---
title: "Query Samples"
description: "Inspect individual PostgreSQL query samples and MongoDB slow operations, including wait events, connection details, execution statistics, and the linked APM trace."
section: "APM"
breadcrumb: "APM > Database Monitoring > Query Samples"
canonical: "https://docs.middleware.io/features/apm/database-monitoring/samples"
---
# Query Samples

The **Samples** tab lists individual query executions, newest first. Use it to see exactly what one execution was doing: who ran it, how long it took, what it waited on, and which service sent it.

- **PostgreSQL**: each row is a query sample from `pg_stat_activity`.
- **MongoDB**: each row is a slow operation from the database profiler.

Open it from **APM → Database → Samples**, or click **View Query Samples** on a query in [Query Metrics](/features/apm/database-monitoring/query-metrics).

## PostgreSQL Samples

![PostgreSQL Samples tab with the activity sample count chart by wait event group and the samples table](/images/apm/database-monitoring/pg-samples.png)

The **Activity Sample Count** chart shows the number of samples over time, stacked by wait event group.

Default columns:

| Column | Description |
| --- | --- |
| **Time** | When the sample was taken |
| **Statement** | Normalized query text |
| **Instance** | PostgreSQL instance |
| **Wait Event Group** | The wait event type at the time of the sample (**—** if the query was running) |
| **Database** | Database the session was connected to |
| **Duration** | Query duration recorded with the sample |
| **Application** | The client's `application_name` |

Add more columns with **Customize**: **Calling Service**, **Query Start**, **Comment**, **Tables**, **PID**, **State**, **Backend Type**, **State Change**, **Wait Event**, **Blocking Pids**, **Service Instance ID**, **Trace ID**, and **Span ID**. Turn on **Full Query Text** to see complete statements.

### Sample Details

Click a sample to open its details.

![PostgreSQL sample details showing the wait state, connection details, calling service, statement and execution charts](/images/apm/database-monitoring/pg-sample-details.png)

- **Headline**: "Query was active using …" or "Query was waiting using …", with the wait event type at the time of the sample.
- **Connection**: **Database**, **User**, **Client IP**, **Application**, **Sampled State** (for example `active` or `idle in transaction`), **Query Start**, **Query Duration**, and **Table Tags**.
- **Calling Service**: the APM service that sent the query, with its **Version**, **Env**, and **Resources**. This appears when the query carries trace context. See [Connect with APM Traces](/features/apm/database-monitoring/connect-apm-traces).
- **Statement**: the query text.
- **Total Executions** and **Duration / Query** charts for this query.
- **Attributes**: every collected field, including `db.query.comment`, `postgresql.pid`, `postgresql.state`, and `postgresql.blocking_pids`.
- **Trace**: the linked APM trace, or "No Trace ID Found in the sample".

**View More Samples** filters the Samples tab to this instance and query.

## MongoDB Samples

![MongoDB Samples tab with average load by operation chart and slow operations table](/images/apm/database-monitoring/mongo-samples.png)

The **Average load by operation** chart shows the number of slow operations over time, stacked by operation type.

Default columns: **Time**, **Statement**, **Operation**, **Namespace**, **Duration**, **Host**, **Plan** (for example `COLLSCAN` or `IXSCAN`), **Query Signature**, **Docs examined**, **Planning time**, **Response length**, **Application**, and **User**.

Optional columns include **Database**, **Query ID**, **Query hash**, **Query shape hash**, **Plan cache key**, **Query framework**, **Keys examined**, **Returned**, **Matched**, **Modified**, **Deleted**, **Inserted**, **Keys inserted**, **CPU time**, **Write conflicts**, **Num yields**, **Has sort stage**, **Cursor exhausted**, **Upsert**, **Used disk**, **Multi-planner**, **Replanned**, **Replan reason**, **Client**, **Comment**, **Raw query**, **Cursor**, **Lock stats**, and **Flow control stats**.

### Sample Details

![MongoDB sample details with statement JSON, tags, total executions and average duration charts and grouped attributes](/images/apm/database-monitoring/mongo-sample-details.png)

- **Query**: the operation in five views: **Statement**, **RawQuery**, **Cursor**, **Locks**, and **FlowControl**.
- **Tags**: host, namespace, operation, database, query ID, user, and client address.
- **Total Executions** and **Avg Duration** charts for this operation.
- **Attributes**, grouped into **Identity**, **Query identity**, **Execution timing**, **Document counts**, **Resource usage**, **Execution strategy**, **Client**, and **Raw blobs**.

**Filter to Query** filters the page to this host and query signature.

> **Note:** Use the **Plan** and **Docs examined** columns together. A `COLLSCAN` plan that examines many documents to return a few usually means the collection is missing an index.

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