{"record":{"id":"b5fc7b911836135e","repo":"pola-rs/polars","slug":"invalid-value-for-polars-memory-prefetch-v","errorCode":null,"errorMessage":"invalid value for POLARS_MEMORY_PREFETCH: {v}","messagePattern":"invalid value for POLARS_MEMORY_PREFETCH: (.+?)","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"crates/polars-utils/src/mem.rs","lineNumber":155,"sourceCode":"                    panic!(\n                        \"POLARS_MEMORY_PREFETCH=madvise_willneed is not supported by this system\"\n                    );\n                }\n            },\n            Some(\"madvise_populate_read\") => {\n                #[cfg(target_os = \"linux\")]\n                {\n                    madvise_populate_read\n                }\n                #[cfg(not(target_os = \"linux\"))]\n                {\n                    panic!(\n                        \"POLARS_MEMORY_PREFETCH=madvise_populate_read is not supported by this system\"\n                    );\n                }\n            },\n            Some(\"force_populate_read\") => force_populate_read,\n            Some(v) => panic!(\"invalid value for POLARS_MEMORY_PREFETCH: {v}\"),\n        };\n\n        if verbose {\n            let func_name = match memory_prefetch_func as usize {\n                v if v == no_prefetch as *const () as usize => \"no_prefetch\",\n                v if v == prefetch_l2 as *const () as usize => \"prefetch_l2\",\n                v if v == madvise_sequential as *const () as usize => \"madvise_sequential\",\n                v if v == madvise_willneed as *const () as usize => \"madvise_willneed\",\n                v if v == madvise_populate_read as *const () as usize => \"madvise_populate_read\",\n                v if v == force_populate_read as *const () as usize => \"force_populate_read\",\n                _ => unreachable!(),\n            };\n\n            eprintln!(\"memory prefetch function: {func_name}\");\n        }\n\n        memory_prefetch_func\n    }","sourceCodeStart":137,"sourceCodeEnd":173,"githubUrl":"https://github.com/pola-rs/polars/blob/9b5d73fd00236295624374b075d16b1fe6ec6df9/crates/polars-utils/src/mem.rs#L137-L173","documentation":"Panic at the fall-through arm of the POLARS_MEMORY_PREFETCH match: the variable's value {v} matched none of the accepted strategies ('no_prefetch', 'prefetch_l2', 'madvise_sequential', 'madvise_willneed', 'madvise_populate_read') nor None, so prefetch configuration aborts with the unrecognized string.","triggerScenarios":"POLARS_MEMORY_PREFETCH contains an unrecognized value.","commonSituations":"See trigger scenarios.","solutions":["Set POLARS_MEMORY_PREFETCH to one of the supported modes (e.g. madvise_sequential, madvise_willneed, madvise_populate_read) or unset it."],"exampleFix":"export POLARS_MEMORY_PREFETCH=madvise_willneed","handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"9b5d73fd00236295624374b075d16b1fe6ec6df9","analyzedAt":"2026-08-19T12:15:06.350Z","contentChangedAt":"2026-08-19T12:15:06.350Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}