diesel-rs/diesel · error

SQLite while reading a value as

Error message

SQLite {reason} while reading a value as {target}

What it means

The SQLite value reader ran out of memory while converting a stored value to the requested target type. The offending input is the SQLite value being read; the failure comes from the allocator during value duplication or conversion, not from the query itself.

Solutions

1. Reduce the size of the stored value or read it in smaller chunks
2. Free memory before processing large SQLite values
3. Avoid duplicating very large blobs or strings when a streaming read is possible

When it happens

Trigger: Thrown at diesel/src/sqlite/connection/sqlite_value.rs:101 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of diesel-rs/diesel@6fa6ed01b2 (2026-09-07). Data as JSON: /api/errors/063ac4552465f44e. Report an issue: GitHub.

Appendix: source

Thrown at diesel/src/sqlite/connection/sqlite_value.rs:101

impl Drop for OwnedSqliteValue {
    fn drop(&mut self) {
        unsafe { ffi::sqlite3_value_free(self.value.as_ptr()) }
    }
}

// Unsafe Send impl safe since sqlite3_value is built with sqlite3_value_dup
// see https://www.sqlite.org/c3ref/value.html
unsafe impl Send for OwnedSqliteValue {}

#[cold]
fn allocation_failed(out_of_memory: bool, target: &str) -> ! {
    let reason = if out_of_memory {
        "ran out of memory"
    } else {
        "failed to allocate memory"
    };
    panic!("SQLite {reason} while reading a value as {target}")
}

#[cold]
fn duplication_failed() -> crate::result::Error {
    crate::result::Error::DeserializationError(
        "SQLite failed to allocate a duplicated value".into(),
    )
}

impl<'row, 'stmt, 'query> SqliteValue<'row, 'stmt, 'query> {
    pub(super) fn new(
        row: Ref<'row, PrivateSqliteRow<'stmt, 'query>>,
        col_idx: usize,
    ) -> Option<SqliteValue<'row, 'stmt, 'query>> {
        let value = match &*row {
            PrivateSqliteRow::Direct(stmt) => stmt.column_value(
                col_idx
                    .try_into()

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