open-telemetry / open-telemetry/opentelemetry-java-instrumentation

[BUG] StringIndexOutOfBoundsException when parsing MySQL Replication mode URL in JDBC instrumentation

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bug needs triage
Dominant language
Java
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Description

Describe the bug

When using the MySQL driver Replication mode, JDBC insert pile trying to parse the internal generated URL **internally_generated** because dbLoc = -1 cause StringIndexOutOfBoundsException anomalies

https://github.com/mysql/mysql-connector-j/blob/20ef8ee9eb4294a03858acccea0ddad3525f1ff9/src/main/core-impl/java/com/mysql/cj/conf/url/LoadBalanceConnectionUrl.java#L73-L81

https://github.com/mysql/mysql-connector-j/blob/20ef8ee9eb4294a03858acccea0ddad3525f1ff9/src/main/core-impl/java/com/mysql/cj/conf/url/ReplicationConnectionUrl.java#L108-L117

Steps to reproduce

I've created a complete reproduction case with: https://github.com/wl2027/otel-java-examples/tree/main/mysql-replication-demo

Expected behavior
  1. fix the exception (at present)
  2. extract real host info (later)
    I think it's necessary to add instrumentation to the MySQL driver to capture the actual url and host information. Only in this way can we construct an accurate service topology diagram.
Actual behavior
  • stack trace
[otel.javaagent 2025-06-27 17:50:00:042 +0800] [Druid-ConnectionPool-Create-866045247] DEBUG io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcConnectionUrlParser - Error parsing URL
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
    at java.lang.String.substring(String.java:1967)
    at io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcConnectionUrlParser$6.doParse(JdbcConnectionUrlParser.java:355)
    at io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcConnectionUrlParser$5.doParse(JdbcConnectionUrlParser.java:281)
    at io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcConnectionUrlParser.parse(JdbcConnectionUrlParser.java:943)
    at io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcUtils.computeDbInfo(JdbcUtils.java:109)
    at io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcUtils.extractDbInfo(JdbcUtils.java:87)
    at io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.DbRequest.create(DbRequest.java:37)
  • arthas
[arthas@1]$ watch io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcConnectionUrlParser\$* doParse '{params,returnObj}' -x 3 -n 5
Press Q or Ctrl+C to abort.
Affect(class count: 20 , method count: 20) cost in 471 ms, listenerId: 1
method=io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcConnectionUrlParser$6.doParse location=AtExceptionExit
ts=2025-06-27 22:38:46.523; [cost=0.043679ms] result=@ArrayList[
    @Object[][
        @String[**internally_generated**17489615264691**],
        @Builder[
            system=@String[mysql],
            subtype=null,
            shortUrl=null,
            user=null,
            name=null,
            db=@String[**internally_generated**17489615264619**],
            host=@String[localhost],
            port=@Integer[3306],
        ],
    ],
    null,
]
method=io.opentelemetry.javaagent.shaded.instrumentation.jdbc.internal.JdbcConnectionUrlParser$5.doParse location=AtExceptionExit
ts=2025-06-27 22:38:46.524; [cost=0.847149ms] result=@ArrayList[
    @Object[][
        @String[mysql:loadbalance://**internally_generated**1748961526469**],
        @Builder[
            system=@String[mysql],
            subtype=null,
            shortUrl=null,
            user=null,
            name=null,
            db=@String[**internally_generated**1748961526469**],
            host=@String[localhost],
            port=@Integer[3306],
        ],
    ],
    null,
]

Javaagent or library instrumentation version

v2.17.0

Environment

JDK: jdk8+
OS: macos

Additional context

recurrence #2741

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with JdbcConnectionUrlParser.java, especially the doParse path shown in the stack trace, and run the mysql-replication-demo reproduction. Trace handling of the internally generated replication URL and confirm the exception is avoided; accurate host extraction is identified as later work in the issue.

Written by the indexing model from the issue text.

Assessment

Tech stack
java, mysql
Domain
backend, databases
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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