Comparison chart: Azure Database for PostgreSQL - Flexible Server vs. Single Server

APPLIES TO: Azure Database for PostgreSQL - Single Server Azure Database for PostgreSQL - Flexible Server


Azure Database for PostgreSQL flexible server is the next generation managed PostgreSQL service in Azure. It provides maximum flexibility over your database, built-in cost-optimizations, and offers several improvements over Azure Database for PostgreSQL single server.


For all your new deployments, we recommend using Azure Database for PostgreSQL flexible server. However, you should consider your own requirements against the comparison table below.

Comparison table

The following table provides a list of high-level features and capabilities comparisons between Azure Database for PostgreSQL single server and Azure Database for PostgreSQL flexible server.

Feature / Capability Azure Database for PostgreSQL single server Azure Database for PostgreSQL flexible server
General availability GA since 2018 GA since 2021
PostgreSQL Community Community
Supported versions 10, 11 11, 12, 13, 14, 15, 16
Underlying O/S Windows Linux
AZ selection for application colocation No Yes
Built-in connection pooler No Yes (PgBouncer)
Uptime SLA 99.99% SLA Up to 99.99% SLA
Username in connection string <user_name>@server_name. For example, pgadmusr@mypgServer Just username. For example, pgadmusr
lc_collate English_United States.1252 en_US.utf8
lc_ctype English_United States.1252 en_US.utf8
lc_messages English_United States.1252 en_US.utf8
lc_monetary English_United States.1252 en_US.utf-8
lc_numeric English_United States.1252 en_US.utf-8
lc_time English_United States.1252 en_US.utf8
Connection port 5432 5432 (DB), 6432 (PgBouncer)
Max. connections 1982 5000
Connections limit configurable? No Yes (max_connections parameter)
Compute & Storage
Compute tiers Basic, General Purpose, Memory Optimized Burstable, General Purpose, Memory Optimized
Burstable SKUs No Yes
Ability to scale across compute tiers Can't scale Basic tier Yes. Can scale across tiers
Stop/Start No Yes (for all compute SKUs). Only compute is stopped/started
Max. Storage size 1 TB (Basic), 4 TB or 16 TB (GP, MO). Note: Not all regions support 16 TB. 64 TB. Note: Not all regions support 64 TB.
Min storage size 5 GB (Basic), 100 GB (GP, MO) 32 GB
Storage auto-grow Yes Yes
Max IOPS Basic - Variable. GP/MO: up to 18 K Up to 80 K
Supported networking Virtual network, private link, public access Private access (VNET injection in a delegated subnet), public access
Public access control Firewall Firewall
Private link support Yes Yes (Preview)
Private VNET injection support No Yes
Private DNS Zone support No Yes
Ability to move between private and public access No No
TLS support TLS 1.2 TLS 1.2, 1.3 enforced
Can turn off SSL Yes Yes (set require_secure_transport to OFF)
SCRAM authentication No Yes
High Availability
Zone-redundant HA No Yes (a synchronous standby is established in another zone within a region)
Same-zone HA No Yes (a synchronous standby is established in the same zone as the primary)
HA Configuration Built-in with storage pinned to a zone. Compute can float across regions. Physically separate compute & storage provisioned
Cost 1x 2x (compute + storage)
Availability with non-HA configuration Automatic restart, compute relocation Automatic restart, compute relocation
Protect from zone failure Compute - Yes. Storage - No Compute & storage - Yes
Protect from region failure No Yes
Mode of HA replication N/A Postgres physical streaming replication in SYNC mode
Standby can be used for read purposes N/A No
Application performance impact No (not replicating) Yes (Due to sync replication. Depends on the workload)
Automatic failover Yes (spins another server) Yes
Application connection string post failover No change No change
Logical Replication
Support for logical decoding Yes Yes
Support for native logical replication No Yes
Support for pglogical extension No Yes
Support logical replication with HA N/A Limited
Disaster Recovery
Cross region DR Using read replicas, geo-redundant backup Using read replicas, Geo-redundant backup (in selected regions)
DR using replica Using async physical replication Using async physical replication
Automatic failover No No
Can use the same r/w endpoint No No
Backup and Recovery
Automated backups Yes Yes
Backup retention 7-35 days 7-35 days
PITR capability to any time within the retention period Yes Yes
Ability to restore on a different zone N/A Yes
Ability to restore to a different VNET No Yes
Ability to restore to a different region Yes (Geo-redundant) Yes (in selected regions)
Ability to restore a deleted server Limited via API Limited via API
Read Replica
Support for read replicas Yes Yes
Number of read replicas 5 5
Mode of replication Async Async
Cross-region support Yes Yes
Maintenance Window
System scheduled window Yes Yes
Customer scheduled window No Yes (can choose any 1 hr on any day)
Notice period Three days Five days
Maintenance period Anytime within 15-hrs window 1 hr window
Errors Failed connections Failed connections
Latency Max lag across replicas, Replica lag Max lag across replicas, Replica lag
Saturation Backup storage used, CPU %, IO %, Memory %, Server log storage limit, server log storage %, server log storage used, Storage limit, Storage %, Storage used Backup storage used, CPU credits consumed, CPU credits remaining, CPU %, Disk queue depth, IOPS, Memory %, Read IOPS, Read throughput bytes/s, storage free, storage %, storage used, Transaction log storage used, Write IOPS, Write throughput bytes/s
Traffic Active connections, Network In, Network out Active connections, Max. used transaction ID, Network In, Network Out, succeeded connections
Extensions (offers latest versions)
TimescaleDB, orafce Yes Yes
pg_cron, pglogical No Yes
pgAudit Yes Yes
Microsoft Entra ID Support (Microsoft Entra ID) Yes Yes
Customer managed encryption key (BYOK) Yes Yes
SCRAM Authentication (SHA-256) No Yes
Secure Sockets Layer support (SSL) Yes Yes
Other features
Alerts Yes Yes
Microsoft Defender for Cloud Yes Yes
Resource health Yes Yes
Service health Yes Yes
Performance insights (iPerf) Yes Yes
Major version upgrades support No Yes
Minor version upgrades Yes. Automatic during maintenance window Yes. Automatic during maintenance window

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