---
title: InfluxDB reference
description: Reference documentation for InfluxDB including release notes, API documentation, tools, syntaxes, database internals, and more.
url: https://docs.influxdata.com/influxdb/v2/reference/
estimated_tokens: 1310
product: InfluxDB OSS v2
version: v2
---

# InfluxDB reference

This page documents an earlier version of InfluxDB OSS. [InfluxDB 3 Core](/influxdb3/core/) is the latest stable version.

#### API token hashing is enabled by default in InfluxDB OSS 2.9.0

Stronger token security: tokens are stored as hashes on disk, so a copy of the database file doesn’t expose usable tokens. Existing tokens are hashed on first startup and the original strings can’t be recovered afterward — **capture any plaintext tokens you still need before you upgrade**.

For more information, see [Token hashing](/influxdb/v2/admin/tokens/#token-hashing).

### [Release notes](/influxdb/v2/reference/release-notes/)

Find important information about what’s included in new versions of InfluxData products.

### [InfluxDB key concepts](/influxdb/v2/reference/key-concepts/)

Concepts related to InfluxDB.

### [InfluxDB configuration options](/influxdb/v2/reference/config-options/)

Customize your InfluxDB configuration by using [`influxd`](/influxdb/v2/reference/cli/influxd/) configuration flags, setting environment variables, or defining configuration options in a configuration file.

### [Command line tools](/influxdb/v2/reference/cli/)

InfluxDB provides command line tools designed to aid in managing and working with InfluxDB from the command line.

### [InfluxDB syntaxes](/influxdb/v2/reference/syntax/)

InfluxDB uses a handful of languages and syntaxes to perform tasks such as writing, querying, processing, and deleting data.

### [InfluxDB OSS URLs](/influxdb/v2/reference/urls/)

InfluxDB OSS is accessed at `localhost:8086` by default, but you can also customize your InfluxDB host and port.

### [InfluxDB internals](/influxdb/v2/reference/internals/)

```
		 <h3 id="influxdb-storage-engine"><a href="/influxdb/v2/reference/internals/storage-engine/" target="">InfluxDB storage engine</a></h3>
		
		<p>An overview of the InfluxDB storage engine architecture.</p>
		
		

		

		
		

		
		
		
		 <h3 id="influxdb-file-system-layout"><a href="/influxdb/v2/reference/internals/file-system-layout/" target="">InfluxDB file system layout</a></h3>
		
		<p>The InfluxDB file system layout depends on the operating system, package manager, or containerization platform used to install InfluxDB.</p>
		
		

		

		
		

		
		
		
		 <h3 id="data-retention-in-influxdb"><a href="/influxdb/v2/reference/internals/data-retention/" target="">Data retention in InfluxDB</a></h3>
		
		<p>The InfluxDB retention service checks for and removes data with timestamps beyond the defined retention period of the bucket the data is stored in.</p>
		
		

		

		
		

		
		
		
		 <h3 id="influxdb-runtime"><a href="/influxdb/v2/reference/internals/runtime/" target="">InfluxDB runtime</a></h3>
		
		<p>Learn how to collect Go runtime profiling and tracing information to help with InfluxDB performance analysis and debugging.</p>

```

### [Sample data](/influxdb/v2/reference/sample-data/)

Use sample data to familiarize yourself with time series data and InfluxDB. InfluxData provides many sample time series datasets to use with InfluxDB and InfluxDB Cloud.

### [Prometheus metric parsing formats](/influxdb/v2/reference/prometheus-metrics/)

When scraping [Prometheus-formatted metrics](https://prometheus.io/docs/concepts/data_model/) and writing them to InfluxDB, metrics are parsed and stored in InfluxDB in different formats.

### [Usage telemetry](/influxdb/v2/reference/telemetry/)

InfluxData collects information, or *telemetry data*, about the usage of InfluxDB to help improve the product. Learn what data InfluxDB collects and sends to InfluxData, how it’s used, and how you can opt out.

### [Frequently asked questions](/influxdb/v2/reference/faq/)

Find answers to common questions related to InfluxDB OSS.

### [Glossary](/influxdb/v2/reference/glossary/)

Terms related to InfluxData products and platforms.

### [Contribute to InfluxDB OSS](/influxdb/v2/reference/contributing/)

Find important information about what’s included in new versions of InfluxData products.