feat(events): Detect oversized events and reduce their size #4903

adinauer · 2025-11-14T08:38:25Z

📜 Description

Detect oversized events and reduce their size by removing breadcrumbs and reducing stack trace size.
Also add onOversizedError callback that allows customers to customize what's dropped.

💡 Motivation and Context

So we can be more lenient with truncation in SDK and only perform it if required to reduce event size.

Closes #4822

💚 How did you test it?

📝 Checklist

I added GH Issue ID & Linear ID
I added tests to verify the changes.
No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
I updated the docs if needed.
I updated the wizard if needed.
Review from the native team if needed.
No breaking change or entry added to the changelog.
No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

github-actions · 2025-11-14T08:38:55Z

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against c7ee1e2

sentry/src/main/java/io/sentry/SentryOptions.java

sentry/src/main/java/io/sentry/util/EventSizeLimitingUtils.java

github-actions · 2025-11-14T08:49:37Z

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	318.48 ms	378.24 ms	59.76 ms
Size	1.58 MiB	2.13 MiB	556.43 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`ee747ae`	357.79 ms	421.84 ms	64.05 ms
`ae7fed0`	293.84 ms	380.22 ms	86.38 ms
`9fbb112`	404.51 ms	475.65 ms	71.14 ms
`27d7cf8`	397.90 ms	498.65 ms	100.75 ms
`a416a65`	333.78 ms	410.37 ms	76.59 ms
`d217708`	411.22 ms	430.86 ms	19.63 ms
`539ca63`	313.51 ms	355.43 ms	41.92 ms
`23d6b12`	354.10 ms	408.38 ms	54.28 ms
`14ff5ee`	419.75 ms	495.73 ms	75.98 ms
`ce0a49e`	532.00 ms	609.96 ms	77.96 ms

App size

Revision	Plain	With Sentry	Diff
`ee747ae`	1.58 MiB	2.10 MiB	530.95 KiB
`ae7fed0`	1.58 MiB	2.12 MiB	551.77 KiB
`9fbb112`	1.58 MiB	2.11 MiB	539.18 KiB
`27d7cf8`	1.58 MiB	2.12 MiB	549.42 KiB
`a416a65`	1.58 MiB	2.12 MiB	555.26 KiB
`d217708`	1.58 MiB	2.10 MiB	532.97 KiB
`539ca63`	1.58 MiB	2.12 MiB	551.41 KiB
`23d6b12`	1.58 MiB	2.10 MiB	532.31 KiB
`14ff5ee`	1.58 MiB	2.10 MiB	535.08 KiB
`ce0a49e`	1.58 MiB	2.10 MiB	532.94 KiB

Previous results on branch: feat/detect-oversized-error-events

Startup times

Revision	Plain	With Sentry	Diff
`238dc90`	318.98 ms	361.46 ms	42.48 ms
`73f341a`	312.72 ms	354.90 ms	42.18 ms
`0c31c0a`	310.15 ms	354.83 ms	44.68 ms
`21ae207`	310.42 ms	355.09 ms	44.67 ms
`606e793`	329.40 ms	395.16 ms	65.76 ms

App size

Revision	Plain	With Sentry	Diff
`238dc90`	1.58 MiB	2.13 MiB	556.43 KiB
`73f341a`	1.58 MiB	2.13 MiB	556.24 KiB
`0c31c0a`	1.58 MiB	2.13 MiB	556.43 KiB
`21ae207`	1.58 MiB	2.13 MiB	556.42 KiB
`606e793`	1.58 MiB	2.13 MiB	556.48 KiB

adinauer · 2025-11-14T09:00:52Z

sentry/src/main/java/io/sentry/SentryOptions.java

+   * Enables event size limiting with {@link EventSizeLimitingEventProcessor}. When enabled, events
+   * exceeding 1MB will have breadcrumbs and stack frames reduced to stay under the limit.
+   */
+  private boolean enableEventSizeLimiting = false;


Kepping this opt-in for now, we could turn it on by default in the next major.

adinauer · 2025-11-14T09:01:42Z

sentry/src/main/java/io/sentry/SentryOptions.java

+     * @return the modified event (should ideally be reduced in size)
+     */
+    @NotNull
+    SentryEvent execute(@NotNull SentryEvent event, @NotNull Hint hint);


IMO running this between beforeSend and passing this on to the transport is the best place to check since customers might be adding large amounts of data in beforeSend, so first reducing size and then adding back to it could easily cause the event to become too large again.

sentry/src/main/java/io/sentry/util/EventSizeLimitingUtils.java

markushi

Looks good to me! I'm a bit worried about the extra overhead of serializing to determine final size on mobile, but as this is opt-in for now, all good 👍

sentry/src/main/java/io/sentry/util/EventSizeLimitingUtils.java

markushi · 2025-11-18T07:06:15Z

sentry/src/main/java/io/sentry/util/EventSizeLimitingUtils.java

+            final @NotNull List<SentryStackFrame> truncatedFrames = new ArrayList<>();
+            truncatedFrames.addAll(frames.subList(0, FRAMES_PER_SIDE));
+            truncatedFrames.addAll(frames.subList(frames.size() - FRAMES_PER_SIDE, frames.size()));
+            stacktrace.setFrames(truncatedFrames);


We could extract this into a truncateFrames(frames) method and re-use it.

Co-authored-by: Markus Hintersteiner <markus.hintersteiner@sentry.io>

sentry/src/main/java/io/sentry/util/EventSizeLimitingUtils.java

adinauer added 4 commits November 3, 2025 13:35

Fix log count in client reports

d2a38cc

add assertion to test

3bd2cf0

Detect oversized events

6c5011f

Merge branch 'main' into feat/detect-oversized-error-events

e6e75dc

adinauer requested review from lcian, markushi, romtsn and stefanosiano as code owners November 14, 2025 08:38

adinauer commented Nov 14, 2025

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adinauer marked this pull request as draft November 14, 2025 08:41

cursor bot reviewed Nov 14, 2025

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adinauer commented Nov 14, 2025

View reviewed changes

adinauer added 4 commits November 14, 2025 10:30

cleanup

ee63d11

invert size check method

486fc42

try catch

9afb21d

rename callback to onOversizedEvent

e818730

adinauer marked this pull request as ready for review November 17, 2025 13:49

cursor bot reviewed Nov 17, 2025

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markushi approved these changes Nov 18, 2025

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adinauer and others added 5 commits November 18, 2025 09:57

Apply suggestions from code review

90fa44c

Co-authored-by: Markus Hintersteiner <markus.hintersteiner@sentry.io>

Format code

af4060d

code review changes

ec91944

changelog

0402a74

Merge branch 'main' into feat/detect-oversized-error-events

00e07b1

cursor bot reviewed Nov 18, 2025

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sentry/src/main/java/io/sentry/util/EventSizeLimitingUtils.java Show resolved Hide resolved

changelog update

c7ee1e2

adinauer merged commit 1b841a7 into main Nov 19, 2025
62 of 63 checks passed

adinauer deleted the feat/detect-oversized-error-events branch November 19, 2025 12:51

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feat(events): Detect oversized events and reduce their size #4903

feat(events): Detect oversized events and reduce their size #4903

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📜 Description

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

🔮 Next steps

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Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

Previous results on branch: feat/detect-oversized-error-events

Startup times

App size

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