perf: Replace java.net.URI with custom string parsing in Dsn by runningcode · Pull Request #5448 · getsentry/sentry-java

runningcode · 2026-05-19T09:24:12Z

Summary

Replaces java.net.URI parsing in the Dsn constructor with lightweight manual
string parsing, and hardens and tests the parser. This is a critical startup path performance improvement.

Here are perfetto traces of the retrieveParsedDsn() method as measured on a Pixel 3. I've repeated the measurement several times and I always get an order of magnitude difference.

This is on master:

This is on this branch:

What changed

Parsing: Replace new URI(dsnString).normalize() with manual
indexOf/substring parsing, avoiding the java.net.URI string parser.
retrieveParsedDsn() runs on the main thread during Sentry.init(), so this
keeps a known-slow API off the init path. The only remaining URI use is
constructing the endpoint from already-parsed components
(new URI(scheme, null, host, port, path, null, null)), which does not
re-parse a string.
Correctness: Strip URI fragments (#…) alongside query strings so they no
longer leak into the project id, and support bracketed IPv6 literal hosts
(e.g. https://key@[::1]:9000/1) — both behaviors the old URI parser handled.

JAVA-532

Relates to: https://linear.app/getsentry/issue/JAVA-532
Also relates to: https://linear.app/getsentry/issue/JAVA-516/move-dsn-parsing-off-the-main-thread-during-init

🤖 Generated with Claude Code

linear-code · 2026-05-19T09:24:17Z

JAVA-516

JAVA-532

sentry · 2026-05-19T09:30:54Z

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.43.1 (1)	release

⚙️ sentry-android Build Distribution Settings

github-actions · 2026-05-19T09:37:13Z

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	287.89 ms	353.78 ms	65.89 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`62b579c`	312.88 ms	361.57 ms	48.70 ms
`d501a7e`	307.33 ms	341.94 ms	34.61 ms
`2195398`	345.88 ms	411.71 ms	65.82 ms
`cf708bd`	434.73 ms	502.96 ms	68.22 ms
`27d7cf8`	397.90 ms	498.65 ms	100.75 ms
`85d7417`	347.21 ms	394.35 ms	47.15 ms
`5dee26b`	315.44 ms	367.25 ms	51.81 ms
`4c04bb8`	307.93 ms	362.34 ms	54.41 ms
`5b1a06b`	310.56 ms	362.79 ms	52.22 ms
`f634d01`	359.58 ms	433.88 ms	74.30 ms

App size

Revision	Plain	With Sentry	Diff
`62b579c`	0 B	0 B	0 B
`d501a7e`	0 B	0 B	0 B
`2195398`	0 B	0 B	0 B
`cf708bd`	1.58 MiB	2.11 MiB	539.71 KiB
`27d7cf8`	1.58 MiB	2.12 MiB	549.42 KiB
`85d7417`	1.58 MiB	2.10 MiB	533.44 KiB
`5dee26b`	0 B	0 B	0 B
`4c04bb8`	0 B	0 B	0 B
`5b1a06b`	0 B	0 B	0 B
`f634d01`	1.58 MiB	2.10 MiB	533.40 KiB

Previous results on branch: no/custom-dsn-parser

Startup times

Revision	Plain	With Sentry	Diff
`85d9e31`	323.66 ms	391.76 ms	68.10 ms
`51a27f4`	318.65 ms	361.66 ms	43.01 ms
`96d1d4a`	354.34 ms	443.40 ms	89.06 ms

App size

Revision	Plain	With Sentry	Diff
`85d9e31`	0 B	0 B	0 B
`51a27f4`	0 B	0 B	0 B
`96d1d4a`	0 B	0 B	0 B

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0xadam-brown

A few optionals; otherwise lgtm

The Dsn constructor used `new URI(dsnString).normalize()` to parse the DSN string, which is known to be slow on Android. Since `retrieveParsedDsn()` is called on the main thread during `Sentry.init()` via `preInitConfigurations()`, this directly impacts app startup time. Replace the URI-based parsing with manual indexOf/substring operations. The only remaining URI construction is from pre-parsed components (`new URI(scheme, null, host, port, path, null, null)`), which is significantly cheaper since the JDK doesn't need to re-parse a string. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Cover edge cases specific to the manual indexOf/substring parser: null input, missing scheme separator, no slash after host, multiple path segments, port with path, multiple double slashes, query string with port, empty secret key, and a realistic Sentry DSN with org id. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Harden the custom DSN parser and convert its tests to Google Truth. - Strip URI fragments (#...) alongside query strings so they no longer leak into the project id and corrupt the constructed Sentry URI. - Detect bracketed IPv6 literal hosts when locating the port separator, restoring behavior that java.net.URI handled. - Narrow the parse error handling from catch (Throwable) to the expected exceptions, which stops swallowing Error and removes the doubled exception message. - Extract the parsing steps into focused private helpers. - Convert DsnTest to Google Truth assertions. - Move the changelog entry to the Unreleased section, since 8.43.0 and 8.43.1 have already been released. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Follow Truth's recommended pattern for exception testing: catch with assertFailsWith, then assert on the caught throwable with assertThat(ex).hasMessageThat(). Also assert the message in the previously bare throw-only cases so they can no longer pass on an unrelated exception. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Parse the port in a dedicated helper that reports the offending value ("Invalid DSN: Invalid port 'abc'.") instead of leaking the raw NumberFormatException text. Narrow the catch to URISyntaxException now that the port is the only parseInt, and add a test. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

0xadam-brown

Thanks for the updates – lgtm 👍

0xadam-brown · 2026-06-04T16:35:33Z

 camerax-lifecycle = { module = "androidx.camera:camera-lifecycle", version.ref = "camerax" }
 camerax-view = { module = "androidx.camera:camera-view", version.ref = "camerax" }

+google-truth = { module = "com.google.truth:truth", version = "1.4.5" }


l: No strong opinions about introducing a new assertion library for tests + it's helpful for verifying error msgs, so I'm okay with this even though we'll only have a few tests using Truth.

Anyone else can feel free to chime in if they think otherwise...

romtsn · 2026-06-08T06:58:33Z

+      final String host = portColon < 0 ? hostPort : hostPort.substring(0, portColon);
+      final int port = portColon < 0 ? -1 : parsePort(hostPort.substring(portColon + 1));
+
+      final String rawPath = stripTrailingSlash(collapseSlashes(hostAndPath.substring(firstSlash)));


theoretically this could've been a single for-loop with a StringBuilder -- would've spared us a couple of more substring calls, but up to you if you'd like to optimize it further.

romtsn

one nit, but LGTM otherwise! great gains

runningcode requested review from 0xadam-brown, adinauer, markushi and romtsn as code owners May 19, 2026 09:24

cursor Bot reviewed May 19, 2026

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Comment thread sentry/src/main/java/io/sentry/Dsn.java Outdated

Comment thread sentry/src/main/java/io/sentry/Dsn.java Outdated

0xadam-brown approved these changes May 20, 2026

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Comment thread sentry/src/main/java/io/sentry/Dsn.java Outdated

Comment thread sentry/src/main/java/io/sentry/Dsn.java Outdated

Comment thread sentry/src/main/java/io/sentry/Dsn.java Outdated

Comment thread sentry/src/test/java/io/sentry/DsnTest.kt Outdated

runningcode changed the title ~~perf: Replace java.net.URI with custom string parsing in Dsn~~ [DNM] [Don't review] perf: Replace java.net.URI with custom string parsing in Dsn May 28, 2026

runningcode and others added 4 commits June 4, 2026 15:43

changelog: Add entry for custom DSN parser

512c440

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

runningcode force-pushed the no/custom-dsn-parser branch from cacc249 to 4851e6d Compare June 4, 2026 14:07

sentry Bot reviewed Jun 4, 2026

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Comment thread sentry/src/main/java/io/sentry/Dsn.java

runningcode changed the title ~~[DNM] [Don't review] perf: Replace java.net.URI with custom string parsing in Dsn~~ perf: Replace java.net.URI with custom string parsing in Dsn Jun 4, 2026

0xadam-brown approved these changes Jun 4, 2026

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romtsn reviewed Jun 8, 2026

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romtsn approved these changes Jun 8, 2026

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📲 Install Builds

Android

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Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

Previous results on branch: no/custom-dsn-parser

Startup times

App size

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