tursodatabase/turso · error

connections must be positive

Error message

connections must be positive

What it means

FtsConfig::validate() rejects configurations where connections is zero. The benchmark opens one session per connection and queries across all of them; with zero connections there is nothing to measure, so validation fails before setup.

Source

Thrown at perf/memory/src/fts.rs:277

        }
        .await;
        if result.is_err() {
            workers.shutdown().await;
        }
        result
    }
}

impl FtsConfig {
    pub fn validate(&self) -> Result<()> {
        ensure!(self.documents > 0, "documents must be positive");
        ensure!(
            self.corpus
                .cache_pages
                .is_none_or(|pages| (200..=i32::MAX as usize).contains(&pages)),
            "cache pages must be between 200 and i32::MAX"
        );
        ensure!(self.connections > 0, "connections must be positive");
        ensure!(
            self.execution.batches() > 0,
            "queries or transactions must be positive"
        );
        ensure!(
            self.execution.queries_per_batch() > 0,
            "queries per transaction must be positive"
        );
        ensure!(
            !matches!(self.state, QueryState::First)
                || (self.execution.batches() == 1 && self.execution.queries_per_batch() == 1),
            "first-query runs require one query per connection; use warm for repeated transactions"
        );
        self.execution
            .batches()
            .checked_mul(self.execution.queries_per_batch())
            .and_then(|n| n.checked_mul(self.connections))
            .ok_or_else(|| anyhow::anyhow!("total query count overflows usize"))?;

View on GitHub (pinned to 492c4a71cd)

Solutions

1. Pass a positive connection count, e.g. --connections 4
2. Clamp or default the computed value: connections.max(1)
3. Validate user input before constructing FtsConfig

Example fix

// before
FtsConfig { connections: 0, .. }
// after
FtsConfig { connections: 4, .. }

if connections == 0 { return Err(anyhow!("connections must be > 0")); }

if let Err(e) = config.validate() {
    if e.to_string().contains("connections must be positive") {
        // rebuild with connections.max(1)
    }
}

When it happens

Trigger: Building FtsConfig with connections == 0, e.g. --connections 0 or a default derived from an empty/zero input.

Common situations: Command-line typo; concurrency value loaded from an unset env var or empty config file; programmatic use where the caller passes a computed parallelism of 0.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• index contains {} segment bytes, below requested minimum {};
• documents must be positive
• queries or transactions must be positive
• queries per transaction must be positive
• first-query runs require one query per connection; use warm

AI-assisted analysis of tursodatabase/turso@492c4a71cd (2026-09-13). Data as JSON: /api/errors/f92a5375e4de9b06. Report an issue: GitHub.