> [!WARNING]
>
> **Preview**
>
>
> This feature is
>
> subject to the "Pre-GA Offerings Terms" in the General Service Terms section of the
> [Service Specific
> Terms](https://docs.cloud.google.com/terms/service-terms#1).
>
> You can process personal data for
>
> this feature
>
> as outlined in the
> [Cloud Data
> Processing Addendum](https://docs.cloud.google.com/terms/data-processing-addendum), subject to the obligations and restrictions described in the
> agreement under which you access Google Cloud.
>
> Pre-GA features are available "as is" and might have limited support.
>
> For more information, see the
> [launch stage descriptions](https://cloud.google.com/products/#product-launch-stages).
This page describes how to manage databases with a high number of simultaneous
client connections and a high number of database connection threads. This
[recommender](https://docs.cloud.google.com/recommender/docs/recommenders.md.txt) is called
**Reconfigure connection settings**.
Every day, this recommender analyzes metrics for the following:
- The peak number of database connections by tracking the value of
the `max_used_connections` flag. If the maximum number of connections since
the server restarted is 80% of the value `max_connections`, **Reconfigure
connection settings** recommends that you increase the value of
`max_connections` .
For more information on increasing the value of `max_connections`, see
[Maximum concurrent connections](https://docs.cloud.google.com/sql/docs/quotas.md.txt#maximum_concurrent_connections).
- The number of new database connection threads compared to the number of
existing database connection threads. If more than 50% of connections result
in new threads instead of reusing cached ones, or if the value of
`thread_cache_size` is set to 0, then **Reconfigure connection settings**
recommends that you increase the value of `thread_cache_size`.
For more information on increasing the value of `max_connections`, see
[Optimize high CPU utilization in instances](https://docs.cloud.google.com/sql/docs/mysql/optimize-cpu-usage.md.txt).
This feature is in [Preview](https://cloud.google.com/products#product-launch-stages).
## Pricing
The **Reconfigure connection settings** recommender is in the *Standard*
[Recommender pricing tier](https://cloud.google.com/recommender/pricing).
## Before you begin
[Enable the Recommender API](https://docs.cloud.google.com/recommender/docs/enabling).
### Required roles and permissions
To get the permissions to view and work with insights and recommendations,
ensure that you have the required [Identity and Access Management (IAM) roles](https://docs.cloud.google.com/sql/docs/mysql/project-access-control#roles).
| Task | Role |
|---|---|
| View recommendations | `recommender.cloudsqlViewer` or `cloudsql.admin`. |
| Apply recommendations | `cloudsql.editor` or `cloudsql.admin`. |
For more information about IAM roles, see [IAM basic and predefined roles reference](https://docs.cloud.google.com/iam/docs/understanding-roles) and [Manage access to projects, folders, and organizations](https://docs.cloud.google.com/iam/docs/granting-changing-revoking-access.md.txt).
## List the recommendations
To list the recommendations, follow these steps:
### Console
To list recommendations about instance performance, follow these steps:
1. Go to the **Cloud SQL Instances** page.
[Go to Cloud SQL Instances](https://console.cloud.google.com/sql/instances)
1. On the **Improve instance health by investigating issues and acting on
recommendations** banner, click **Expand Details**.
Alternatively, follow these steps:
1. Go to the **Active Assist** . See also [Find and apply recommendations with the Recommendations](https://docs.cloud.google.com/recommender/docs/recommendation-hub/identify-configuration-problems).
[Go to the Active Assist](https://console.cloud.google.com/home/recommendations/)
2. In the **All recommendations** card, click **Performance** .
### gcloud
Run the [`gcloud recommender recommendations list`](https://docs.cloud.google.com/sdk/gcloud/reference/recommender/recommendations/list) command as follows:
```
gcloud recommender recommendations list \
--project=PROJECT_ID \
--location=LOCATION \
--recommender=google.cloudsql.instance.PerformanceRecommender \
--filter=recommenderSubtype=MYSQL_RECONFIG_CONNECTIONS
```
Replace the following:
- PROJECT_ID: your project ID
- LOCATION: a region where your instances are located, such as `us-central1`
### API
Call the [`recommendations.list`](https://docs.cloud.google.com/recommender/docs/reference/rest/v1/projects.locations.recommenders.recommendations/list.md.txt) method as follows:
```
GET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/google.cloudsql.instance.PerformanceRecommender/recommendations
```
Replace the following:
- PROJECT_ID: your project ID
- LOCATION: a region where your instances are located, such as `us-central1`
## View insights and detailed recommendations
To view insights and detailed recommendations, follow these steps:
### Console
Do one of the following:
- On the **Performance Recommendations** page, click the **Performance
recommendations** card and then click **Reconfigure connection settings**.
The recommendation panel appears, which contains insights and detailed
recommendations for the instance.
- On the **Instances** page, click **Reconfigure connection settings**.
The list of instances displays only those instances for which the
recommendation applies.
### gcloud
Run the [`gcloud recommender insights list`](https://docs.cloud.google.com/sdk/gcloud/reference/recommender/insights/list) command as follows:
```
gcloud recommender insights list \
--project=PROJECT_ID \
--location=LOCATION \
--insight-type=google.cloudsql.instance.PerformanceInsight \
--filter=insightSubtype=INSIGHT_SUBTYPE
```
Replace the following:
- PROJECT_ID: your project ID
- LOCATION: a region where your instances are located, such as `us-central1`
- INSIGHT_SUBTYPE: set this parameter to one of the following:
- `MYSQL_HIGH_NUMER_OF_CONNECTIONS`: display insights for the number of database connections for your instance
- `MYSQL_HIGH_THREAD_CACHE_MISS_RATE`: display insights for the number of new database connection threads without using the thread cache for your instance
### API
Call the [`insights.list`](https://docs.cloud.google.com/recommender/docs/reference/rest/v1/projects.locations.insightTypes.insights/list.md.txt) method as follows:
```
GET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/insightTypes/google.cloudsql.instance.PerformanceInsight/insights
```
Replace the following:
- PROJECT_ID: your project ID
- LOCATION: a region where your instances are located, such as `us-central1`
## Apply the recommendation
To implement this recommendation, do one of the following:
- To apply the recommendation for the connection thread cache size, do one of
the following:
- If the value of `thread_cache_size` is set to 0, then enable the thread
cache by setting this flag to a value greater than 0.
- If the value of `thread_cache_size` is greater than 0, then increase the
value of this flag. `thread_cache_size` should be equivalent to the average
number of connections to the database. Increase the value of
`thread_cache_size` if the number of new threads is higher than the current
setting.
- To apply the database connection recommendation, increase the value of the
`max_connections` flag. The recommendation is updated daily, so after you
increase the value of this flag, wait for 24 hours before checking the recommendation again. For more information on
increasing the value of `max_connections`, see [Maximum concurrent connections](https://docs.cloud.google.com/sql/docs/quotas.md.txt#maximum_concurrent_connections).
> [!NOTE]
> **Note:** Increasing `thread_cache_size` and `max_connections` requires more memory. After increasing these flags, monitor the memory usage.
## What's next
- [Google Cloud recommenders](https://docs.cloud.google.com/recommender/docs/recommenders.md.txt)