> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Monitoring Query Execution

## Setting limits for Query Results

Controlling the size of **GetAggregatesQuery** queries can be very handy when there is a need to limit the number of resulting locations.
A typical example is the possibility to control big queries hitting a cluster at a data node level, allowing thus to limit / reduce
the traffic when using distribution. It can also act as a safeguard to prevent queries from consuming too much memory.

### Configurable limits on Query Results

Limiting queries results can be achieved using the `IQueriesResultLimit` context value. We distinguish two types of limit:

* **intermediateLimit**: It defines the limit number of point locations for a single intermediate result (i.e. retrieval).
* **transientLimit**: It defines the transient limit resulting from the accumulation of all the intermediate results within
  **a single query**.

> Note that the default transient and intermediate result limit amount to 100,000 and 1,000,000 point locations respectively, and can be obtained by calling
> `QueriesResultLimit#defaultLimit()`.

Query results limit property can be enabled through Atoti context values,

```java theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
pivot.getContext().set(IQueriesResultLimit.class, QueriesResultLimit.defaultLimit());
```

or in the cube description

```java theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
StartBuilding.cube("tweets")
    .withSingleLevelDimensions("sender_id")
    .withDimension("time")
    .withHierarchy("time")
    .withLevel("year")
    .withLevel("month")
    .withLevel("day")
    .withSharedContextValue(QueriesResultLimit.withLimit(10_000, 1_000_000))
```

or through query context values

<Frame>
  <img src="https://mintcdn.com/activeviam/KszPZqdDnmT6EpJc/engine/java-sdk/6.1/assets/monitoring/queries-result-limit-context-values.png?fit=max&auto=format&n=KszPZqdDnmT6EpJc&q=85&s=6573852cd9bc469dba13943f2907dff1" alt="" width="807" height="808" data-path="engine/java-sdk/6.1/assets/monitoring/queries-result-limit-context-values.png" />
</Frame>

> Not defining a limit for queries is equivalent to using `QueriesResultLimit#withoutLimit()`.

Exceeding the configured limit will result in a `RetrievalResultSizeException`, aborting the execution of all operations involved in the query.

### Miscellaneous

When setting a limit for queries results, there is a couple of points to keep in mind:

* Intermediate queries results may exceed the configured limit even though the final result does not. A typical example is a copper join
  including factless points that will be removed from the final result.
* In a distributed setup, if a data node exceeds the configured limit then the initial query will fail (partial results from other data nodes won't be accounted for).
* In a distributed polymorphic setup, expect the replication to produce additional locations and in some cases introduce points without underlying contribution.