{"record":{"id":"47390ec550cc906f","repo":"influxdata/influxdb","slug":"disabling-lifo-slot-requires-tokio-unstable","errorCode":null,"errorMessage":"disabling LIFO slot requires `tokio_unstable`","messagePattern":"disabling LIFO slot requires `tokio_unstable`","errorType":"console","errorClass":"std::io::Error","httpStatus":null,"severity":"error","filePath":"influxdb3_clap_blocks/src/tokio.rs","lineNumber":207,"sourceCode":"                        format!(\"InfluxDB 3 Core Tokio {} {}\", name, thread_counter.fetch_add(1, Ordering::SeqCst))\n                    });\n\n                    // worker thread count\n                    let num_threads = match self.num_threads {\n                        None => std::thread::available_parallelism()\n                            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?,\n                        Some(n) => n,\n                    };\n                    builder.worker_threads(num_threads.get());\n\n                    if self.disable_lifo == Some(true) {\n                        #[cfg(tokio_unstable)]\n                        {\n                            builder.disable_lifo_slot();\n                        }\n                        #[cfg(not(tokio_unstable))]\n                        {\n                            return Err(std::io::Error::new(\n                                std::io::ErrorKind::Other,\n                                \"disabling LIFO slot requires `tokio_unstable`\",\n                            ));\n                        }\n                    }\n\n                    if let Some(x) = self.event_interval {\n                        builder.event_interval(x.get());\n                    }\n\n                    if let Some(x) = self.global_queue_interval {\n                        builder.global_queue_interval(x.get());\n                    }\n\n                    if let Some(x) = self.max_blocking_threads {\n                        builder.max_blocking_threads(x.get());\n                    }\n","sourceCodeStart":189,"sourceCodeEnd":225,"githubUrl":"https://github.com/influxdata/influxdb/blob/d28e26e048401c53cbb98cf2d6ab0cf1e98048ca/influxdb3_clap_blocks/src/tokio.rs#L189-L225","documentation":"The tokio runtime builder block in influxdb3_clap_blocks maps the disable-lifo option to builder.disable_lifo_slot(), which only exists when tokio is compiled with RUSTFLAGS=\"--cfg tokio_unstable\". On a normal build the cfg(not(tokio_unstable)) arm returns this io::Error during runtime construction, so startup fails before the server runs.","triggerScenarios":"Passing --disable-lifo-slot (or setting disable_lifo=true in config/env) on an influxdb3 binary compiled without the tokio_unstable cfg.","commonSituations":"Latency-tuning flags carried over from an internal benchmark build; release binaries that never enable unstable tokio features.","solutions":["Remove the disable-lifo option from the command line/config","If you need it, rebuild from source with RUSTFLAGS=\"--cfg tokio_unstable\" cargo build --release (experimental, unsupported)","Prefer supported tuning knobs (worker-threads, event-interval, global-queue-interval) instead"],"exampleFix":"# before\ninfluxdb3 serve --disable-lifo-slot ...\n\n# after\ninfluxdb3 serve ...\n","handlingStrategy":"validation","validationCode":"# reject experimental tokio knobs unless the build supports them\nif [ \"$DISABLE_LIFO\" = \"true\" ]; then\n  echo \"--disable-lifo-slot requires a tokio_unstable build; ignoring\" >&2\n  DISABLE_LIFO=\"\"\nfi\n","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Treat disable-lifo as benchmark-only tooling, not a production knob","Prefer supported tuning options (worker-threads, event-interval, global-queue-interval)","Document which build flags each environment's binary was compiled with"],"tags":["tokio","runtime","cli","config","tokio-unstable","lifo-slot"],"backgroundTag":"tokio-unstable-feature-missing","analyzedSha":"d28e26e048401c53cbb98cf2d6ab0cf1e98048ca","analyzedAt":"2026-08-16T19:53:34.623Z","schemaVersion":2},"datasetVersion":"2026-08-16T23:17:17.608Z"}