--- title: "Databases" description: "List every monitored PostgreSQL and MongoDB instance and drill into connections, throughput, latency, load, blocking queries and related logs." section: "APM" breadcrumb: "APM > Database Monitoring > Databases" canonical: "https://docs.middleware.io/features/apm/database-monitoring/databases" --- # Databases The **Databases** tab lists every monitored database instance. Each instance opens a detail panel with its health overview, metrics, top queries, and logs. Open it from **APM → Database → Databases**. ## Instance List Instances are grouped by engine. When more than one engine is configured, each group is a collapsible **PostgreSQL** or **MongoDB** section. Use the search bar to find an instance by name. ![Databases tab with PostgreSQL and MongoDB sections, each listing an instance with query sparkline, connections and load](/images/apm/database-monitoring/databases-list.png) #### PostgreSQL | Column | Description | | --- | --- | | **Instance** | Instance name, followed by its host, cloud or Kubernetes pod, and the `host:port` it listens on | | **Queries** | Average number of query samples per interval, with a sparkline | | **Connections** | Active connections compared with `max_connections` (**Active / Max Connections**) | | **Load By Wait Group** | Query samples over time, stacked by wait event group | #### MongoDB | Column | Description | | --- | --- | | **Instance** | Host name of the MongoDB server, followed by its host, cloud, or Kubernetes pod | | **Queries** | Average number of profiled operations per interval, with a sparkline | | **Connections** | Active connections compared with the total (**Active / (Active + Available)**) | | **Load By Operation** | Profiled operations over time, stacked by operation type (`insert`, `query`, `update`, `command`, and so on) | Hover over a mini chart to see the values for each time bucket. Click an instance to open its detail panel. ## PostgreSQL Instance Details The panel header shows the instance name and a time picker. The panel has four tabs: **Summary**, **Metrics**, **Queries**, and **Logs**. ### Summary ![PostgreSQL instance summary with active connections, CPU utilization, query throughput and average duration charts above the top queries table](/images/apm/database-monitoring/pg-instance-summary.png) - **Overview** - **Active Connections**: connections over time, grouped by backend state (for example `active`, `idle`, `idle in transaction`) and user. - **CPU Utilization**: CPU usage of the database host. Shown only when the Middleware Agent also monitors that host. - **Query Throughput By**: query sample count over time. Group it by `query`, `db`, `user`, or all. - **Average Duration By**: average query execution time in milliseconds, with the same grouping options. - The top queries for this instance, in the same format as [Query Metrics](/features/apm/database-monitoring/query-metrics). - **Databases**: one row per database, with **Database Size**, **Active Connections**, **Commits**, **Rollbacks**, **Disk Reads**, **Buffer Hits**, and **Autovacuum** counts. - **Blocking Queries**: charts for **Root Blocking Query Durations**, **Root Blocking Query Executions**, and **Waiting Queries**. Below them, **Blocking Overview** and **Blocking Samples** list the queries that held locks. See [Wait events and blocking](/features/apm/database-monitoring/query-metrics#wait-events-and-blocking). - **Schema**: a schema explorer for this instance. See [Schemas](/features/apm/database-monitoring/schemas#schema-explorer). - **Calling Services**: query samples that are linked to APM services. See [Connect with APM Traces](/features/apm/database-monitoring/connect-apm-traces). ![PostgreSQL instance Databases table with size, connections, commits, rollbacks and buffer hits, above the Blocking Queries charts](/images/apm/database-monitoring/pg-instance-databases.png) ### Metrics Use **Filter by** at the top to scope every chart to one database (`db:`) or all databases (`db:*`). ![PostgreSQL instance Metrics tab showing the Average Load chart by wait event type and the Activity charts](/images/apm/database-monitoring/pg-instance-metrics.png) - **Average load**: query samples over time, stacked by the dimension you pick. Switch between **Average Load** and **Blocking Connections**, and group **by** Wait Event Type, Wait Event, SQL, User, Database, Client, or Application. When grouped by wait event, the colors match the wait event groups used everywhere else. - **Activity**: query throughput and average duration, **Commits by** and **Rollbacks by** database (transactions per second), **Connections by** application, user, or database, **Rows Modified by Operation Type**, **Max Transaction Time**, and **Total Transaction Time**. - **Locks**: **Locks by Relation, Type and Mode**. - **Replication**: **Write Ahead Log (WAL) Size**. - **Indexes**: index blocks hit and read per table, index scans, and index rows read per table and index. - **Blocks**: shared and temporary block hits, reads, dirtied, and written blocks per query. These charts need **Top Query Collection**. - **Vacuum**: live and dead rows per table, last autoanalyze, and heap blocks scanned. - **Functions**: **Function Calls**. - **Objects**: **Database Sizes**, **Table Count by DB**, and **Table Sizes**. ### Queries The **Average Load** chart followed by three lists for this instance: **Queries** (grouped query metrics), **Blocking Queries**, and **Query Samples**. Use **Search query** to filter the lists, and **Full Query Text** to show queries without truncation. ### Logs Log records associated with this instance, filtered to the instance name and host. ## MongoDB Instance Details The panel has five tabs: **Summary**, **Metrics**, **Queries**, **Samples**, and **Logs**. ### Summary ![MongoDB instance summary with connections, query throughput by operation and average duration by namespace](/images/apm/database-monitoring/mongo-instance-summary.png) - **Overview** - **Connections**: **Active**, **Available**, and **Current** connections over time. - **Query Throughput By**: profiled operations over time. Group it by `operation`, `namespace`, `database`, or all. - **Average Duration By**: average operation latency in milliseconds, with the same grouping options. - The top operations for this instance, in the same format as [Query Metrics](/features/apm/database-monitoring/query-metrics). - **Collections**: one row per collection with **Database**, **Collection**, **Documents**, **Data Size**, **Storage Size**, **Indexes**, and **Avg Object Size**. ### Metrics Use **Filter by** to scope the charts to one database. The tab shows **Average load by operation**, the **Collections** table, and a **Metrics** section with these sub-tabs: ![MongoDB instance Metrics tab with the Throughput sub-tab showing operations count, operation time and opcounters](/images/apm/database-monitoring/mongo-instance-metrics.png) | Sub-tab | Charts | | --- | --- | | **Throughput** | Operations Count, Total Operation Time, Opcounters, Replicated Opcounters, Asserts / sec | | **Query Performance** | Average keys examined, documents examined, keys inserted, CPU time, planning time, and response length | | **Connections** | Connections by state, Rejected / Created, Connections Pool | | **Database statistics** | Storage Size, Data Size, Index size, object count by database, collections and indexes count, average object size | | **Locks & Concurrency** | Global lock active clients and time held, WiredTiger read and write tickets, collection lock acquires, waits, and wait time | | **WiredTiger Cache** | Cache size vs max, dirty bytes, pages held in cache, cache read and write activity, pages evicted, eviction pressure | | **Index & Query Executor** | Index hits and misses, index miss ratio, index accesses (total and by collection), total indexes, documents and keys scanned | | **Memory** | Resident and virtual memory, page faults, heap usage | | **TCMalloc allocator** | Allocated and heap, thread and central cache free, page heap | | **Network** | Bytes in and out, requests rate, bytes received and transmitted, requests count | | **Replication** | Replica set health, state, lag, votes, replication buffer, replication network and apply rates | | **Oplog & Journaling** | Oplog size vs used, oplog window, journal commits, journaled data, and write times | ### Queries and Samples **Queries** shows **Average load by operation** and the grouped operations for this instance. **Samples** lists the individual slow operations. Both have their own search bar. See [Query Metrics](/features/apm/database-monitoring/query-metrics) and [Query Samples](/features/apm/database-monitoring/samples) for column details. ### Logs Log records from the MongoDB host, including the slow operation records collected from the profiler. Need assistance or want to learn more about Middleware? Get in touch with us via our Contact Us page or join our Slack channel.