# Monitoring Aurora PostgreSQL Limitless Database with Performance Insights
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Use Performance Insights to monitor your Aurora PostgreSQL Limitless Database cluster. Performance Insights works similarly for Aurora PostgreSQL Limitless Database as it does for standard Aurora DB clusters. However, you track metrics at the shard group level for Aurora PostgreSQL Limitless Database.

The two main Performance Insights metrics to track are the following:
+ Database load – Measures the level of activity in your database. The key metric in Performance Insights is `DBLoad`, which is collected every second.

  The unit for the `DBLoad` metric in Performance Insights is average active sessions (AAS). To get the average active sessions, Performance Insights samples the number of sessions concurrently running a query. The AAS is the total number of sessions divided by the total number of samples for a specific time period. For more information on `DBLoad` and AAS, see [Database load](USER_PerfInsights.Overview.ActiveSessions.md).
+ Maximum CPU – The maximum computational power available to your database. To see whether active sessions are exceeding the maximum CPU, look at their relationship to the `Max vCPU` line. The `Max vCPU` value is determined by the number of vCPU (virtual CPU) cores for your DB instance. For more information on `Max vCPU`, see [Maximum CPU](USER_PerfInsights.Overview.MaxCPU.md).

In addition, you can "slice" the `DBLoad` metric into *dimensions*, which are subcategories of the metric. The most useful dimensions are the following:
+ Top instances – Shows the relative DB load for your instances (shards and routers) in descending order.
+ Wait events – Cause SQL statements to wait for specific events to happen before they can continue running. Wait events indicate where work is impeded.
+ Top SQL – Shows which queries contribute the most to DB load.

For more information about Performance Insights dimensions, see [Dimensions](USER_PerfInsights.Overview.ActiveSessions.md#USER_PerfInsights.Overview.ActiveSessions.dimensions).

The following figure shows the **Top instances** dimension for a DB shard group.

![\[Top instances dimension for a DB shard group.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-top-instances.png)


**Topics**
+ [Analyzing DB load for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard](USER_PerfInsights.AnalyzeLimitlessTables.md)

# Analyzing DB load for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard
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With Performance Insights, you can track metrics at the shard group level and at the instance level for an Aurora PostgreSQL Limitless Database. When analyzing DB load for an Aurora PostgreSQL Limitless Database, you might want to compare the DB load for each shard and router to the maximum vCPU.

**Note**  
Aurora PostgreSQL Limitless Database always has Performance Insights and Enhanced Monitoring enabled. The minimum retention period for Performance Insights data for Limitless Database is 31 days (1 month).

The **Absolute** view shows the number of Average active sessions (AAS) and the estimated vCPU. The **Relative** view shows the ratio of AAS to the estimated vCPU.

**Topics**
+ [Analyzing relative DB load for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard](#USER_PerfInsights.AnalyzeLimitlessTables.RelativeLoad)
+ [Analyzing DB load by waits for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard](USER_PerfInsights.AnalyzeLimitlessTables.Waits.md)
+ [Analyzing load distribution for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard](USER_PerfInsights.AnalyzeLimitlessTables.LoadDistribution.md)

## Analyzing relative DB load for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard
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You might want to improve the performance of your Aurora PostgreSQL Limitless Database by tracking relative DB load. To analyze relative DB load by instance for your Aurora PostgreSQL Limitless Database, use the following procedure.

**To analyze relative DB load for Aurora PostgreSQL Limitless Database using the console**

1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).

1. In the navigation pane, choose **Performance Insights**.

1. Choose an Aurora PostgreSQL Limitless Database. The Performance Insights dashboard is displayed for that Aurora PostgreSQL Limitless Database.

1. In the **Database load (DB load)** section, choose **Instances** for **Sliced by**. To see the ratio of Average active sessions (AAS) to vCPU cores for all of the instances in your Aurora PostgreSQL Limitless Database, choose **Relative** for **Viewed as**.

   The Average active sessions chart shows the DB load for instances in your Aurora PostgreSQL Limitless Database.  
![\[View the Performance Insights dashboard for your Aurora PostgreSQL Limitless Database sliced by instances.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-relative-instances.png)

1. To view the top instances, choose the **Top instances** tab.

   In the following example, the instance with the highest DB load is `DTR-2-2`.  
![\[Use the Top instances tab for an Aurora PostgreSQL Limitless Database sliced by instances.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-top-instances.png)

1. (Optional) To analyze DB load for an instance in your Aurora PostgreSQL Limitless Database, choose the instance name in the **Instances** column. To view the DB load for `DTR-2-2`, choose `DTR-2-2` in the **Instances** column. 
**Note**  
You can view Performance Insights metrics only for instances in an Aurora PostgreSQL Limitless Database.

# Analyzing DB load by waits for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard
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You might want to improve the performance for your Aurora PostgreSQL Limitless Database by tracking wait events. To analyze DB load by wait events for your Aurora PostgreSQL Limitless Database, use the following procedure.

**To analyze DB load by waits for Aurora PostgreSQL Limitless Database using the console**

1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).

1. In the navigation pane, choose **Performance Insights**.

1. Choose an Aurora PostgreSQL Limitless Database. The Performance Insights dashboard is displayed for that Aurora PostgreSQL Limitless Database.

1. In the **Database load (DB load)** section, choose **Waits** for **Sliced by**. To view the number of AAS and the estimated vCPU, choose **Absolute** for **Viewed as**.

   The Average active sessions chart shows the DB load for instances in your Aurora PostgreSQL Limitless Database.  
![\[Sliced by waits.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-absolute-waits.png)

1. Scroll down to the **Top SQL** tab.

   In the following example, the SQL statement with the highest load by waits is the `DELETE` statement.  
![\[Top SQL tab when sliced by waits.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-waits-top-sql.png)

1. Choose the SQL statement to expand it into its component statements.

   In the following example, the `SELECT` statement has 3 component statements.  
![\[Choose a SQL statement to expand it.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-waits-top-sql-selected.png)

# Analyzing load distribution for Aurora PostgreSQL Limitless Database using the Performance Insights dashboard
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You might want to balance the load distribution for instances on your Aurora PostgreSQL Limitless Database. To analyze load distribution of the instances on an Aurora PostgreSQL Limitless Database, use the following procedure.

**To analyze load distribution of the instances on an Aurora PostgreSQL Limitless Database using the console**

1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).

1. In the navigation pane, choose **Performance Insights**.

1. Choose an Aurora PostgreSQL Limitless Database. The Performance Insights dashboard is displayed for that Aurora PostgreSQL Limitless Database.

1. In the **Database load (DB load)** section, choose **Instances** for **Sliced by**. To view the number of AAS and the estimated vCPU for all instances in your Aurora PostgreSQL Limitless Database, choose **Absolute** for **Viewed as**.

   The Average active sessions chart shows the DB load for instances in your Aurora PostgreSQL Limitless Database.  
![\[View the absolute Performance Insights dashboard for your Aurora PostgreSQL Limitless Database sliced by instances.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-absolute-instances.png)

1. To see a chart of the load distribution of the instances in your Aurora PostgreSQL Limitless Database, choose the **Load distribution** tab.

   In the following example, the instance with the highest DB load is `DTR-2-2`.  
![\[Top SQL tab when you slice by waits at the instance level.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/pi-load-distribution.png)