Entity.get() should issue 'limit 2'

[socketpair]

One of the purposes of entity.get() is to detect MultipleObjectsFoundError. If you add limit 2 to SQL queries, SQL server can use less resources while executing the query. For example, SQL server can stop populating internal cache if only two records needed. Yes I know that we may use cursors, but still sure that limit 2 will not hurt in performance in any way.

[kozlovsky]

Agreed, should be fixed

[kozlovsky]

Now Pony adds LIMIT 2 when it thinks that a query can return more than one row. But when Pony sees that the query uses an unique key and thus no duplicates are possible, then LIMIT 2 will not be added, because it looks redundant and shouldn't influence anything.