SQL: frequent switch between schemas cause severe slowdown

We have thread-bound cached connection to H2 database which is bound to specific schema. See IgniteH2Indexing.connectionForThread.

When query with different schema is executed, we call SET SCHEMA command, which is rather expensive and may cause slowdown when queries form different caches are executed.

To avoid this we should maintain thread-local map of such connections. Be careful with concurrency and resource leaks.