# Managing queries

## Termination Control

```sql
SELECT * FROM topicA WHERE _key.deviceId=123 LIMIT 10
```

Adding a **LIMIT 10** in the SQL query will result in the SQL terminating early, as soon as 10 x messages have been discovered. It’s not a perfect solution as we might never find 10 x messages, and thus perform a full scan.

You can also set a maximum query or idle time:

```
SET max.query.time = 30s;
```

or max idle time, the idea is that there is no reason to keep polling if we have exhausted the entire topic:

```
SET max.idle.time = 5s;
```

or a maximum amount of data to read from Kafka. This controls how much data to read from Kafka **NOT** the required memory.

```
SET max.size = 1M;
```

## Recent queries

Recent queries are displayed, but only for the current session, they are not currently retained.

Click on the play button to run a previous query. If a query is already running, you will be asked if you want to stop it first.

**View All queries**

```sql
SHOW ALL QUERIES
```

**View Running queries**

You can see all running queries by Lenses users using SQL:

```sql
SHOW QUERIES
```

## Kill Running queries

You can force stop a query by another user using SQL:

```sql
KILL QUERY <id>
```

\
Concurrent queries limit
------------------------

Starting with 6.1.3 version, there's a global limit on concurrent queries, as well as a limit per user. They can be set via the agent configuration:

```
lenses.sql.settings.max.concurrent.queries=200
lenses.sql.settings.max.concurrent.queries.per.user=2
```