---
title: InfluxDB Cloud Serverless internals
description: Learn about InfluxDB Cloud Serverless internal systems and mechanisms.
url: https://docs.influxdata.com/influxdb3/cloud-serverless/reference/internals/
estimated_tokens: 407
product: InfluxDB Cloud Serverless
version: cloud-serverless
---

# InfluxDB Cloud Serverless internals

### [Arrow Flight SQL](/influxdb3/cloud-serverless/reference/internals/arrow-flightsql/)

The InfluxDB SQL implementation uses **Arrow Flight SQL** to query InfluxDB and return results.

### [InfluxDB Cloud Serverless data durability](/influxdb3/cloud-serverless/reference/internals/durability/)

InfluxDB Cloud Serverless replicates all time series data in the storage tier across multiple availability zones within a cloud region and automatically creates backups that can be used to restore data in the event of a node failure or data corruption.

### [Data retention in InfluxDB Cloud Serverless](/influxdb3/cloud-serverless/reference/internals/data-retention/)

InfluxDB Cloud Serverless enforces bucket retention periods at query time and, to optimize storage, routinely deletes [Parquet](https://parquet.apache.org/) files containing only expired data.

### [Query plans](/influxdb3/cloud-serverless/reference/internals/query-plan/)

A query plan is a sequence of steps that the InfluxDB Querier devises and executes to calculate the result of a query in the least amount of time. InfluxDB query plans include DataFusion and InfluxDB logical plan and execution plan nodes for scanning, deduplicating, filtering, merging, and sorting data.