Analytics Terminology
=====================

This page defines key terms used in the Analytics Accelerator and Hybrid
Manager (HM) analytics features.

Use it as a quick reference when exploring concepts, how-tos, and
feature guides.

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Apache Iceberg
--------------

An open table format for large analytic datasets stored in object
storage. Provides schema evolution, time travel, and interoperability
with many analytics engines (Spark, Trino, Flink, and Postgres).

:ref:`Apache Iceberg <Apache Iceberg>` 

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Delta Lake
----------

An open table format and storage layer that adds ACID transactions and
reliability to data lakes. Built on Parquet files with a \_delta_log
transaction log.

:ref:`Delta Lake <Delta Lake>` 

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Data Lakehouse
--------------

A modern architecture that combines elements of data lakes and data
warehouses:

- Stores data in object storage

- Supports open table formats (Iceberg, Delta Lake)

- Provides fast SQL analytics using vectorized query engines

- Decouples storage from compute

Related concept: :ref:`Data lakehouse <Data lakehouse>` 

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EDB Postgres Lakehouse Cluster
------------------------------

A managed analytical compute cluster provisioned by Hybrid Manager to
run fast SQL queries on data stored in object storage.

- Supports Iceberg and Delta Lake formats

- Uses a vectorized query engine (Apache DataFusion)

- Separates storage and compute for scalability and cost efficiency

:ref:`EDB Postgres Lakehouse <EDB Postgres Lakehouse>` 

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EDB Postgres Distributed (PGD)
------------------------------

An advanced, distributed version of Postgres:

- Provides high availability and multi-master replication

- Enables advanced data tiering patterns (Tiered Tables)

- Works seamlessly with Lakehouse clusters for scalable analytics

`Learn more <https://enterprisedb.com/docs/edb-postgres-ai/hybrid-manager/overview/database_types/distributed_highavailability/>`_ 

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Tiered Tables
-------------

A feature that uses PGD **AutoPartition** to manage large time-based
datasets:

- **Hot data** stays in the PGD transactional cluster

- **Cold data** is offloaded to object storage as Apache Iceberg tables

- Queries can transparently access both hot and cold data

:ref:`EDB Postgres Distributed (PGD) and Tiered Tables <EDB Postgres Distributed (PGD) and Tiered Tables>` 

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PGAA (Postgres Generic Analytics Adapter)
-----------------------------------------

An extension that enables Postgres to:

- Query open table formats (Iceberg, Delta Lake)

- Define **external tables** that map to object storage

- Power Lakehouse cluster queries

- Enable PGD Tiered Table offloading and querying

:ref:`Example in use <Apache Iceberg>` 

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PGFS (Postgres File System)
---------------------------

An extension that defines **storage locations** Postgres can use to
access object storage.

- Used by PGAA and PGD for Iceberg and Delta Lake access

- Supports AWS S3, Google Cloud Storage, and compatible services

- Must be configured on each Lakehouse or PGD cluster that needs to
  query object storage

`Example in use <https://enterprisedb.com/docs/edb-postgres-ai/hybrid-manager/analytics/learn/how-to/configure-delta-pgfs>`_ 

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AutoPartition
-------------

A capability of PGD BDR (Bi-Directional Replication):

- Automatically creates time-based partitions for a PGD table

- Automatically offloads older partitions to object storage when
  configured with an ``analytics_offload_period``

`Example in use <https://enterprisedb.com/docs/edb-postgres-ai/hybrid-manager/analytics/learn/how-to/configure-tiered-autopartition>`_ 

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BDR Analytics Table
-------------------

An internal PGD concept:

- The **analytics_table** view tracks which PGD tables are marked for
  Tiered Table offload

- Tracks the state of each table and offload progress

Useful for monitoring and validating Tiered Table behavior.

`Example in use <https://enterprisedb.com/docs/edb-postgres-ai/hybrid-manager/analytics/learn/how-to/monitor-tiered-tables>`_ 

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Iceberg Catalog
---------------

A metadata service that tracks Iceberg table schemas, locations, and
versions:

- Required for full interoperability across multiple engines (Spark,
  Trino, Postgres)

- Can be HM-managed (Lakekeeper) or external (AWS Glue, Nessie, Polaris,
  etc.)

- PGAA and PGD both support connecting to an Iceberg REST catalog

:ref:`Example in use <Apache Iceberg>` 

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Lakekeeper
----------

An HM-managed Iceberg catalog service:

- Provides a central catalog for Iceberg tables

- Supports PGD Tiered Table offload with catalog integration

- Supports Lakehouse cluster queries through catalog-based table
  discovery

- Uses Iceberg REST Catalog API

:ref:`Example in use <Apache Iceberg>` 

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Open Table Formats
------------------

Standardized file layouts and metadata formats used for analytics:

- **Apache Iceberg**

- **Delta Lake**

Enable multi-engine access to the same data (Spark, Trino, Postgres
Lakehouse, etc.).

:ref:`Open table formats <Open table formats>` 

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Vectorized Query Engine
-----------------------

An analytics engine that processes data in **columnar batches** (instead
of row-by-row):

- Accelerates analytics queries

- Makes use of modern CPU features (SIMD)

- Powers Lakehouse cluster query performance

EDB Lakehouse clusters embed `Apache DataFusion <https://datafusion.apache.org/>`_  for this.

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Data Tiering
------------

The practice of storing **hot**, **warm**, and **cold** data on
different storage tiers:

- Hot → fast transactional PGD nodes

- Cold → object storage (Iceberg tables)

- Tiered Tables automate this pattern in Postgres + HM

Related concept: :ref:`Data tiering <Data tiering>` 

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Separation of Storage and Compute
---------------------------------

A pattern used by Lakehouse architectures:

- Store data in **object storage** (independently scaled)

- Scale analytical compute (Lakehouse clusters) independently of storage

Enables cost-efficient, elastic analytics architectures.

Related concept: :ref:`Separation of storage and compute <Separation of storage and compute>` 

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Next steps
----------

Now that you understand key terminology:

- :ref:`Learn Analytics Concepts <Analytics Accelerator concepts>` 

- :ref:`EDB Postgres Lakehouse <EDB Postgres Lakehouse>` 

- :ref:`EDB Postgres Distributed (PGD) and Tiered Tables <EDB Postgres Distributed (PGD) and Tiered Tables>` 

- `See How-To Guides <https://enterprisedb.com/docs/edb-postgres-ai/hybrid-manager/analytics/learn/how-to/>`_ 
