[DOC] Disable collectors

documentation/docs/install-pmm/install-pmm-client/connect-database/mysql/mysql.md

@@ -427,6 +427,10 @@ After creating your PMM database user, you can quickly add your MySQL service to
         - **Query Source**: Choose between **Slow Log** or **Performance Schema**
         - **PMM Agent**: Select which PMM agent should monitor this instance
         - **Disable query examples**: Check this option to prevent collection of actual query values in QAN. When enabled, PMM will continue to collect query metrics and statistics but will not store the actual query examples with real data values.
+        - **Disable collectors**: Under **Additional options**, enter a comma-separated list of collector names to exclude from metric collection. Use this to reduce monitoring overhead or suppress metrics that are not relevant to your environment.
+
+            ??? info "Available MySQL collectors"
+                `auto_increment.columns`, `binlog_size`, `custom_query.hr`, `custom_query.lr`, `custom_query.mr`, `engine_innodb_status`, `engine_tokudb_status`, `global_status`, `global_variables`, `heartbeat`, `info_schema.clientstats`, `info_schema.innodb_cmp`, `info_schema.innodb_cmpmem`, `info_schema.innodb_metrics`, `info_schema.innodb_tablespaces`, `info_schema.processlist`, `info_schema.query_response_time`, `info_schema.tables`, `info_schema.tablestats`, `info_schema.userstats`, `perf_schema.eventsstatements`, `perf_schema.eventswaits`, `perf_schema.file_events`, `perf_schema.file_instances`, `perf_schema.indexiowaits`, `perf_schema.tableiowaits`, `perf_schema.tablelocks`, `plugins`, `slave_status`, `standard.go`, `standard.process`
 
     4. Click **Add Service**.
 

documentation/docs/install-pmm/install-pmm-client/connect-database/postgresql.md

@@ -260,7 +260,12 @@ After configuring your database server with the appropriate extension, you need
 
     3. (Optional) If using `pgstatmonitor`, check **Disable query examples** under **Additional options** to prevent collection of actual query values. This protects sensitive data while preserving all query metrics and performance statistics in QAN.    
 
-    4. Click **Add service**.
+    4. (Optional) Under **Additional options**, in the **Disable collectors** field, enter a comma-separated list of collector names to exclude from metric collection. Use this to reduce monitoring overhead or suppress metrics that are not relevant to your environment.
+
+        ??? info "Available PostgreSQL collectors"
+            `custom_query.hr`, `custom_query.lr`, `custom_query.mr`, `database`, `database_wraparound`, `extensions`, `locks`, `replication`, `replication_slot`, `stat_bgwriter`, `stat_database`, `stat_user_tables`, `statio_user_tables`, `wal`
+
+    5. Click **Add service**.
     ![!](../../../images/PMM_Add_Instance_PostgreSQL.png)
 
     5. If using TLS, check **Use TLS for database connections** and fill in your TLS certificates and key.        

documentation/docs/release-notes/3.7.0.md

@@ -317,6 +317,21 @@ To lower risk further, Percona recommends that you:
 
 - [PMM-14801](https://perconadev.atlassian.net/browse/PMM-14801): Fixed PostgreSQL exporter crash when monitoring GCP Cloud SQL PostgreSQL 13 and 14 instances.
 
+## 🔶 Known issues
+
+### pmm-client RPM reports a self-conflict when running dnf check
+
+On RHEL and compatible EL8+ systems, running `dnf check` after installing pmm-client 3.7.0 may report:
+
+```
+pmm-client-3.7.0-7.el8.x86_64 has installed conflict "pmm-client": pmm-client-3.7.0-7.el8.x86_64
+```
+
+This is a packaging defect and does not affect PMM functionality. You can safely ignore it.
+
+Fixed in PMM 3.9.0.
+
+
 ## 🚀 Ready to upgrade to PMM 3.7.0?
 
 - [New installation](../quickstart/quickstart.md)

documentation/docs/release-notes/3.9.0.md

@@ -0,0 +1,39 @@
+# Percona Monitoring and Management 3.9.0
+
+**Release date**: July 2026
+
+Percona Monitoring and Management (PMM) is an open source database monitoring, management, and observability solution for MySQL, PostgreSQL, MongoDB, Valkey and Redis. PMM empowers you to:
+
+- monitor the health and performance of your database systems
+- identify patterns and trends in database behavior
+- diagnose and resolve issues faster with actionable insights
+- manage databases across on-premises, cloud, and hybrid environments
+
+## 📋 Release summary
+
+!!! note
+    Release summary to be added.
+
+## ✨ Release highlights
+
+### Disable individual metric collectors per service
+
+PMM 3.9.0 adds a **Disable collectors** field to the Add service form for MySQL, PostgreSQL, MongoDB, and ProxySQL. You can now exclude specific metric collectors from collection without removing the service or modifying the exporter configuration.
+
+This is useful when certain collectors generate metrics you don't need, add overhead on resource-constrained hosts, or cause issues with specific database configurations.
+
+![Disable collectors field in Additional options](../images/PMM_disable_collectors.png)
+
+To use it, go to **PMM Configuration > Add Service**, expand **Additional options**, and enter a comma-separated list of collector names in the **Disable collectors** field.
+
+For the full list of available collectors per database type, see [Connect MySQL databases to PMM](../install-pmm/install-pmm-client/connect-database/mysql/mysql.md) and [Connect PostgreSQL databases to PMM](../install-pmm/install-pmm-client/connect-database/postgresql.md).
+
+## 📈 Improvements
+
+!!! note
+    Improvements to be added.
+
+## ✅ Fixed issues
+
+!!! note
+    Fixed issues to be added.

documentation/docs/release-notes/index.md

@@ -1,4 +1,5 @@
 # Release notes
+- [Percona Monitoring and Management 3.9.0](3.9.0.md)
 - [Percona Monitoring and Management 3.7.1](3.7.1.md)
 - [Percona Monitoring and Management 3.7.0](3.7.0.md)
 - [Percona Monitoring and Management 3.6.0](3.6.0.md)