{"record":{"id":"9db4d5782a3ff33f","repo":"influxdata/influxdb","slug":"error-in-last-cache-0","errorCode":null,"errorMessage":"error in last cache: {0}","messagePattern":"error in last cache: (.+?)","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"influxdb3_write/src/write_buffer/mod.rs","lineNumber":98,"sourceCode":"        new: ColumnType,\n    },\n\n    #[error(\"catalog update error: {0}\")]\n    CatalogUpdateError(#[from] CatalogError),\n\n    #[error(\"error from persister: {0}\")]\n    PersisterError(#[from] PersisterError),\n\n    #[error(\"corrupt load state: {0}\")]\n    CorruptLoadState(String),\n\n    #[error(\"database name error: {0}\")]\n    DatabaseNameError(#[from] DatabaseNameError),\n\n    #[error(\"error from table buffer: {0}\")]\n    TableBufferError(#[from] table_buffer::Error),\n\n    #[error(\"error in last cache: {0}\")]\n    LastCacheError(#[from] last_cache::Error),\n\n    #[error(\"database not found {db_name:?}\")]\n    DatabaseNotFound { db_name: String },\n\n    #[error(\"table not found {table_name:?} in db {db_name:?}\")]\n    TableNotFound { db_name: String, table_name: String },\n\n    #[error(\"tried accessing database that does not exist\")]\n    DbDoesNotExist,\n\n    #[error(\"tried creating database named '{0}' that already exists\")]\n    DatabaseExists(String),\n\n    #[error(\"cannot write to soft-deleted database '{0}' - it is marked for deletion\")]\n    DatabaseDeleted(String),\n\n    #[error(\"tried accessing table that do not exist\")]","sourceCodeStart":80,"sourceCodeEnd":116,"githubUrl":"https://github.com/influxdata/influxdb/blob/06200ef96ba82c5f6727e5038a83af8e722c6875/influxdb3_write/src/write_buffer/mod.rs#L80-L116","documentation":"This transparent wrapper converts a `last_cache::Error` — a failure in the last-N-values cache attached to a table. The last cache stores the most recent values per tag combination for fast lookup; errors here mean cache creation, update, or lookup failed, independent of the core write.","triggerScenarios":"Creating a last cache with invalid configuration (bad TTL/count, nonexistent columns used as key/value columns), or updating/looking up a cache during writes when the cache state is inconsistent with the table schema.","commonSituations":"Configuring a cache on a column that was later dropped or type-changed; cache size/TTL values out of accepted bounds; referencing renamed columns in cached definitions after a schema change.","solutions":["Read the inner last_cache::Error for the exact cause","Verify cache key/value columns still exist in the table schema with the expected types","Recreate the last cache with valid size/TTL and existing column names"],"exampleFix":"// before\ncreate_last_cache(db, table, \"c\", Some(vec![\"old_col\"]), None, None)?; // column gone\n// after\nlet cols = valid_key_columns(db, table)?; // check schema first\ncreate_last_cache(db, table, \"c\", Some(cols), None, None)?;","handlingStrategy":"validation","validationCode":"// validate last-cache config before creation\nlet schema = catalog.table(db, table)?.schema();\nfor key in &key_columns {\n    assert!(schema.field(key).is_some(), \"cache key column {key} not in schema\");\n}\nassert!(cache_size.is_none() || cache_size.unwrap() > 0, \"cache size must be > 0\");","typeGuard":"fn is_last_cache_error(e: &WriteBufferError) -> Option<&last_cache::Error> {\n    match e { WriteBufferError::LastCacheError(e) => Some(e), _ => None }\n}","tryCatchPattern":null,"preventionTips":["Re-check cache column definitions after any schema migration","Use only existing, stable columns as cache keys/values","Keep TTL and count within documented bounds","Delete and recreate caches rather than mutating stale definitions"],"tags":["last-cache","cache","influxdb","rust"],"backgroundTag":"invalid-config-value","analyzedSha":"06200ef96ba82c5f6727e5038a83af8e722c6875","analyzedAt":"2026-09-19T12:55:30.003Z","contentChangedAt":"2026-09-19T12:55:30.003Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}