52 lines
2.0 KiB
Markdown
52 lines
2.0 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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influxdb_clustered:
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name: Troubleshoot queries
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parent: Troubleshoot and optimize queries
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influxdb/clustered/tags: [query, performance, observability, errors, sql, influxql]
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related:
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- /influxdb/clustered/query-data/sql/
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- /influxdb/clustered/query-data/influxql/
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- /influxdb/clustered/reference/client-libraries/v3/
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aliases:
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- /influxdb/clustered/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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## 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](/influxdb/clustered/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](/influxdb/clustered/query-data/troubleshoot-and-optimize/optimize-queries/) and use tools to view runtime metrics, identify bottlenecks, and debug queries.
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