Include support to limit rows in a group by operation #3121
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The limit is based on a system property "h2.maxGroupByEntries". The default value for the system property is -1, which keeps the current behaviour of the system.
If the value is changed to a positive number, it will limit the maximum number of different rows in the groupByData tree map in Grouped.
If someone issues a query that would create a table that is too big, only that query will fail. I've done this change to diminish the risk of OOM when running the embedded server. It doesn't solve it completely of course, because it doesn't actually consider the memory being used by the tree map, but given it's simplicity I think it could be a useful setting in some situations.