influxdata/influxdb · error · TableIndexError

Failed to deserialize table index

Error message

Failed to deserialize table index

What it means

TableIndexError::SerializeIndex wraps a serde_json::Error raised when serializing the table index to JSON (despite its message saying "deserialize", the SerializeIndex variant wraps to_json calls). If the index structure cannot be converted to JSON (rare for serde-compatible structs, but possible via map keys or custom serde impls) this error is returned before writing to the object store.

Solutions

1. Check the #[source] serde_json::Error for the exact serialization failure point
2. Ensure all fields of the index (table names, snapshot ids) are JSON-compatible types (string keys, no untagged exotic types)
3. Update InfluxDB3 to a version where index types are known-good serde structs
4. If a fork added custom fields, fix their Serialize impl or mark them #[serde(skip)]

Example fix

// before
struct CustomIndex { meta: std::collections::HashMap<NonZeroU32, String> } // non-string keys can fail
// after
#[derive(serde::Serialize)]
struct CustomIndex { meta: std::collections::HashMap<String, String> }

// validate index contents are JSON-serializable before persisting
serde_json::to_value(&index).expect("index must serialize");

fn index_serializable<T: serde::Serialize>(idx: &T) -> bool {
    serde_json::to_vec(idx).is_ok()
}

match persist_result {
    Err(TableIndexError::SerializeIndex(e)) => {
        log::error("index serialization failed: {e}");
        // report bug / skip custom fields
    }
    other => other?,
}

When it happens

Trigger: Calling the persist path that runs serde_json::to_vec_pretty(&self) on CoreTableIndex/TableIndexSnapshot and maps the error to SerializeIndex (table_index.rs:284).

Common situations: Custom serde::Serialize implementations that error (e.g. serializing non-string map keys); instrumentation or forks that inject non-JSON-serializable data into the index struct; memory corruption/bugs in modified builds.

Understand the failure class

Background: "JSON serialization failed", "not JSON serializable", "Failed to serialize": why JSON marshaling errors happen and how to fix them — this error's family across 46 libraries.

Related errors

• failed to serialize the request body
• JSON serialization/deserialization failed
• JSON serialization/deserialization failed
• serde_json error
• deserializing show tables

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/118835aa1664bf20. Report an issue: GitHub.

Appendix: source

Thrown at influxdb3_write/src/table_index.rs:25

use observability_deps::tracing::{debug, warn};
use serde::{Deserialize, Serialize};
use thiserror::Error;
use tokio::sync::Semaphore;

use influxdb3_id::{DbId, ParquetFileId, TableId, TableIndexId};
use influxdb3_wal::SnapshotSequenceNumber;

use crate::{
    ParquetFile, PersistedSnapshot, PersistedSnapshotVersion,
    paths::{SnapshotInfoFilePath, TableIndexPath, TableIndexSnapshotPath},
};

#[derive(Debug, Error)]
pub enum TableIndexError {
    #[error("Failed to load table index from object store")]
    LoadIndex(#[source] object_store::Error),

    #[error("Failed to deserialize table index")]
    SerializeIndex(#[source] serde_json::Error),

    #[error("Failed to deserialize table index")]
    DeserializeIndex(#[source] serde_json::Error),

    #[error("Failed to list table index snapshots from object store")]
    ListSnapshots(#[source] object_store::Error),

    #[error("Failed to list table indices from object store")]
    ListIndices(#[source] object_store::Error),

    #[error("Failed to load table index snapshot from object store")]
    LoadSnapshot(#[source] object_store::Error),

    #[error("Failed to deserialize table index snapshot")]
    DeserializeSnapshot(#[source] serde_json::Error),

    #[error("Failed to persist table index to object store")]

View on GitHub (pinned to 06200ef96b)