How does polar_csi.memory_limit interact with work_mem in PolarDB for PostgreSQL?

I am trying to budget memory for concurrent analytical queries executed through IMCI in PolarDB for PostgreSQL. PostgreSQL provides work_mem, while IMCI exposes a separate polar_csi.memory_limit setting. I am unsure how these limits interact when an IMCI query performs joins and aggregations. Does work_mem constrain any part of IMCI execution, or does IMCI use an independent memory budget? Also, is polar_csi.memory_limit shared across concurrent queries, or applied separately to each query or backend? My goal is to choose a safe memory budget under concurrency without assuming that the configured limit equals the process's total memory consumption.