Burstable compute

Author: jonels-msft

articles/cosmos-db/postgresql/TOC.yml

@@ -103,6 +103,8 @@
       items:
         - name: Scheduled maintenance
           href: concepts-maintenance.md
+        - name: Burstable compute
+          href: concepts-burstable-compute.md
         - name: Upgrade
           href: concepts-upgrade.md
     - name: Business continuity

articles/cosmos-db/postgresql/concepts-burstable-compute.md

@@ -0,0 +1,32 @@
+---
+title: Burstable compute - Azure Cosmos DB for PostgreSQL
+description: Definition and workloads of burstable compute.
+ms.author: jonels
+author: jonels-msft
+ms.service: cosmos-db
+ms.subservice: postgresql
+ms.topic: conceptual
+ms.date: 01/18/2023
+---
+
+# Burstable compute
+
+[!INCLUDE [PostgreSQL](../includes/appliesto-postgresql.md)]
+
+Burstable compute on a single node cluster is ideal for workloads like
+development environments or small databases that don't need the full
+performance of the node's CPU continuously. These workloads typically have
+burstable performance requirements.
+
+The Azure burstable compute options allow you to configure a single node with
+baseline performance that can build up credits when it's using less than its
+baseline. When the node has accumulated credits, the node can burst above the
+baseline when your workload requires higher CPU performance. You can use the
+**CPU credits remaining** and **CPU credits consumed** metrics to track
+accumulated and used credits respectively.
+
+**Next steps**
+
+* See the [Limits and limitations](reference-limits.md#burstable-compute) of
+  burstable compute.
+* Review available [cluster metrics](concepts-monitoring.md#metrics).

articles/cosmos-db/postgresql/concepts-monitoring.md

@@ -7,7 +7,7 @@ ms.service: cosmos-db
 ms.subservice: postgresql
 ms.custom: ignite-2022
 ms.topic: conceptual
-ms.date: 09/27/2022
+ms.date: 01/18/2023
 ---
 
 # Monitor and tune Azure Cosmos DB for PostgreSQL
@@ -56,6 +56,8 @@ These metrics are available for nodes:
 |---|---|---|---|
 |active_connections|Active Connections|Count|The number of active connections to the server.|
 |apps_reserved_memory_percent|Reserved Memory Percent|Percent|Calculated from the ratio of Committed_AS/CommitLimit as shown in /proc/meminfo.|
+|cpu_credits_consumed|CPU credits consumed|Credits|Total number of credits consumed by the node. (Only available when burstable compute is provisioned on the node.)|
+|cpu_credits_remaining|CPU credits remaining|Credits|Total number of credits available to burst. (Only available when burstable compute is provisioned on the node.)|
 |cpu_percent|CPU percent|Percent|The percentage of CPU in use.|
 |iops|IOPS|Count|See the [IOPS definition](../../virtual-machines/premium-storage-performance.md#iops) and [Azure Cosmos DB for PostgreSQL throughput](resources-compute.md)|
 |memory_percent|Memory percent|Percent|The percentage of memory in use.|

articles/cosmos-db/postgresql/reference-limits.md

@@ -35,6 +35,9 @@ to keep nodes healthy:
    * 300 for 0-3 vCores
    * 500 for 4-15 vCores
    * 1000 for 16+ vCores
+* Maximum connections per node with burstable compute
+   * 20 for 1 vCore burstable
+   * 40 for 2 vCores burstable
 
 The connection limits above are for *user* connections (`max_connections` minus
 `superuser_reserved_connections`). We reserve extra connections for
@@ -74,6 +77,20 @@ Azure Cosmos DB for PostgreSQL. If you do need more vCores for a region in your
 subscription, see how to [adjust compute
 quotas](howto-compute-quota.md).
 
+### Burstable compute
+
+In Azure Cosmos DB for PostgreSQL clusters with [burstable
+compute](concepts-burstable-compute.md) enabled, the following features are
+currently **not supported**:
+
+* Accelerated networking
+* Local caching
+* PostgreSQL and Citus version upgrades
+* PostgreSQL 11 support
+* Read replicas
+* High availability
+* The [azure_storage](howto-ingest-azure-blob-storage.md) extension
+
 ## PostgreSQL
 
 ### Database creation