Unable to Connect to StarRocks in Version 0.8.5 (Works Fine in 0.8.3)

[scottxing]

I have found these related issues/pull requests

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Description

Could you investigate whether there were any changes in the MySQL driver or connection handling logic between versions 0.8.3 and 0.8.5 that might cause this issue? Alternatively, if this is a known issue, guidance on how to resolve it would be appreciated.

Thank you for your time and support!

Reproduction steps

Steps to Reproduce:
1.Use the following connection string or configuration to connect to StarRocks:

let options = MySqlConnectOptions::new()
.host(conf.get("host").unwrap())
.port(conf.get("port").unwrap().parse()?)
.username(conf.get("username").unwrap())
.password(conf.get("password").unwrap())
.timezone(String::from("+08:00"))
.no_engine_substitution(false)
.pipes_as_concat(false);

2.Run the code with sqlx version 0.8.5.
3.Observe that the connection fails.
4.Downgrade to sqlx version 0.8.3 and run the same code.
5.Observe that the connection succeeds.

SQLx version

0.8.5

Enabled SQLx features

"chrono", "mysql", "runtime-tokio", "bigdecimal"

Database server and version

StarRocks3.3.9

Operating system

CentOS7.9

Rust version

rustc 1.85.1 (4eb161250 2025-03-15)

[abonander]

It would be helpful if you provided the actual error message.

The only significant change to the internals of the MySQL driver since 0.8.3 would be #3812

[scottxing]

@abonander

Error: got unexpected connection status after attempting to begin transaction

Stack backtrace:
   0: anyhow::error::<impl core::convert::From<E> for anyhow::Error>::from
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/anyhow-1.0.98/src/backtrace.rs:27:14
   1: <core::result::Result<T,F> as core::ops::try_trait::FromResidual<core::result::Result<core::convert::Infallible,E>>>::from_residual
             at /home/PC/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/result.rs:2014:27
   2: srctl::main::{{closure}}
             at ./srctl/src/bin/main.rs:68:18
   3: <core::pin::Pin<P> as core::future::future::Future>::poll
             at /home/PC/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/future/future.rs:124:9
   4: tokio::runtime::park::CachedParkThread::block_on::{{closure}}
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/park.rs:284:60
   5: tokio::task::coop::with_budget
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/task/coop/mod.rs:167:5
   6: tokio::task::coop::budget
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/task/coop/mod.rs:133:5
   7: tokio::runtime::park::CachedParkThread::block_on
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/park.rs:284:31
   8: tokio::runtime::context::blocking::BlockingRegionGuard::block_on
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/context/blocking.rs:66:9
   9: tokio::runtime::scheduler::multi_thread::MultiThread::block_on::{{closure}}
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/scheduler/multi_thread/mod.rs:87:13
  10: tokio::runtime::context::runtime::enter_runtime
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/context/runtime.rs:65:16
  11: tokio::runtime::scheduler::multi_thread::MultiThread::block_on
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/scheduler/multi_thread/mod.rs:86:9
  12: tokio::runtime::runtime::Runtime::block_on_inner
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/runtime.rs:370:45
  13: tokio::runtime::runtime::Runtime::block_on
             at /home/PC/.cargo/registry/src/rsproxy.cn-e3de039b2554c837/tokio-1.44.2/src/runtime/runtime.rs:340:13
  14: srctl::main
             at ./srctl/src/bin/main.rs:88:5
  15: core::ops::function::FnOnce::call_once
             at /home/PC/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
  16: std::sys::backtrace::__rust_begin_short_backtrace
             at /home/PC/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/backtrace.rs:152:18
  17: std::rt::lang_start::{{closure}}
             at /home/PC/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/rt.rs:199:18
  18: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/core/src/ops/function.rs:284:13
  19: std::panicking::try::do_call
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/panicking.rs:587:40
  20: std::panicking::try
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/panicking.rs:550:19
  21: std::panic::catch_unwind
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/panic.rs:358:14
  22: std::rt::lang_start_internal::{{closure}}
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/rt.rs:168:24
  23: std::panicking::try::do_call
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/panicking.rs:587:40
  24: std::panicking::try
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/panicking.rs:550:19
  25: std::panic::catch_unwind
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/panic.rs:358:14
  26: std::rt::lang_start_internal
             at /rustc/05f9846f893b09a1be1fc8560e33fc3c815cfecb/library/std/src/rt.rs:164:5
  27: std::rt::lang_start
             at /home/PC/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/rt.rs:198:5
  28: main
  29: __libc_start_call_main
             at ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
  30: __libc_start_main_impl
             at ./csu/../csu/libc-start.c:360:3
  31: _start

Process finished with exit code 1

[abonander]

That's likely a result of #3765, specifically this bit of code:

sqlx/sqlx-mysql/src/transaction.rs

Lines 33 to 35 in bab1b02

	if !conn.in_transaction() {
	return Err(Error::BeginFailed);
	}

It likely means that StarRocks responded to a BEGIN statement with an OK packet without the SERVER_STATUS_IN_TRANS flag set.

SQLx is behaving correctly here. This is a protocol compatibility bug in StarRocks.

[abonander]

Reported upstream as StarRocks/starrocks#59125

[scottxing]

@abonander As Starrocks is an OLAP database, not like MySQL which is an OLTP, it does not support multi-row SQL transactions that may change some connection characteristics. Previously in version 0.8.3, I used the method .no_engine_substitution(false) to connect to Starrocks. However, even in version 0.8.5, I still used .no_engine_substitution(false). The code is as follows:

let options = MySqlConnectOptions::new()
.host(conf.get("host").unwrap())
.port(conf.get("port").unwrap().parse()?)
.username(conf.get("username").unwrap())
.password(conf.get("password").unwrap())
.timezone(String::from("+08:00"))
.no_engine_substitution(false)
.pipes_as_concat(false);

"Is it possible that modifying the value of .no_engine_substitution can solve the issue?"

[abonander]

No, but there's also nowhere that we begin a transaction in the code path of opening a connection.

The only time the MySQL driver implicitly begins a transaction is when running migrations:

sqlx/sqlx-mysql/src/migrate.rs

Line 180 in bab1b02

let mut tx = self.begin().await?;