Sets the amount of memory, in bytes, that the query coordinator can consume during execution per query. This limit directly influences how much memory a query is allowed to use and hold on to. The query coordinator needs to keep at least 4 representations of each query's state in memory, which in turn means that data a query can collect will at most be 1/4th of whatever this value is. This limit ensures that the coordinating nodes of a cluster do not run out of memory.