Hi Evgenij, Actually, I was initially exploring apache derby and came across different join methods which are Nested loop join, hash join and merge join. Derby has implemented their join strategy <https://github.com/apache/derby/blob/trunk/java/org.apache.derby.engine/org/apache/derby/iapi/sql/compile/JoinStrategy.java> as an interface which represents the aforementioned approaches which the optimizer may pick for joining tables. However, I couldn't find such implementation in H2. I am referring to join methods (i.e. nested loop, hash, block nested loop, merge etc) not join types (i.e. inner, outer, left etc).
Thank You Regards On Tuesday, February 16, 2021 at 12:08:42 PM UTC+5:30 Evgenij Ryazanov wrote: > Why you think that this method is only about nested joins? It iterates > over tables or subqueries, including joined and nested ones (if there are > any) and their table filters do the same recursively. Index conditions are > used when possible to avoid iteration over the whole tables. They are > created by search and join conditions and query optimizer tries to choose > the best execution plan with taking existing indexes and their selectivity > into account. Only the usable index conditions are preserved. All these > operations are performed before the actual query execution and cursors > process conditions by themselves, so TableFilter.next() is a relatively > simple method. Sorry, but you need to understand how it works by yourself. > > Usually it's better to start from some trivial or at least simple enough > tasks to get some initial knowledge about the product you want to improve, > but you may have own reasons. > -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/h2-database/5157392b-4bbe-4c11-bed6-8d6b03f5ab18n%40googlegroups.com.
