Parameter Categories

Warning: Do not use 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 Database 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

GPORCA Parameters

These parameters control the usage of GPORCA by Greenplum Database. For information about GPORCA, see About GPORCA.

gp_enable_relsize_collection

optimizer

optimizer_analyze_root_partition

optimizer_array_expansion_threshold

optimizer_cte_inlining_bound

optimizer_control

optimizer_enable_associativity

optimizer_enable_master_only_queries

optimizer_force_agg_skew_avoidance

optimizer_force_multistage_agg

optimizer_force_three_stage_scalar_dqa

optimizer_join_arity_for_associativity_commutativity

optimizer_join_order

optimizer_join_order_threshold

optimizer_mdcache_size

optimizer_metadata_caching

optimizer_parallel_union

optimizer_print_missing_stats

optimizer_print_optimization_stats

optimizer_sort_factor

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.

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_relsize_collection

gp_enable_sequential_window_plans

gp_enable_sort_distinct

gp_enable_sort_limit

Legacy Query Optimizer Costing Parameters

Warning: 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

Query Plan Execution

Control the query plan execution.

gp_max_slices

Error Reporting and Logging Parameters

These configuration parameters control Greenplum Database logging.

Log Rotation

log_rotation_age

log_rotation_size

log_truncate_on_rotation

When to Log

client_min_messages

gp_interconnect_debug_retry_interval

log_error_verbosity

log_min_duration_statement

log_min_error_statement

log_min_messages

optimizer_minidump

What to Log

debug_pretty_print

debug_print_parse

debug_print_plan

debug_print_prelim_plan

debug_print_rewritten

debug_print_slice_table

gp_max_csv_line_length

gp_reraise_signal

System Monitoring Parameters

These configuration parameters control Greenplum Database data collection and notifications related to database monitoring.

SNMP Alerts

The following parameters send SNMP notifications when events occur.

gp_snmp_community

gp_snmp_monitor_address

gp_snmp_use_inform_or_trap

Email Alerts

The following parameters configure the system to send email alerts for fatal error events, such as a segment going down or a server crash and reset.

gp_email_from

gp_email_smtp_password

gp_email_smtp_server

gp_email_smtp_userid

gp_email_to

Greenplum Command Center Agent

The following parameters configure the data collection agents that populate the gpperfmon database for Greenplum Command Center.

gp_enable_gpperfmon

gp_gpperfmon_send_interval

gpperfmon_log_alert_level

gpperfmon_port

Runtime Statistics Collection Parameters

These parameters control the server statistics collection feature. When statistics collection is enabled, you can access the statistics data using the pg_stat family of system catalog views.

stats_queue_level

update_process_title

Automatic Statistics Collection Parameters

When automatic statistics collection is enabled, you can run ANALYZE automatically in the same transaction as an INSERT, UPDATE, DELETE, COPY or CREATE TABLE...AS SELECT statement when a certain threshold of rows is affected (on_change), or when a newly generated table has no statistics (on_no_stats). To enable this feature, set the following server configuration parameters in your Greenplum Database master postgresql.conf file and restart Greenplum Database:

gp_autostats_mode

gp_autostats_mode_in_functions

gp_autostats_on_change_threshold

log_autostats

Warning: Depending on the specific nature of your database operations, automatic statistics collection can have a negative performance impact. Carefully evaluate whether the default setting of on_no_stats is appropriate for your system.

Client Connection Default Parameters

These configuration parameters set defaults that are used for client connections.

Statement Behavior Parameters

check_function_bodies

default_tablespace

default_transaction_isolation

default_transaction_read_only

search_path

statement_timeout

vacuum_freeze_min_age

Locale and Formatting Parameters

Other Client Default Parameters

dynamic_library_path

explain_pretty_print

local_preload_libraries

Lock Management Parameters

These configuration parameters set limits for locks and deadlocks.

deadlock_timeout

max_locks_per_transaction

Resource Management Parameters (Resource Queues)

The following configuration parameters configure the Greenplum Database resource management feature (resource queues), query prioritization, memory utilization and concurrency control.

gp_resqueue_memory_policy

gp_resqueue_priority

gp_resqueue_priority_cpucores_per_segment

gp_resqueue_priority_sweeper_interval

gp_vmem_idle_resource_timeout

gp_vmem_protect_limit

gp_vmem_protect_segworker_cache_limit

max_resource_queues

max_resource_portals_per_transaction

max_statement_mem

resource_cleanup_gangs_on_wait

resource_select_only

runaway_detector_activation_percent

statement_mem

stats_queue_level

vmem_process_interrupt

Resource Management Parameters (Resource Groups)

The following parameters configure the Greenplum Database resource group workload management feature.

gp_resgroup_memory_policy

gp_resource_group_bypass

gp_resource_group_cpu_limit

gp_resource_group_memory_limit

gp_resource_manager

gp_vmem_idle_resource_timeout

gp_vmem_protect_segworker_cache_limit

memory_spill_ratio

vmem_process_interrupt

External Table Parameters

The following parameters configure the external tables feature of Greenplum Database.

gp_external_enable_exec

gp_external_enable_filter_pushdown

gp_external_max_segs

gp_initial_bad_row_limit

gp_reject_percent_threshold

readable_external_table_timeout

writable_external_table_bufsize

verify_gpfdists_cert

Database Table Parameters

The following parameter configures default option settings for Greenplum Database tables.

gp_create_table_random_default_distribution

gp_default_storage_options

gp_enable_exchange_default_partition

gp_enable_segment_copy_checking

Append-Optimized Table Parameters

The following parameters configure the append-optimized tables feature of Greenplum Database.

max_appendonly_tables

gp_appendonly_compaction

gp_appendonly_compaction_threshold

validate_previous_free_tid

Database and Tablespace/Filespace Parameters

The following parameters configure the maximum number of databases, tablespaces, and filespaces allowed in a system.

gp_max_tablespaces

gp_max_filespaces

gp_max_databases

Past Version Compatibility Parameters

The following parameters provide compatibility with older PostgreSQL and Greenplum Database versions. You do not need to change these parameters in Greenplum Database.

PostgreSQL

add_missing_from

array_nulls

backslash_quote

escape_string_warning

regex_flavor

standard_conforming_strings

transform_null_equals

Greenplum Database

gp_ignore_error_table

Greenplum Database Array Configuration Parameters

The parameters in this topic control the configuration of the Greenplum Database array and its components: segments, master, distributed transaction manager, master mirror, and interconnect.