Comparing replication solutions
===============================

レプリケーションソリューションは、マルチリージョンの展開、競合管理、スキーマの変更、およびメジャーバージョンのアップグレードを処理する方法が大きく異なります。この比較を使用して、これらのディメンションの他のオプションと比較してPGDを評価します。

**最終更新日2026-04-14**

.. csv-table::
  :header: Product,Version
  :widths: 10,30
  :align: left
  :class: longtable

  PGD Standalone,Version 6.4
  PGD HM-managed,Version 6.4
  PSR + EFM,5.3

展開
----

.. csv-table::
  :header: Product,On premise,Cloud,Multi-cloud,Hybrid (on-prem + cloud),SLA,Native Kubernetes Operator
  :widths: 10,3,3,3,7,7,7
  :align: left
  :class: longtable

  PGD Standalone,✓,✓,✓,✓,99.999,"✓ (PGD for Kubernetes (GA Q1 2025), based on CloudNativePG)"
  PGD HM-managed,✓,✓,✓,✗,99.995,✓
  PSR + EFM,✓,✓,✓,✓,99.99,"Partial (CloudNativePG, no native EFM integration)"

パフォーマンス
--------------

.. csv-table::
  :header: Product,Read scalability,Horizontal scalability,Transaction streaming,Parallel apply (vertical scalability),Logical Change Record (LCR) sharing
  :widths: 10,3,8,8,8,8
  :align: left
  :class: longtable

  PGD Standalone,✓ (subscriber only nodes),✗,✓,✓,"✓ (decodes WAL once, shares to all subscribers)"
  PGD HM-managed,✗,✗,✓,✓,✓
  PSR + EFM,✓ (physical standbys),✗,✓,✗,✗ (decodes per subscriber)

耐久性
------

.. csv-table::
  :header: Product,Asynchronous replication,Optional RPO limit for asynchronous replication,Synchronous replication,Consensus based replication,Per transaction durability setting
  :widths: 10,4,4,4,4,4
  :align: left
  :class: longtable

  PGD Standalone,✓,✓,✓,✓,✓
  PGD HM-managed,✓,✓,✓,✓,✓
  PSR + EFM,✓,✗,✓,✗,✓

一貫性
------

.. csv-table::
  :header: Product,Automatic conflict management,Conflict avoidance types,Conflict avoidance at commit (pessimistic conflict handling),Builtin distributed sequence,CRDT (Conflict-Free Replicated Data Types)
  :widths: 10,5,5,5,5,7
  :align: left
  :class: longtable

  PGD Standalone,✓,✓,✓,"✓ (snowflake (bigint), galloc (int/bigint))",✓ (multiple nodes update same row simultaneously without global locking)
  PGD HM-managed,✓,✓,✓,"✓ (snowflake (bigint), galloc (int/bigint))",✓
  PSR + EFM,N/A,N/A,N/A,N/A,✗

データ分散
----------

.. csv-table::
  :header: Product,Data residency/selective replication,Cluster level Active-Active (writers in different regions),Regional Active-Active (multiple writers within region),Automatic partitioning,Offload cold data to cheaper storage
  :widths: 10,3,3,3,7,7
  :align: left
  :class: longtable

  PGD Standalone,✓,✓,✓ (not recommended unless specific setup),✓,✓
  PGD HM-managed,✓,✓,✗,✓,✓
  PSR + EFM,✗,✗,✗,✓ with EPAS,✗

メンテナンス
------------

.. csv-table::
  :header: Product,Near-zero downtime major version upgrades by adding nodes,Near-zero downtime inplace major version upgrades,Rolling schema upgrades/green-blue (with application assistance),Rolling maintenance operations
  :widths: 10,5,5,5,5
  :align: left
  :class: longtable

  PGD Standalone,✓,✓,✓,✓
  PGD HM-managed,✓,✓,✓,✓
  PSR + EFM,✓ (using logical replication),✗,✗,✗

接続管理
--------

.. csv-table::
  :header: Product,Automatic failover,Automatic connection failover for switchover,Cluster level connection routing,Region level connection routing,pgbouncer support,Built-in connection manager (no external consensus/proxy required)
  :widths: 10,5,5,5,5,5,7
  :align: left
  :class: longtable

  PGD Standalone,✓,✓,✓,✓,✓,"✓ (PGD 6.0+, eliminates HARP + etcd dependency)"
  PGD HM-managed,✓,✓,✓,✓,✗,✓
  PSR + EFM,✓,✓,✓,✗,✓,✗ (requires pgbouncer / HAProxy)

DDLサポート
-----------

.. csv-table::
  :header: Product,General DDL replication,Granular (per-object) DDL locking,Create and drop objects,Add columns to table,Change column type,CREATE TABLE AS
  widths: 10,5,5,5,5,5,7
  :align: left
  :class: longtable

  PGD Standalone,✓,✓,✓,✓,✓ (rewrite requires permit_unsafe_commands),✓ (with restrictions)
  PGD HM-managed,✓,✓,✓,✓,✓ (rewrite requires permit_unsafe_commands),✓ (with restrictions)
  PSR + EFM,✓,✓,✓,✓,✓,✓

Postgresの互換性
----------------

.. csv-table::
  :header: Product,Latest supported version,Works on standard PG,Supports TDE,Supports custom types (i.e. PostGIS),Supports extensions,CDC failover support,Large Object support,Multiple DB support
  :widths: 10,3,3,5,3,5,5,3,5
  :align: left
  :class: longtable

  PGD Standalone,18,✓,✓ with EPAS/PGE,✓,Many,✓ (PGD 5.7+),✗,✗
  PGD HM-managed,18,✗,✓ with EPAS/PGE,✓,Many,✓ (PGD 5.7+),✗,✗
  PSR + EFM,17,✓,✓ with EPAS/PGE,✓,All,✓,✓,✓

管理
----

.. csv-table::
  :header: Product,CLI,UI,Monitoring options
  :widths: 15,12,12,20
  :align: left
  :class: longtable

  PGD Standalone,✓,✓ (PEM),"Hybrid Manager, SQL, CLI, PEM"
  PGD HM-managed,✓,✓,"Hybrid Manager, SQL, CLI, edbctl"
  PSR + EFM,✓,✓ (PEM),"Hybrid Manager, SQL, CLI, PEM"

ライセンス
----------

.. csv-table::
  :header: Product,Source available,Open source
  :widths: 12,25,15
  :align: left
  :class: longtable

  PGD Standalone,✗,✗
  PGD HM-managed,✗,✗
  PSR + EFM,✗,✗