Query Tuning Parameters

These parameters control aspects of SQL query processing such as query operators and operator settings and statistics sampling.

Legacy Query Optimizer Operator Control Parameters

The following parameters control the types of plan operations the legacy query optimizer can use. Enable or disable plan operations to force the legacy optimizer to choose a different plan. This is useful for testing and comparing query performance using different plan types.

enable_bitmapscan

gp_enable_adaptive_nestloop

gp_enable_agg_distinct

gp_enable_agg_distinct_pruning

gp_enable_direct_dispatch

gp_enable_fallback_plan

gp_enable_fast_sri

gp_enable_groupext_distinct_gather

gp_enable_groupext_distinct_pruning

gp_enable_multiphase_agg

gp_enable_predicate_propagation

gp_enable_preunique

gp_enable_sequential_window_plans

gp_enable_sort_distinct

gp_enable_sort_limit

Legacy Query Optimizer Costing Parameters

Warning: Pivotal recommends that you do not adjust these query costing parameters. They are tuned to reflect Greenplum Database hardware configurations and typical workloads. All of these parameters are related. Changing one without changing the others can have adverse affects on performance.

cpu_index_tuple_cost

cpu_operator_cost

cpu_tuple_cost

cursor_tuple_fraction

effective_cache_size

gp_motion_cost_per_row

gp_segments_for_planner

random_page_cost

seq_page_cost

Database Statistics Sampling Parameters

These parameters adjust the amount of data sampled by an ANALYZE operation. Adjusting these parameters affects statistics collection system-wide. You can configure statistics collection on particular tables and columns by using the ALTER TABLESET STATISTICS clause.

default_statistics_target

gp_analyze_relative_error