommitTransactionOperation.getRetryCommandModifier` does the same, and more. - Made `ClientSessionImpl` and `ClientSessionPublisherImpl` compute `alreadyCommitted` the same way. - Made `ClientSessionImpl.commitTransaction` and `ClientSessionPublisherImpl.commitTransaction` handle `transactionState` and `commitInProgress` the same way. - Passed `OperationContext` instead of `TimeoutContext` to `AbortTransactionOperation.getRetryCommandModifier` JAVA-6248

JAVA-6248

…ot adding `startTransaction` JAVA-6248

…Operation.getRetryCommandModifier` adding `withW("majority")` when not needed JAVA-6248

stIncMale · 2026-08-19T20:24:50Z

+     * @param attemptNumber attempt number > 0
+     * @return The calculated backoff in milliseconds.
+     */
+    public static long calculateBackoffMs(final double baseMs, final double maxMs, final double growth, final int attemptNumber) {


VAKOTODO Make private.

Done in 9e447d5.

stIncMale · 2026-08-19T21:23:24Z

            } else if (policies.containsKey(Descriptor.READ)) {
                maxRetries = Descriptor.READ.maxRetries;
+            } else if (policies.containsKey(Descriptor.OVERLOAD)) {
+                maxRetries = overload().map(State.Overload::getMaxAttempts).orElse(Descriptor.OVERLOAD.maxRetries);


VAKOTODO Assert overload() returns non-empty Optional, because policies are never empty (see assertValid).

Done in 85f1df5.

stIncMale · 2026-08-19T21:26:05Z

+                int getMaxAttempts() {
+                    return maxAttempts(maxAdaptiveRetriesSetting == null
+                            ? IndividualPolicies.Descriptor.OVERLOAD.maxRetries
+                            : maxAdaptiveRetriesSetting);
+                }


VAKOTODO The getMaxAttempts method is called to compute maxRetries in IndividualPolicies.getMaxAttempts, which is then converted to max attempts again via maxAttempts(maxRetries). This is wrong.

Done in f677474.

…nal` in `IndividualPolicies.getMaxAttempts`

stIncMale · 2026-08-20T17:16:03Z

@vbabanin Create a ticket on refactoring BaseClientSessionImpl and its subclasses (ClientSessionImpl, ClientSessionPublisherImpl):

We need to reduce the state and code duplication between subclasses.

We need to split this god object into multiple objects each implemented by a different class responsible for its own area. BaseClientSessionImpl.OverloadRetryPolicyState (BaseClientSessionImpl.overloadRetryPolicyState) is a precedent of the new state and logic being put in separate classes, and BaseClientSessionImpl being composed of their instances.

stIncMale · 2026-08-20T17:18:19Z

+        void closeCommitScope();
+
+        /**
+         * A part of {@link DefaultOverloadRetryPolicyState} restricted to the execution of a command


VAKOTODO DefaultOverloadRetryPolicyState -> OverloadRetryPolicyState

stIncMale · 2026-08-20T17:28:33Z

+            Throwable prospectiveFailedResult = prospectiveFailedResult();
+            if (attemptFailedResult instanceof Error) {
+                onAttemptFatalFailure(policy, prospectiveFailedResult, (Error) attemptFailedResult);
+                policy.onAttemptFatalFailure();


VAKOTODO Remove policy.onAttemptFatalFailure();

stIncMale · 2026-08-20T17:39:52Z

            }
-            // this `RetryControl` must not be mutated before calling `onAttemptFailure`
-            Decision decision = onAttemptFailure(policy, this, prospectiveFailedResult(), attemptFailedResult);
+            Throwable prospectiveFailedResult = prospectiveFailedResult();


VAKOTODO Use getProspectiveFailedResult().orElse(null).

stIncMale added 5 commits August 18, 2026 17:32

Pass the maxAdaptiveRetries setting to SpecRetryPolicy

d44dd93

JAVA-6248

Add ExponentialBackoff.calculateOverloadBackoff

7e71ee7

JAVA-6248

Implement simple overload retry policy

4704154

Also add `UnifiedClientBackpressureTest` and enable prose tests JAVA-6248

Add RetryPolicy.onAttemptFatalFailure

38cb111

JAVA-6248

stIncMale self-assigned this Aug 18, 2026

stIncMale mentioned this pull request Aug 19, 2026

Implement the overload retry policy for commands that are read/write retryable stIncMale/mongo-java-driver#4

Closed

stIncMale force-pushed the overloadRetryPolicyForCommandsThatAreRWRetryable_real branch 2 times, most recently from f5fab08 to 15fc28b Compare August 19, 2026 00:46

stIncMale added 3 commits August 19, 2026 12:15

Interactions between transactions and the ORP: fix CommandMessage n…

45b0fad

…ot adding `startTransaction` JAVA-6248

Expose getOverloadRetryPolicyState

5b5fe34

Interactions between transactions and the ORP: fix `CommitTransaction…

f6fabe4

…Operation.getRetryCommandModifier` adding `withW("majority")` when not needed JAVA-6248

stIncMale force-pushed the overloadRetryPolicyForCommandsThatAreRWRetryable_real branch from 15fc28b to f6fabe4 Compare August 19, 2026 18:28

stIncMale requested a review from vbabanin August 19, 2026 18:29

stIncMale commented Aug 19, 2026

View reviewed changes

stIncMale added 3 commits August 19, 2026 17:35

Review: make ExponentialBackoff.calculateBackoffMs private

9e447d5

Review: take into account that overload() can't return empty `Optio…

85f1df5

…nal` in `IndividualPolicies.getMaxAttempts`

Review: fix IndividualPolicies.getMaxAttempts

f677474

stIncMale commented Aug 20, 2026

View reviewed changes

Navigation Menu

Uh oh!

Implement the overload retry policy for commands that are read/write retryable - #2041

Implement the overload retry policy for commands that are read/write retryable#2041
stIncMale wants to merge 11 commits into
mongodb:backpressurefrom
stIncMale:overloadRetryPolicyForCommandsThatAreRWRetryable_real

stIncMale commented Aug 18, 2026 •

edited

Loading

Uh oh!

stIncMale Aug 19, 2026

Uh oh!

stIncMale Aug 19, 2026

Uh oh!

stIncMale Aug 19, 2026

Uh oh!

stIncMale Aug 20, 2026

Uh oh!

stIncMale Aug 19, 2026

Uh oh!

stIncMale Aug 20, 2026

Uh oh!

stIncMale Aug 20, 2026

Uh oh!

stIncMale Aug 20, 2026

Uh oh!

stIncMale Aug 20, 2026

Uh oh!

stIncMale Aug 20, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Uh oh!

Conversation

stIncMale commented Aug 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

stIncMale commented Aug 18, 2026 •

edited

Loading