Troubleshoot

Learn how to avoid unexpected results and recover from errors when writing to {{% product-name %}}.

• Handle write responses
  • Review HTTP status codes
• Troubleshoot failures
• Troubleshoot rejected points {{% show-in "core,enterprise" %}}- Troubleshoot write performance issues
  • Use debug logs for troubleshooting{{% /show-in %}}

Handle write responses

{{% product-name %}} does the following when you send a write request:

1. Validates the request.

2. If successful, attempts to ingest data from the request body; otherwise, responds with an error status.

3. Ingests or rejects data in the batch and returns one of the following HTTP status codes:

   • 204 No Content: All data in the batch is ingested.
   • 400 Bad Request: Some or all of the data has been rejected. Data that has not been rejected is ingested and queryable.

The response body contains error details about rejected points, up to 100 points.

Writes are synchronous--the response status indicates the final status of the write and all ingested data is queryable.

To ensure that InfluxDB handles writes in the order you request them, wait for the response before you send the next request.

Review HTTP status codes

{{< product-name >}} uses conventional HTTP status codes to indicate the success or failure of a request. The message property of the response body may contain additional details about the error. Write requests return the following status codes:

If your data did not write to the database, see how to troubleshoot rejected points.

Troubleshoot failures

If you notice data is missing in your database, do the following:

• Check the message property in the response body for details about the error.
• If the message describes a field error, troubleshoot rejected points.
• Verify all lines contain valid syntax (line protocol).
• Verify the timestamps in your data match the precision parameter in your request.
• Minimize payload size and network errors by optimizing writes.

Troubleshoot rejected points

InfluxDB rejects points that don't match the schema of existing data.

Check for field data type differences between the rejected data point and points within the same database--for example, did you attempt to write string data to an int field?

{{% show-in "core,enterprise" %}}

Troubleshoot write performance issues

If you experience slow write performance or timeouts during high-volume ingestion, consider the following:

Memory configuration

{{% product-name %}} uses memory for both query processing and internal data operations, including converting data to Parquet format during persistence. For write-heavy workloads, insufficient memory allocation can cause performance issues.

Symptoms of memory-related write issues:

• Slow write performance during data persistence (typically every 10 minutes)
• Increased response times during high-volume ingestion
• Memory-related errors in server logs

Solutions:

• Increase the exec-mem-pool-bytes configuration to allocate more memory for data operations. For write-heavy workloads, consider setting this to 30-40% of available memory.
• Monitor memory usage during peak write periods to identify bottlenecks.
• Adjust the gen1-duration to control how frequently data is persisted to Parquet format.

Example configuration for write-heavy workloads

influxdb3 serve \
  --exec-mem-pool-bytes PERCENTAGE \
  --gen1-duration 15m \
  # ... other options

Replace {{% code-placeholder-key %}}PERCENTAGE{{% /code-placeholder-key %}} with the percentage of available memory to allocate (for example, 35% for write-heavy workloads).

Use debug logs for troubleshooting

For deeper investigation of write issues, enable debug logging for specific components. Debug logs provide detailed information about write buffer operations and WAL activity.

To enable debug logs for write operations, restart {{% product-name %}} with targeted log filters:

influxdb3 serve --log-filter info,influxdb3_write_buffer=debug

influxdb3 serve --log-filter info,influxdb3_wal=debug

For more information about log levels and targeted filtering, see log-filter configuration.

{{% /show-in %}}