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      • Monitoring with Grafana
      • Running behind a proxy
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      • Helm chart configuration
      • Deploying ClickHouse using Altinity.Cloud
      • Configuring Slack
      • Overview
        • Overview
        • Upgrade notes
        • Overview
        • 0001-events-sample-by
        • 0002_events_sample_by
        • 0003_fill_person_distinct_id2
        • ClickHouse
          • Backup
          • Debug hanging / freezing process
          • Horizontal scaling (Sharding & replication)
          • Kafka Engine
          • Resize disk
          • Restore
          • Vertical scaling
        • Kafka
          • Resize disk
          • Log retention
        • PostgreSQL
          • Resize disk
          • Troubleshooting long-running migrations
        • Plugin server
        • MinIO
        • Redis
        • Zookeeper
      • Disaster recovery
    • Troubleshooting and FAQs
    • Support for self-hosting (open-source and enterprise)
    • Managing hosting costs
    • Overview
    • Ingest live data
    • Ingest historical data
    • Identify users
    • User properties
    • Deploying a reverse proxy
    • Library comparison
    • Badge
    • Browser Extensions
      • Snippet installation
      • Android
      • iOS
      • JavaScript
      • Flutter
      • React Native
      • Node.js
      • Go
      • Python
      • Rust
      • Java
      • PHP
      • Ruby
      • Elixir
      • Docusaurus v2
      • Gatsby
      • Google Tag Manager
      • Next.js
      • Nuxt.js
      • Retool
      • RudderStack
      • Segment
      • Sentry
      • Slack
      • Shopify
      • WordPress
      • Message formatting
      • Microsoft Teams
      • Slack
      • Discord
    • To another self-hosted instance
    • To PostHog from Amplitude
    • To PostHog Cloud EU
    • Between Cloud and self-hosted
    • Overview
    • Tutorial
    • Troubleshooting
    • Developer reference
    • Using the PostHog API
    • Jobs
    • Testing
    • TypeScript types
    • Overview
    • POST-only public endpoints
    • Actions
    • Annotations
    • Cohorts
    • Dashboards
    • Event definitions
    • Events
    • Experiments
    • Feature flags
    • Funnels
    • Groups
    • Groups types
    • Insights
    • Invites
    • Members
    • Persons
    • Plugin configs
    • Plugins
    • Projects
    • Property definitions
    • Session recordings
    • Trends
    • Users
    • Data model
    • Overview
    • Data model
    • Ingestion pipeline
    • ClickHouse
    • Querying data
    • Overview
    • GDPR guidance
    • HIPAA guidance
    • CCPA guidance
    • Data egress & compliance
    • Data deletion
    • Overview
    • Code of conduct
    • Recognizing contributions
  • Using PostHog

  • Table of contents
      • Dashboards
      • Funnels
      • Group Analytics
      • Insights
      • Lifecycle
      • Path analysis
      • Retention
      • Stickiness
      • Trends
      • Heatmaps
      • Session Recording
      • Correlation Analysis
      • Experimentation
      • Feature Flags
      • Actions
      • Annotations
      • Cohorts
      • Data Management
      • Events
      • Persons
      • Sessions
      • UTM segmentation
      • Team collaboration
      • Organizations & projects
      • Settings
      • SSO & SAML
      • Toolbar
      • Notifications & alerts
    • Overview
      • Amazon Kinesis Import
      • BitBucket Release Tracker
      • Event Replicator
      • GitHub Release Tracker
      • GitHub Star Sync
      • GitLab Release Tracker
      • Heartbeat
      • Ingestion Alert
      • Email Scoring
      • n8n Connector
      • Orbit Connector
      • Redshift Import
      • Segment Connector
      • Shopify Connector
      • Twitter Followers Tracker
      • Zendesk Connector
      • Airbyte Exporter
      • Amazon S3 Export
      • BigQuery Export
      • Customer.io Connector
      • Databricks Export
      • Engage Connector
      • GCP Pub/Sub Connector
      • Google Cloud Storage Export
      • Hubspot Connector
      • Intercom Connector
      • Migrator 3000
      • PagerDuty Connector
      • PostgreSQL Export
      • Redshift Export
      • RudderStack Export
      • Salesforce Connector
      • Sendgrid Connector
      • Sentry Connector
      • Snowflake Export
      • Twilio Connector
      • Variance Connector
      • Zapier Connector
      • Downsampler
      • Event Sequence Timer
      • First Time Event Tracker
      • Property Filter
      • Property Flattener
      • Schema Enforcer
      • Taxonomy Standardizer
      • Unduplicator
      • Automatic Cohort Creator
      • Currency Normalizer
      • GeoIP Enricher
      • Timestamp Parser
      • URL Normalizer
      • User Agent Populator
  • Tutorials
    • All tutorials
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Architecture

Last updated: Oct 13, 2022

The following pages in this section cover Data model, Ingestion pipeline, ClickHouse and Querying data. This document gives an overview of the general architecture. How our cloud or a deployed PostHog Helm chart works on Kubernetes.

K8s PostHog namespace
K8s Services
K8s Services
Other traffic
Events endpoint
Write path
Read path
Optional Utilization telemetry
Ingress
Postgres Stateful service
Kafka Stateful Service
Kafka Stateful Service
Redis SS
Service Load Balancer
Service Load Balancer
K8s Services
PGBouncer
ClickHouse Cluster (Operator Managed)
Replica 1 Shard 1
Replica 1 Shard 2
Replica 2 Shard 1
Replica 2 Shard 2
K8s ZooKeeper cluster
ZK1
ZK2
ZK3
Plugin Service
Worker Service
Events Service
Web Service
Client Apps
Posthog License Telemetry service

No communication is needed into or out of this namespace other than the ingress controller for app and collecting data.

Note that the specifics of this may vary:

  • ClickHouse, Kafka, PostgreSQL and Redis services may be hosted outside of the namespace or configured differently.
  • The ClickHouse cluster is managed by clickhouse-operator and the exact number of pods vary according to sharding settings.

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Data model

This document provides a high-level overview of the various objects and primitives that make up the PostHog data model. For more information on exactly how data is stored in our database, check out the ClickHouse overview . The two most-basic entities in PostHog are the Event and Person objects, and represent the core of our analytics functionalities. Event An event is the most important object in PostHog, and represents a single action that a user performed at a specific point in time…

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Authors

  • Paul Hultgren
    Paul Hultgren
  • kuberaspeaking
    kuberaspeaking
  • Tiina Turban
    Tiina Turban

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