> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/analytics/mariadb-columnstore/high-availability/columnstore-query-tuning/query-plans-and-optimizer-trace.md).

# Query Plans and Optimizer Trace

- [Execution Plan (CSEP)](https://mariadb.com/docs/analytics/mariadb-columnstore/high-availability/columnstore-query-tuning/query-plans-and-optimizer-trace/columnstore-execution-plan-csep-for-mariadb-enterprise-columnstore.md): The ColumnStore Execution Plan (CSEP) is the internal query-plan representation in MariaDB ColumnStore, generated from SELECT\_LEX and viewable through calSetTrace.
- [Job Steps](https://mariadb.com/docs/analytics/mariadb-columnstore/high-availability/columnstore-query-tuning/query-plans-and-optimizer-trace/job-steps-for-mariadb-enterprise-columnstore.md): Job steps in MariaDB ColumnStore: ExeMgr translates the CSEP into a job list of distributed and multi-threaded steps (BPS, CES, etc.) for parallel query execution across nodes.