What causes "last cache size must be greater than 0" in influxdata/influxdb?

Pass a positive integer for the cache size (e.g. --size 10).

influxdata/influxdb · error · CatalogError

last cache size must be greater than 0

Error message

last cache size must be greater than 0

What it means

A last-n-cache (LastCache) was created with a size parameter of zero or less. The catalog requires the cache size (number of entries/values to retain) to be a positive integer, and throws InvalidLastCacheSize otherwise.

Solutions

Pass a positive integer for the cache size (e.g. --size 10).
If size comes from configuration, add validation/defaulting so unset values fall back to a sensible positive default.
Omit the size option entirely if you want the server's default cache size.

Example fix

// before
CREATE LAST CACHE ON mydb mytable SIZE 0;
// after
CREATE LAST CACHE ON mydb mytable SIZE 10;

Defensive patterns

Strategy: validation

Validate before calling

// Clamp/default the size before creating a last cache
const size = Number.parseInt(cfg.lastCacheSize, 10);
if (!Number.isInteger(size) || size <= 0) {
  throw new Error(`last cache size must be > 0, got ${cfg.lastCacheSize}`);
}
await client.createLastCache(db, table, { size });

Type guard

function isValidCacheSize(v) {
  return Number.isInteger(v) && v > 0;
}

Try / catch

try {
  await createLastCache(db, table, { size });
} catch (e) {
  if (String(e).includes('last cache size must be greater than 0')) {
    await createLastCache(db, table, { size: 10 }); // documented default
  } else throw e;
}

Prevention

Validate cache size config at startup, not at first use
Default unset size values to a positive server default
Add range checks wherever size is computed from user input

When it happens

Trigger: Calling the last cache creation API (ADD LAST CACHE / catalog add_last_cache) with a size value of 0 or a negative number.

Common situations: Computing the cache size from config/env where the variable defaulted to 0; off-by-one or unset CLI flag leading to size=0; template expansion that left the size placeholder empty.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/228879fc087a6fc7. Report an issue: GitHub.

Appendix: source

Thrown at influxdb3_catalog/src/error.rs:267

    },

    #[error("Processing Engine Unimplemented: {}", feature_description)]
    ProcessingEngineUnimplemented { feature_description: String },

    #[error(
        "Processing Engine Trigger {} not in DB {}",
        trigger_name,
        database_name
    )]
    ProcessingEngineTriggerNotFound {
        database_name: String,
        trigger_name: String,
    },

    #[error("failed to parse trigger from {}", trigger_spec)]
    ProcessingEngineTriggerSpecParseError { trigger_spec: String },

    #[error("last cache size must be greater than 0")]
    InvalidLastCacheSize,

    #[error("failed to parse trigger from {trigger_spec}{}", .context.as_ref().map(|context| format!(": {context}")).unwrap_or_default())]
    TriggerSpecificationParseError {
        trigger_spec: String,
        context: Option<String>,
    },

    #[error("invalid error behavior {0}")]
    InvalidErrorBehavior(String),

    #[error("cannot parse token permission, {0}")]
    CannotParsePermissionForToken(String),

    #[error("token name already exists, {0}")]
    TokenNameAlreadyExists(String),

    #[error("token hash already exists")]

View on GitHub (pinned to 06200ef96b)