---
title: Timeouts for Long-Running Queries
---

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<a id="topic_long-running-queries"></a>

<%=vars.product_name%> can monitor and throw an exception when
a query runs longer than a configured amount of time.
This feature is enabled by setting the `critical-heap-percentage` attribute 
which detects that the JVM has too little heap memory.

The default query timeout is five hours.
Set a different amount of time, in milliseconds,
by specifying the system variable `gemfire.Cache.MAX_QUERY_EXECUTION_TIME`.
A value of -1 explicitly disables the timeout.

When enabled, a query that runs longer than the configured timeout
will be cancelled such that it does not finish,
and <%=vars.product_name%> throws a `QueryExecutionTimeoutException`.