MAX_MEM_ESTIMATE_FOR_ADMISSION Query Option
Use the MAX_MEM_ESTIMATE_FOR_ADMISSION query option to set an upper limit on the memory estimates of a query as a workaround for over-estimates precluding a query from being admitted.
The query option takes effect when all of the below conditions are met:
- Memory-based admission control is enabled for the pool.
- The MEM_LIMIT query option is not set at the query, session, resource pool, or global level.
When the above conditions are met, MIN(MAX_MEM_ESTIMATE_FOR_ADMISSION, mem_estimate) is used for admission control.
Setting the MEM_LIMIT query option is usually a better option. Use the MAX_MEM_ESTIMATE_FOR_ADMISSION query option when it is not feasible to set MEM_LIMIT for each individual query.
Added in: CDH 5.16