# Overview of the Top queries tab
<a name="performance-insights-top-queries"></a>

By default, the **Top query** tab shows the queries that are contributing the most to DB load. You can analyze the query text to help tune your queries.

**Topics**
+ [Query digests](#performance-insights-top-queries-digests)
+ [Load by waits (AAS)](#performance-insights-top-queries-aas)
+ [Viewing detailed query information](#performance-insights-top-queries-query-info)
+ [Accessing statement query text](#performance-insights-top-queries-accessing-text)
+ [Viewing and downloading statement query text](#performance-insights-top-queries-viewing-downloading)

## Query digests
<a name="performance-insights-top-queries-digests"></a>

A *query digest* is a composite of multiple actual queries that are structurally similar but might have different literal values. The digest replaces hardcoded values with a question mark. For example, a query digest might look like this:

```
{"find":"customerscollection","filter":{"FirstName":"?"},"sort":{"key":{"$numberInt":"?"}},"limit":{"$numberInt":"?"}}
```

This digest might include the following child queries:

```
{"find":"customerscollection","filter":{"FirstName":"Karrie"},"sort":{"key":{"$numberInt":"1"}},"limit":{"$numberInt":"3"}}
{"find":"customerscollection","filter":{"FirstName":"Met"},"sort":{"key":{"$numberInt":"1"}},"limit":{"$numberInt":"3"}}
{"find":"customerscollection","filter":{"FirstName":"Rashin"},"sort":{"key":{"$numberInt":"1"}},"limit":{"$numberInt":"3"}}
```

To see the literal query statements in a digest, select the query, and then choose the plus symbol (`+`). In the following screenshot, the selected query is a digest.

![\[The Top queries table showing an expanded query digest with one child query selected.\]](http://docs.aws.amazon.com/documentdb/latest/developerguide/images/performance-insights/top-queries-literal.png)


**Note**  
A query digest groups similar query statements, but does not redact sensitive information. 

## Load by waits (AAS)
<a name="performance-insights-top-queries-aas"></a>

In **Top queries**, the **Load by waits (AAS)** column illustrates the percentage of the database load associated with each top load item. This column reflects the load for that item by whatever grouping is currently selected in the **DB load chart**. For example, you might group the **DB load chart** by wait states. In this case, the **DB Load by Waits** bar is sized, segmented, and color-coded to show how much of a given wait state that query is contributing to. It also shows which wait states are affecting the selected query.

![\[Bar chart showing database load grouped by CPU, IO, and latch wait states. The corresponding table shows the top queries based on load by wait.\]](http://docs.aws.amazon.com/documentdb/latest/developerguide/images/performance-insights/top-queries-aas.png)


## Viewing detailed query information
<a name="performance-insights-top-queries-query-info"></a>

In the **Top query** table, you can open a *digest statement* to view its information. The information appears in the bottom pane.

![\[The Top queries table showing a selected query statement and its query information below.\]](http://docs.aws.amazon.com/documentdb/latest/developerguide/images/performance-insights/top-queries-detailed.png)


The following types of identifiers (IDs) are associated with query statements:

1. **Support query ID** – A hash value of the query ID. This value is only for referencing a query ID when you are working with AWS Support. AWS Support doesn't have access to your actual query IDs and query text.

1. **Support digest ID** – A hash value of the digest ID. This value is only for referencing a digest ID when you are working with AWS Support. AWS Support doesn't have access to your actual digest IDs and query text.

## Accessing statement query text
<a name="performance-insights-top-queries-accessing-text"></a>

By default, each row in the **Top queries** table shows 500 bytes of query text for each query statement. When a digest statement exceeds 500 bytes, you can view more text by opening the statement in the Performance Insights dashboard. In this case, the maximum length for the displayed query is 1 KB. If you view a full query statement, you can also choose **Download**.

## Viewing and downloading statement query text
<a name="performance-insights-top-queries-viewing-downloading"></a>

In the Performance Insights dashboard, you can view or download query text.

**To view more query text in the Performance Insights dashboard**

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

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

1. Choose a DB instance. The Performance Insights dashboard is displayed for that DB instance.

   Query statements with text larger than 500 bytes will look like the following image:  
![\[The Top queries table with a child query selected.\]](http://docs.aws.amazon.com/documentdb/latest/developerguide/images/performance-insights/top-queries-statement.png)

1. Examine the query information section to view more of the query text.  
![\[The Query information section showing the full text of the selected query.\]](http://docs.aws.amazon.com/documentdb/latest/developerguide/images/performance-insights/top-queries-query-text.png)

The Performance Insights dashboard can display up to 1 KB for each full query statement.

**Note**  
To copy or download the query statement, disable any pop-up blockers.