# Examples

## Finding Expensive Queries

For example, to find the five most expensive queries, run:

```sql
SELECT EXECUTION_TIME/COMMITS, QUERY_TEXT from information_schema.PLANCACHE
ORDER BY EXECUTION_TIME/COMMITS DESC LIMIT 5;

```

## Finding Specific Queries

In SingleStore, the `PROCESSLIST` view also has a `PLAN_ID` column that can be used to look up the query currently running on a given connection in `PLANCACHE`. For example:

```sql
SELECT QUERY_TEXT FROM information_schema.PROCESSLIST
as pl JOIN information_schema.PLANCACHE
as pc ON pl.PLAN_ID = pc.PLAN_ID;

```

This is the most reliable way to find the query executing on a given connection. The `PROCESSLIST.INFO` column is not always set by SingleStore.

> **📝 Note**: If you are dealing with sensitive data and want to limit access to query information, but not the full `PROCESSLIST` view, this can be controlled via the variable, `show_query_parameters`. By default, this variable is set to `ON`, so query parameters will be visible in the output of `SELECT` from `information_schema.processlist`. If set to `OFF`, parameters will be hidden. This can be changed only at startup, not during runtime; it must be set in the memsql.cnf file, followed by a system restart.

## Finding the Number of Queries Running on All Databases

You can use the `processlist` to get connections on the database level.

`SELECT * FROM INFORMATION_SCHEMA.MV_PROCESSLIST` shows all the queries running on the cluster. If you filter or group by the field `db`, you can get the number of connections by database.

For example:

```sql
SELECT db, COUNT(*) FROM information_schema.mv_processlist WHERE db IS NOT NULL GROUP BY 1;

```

```output

+--------------------+----------+
| db                 | COUNT(*) |
+--------------------+----------+
| information_schema |        2 |
| metrics            |        2 |
+--------------------+----------+
```

***

Modified at: September 17, 2024

Source: [/db/v9.1/reference/information-schema-reference/examples/](https://docs.singlestore.com/db/v9.1/reference/information-schema-reference/examples/)

(An index of the documentation is available at /llms.txt)