---
title: Troubleshoot queries
description: Troubleshoot SQL and InfluxQL queries in InfluxDB.
url: https://docs.influxdata.com/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/troubleshoot/
estimated_tokens: 1245
product: InfluxDB Cloud Dedicated
version: cloud-dedicated
---

# Troubleshoot queries

Troubleshoot SQL and InfluxQL queries that return unexpected results.

-   [Why doesn’t my query return data?](#why-doesnt-my-query-return-data)
-   [Optimize slow or expensive queries](#optimize-slow-or-expensive-queries)
-   [Analyze your queries](#analyze-your-queries)
-   [Request help to troubleshoot queries](#request-help-to-troubleshoot-queries)

## Why doesn’t my query return data?

If a query doesn’t return any data, it might be due to the following:

-   Your data falls outside the time range (or other conditions) in the query–for example, the InfluxQL `SHOW TAG VALUES` command uses a default time range of 1 day.
    
-   The query (InfluxDB server) timed out.
    
-   The query client timed out. See [Query timeout best practices](/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/query-timeout-best-practices/) for guidance on setting appropriate timeouts.
    
-   The query return type is not supported by the client library. For example, array or list types may not be supported. In this case, use `array_to_string()` to convert the array value to a string–for example:
    
    ```sql
    SELECT array_to_string(array_agg([1, 2, 3]), ', ')
    ```
    

If a query times out or returns an error, it might be due to the following:

-   a bad request
-   a server or network problem
-   it queries too much data

[Understand Arrow Flight responses](/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/flight-responses/) and error messages for queries.

## Optimize slow or expensive queries

If a query is slow or uses too many compute resources, limit the amount of data that it queries.

See how to [optimize queries](/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/optimize-queries/).

## Analyze your queries

Use the following tools to retrieve system query information, analyze query execution, and find performance bottlenecks:

-   [Analyze a query plan](/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/analyze-query-plan/)
-   [Retrieve `system.queries` information for a query](/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/system-information/)

#### Request help to troubleshoot queries

Some bottlenecks may result from suboptimal query [execution plans](/influxdb3/cloud-dedicated/reference/internals/query-plan/#physical-plan) and are outside your control–for example:

-   Sorting (`ORDER BY`) data that is already sorted
-   Retrieving numerous small Parquet files from the object store, instead of fewer, larger files
-   Querying many overlapped Parquet files
-   Performing a high number of table scans

If you’ve followed steps to [optimize](/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/optimize-queries/) and [troubleshoot a query](#why-doesnt-my-query-return-data), but it still doesn’t meet performance requirements, contact the [InfluxData Support team](https://support.influxdata.com) for assistance.

#### Query trace logging

Currently, customers cannot enable trace logging for InfluxDB Cloud Dedicated clusters. InfluxData engineers can use query plans and trace logging to help pinpoint performance bottlenecks in a query.

For help troubleshooting a query, contact the [InfluxData Support team](https://support.influxdata.com).

#### Related

-   [Query data with SQL](/influxdb3/cloud-dedicated/query-data/sql/)
-   [Query data with InfluxQL](/influxdb3/cloud-dedicated/query-data/influxql/)
-   [InfluxDB 3 API client libraries](/influxdb3/cloud-dedicated/reference/client-libraries/v3/)
-   [Query timeout best practices](/influxdb3/cloud-dedicated/query-data/troubleshoot-and-optimize/query-timeout-best-practices/)