Certain SQL operations like group by, sort, joins may use Aurora temporary storage. This local storage within the cluster. The amount of temporary storage allocated and available to use is dependent on the class and size of the cluster you spin up. Smallish clusters will exhaust and cause errors like ERROR: XXX temporary file NO SPACE LEFT ON DEVICE.
You can troubleshoot these issues by looking at the RDS CloudWatch parameters FreeLocalStorage and FreeableMemory.
Additionally, you can also monitor Native Counters in RDS Performance Insights.
You can also increase either or both of the parameters MAX_HEAP_TABLE_SIZE or TEMP_TABLE_SIZE but this will also decrease availability resources (memory) for other options.
Another option is to increase the size of the cluster.
log_temp_files parameter to monitor and RDS.log_retention to reclaim space can also be manipulated