90 lines
4.1 KiB
Markdown
90 lines
4.1 KiB
Markdown
---
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title: Troubleshoot queries
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description: >
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Troubleshoot SQL and InfluxQL queries in InfluxDB.
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weight: 201
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menu:
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influxdb3_cloud_serverless:
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name: Troubleshoot queries
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parent: Troubleshoot and optimize queries
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influxdb3/cloud-serverless/tags: [query, performance, observability, errors, sql, influxql]
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related:
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- /influxdb3/cloud-serverless/query-data/sql/
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- /influxdb3/cloud-serverless/query-data/influxql/
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- /influxdb3/cloud-serverless/reference/client-libraries/v3/
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aliases:
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- /influxdb3/cloud-serverless/query-data/execute-queries/troubleshoot/
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---
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Troubleshoot SQL and InfluxQL queries that return unexpected results.
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- [Why doesn't my query return data?](#why-doesnt-my-query-return-data)
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- [Optimize slow or expensive queries](#optimize-slow-or-expensive-queries)
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- [Analyze your queries](#analyze-your-queries)
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- [Request help to troubleshoot queries](#request-help-to-troubleshoot-queries)
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## Why doesn't my query return data?
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If a query doesn't return any data, it might be due to the following:
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- 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.
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- The query (InfluxDB server) timed out.
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- The query client timed out.
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- The query return type is not supported by the client library.
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For example, array or list types may not be supported.
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In this case, use `array_to_string()` to convert the array value to a string--for example:
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```sql
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SELECT array_to_string(array_agg([1, 2, 3]), ', ')
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```
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If a query times out or returns an error, it might be due to the following:
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- a bad request
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- a server or network problem
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- it queries too much data
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[Understand Arrow Flight responses](/influxdb3/cloud-serverless/query-data/troubleshoot-and-optimize/flight-responses/) and error messages for queries.
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## Optimize slow or expensive queries
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If a query is slow or uses too many compute resources, limit the amount of data that it queries.
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See how to [optimize queries](/influxdb3/cloud-serverless/query-data/troubleshoot-and-optimize/optimize-queries/).
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## Analyze your queries
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Use the following tools to retrieve system query information, analyze query execution,
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and find performance bottlenecks:
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- [Analyze a query plan](/influxdb3/cloud-serverless/query-data/troubleshoot-and-optimize/analyze-query-plan/)
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- [Retrieve `system.queries` information for a query](/influxdb3/cloud-serverless/query-data/troubleshoot-and-optimize/system-information/)
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#### Request help to troubleshoot queries
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Some bottlenecks may result from suboptimal query [execution plans](/influxdb3/cloud-serverless/reference/internals/query-plan/#physical-plan) and are outside your control--for example:
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- Sorting (`ORDER BY`) data that is already sorted
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- Retrieving numerous small Parquet files from the object store, instead of fewer, larger files
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- Querying many overlapped Parquet files
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- Performing a high number of table scans
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If you've followed steps to [optimize](#why-is-my-query-slow) and
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[troubleshoot a query](/influxdb3/cloud-serverless/query-data/troubleshoot-and-optimize/troubleshoot/),
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but it still doesn't meet performance requirements, request help troubleshooting.
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Customers with an {{% product-name %}} [annual or support contract](https://www.influxdata.com/influxdb-cloud-pricing/)
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can [contact InfluxData Support](https://support.influxdata.com/) for assistance.
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> [!Note]
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>
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> #### Query trace logging
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>
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> Currently, customers cannot enable trace logging for {{% product-name omit="Clustered" %}} clusters.
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> InfluxData engineers can use query plans and trace logging to help pinpoint performance bottlenecks in a query.
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>
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> If you've followed steps to [optimize](#why-is-my-query-slow) and
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> [troubleshoot a query](/influxdb3/cloud-serverless/query-data/troubleshoot-and-optimize/troubleshoot/),
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> but it still doesn't meet performance requirements, request help troubleshooting.
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> Customers with an {{% product-name %}} [annual or support contract](https://www.influxdata.com/influxdb-cloud-pricing/)
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> can [contact InfluxData Support](https://support.influxdata.com/) for assistance.
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