WindowParallelComputeOpt use LCA algorithm may not handle specified physical plan

Now the LCA algorithm in WindowParallelComputeOpt may not handle this graph.


The issue references a graph where the LCA algorithm in WindowParallelComputeOpt fails. Start by locating the WindowParallelComputeOpt component in the codebase, likely in a query optimization or execution module. Examine the LCA algorithm implementation and the specific graph structure shown in the image to understand the failure case. Determine what modifications are needed to handle the graph correctly, and verify with existing tests related to window parallel computation.

Written by the indexing model from the issue text.