Verdict: infrastructure flake — not caused by PR #7816

The Java Tests job in the merge-queue run for PR #7816 failed because the sccache remote service was unreachable, aborting a rustc invocation inside the SQL compiler's test suite. It is unrelated to the content of PR #7816, which only touches python/tests/ files.

Evidence

• Failing test: org.dbsp.sqlCompiler.compiler.ir.SaturatingOperationsTests.saturatingOperations (via BaseSQLTests.compileAndTestRust)
• Log lines 612-621:

  error: process didn't exit successfully: `sccache /home/ubuntu/.rustup/toolchains/1.99.0-x86_64-unknown-linux-gnu/bin/rustc -vV` (exit status: 2)
  --- stderr
  sccache: error: Timed out waiting for server startup. Maybe the remote service is unreachable?
  

  which surfaces as:

  java.lang.RuntimeException: Process failed with exit code 101
      at org.dbsp.util.Utilities.compileAndTestRust(Utilities.java:528)
      at org.dbsp.sqlCompiler.compiler.ir.SaturatingOperationsTests.saturatingOperations(SaturatingOperationsTests.java:141)
  

• Only one test out of 2742 failed (Tests run: 2742, Failures: 0, Errors: 1, Skipped: 24), with no logic assertion involved — the rustc wrapper itself never started.
• SaturatingOperationsTests was last touched by Runtime Integration Tests (amd64): aggregate_tests4/varchar_arg_min_gby fails empty after 650s+ compile under slow CI #7688's ancestor commit (9ea67aaecc, "[SQL] Saturating forms of the operations and casts that can fail"), weeks before this PR; PR [python] Report a pipeline restart instead of an empty view in the aggtest harness #7816 did not touch SQL-compiler or sccache config.
• The same error text (sccache: error: Timed out waiting for server startup) is already reported against the production sccache integration in sccache UX #6763, so this is a recurring reliability issue with the sccache remote backend, now also hitting CI.

Next step

Worth checking sccache server/network health on the gke-runners-amd64 pool around 2026-11-04T09:50Z, and considering a retry/backoff or local-compile fallback for RUSTC_WRAPPER=sccache in .github/workflows/test-java.yml so a transient sccache outage doesn't fail the whole Java Tests job.

Re-queueing PR #7816 should pass, since this isn't related to its diff.