System Resource Consumption Parameters

Memory Consumption Parameters

These parameters control system memory usage. You can adjust gp_vmem_protect_limit to avoid running out of memory at the segment hosts during query processing.

gp_vmem_idle_resource_timeout

gp_vmem_protect_limit

gp_vmem_protect_segworker_cache_limit

gp_workfile_limit_files_per_query

gp_workfile_limit_per_query

gp_workfile_limit_per_segment

max_appendonly_tables

max_prepared_transactions

max_stack_depth

shared_buffers

temp_buffers

Free Space Map Parameters

These parameters control the sizing of the free space map, which contains expired rows. Use VACUUM to reclaim the free space map disk space.

See Vacuum and Analyze for Query Optimization for information about vacuuming a database.

  • max_fsm_pages
  • max_fsm_relations

OS Resource Parameters

  • max_files_per_process
  • shared_preload_libraries

Cost-Based Vacuum Delay Parameters

Warning: Pivotal does not recommend cost-based vacuum delay because it runs asynchronously among the segment instances. The vacuum cost limit and delay is invoked at the segment level without taking into account the state of the entire Greenplum array.

You can configure the execution cost of VACUUM and ANALYZE commands to reduce the I/O impact on concurrent database activity. When the accumulated cost of I/O operations reaches the limit, the process performing the operation sleeps for a while, Then resets the counter and continues execution

vacuum_cost_delay

vacuum_cost_limit

vacuum_cost_page_dirty

vacuum_cost_page_hit

vacuum_cost_page_miss

Transaction ID Management Parameters

  • xid_stop_limit
  • xid_warn_limit