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parameter_definitions.html.md.erb
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parameter_definitions.html.md.erb
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---
title: Configuration Parameters
---
Descriptions of the HAWQ server configuration parameters listed alphabetically.
- **[add\_missing\_from](../../reference/guc/parameter_definitions.html#add_missing_from)**
- **[application\_name](../../reference/guc/parameter_definitions.html#application_name)**
- **[array\_nulls](../../reference/guc/parameter_definitions.html#array_nulls)**
- **[authentication\_timeout](../../reference/guc/parameter_definitions.html#authentication_timeout)**
- **[backslash\_quote](../../reference/guc/parameter_definitions.html#backslash_quote)**
- **[block\_size](../../reference/guc/parameter_definitions.html#block_size)**
- **[bonjour\_name](../../reference/guc/parameter_definitions.html#bonjour_name)**
- **[check\_function\_bodies](../../reference/guc/parameter_definitions.html#check_function_bodies)**
- **[client\_encoding](../../reference/guc/parameter_definitions.html#client_encoding)**
- **[client\_min\_messages](../../reference/guc/parameter_definitions.html#client_min_messages)**
- **[cpu\_index\_tuple\_cost](../../reference/guc/parameter_definitions.html#cpu_index_tuple_cost)**
- **[cpu\_operator\_cost](../../reference/guc/parameter_definitions.html#cpu_operator_cost)**
- **[cpu\_tuple\_cost](../../reference/guc/parameter_definitions.html#cpu_tuple_cost)**
- **[cursor\_tuple\_fraction](../../reference/guc/parameter_definitions.html#cursor_tuple_fraction)**
- **[custom\_variable\_classes](../../reference/guc/parameter_definitions.html#custom_variable_classes)**
- **[DateStyle](../../reference/guc/parameter_definitions.html#DateStyle)**
- **[db\_user\_namespace](../../reference/guc/parameter_definitions.html#db_user_namespace)**
- **[deadlock\_timeout](../../reference/guc/parameter_definitions.html#deadlock_timeout)**
- **[debug\_assertions](../../reference/guc/parameter_definitions.html#debug_assertions)**
- **[debug\_pretty\_print](../../reference/guc/parameter_definitions.html#debug_pretty_print)**
- **[debug\_print\_parse](../../reference/guc/parameter_definitions.html#debug_print_parse)**
- **[debug\_print\_plan](../../reference/guc/parameter_definitions.html#debug_print_plan)**
- **[debug\_print\_prelim\_plan](../../reference/guc/parameter_definitions.html#debug_print_prelim_plan)**
- **[debug\_print\_rewritten](../../reference/guc/parameter_definitions.html#debug_print_rewritten)**
- **[debug\_print\_slice\_table](../../reference/guc/parameter_definitions.html#debug_print_slice_table)**
- **[default\_hash\_table\_bucket\_number](../../reference/guc/parameter_definitions.html#topic_fqj_4fd_kv)**
- **[default\_statement\_mem](../../reference/guc/parameter_definitions.html#default_statement_mem)**
- **[default\_statistics\_target](../../reference/guc/parameter_definitions.html#default_statistics_target)**
- **[default\_tablespace](../../reference/guc/parameter_definitions.html#default_tablespace)**
- **[default\_transaction\_isolation](../../reference/guc/parameter_definitions.html#default_transaction_isolation)**
- **[default\_transaction\_read\_only](../../reference/guc/parameter_definitions.html#default_transaction_read_only)**
- **[dfs\_url](../../reference/guc/parameter_definitions.html#dfs_url)**
- **[dynamic\_library\_path](../../reference/guc/parameter_definitions.html#dynamic_library_path)**
- **[effective\_cache\_size](../../reference/guc/parameter_definitions.html#effective_cache_size)**
- **[enable\_bitmapscan](../../reference/guc/parameter_definitions.html#enable_bitmapscan)**
- **[enable\_groupagg](../../reference/guc/parameter_definitions.html#enable_groupagg)**
- **[enable\_hashagg](../../reference/guc/parameter_definitions.html#enable_hashagg)**
- **[enable\_hashjoin](../../reference/guc/parameter_definitions.html#enable_hashjoin)**
- **[enable\_indexscan](../../reference/guc/parameter_definitions.html#enable_indexscan)**
- **[enable\_mergejoin](../../reference/guc/parameter_definitions.html#enable_mergejoin)**
- **[enable\_nestloop](../../reference/guc/parameter_definitions.html#enable_nestloop)**
- **[enable\_secure\_filesystem](../../reference/guc/parameter_definitions.html#enable_secure_filesystem)**
- **[enable\_seqscan](../../reference/guc/parameter_definitions.html#enable_seqscan)**
- **[enable\_sort](../../reference/guc/parameter_definitions.html#enable_sort)**
- **[enable\_tidscan](../../reference/guc/parameter_definitions.html#enable_tidscan)**
- **[escape\_string\_warning](../../reference/guc/parameter_definitions.html#escape_string_warning)**
- **[explain\_memory\_verbosity](../../reference/guc/parameter_definitions.html#explain_memory_verbosity)**
- **[explain\_pretty\_print](../../reference/guc/parameter_definitions.html#explain_pretty_print)**
- **[extra\_float\_digits](../../reference/guc/parameter_definitions.html#extra_float_digits)**
- **[from\_collapse\_limit](../../reference/guc/parameter_definitions.html#from_collapse_limit)**
- **[gp\_adjust\_selectivity\_for\_outerjoins](../../reference/guc/parameter_definitions.html#gp_adjust_selectivity_for_outerjoins)**
- **[gp\_analyze\_relative\_error](../../reference/guc/parameter_definitions.html#gp_analyze_relative_error)**
- **[gp\_autostats\_mode](../../reference/guc/parameter_definitions.html#gp_autostats_mode)**
- **[gp\_autostats\_on\_change\_threshold](../../reference/guc/parameter_definitions.html#topic_imj_zhf_gw)**
- **[gp\_backup\_directIO](../../reference/guc/parameter_definitions.html#gp_backup_directIO)**
- **[gp\_backup\_directIO\_read\_chunk\_mb](../../reference/guc/parameter_definitions.html#gp_backup_directIO_read_chunk_mb)**
- **[gp\_cached\_segworkers\_threshold](../../reference/guc/parameter_definitions.html#gp_cached_segworkers_threshold)**
- **[gp\_command\_count](../../reference/guc/parameter_definitions.html#gp_command_count)**
- **[gp\_connections\_per\_thread](../../reference/guc/parameter_definitions.html#gp_connections_per_thread)**
- **[gp\_debug\_linger](../../reference/guc/parameter_definitions.html#gp_debug_linger)**
- **[gp\_dynamic\_partition\_pruning](../../reference/guc/parameter_definitions.html#gp_dynamic_partition_pruning)**
- **[gp\_enable\_agg\_distinct](../../reference/guc/parameter_definitions.html#gp_enable_agg_distinct)**
- **[gp\_enable\_agg\_distinct\_pruning](../../reference/guc/parameter_definitions.html#gp_enable_agg_distinct_pruning)**
- **[gp\_enable\_direct\_dispatch](../../reference/guc/parameter_definitions.html#gp_enable_direct_dispatch)**
- **[gp\_enable\_fallback\_plan](../../reference/guc/parameter_definitions.html#gp_enable_fallback_plan)**
- **[gp\_enable\_fast\_sri](../../reference/guc/parameter_definitions.html#gp_enable_fast_sri)**
- **[gp\_enable\_groupext\_distinct\_gather](../../reference/guc/parameter_definitions.html#gp_enable_groupext_distinct_gather)**
- **[gp\_enable\_groupext\_distinct\_pruning](../../reference/guc/parameter_definitions.html#gp_enable_groupext_distinct_pruning)**
- **[gp\_enable\_multiphase\_agg](../../reference/guc/parameter_definitions.html#gp_enable_multiphase_agg)**
- **[gp\_enable\_predicate\_propagation](../../reference/guc/parameter_definitions.html#gp_enable_predicate_propagation)**
- **[gp\_enable\_preunique](../../reference/guc/parameter_definitions.html#gp_enable_preunique)**
- **[gp\_enable\_sequential\_window\_plans](../../reference/guc/parameter_definitions.html#gp_enable_sequential_window_plans)**
- **[gp\_enable\_sort\_distinct](../../reference/guc/parameter_definitions.html#gp_enable_sort_distinct)**
- **[gp\_enable\_sort\_limit](../../reference/guc/parameter_definitions.html#gp_enable_sort_limit)**
- **[gp\_external\_enable\_exec](../../reference/guc/parameter_definitions.html#gp_external_enable_exec)**
- **[gp\_external\_grant\_privileges](../../reference/guc/parameter_definitions.html#gp_external_grant_privileges)**
- **[gp\_external\_max\_segs](../../reference/guc/parameter_definitions.html#gp_external_max_segs)**
- **[gp\_filerep\_tcp\_keepalives\_count](../../reference/guc/parameter_definitions.html#gp_filerep_tcp_keepalives_count)**
- **[gp\_filerep\_tcp\_keepalives\_idle](../../reference/guc/parameter_definitions.html#gp_filerep_tcp_keepalives_idle)**
- **[gp\_filerep\_tcp\_keepalives\_interval](../../reference/guc/parameter_definitions.html#gp_filerep_tcp_keepalives_interval)**
- **[gp\_hashjoin\_tuples\_per\_bucket](../../reference/guc/parameter_definitions.html#gp_hashjoin_tuples_per_bucket)**
- **[gp\_idf\_deduplicate](../../reference/guc/parameter_definitions.html#gp_idf_deduplicate)**
- **[gp\_interconnect\_fc\_method](../../reference/guc/parameter_definitions.html#gp_interconnect_fc_method)**
- **[gp\_interconnect\_hash\_multiplier](../../reference/guc/parameter_definitions.html#gp_interconnect_hash_multiplier)**
- **[gp\_interconnect\_queue\_depth](../../reference/guc/parameter_definitions.html#gp_interconnect_queue_depth)**
- **[gp\_interconnect\_setup\_timeout](../../reference/guc/parameter_definitions.html#gp_interconnect_setup_timeout)**
- **[gp\_interconnect\_snd\_queue\_depth](../../reference/guc/parameter_definitions.html#gp_interconnect_snd_queue_depth)**
- **[gp\_interconnect\_type](../../reference/guc/parameter_definitions.html#gp_interconnect_type)**
- **[gp\_log\_format](../../reference/guc/parameter_definitions.html#gp_log_format)**
- **[gp\_max\_csv\_line\_length](../../reference/guc/parameter_definitions.html#gp_max_csv_line_length)**
- **[gp\_max\_databases](../../reference/guc/parameter_definitions.html#gp_max_databases)**
- **[gp\_max\_filespaces](../../reference/guc/parameter_definitions.html#gp_max_filespaces)**
- **[gp\_max\_packet\_size](../../reference/guc/parameter_definitions.html#gp_max_packet_size)**
- **[gp\_max\_plan\_size](../../reference/guc/parameter_definitions.html#gp_max_plan_size)**
- **[gp\_max\_tablespaces](../../reference/guc/parameter_definitions.html#gp_max_tablespaces)**
- **[gp\_motion\_cost\_per\_row](../../reference/guc/parameter_definitions.html#gp_motion_cost_per_row)**
- **[gp\_reject\_percent\_threshold](../../reference/guc/parameter_definitions.html#gp_reject_percent_threshold)**
- **[gp\_reraise\_signal](../../reference/guc/parameter_definitions.html#gp_reraise_signal)**
- **[gp\_role](../../reference/guc/parameter_definitions.html#gp_role)**
- **[gp\_safefswritesize](../../reference/guc/parameter_definitions.html#gp_safefswritesize)**
- **[gp\_segment\_connect\_timeout](../../reference/guc/parameter_definitions.html#gp_segment_connect_timeout)**
- **[gp\_segments\_for\_planner](../../reference/guc/parameter_definitions.html#gp_segments_for_planner)**
- **[gp\_session\_id](../../reference/guc/parameter_definitions.html#gp_session_id)**
- **[gp\_set\_proc\_affinity](../../reference/guc/parameter_definitions.html#gp_set_proc_affinity)**
- **[gp\_set\_read\_only](../../reference/guc/parameter_definitions.html#gp_set_read_only)**
- **[gp\_statistics\_pullup\_from\_child\_partition](../../reference/guc/parameter_definitions.html#gp_statistics_pullup_from_child_partition)**
- **[gp\_statistics\_use\_fkeys](../../reference/guc/parameter_definitions.html#gp_statistics_use_fkeys)**
- **[gp\_vmem\_idle\_resource\_timeout](../../reference/guc/parameter_definitions.html#gp_vmem_idle_resource_timeout)**
- **[gp\_vmem\_protect\_segworker\_cache\_limit](../../reference/guc/parameter_definitions.html#gp_vmem_protect_segworker_cache_limit)**
- **[gp\_workfile\_checksumming](../../reference/guc/parameter_definitions.html#gp_workfile_checksumming)**
- **[gp\_workfile\_compress\_algorithm](../../reference/guc/parameter_definitions.html#gp_workfile_compress_algorithm)**
- **[gp\_workfile\_limit\_files\_per\_query](../../reference/guc/parameter_definitions.html#gp_workfile_limit_files_per_query)**
- **[gp\_workfile\_limit\_per\_query](../../reference/guc/parameter_definitions.html#gp_workfile_limit_per_query)**
- **[gp\_workfile\_limit\_per\_segment](../../reference/guc/parameter_definitions.html#gp_workfile_limit_per_segment)**
- **[hawq\_dfs\_url](../../reference/guc/parameter_definitions.html#hawq_dfs_url)**
- **[hawq\_global\_rm\_type](../../reference/guc/parameter_definitions.html#hawq_global_rm_type)**
- **[hawq\_master\_address\_host](../../reference/guc/parameter_definitions.html#hawq_master_address_host)**
- **[hawq\_master\_address\_port](../../reference/guc/parameter_definitions.html#hawq_master_address_port)**
- **[hawq\_master\_directory](../../reference/guc/parameter_definitions.html#hawq_master_directory)**
- **[hawq\_master\_temp\_directory](../../reference/guc/parameter_definitions.html#hawq_master_temp_directory)**
- **[hawq\_re\_memory\_overcommit\_max](../../reference/guc/parameter_definitions.html#hawq_re_memory_overcommit_max)**
- **[hawq\_rm\_cluster\_report\_period](../../reference/guc/parameter_definitions.html#hawq_rm_cluster_report)**
- **[hawq\_rm\_force\_alterqueue\_cancel\_queued\_request](../../reference/guc/parameter_definitions.html#hawq_rm_force_alterqueue_cancel_queued_request)**
- **[hawq\_rm\_master\_port](../../reference/guc/parameter_definitions.html#hawq_rm_master_port)**
- **[hawq\_rm\_memory\_limit\_perseg](../../reference/guc/parameter_definitions.html#hawq_rm_memory_limit_perseg)**
- **[hawq\_rm\_min\_resource\_perseg](../../reference/guc/parameter_definitions.html#hawq_rm_min_resource_perseg)**
- **[hawq\_rm\_nresqueue\_limit](../../reference/guc/parameter_definitions.html#hawq_rm_nresqueue_limit)**
- **[hawq\_rm\_nslice\_perseg\_limit](../../reference/guc/parameter_definitions.html#hawq_rm_nslice_perseg_limit)**
- **[hawq\_rm\_nvcore\_limit\_perseg](../../reference/guc/parameter_definitions.html#hawq_rm_nvcore_limit_perseg)**
- **[hawq\_rm\_nvseg\_perquery\_limit](../../reference/guc/parameter_definitions.html#hawq_rm_nvseg_perquery_limit)**
- **[hawq\_rm\_nvseg\_perquery\_perseg\_limit](../../reference/guc/parameter_definitions.html#hawq_rm_nvseg_perquery_perseg_limit)**
- **[hawq\_rm\_nvseg\_variance\_amon\_seg\_limit](../../reference/guc/parameter_definitions.html#hawq_rm_nvseg_variance_amon_seg_limit)**
- **[hawq\_rm\_rejectrequest\_nseg\_limit](../../reference/guc/parameter_definitions.html#hawq_rm_rejectrequest_nseg_limit)**
- **[hawq\_rm\_resource\_idle\_timeout](../../reference/guc/parameter_definitions.html#hawq_rm_resource_idle_timeout)**
- **[hawq\_rm\_return\_percent\_on\_overcommit](../../reference/guc/parameter_definitions.html#hawq_rm_return_percent_on_overcommit)**
- **[hawq\_rm\_segment\_heartbeat\_interval](../../reference/guc/parameter_definitions.html#hawq_rm_segment_heartbeat_interval)**
- **[hawq\_rm\_segment\_port](../../reference/guc/parameter_definitions.html#hawq_rm_segment_port)**
- **[hawq\_rm\_stmt\_nvseg](../../reference/guc/parameter_definitions.html#hawq_rm_stmt_nvseg)**
- **[hawq\_rm\_stmt\_vseg\_memory](../../reference/guc/parameter_definitions.html#hawq_rm_stmt_vseg_memory)**
- **[hawq\_rm\_tolerate\_nseg\_limit](../../reference/guc/parameter_definitions.html#hawq_rm_tolerate_nseg_limit)**
- **[hawq\_rm\_yarn\_address](../../reference/guc/parameter_definitions.html#hawq_rm_yarn_address)**
- **[hawq\_rm\_yarn\_app\_name](../../reference/guc/parameter_definitions.html#hawq_rm_yarn_app_name)**
- **[hawq\_rm\_yarn\_queue\_name](../../reference/guc/parameter_definitions.html#hawq_rm_yarn_queue_name)**
- **[hawq\_rm\_yarn\_scheduler\_address](../../reference/guc/parameter_definitions.html#hawq_rm_yarn_scheduler_address)**
- **[hawq\_segment\_address\_port](../../reference/guc/parameter_definitions.html#hawq_segment_address_port)**
- **[hawq\_segment\_directory](../../reference/guc/parameter_definitions.html#hawq_segment_directory)**
- **[hawq\_segment\_temp\_directory](../../reference/guc/parameter_definitions.html#hawq_segment_temp_directory)**
- **[integer\_datetimes](../../reference/guc/parameter_definitions.html#integer_datetimes)**
- **[IntervalStyle](../../reference/guc/parameter_definitions.html#IntervalStyle)**
- **[join\_collapse\_limit](../../reference/guc/parameter_definitions.html#join_collapse_limit)**
- **[krb\_caseins\_users](../../reference/guc/parameter_definitions.html#krb_caseins_users)**
- **[krb\_server\_keyfile](../../reference/guc/parameter_definitions.html#krb_server_keyfile)**
- **[krb\_srvname](../../reference/guc/parameter_definitions.html#krb_srvname)**
- **[lc\_collate](../../reference/guc/parameter_definitions.html#lc_collate)**
- **[lc\_ctype](../../reference/guc/parameter_definitions.html#lc_ctype)**
- **[lc\_messages](../../reference/guc/parameter_definitions.html#lc_messages)**
- **[lc\_monetary](../../reference/guc/parameter_definitions.html#lc_monetary)**
- **[lc\_numeric](../../reference/guc/parameter_definitions.html#lc_numeric)**
- **[lc\_time](../../reference/guc/parameter_definitions.html#lc_time)**
- **[listen\_addresses](../../reference/guc/parameter_definitions.html#listen_addresses)**
- **[local\_preload\_libraries](../../reference/guc/parameter_definitions.html#local_preload_libraries)**
- **[log\_autostats](../../reference/guc/parameter_definitions.html#log_autostats)**
- **[log\_connections](../../reference/guc/parameter_definitions.html#log_connections)**
- **[log\_disconnections](../../reference/guc/parameter_definitions.html#log_disconnections)**
- **[log\_dispatch\_stats](../../reference/guc/parameter_definitions.html#log_dispatch_stats)**
- **[log\_duration](../../reference/guc/parameter_definitions.html#log_duration)**
- **[log\_error\_verbosity](../../reference/guc/parameter_definitions.html#log_error_verbosity)**
- **[log\_executor\_stats](../../reference/guc/parameter_definitions.html#log_executor_stats)**
- **[log\_hostname](../../reference/guc/parameter_definitions.html#log_hostname)**
- **[log\_min\_duration\_statement](../../reference/guc/parameter_definitions.html#log_min_duration_statement)**
- **[log\_min\_error\_statement](../../reference/guc/parameter_definitions.html#log_min_error_statement)**
- **[log\_min\_messages](../../reference/guc/parameter_definitions.html#log_min_messages)**
- **[log\_parser\_stats](../../reference/guc/parameter_definitions.html#log_parser_stats)**
- **[log\_planner\_stats](../../reference/guc/parameter_definitions.html#log_planner_stats)**
- **[log\_rotation\_age](../../reference/guc/parameter_definitions.html#log_rotation_age)**
- **[log\_rotation\_size](../../reference/guc/parameter_definitions.html#log_rotation_size)**
- **[log\_statement](../../reference/guc/parameter_definitions.html#log_statement)**
- **[log\_statement\_stats](../../reference/guc/parameter_definitions.html#log_statement_stats)**
- **[log\_timezone](../../reference/guc/parameter_definitions.html#log_timezone)**
- **[log\_truncate\_on\_rotation](../../reference/guc/parameter_definitions.html#log_truncate_on_rotation)**
- **[maintenance\_work\_mem](../../reference/guc/parameter_definitions.html#maintenance_work_mem)**
- **[max\_appendonly\_tables](../../reference/guc/parameter_definitions.html#max_appendonly_tables)**
- **[max\_connections](../../reference/guc/parameter_definitions.html#max_connections)**
- **[max\_files\_per\_process](../../reference/guc/parameter_definitions.html#max_files_per_process)**
- **[max\_fsm\_pages](../../reference/guc/parameter_definitions.html#max_fsm_pages)**
- **[max\_fsm\_relations](../../reference/guc/parameter_definitions.html#max_fsm_relations)**
- **[max\_function\_args](../../reference/guc/parameter_definitions.html#max_function_args)**
- **[max\_identifier\_length](../../reference/guc/parameter_definitions.html#max_identifier_length)**
- **[max\_index\_keys](../../reference/guc/parameter_definitions.html#max_index_keys)**
- **[max\_locks\_per\_transaction](../../reference/guc/parameter_definitions.html#max_locks_per_transaction)**
- **[max\_prepared\_transactions](../../reference/guc/parameter_definitions.html#max_prepared_transactions)**
- **[max\_stack\_depth](../../reference/guc/parameter_definitions.html#max_stack_depth)**
- **[optimizer](../../reference/guc/parameter_definitions.html#optimizer)**
- **[optimizer\_analyze\_root\_partition](../../reference/guc/parameter_definitions.html#optimizer_analyze_root_partition)**
- **[optimizer\_minidump](../../reference/guc/parameter_definitions.html#optimizer_minidump)**
- **[optimizer\_parts\_to\_force\_sort\_on\_insert](../../reference/guc/parameter_definitions.html#optimizer_parts_to_force_sort_on_insert)**
- **[optimizer\_prefer\_scalar\_dqa\_multistage\_agg](../../reference/guc/parameter_definitions.html#optimizer_prefer_scalar_dqa_multistage_agg)**
- **[password\_encryption](../../reference/guc/parameter_definitions.html#password_encryption)**
- **[password\_hash\_algorithm](../../reference/guc/parameter_definitions.html#password_hash_algorithm)**
- **[pgstat\_track\_activity\_query\_size](../../reference/guc/parameter_definitions.html#pgstat_track_activity_query_size)**
- **[pljava\_classpath](../../reference/guc/parameter_definitions.html#pljava_classpath)**
- **[pljava\_release\_lingering\_savepoints](../../reference/guc/parameter_definitions.html#pljava_release_lingering_savepoints)**
- **[pljava\_statement\_cache\_size](../../reference/guc/parameter_definitions.html#pljava_statement_cache_size)**
- **[pljava\_vmoptions](../../reference/guc/parameter_definitions.html#pljava_vmoptions)**
- **[port](../../reference/guc/parameter_definitions.html#port)**
- **[pxf\_enable\_filter\_pushdown](../../reference/guc/parameter_definitions.html#pxf_enable_filter_pushdown)**
- **[pxf\_enable\_stat\_collection](../../reference/guc/parameter_definitions.html#pxf_enable_stat_collection)**
- **[pxf\_remote\_service\_login](../../reference/guc/parameter_definitions.html#pxf_remote_service_login)**
- **[pxf\_remote\_service\_secret](../../reference/guc/parameter_definitions.html#pxf_remote_service_secret)**
- **[pxf\_service\_address](../../reference/guc/parameter_definitions.html#pxf_service_address)**
- **[pxf\_service\_port](../../reference/guc/parameter_definitions.html#pxf_service_port)**
- **[pxf\_stat\_max\_fragments](../../reference/guc/parameter_definitions.html#pxf_stat_max_fragments)**
- **[random\_page\_cost](../../reference/guc/parameter_definitions.html#random_page_cost)**
- **[regex\_flavor](../../reference/guc/parameter_definitions.html#regex_flavor)**
- **[runaway\_detector\_activation\_percent](../../reference/guc/parameter_definitions.html#runaway_detector_activation_percent)**
- **[search\_path](../../reference/guc/parameter_definitions.html#search_path)**
- **[seg\_max\_connections](../../reference/guc/parameter_definitions.html#seg_max_connections)**
- **[seq\_page\_cost](../../reference/guc/parameter_definitions.html#seq_page_cost)**
- **[server\_encoding](../../reference/guc/parameter_definitions.html#server_encoding)**
- **[server\_version](../../reference/guc/parameter_definitions.html#server_version)**
- **[server\_version\_num](../../reference/guc/parameter_definitions.html#server_version_num)**
- **[shared\_buffers](../../reference/guc/parameter_definitions.html#shared_buffers)**
- **[shared\_preload\_libraries](../../reference/guc/parameter_definitions.html#shared_preload_libraries)**
- **[ssl](../../reference/guc/parameter_definitions.html#ssl)**
- **[ssl\_ciphers](../../reference/guc/parameter_definitions.html#ssl_ciphers)**
- **[standard\_conforming\_strings](../../reference/guc/parameter_definitions.html#standard_conforming_strings)**
- **[statement\_timeout](../../reference/guc/parameter_definitions.html#statement_timeout)**
- **[superuser\_reserved\_connections](../../reference/guc/parameter_definitions.html#superuser_reserved_connections)**
- **[tcp\_keepalives\_count](../../reference/guc/parameter_definitions.html#tcp_keepalives_count)**
- **[tcp\_keepalives\_idle](../../reference/guc/parameter_definitions.html#tcp_keepalives_idle)**
- **[tcp\_keepalives\_interval](../../reference/guc/parameter_definitions.html#tcp_keepalives_interval)**
- **[temp\_buffers](../../reference/guc/parameter_definitions.html#temp_buffers)**
- **[TimeZone](../../reference/guc/parameter_definitions.html#TimeZone)**
- **[timezone\_abbreviations](../../reference/guc/parameter_definitions.html#timezone_abbreviations)**
- **[track\_activities](../../reference/guc/parameter_definitions.html#track_activities)**
- **[track\_counts](../../reference/guc/parameter_definitions.html#track_counts)**
- **[transaction\_isolation](../../reference/guc/parameter_definitions.html#transaction_isolation)**
- **[transaction\_read\_only](../../reference/guc/parameter_definitions.html#transaction_read_only)**
- **[transform\_null\_equals](../../reference/guc/parameter_definitions.html#transform_null_equals)**
- **[unix\_socket\_directory](../../reference/guc/parameter_definitions.html#unix_socket_directory)**
- **[unix\_socket\_group](../../reference/guc/parameter_definitions.html#unix_socket_group)**
- **[unix\_socket\_permissions](../../reference/guc/parameter_definitions.html#unix_socket_permissions)**
- **[update\_process\_title](../../reference/guc/parameter_definitions.html#update_process_title)**
- **[vacuum\_cost\_delay](../../reference/guc/parameter_definitions.html#vacuum_cost_delay)**
- **[vacuum\_cost\_limit](../../reference/guc/parameter_definitions.html#vacuum_cost_limit)**
- **[vacuum\_cost\_page\_dirty](../../reference/guc/parameter_definitions.html#vacuum_cost_page_dirty)**
- **[vacuum\_cost\_page\_miss](../../reference/guc/parameter_definitions.html#vacuum_cost_page_miss)**
- **[vacuum\_freeze\_min\_age](../../reference/guc/parameter_definitions.html#vacuum_freeze_min_age)**
- **[xid\_stop\_limit](../../reference/guc/parameter_definitions.html#xid_stop_limit)**
## <a name="add_missing_from"></a>add\_missing\_from
Automatically adds missing table references to FROM clauses. Present for compatibility with releases of PostgreSQL prior to 8.1, where this behavior was allowed by default.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="application_name"></a>application\_name
Sets the application name for a client session. For example, if connecting via `psql`, this will be set to `psql`. Setting an application name allows it to be reported in log messages and statistics views.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| string | | master, session, reload |
## <a name="array_nulls"></a>array\_nulls
This controls whether the array input parser recognizes unquoted NULL as specifying a null array element. By default, this is on, allowing array values containing null values to be entered.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="authentication_timeout"></a>authentication\_timeout
Maximum time to complete client authentication. This prevents hung clients from occupying a connection indefinitely.
| Value Range | Default | Set Classifications |
|---------------------------------------------|---------|------------------------|
| Any valid time expression (number and unit) | 1min | local, system, restart |
## <a name="backslash_quote"></a>backslash\_quote
This controls whether a quote mark can be represented by `\'` in a string literal. The preferred, SQL-standard way to represent a quote mark is by doubling it (`''`) but PostgreSQL has historically also accepted `\'`. However, use of `\'` creates security risks because in some client character set encodings, there are multibyte characters in which the last byte is numerically equivalent to ASCII `\`.
<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th>Value Range</th>
<th>Default</th>
<th>Set Classifications</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td>on (allow <code class="ph codeph">\'</code> always)
<p>off (reject always)</p>
<p>safe_encoding (allow only if client encoding does not allow ASCII <code class="ph codeph">\</code> within a multibyte character)</p></td>
<td>safe_encoding</td>
<td>master, session, reload</td>
</tr>
</tbody>
</table>
## <a name="block_size"></a>block\_size
Reports the size of a disk block.
| Value Range | Default | Set Classifications |
|-----------------|---------|---------------------|
| number of bytes | 32768 | read only |
## <a name="bonjour_name"></a>bonjour\_name
Specifies the Bonjour broadcast name. By default, the computer name is used, specified as an empty string. This option is ignored if the server was not compiled with Bonjour support.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| string | unset | master, system, restart |
## <a name="check_function_bodies"></a>check\_function\_bodies
When set to off, disables validation of the function body string during `CREATE FUNCTION`. Disabling validation is occasionally useful to avoid problems such as forward references when restoring function definitions from a dump.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="client_encoding"></a>client\_encoding
Sets the client-side encoding (character set). The default is to use the same as the database encoding. See [Supported Character Sets](http://www.postgresql.org/docs/8.1/static/multibyte.html#MULTIBYTE-CHARSET-SUPPORTED) in the PostgreSQL documentation.
| Value Range | Default | Set Classifications |
|---------------|---------|-------------------------|
| character set | UTF8 | master, session, reload |
## <a name="client_min_messages"></a>client\_min\_messages
Controls which message levels are sent to the client. Each level includes all the levels that follow it. The later the level, the fewer messages are sent.
<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th>Value Range</th>
<th>Default</th>
<th>Set Classifications</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td>DEBUG5
<p>DEBUG4</p>
<p>DEBUG3</p>
<p>DEBUG2</p>
<p>DEBUG1</p>
<p>LOG NOTICE</p>
<p>WARNING</p>
<p>ERROR</p>
<p>FATAL</p>
<p>PANIC</p></td>
<td>NOTICE</td>
<td>master, session, reload</td>
</tr>
</tbody>
</table>
## <a name="cpu_index_tuple_cost"></a>cpu\_index\_tuple\_cost
For the legacy query optimizer (planner), sets the estimate of the cost of processing each index row during an index scan. This is measured as a fraction of the cost of a sequential page fetch.
| Value Range | Default | Set Classifications |
|----------------|---------|-------------------------|
| floating point | 0.005 | master, session, reload |
## <a name="cpu_operator_cost"></a>cpu\_operator\_cost
For the legacy query optimizer (planner), sets the estimate of the cost of processing each operator in a WHERE clause. This is measured as a fraction of the cost of a sequential page fetch.
| Value Range | Default | Set Classifications |
|----------------|---------|-------------------------|
| floating point | 0.0025 | master, session, reload |
## <a name="cpu_tuple_cost"></a>cpu\_tuple\_cost
For the legacy query optimizer (planner), Sets the estimate of the cost of processing each row during a query. This is measured as a fraction of the cost of a sequential page fetch.
| Value Range | Default | Set Classifications |
|----------------|---------|-------------------------|
| floating point | 0.01 | master, session, reload |
## <a name="cursor_tuple_fraction"></a>cursor\_tuple\_fraction
Tells the legacy query optimizer (planner) how many rows are expected to be fetched in a cursor query, thereby allowing the legacy optimizer to use this information to optimize the query plan. The default of 1 means all rows will be fetched.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| integer | 1 | master, session, reload |
## <a name="custom_variable_classes"></a>custom\_variable\_classes
Specifies one or several class names to be used for custom variables. A custom variable is a variable not normally known to the server but used by some add-on modules. Such variables must have names consisting of a class name, a dot, and a variable name.
| Value Range | Default | Set Classifications |
|-------------------------------------|---------|------------------------|
| comma-separated list of class names | unset | local, system, restart |
## <a name="DateStyle"></a>DateStyle
Sets the display format for date and time values, as well as the rules for interpreting ambiguous date input values. This variable contains two independent components: the output format specification and the input/output specification for year/month/day ordering.
<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th>Value Range</th>
<th>Default</th>
<th>Set Classifications</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td><format>, <date style>
<p>where:</p>
<p><format> is ISO, Postgres, SQL, or German</p>
<p><date style> is DMY, MDY, or YMD</p></td>
<td>ISO, MDY</td>
<td>master, session, reload</td>
</tr>
</tbody>
</table>
## <a name="db_user_namespace"></a>db\_user\_namespace
This enables per-database user names. If on, you should create users as *username@dbname*. To create ordinary global users, simply append @ when specifying the user name in the client.
| Value Range | Default | Set Classifications |
|-------------|---------|------------------------|
| Boolean | off | local, system, restart |
## <a name="deadlock_timeout"></a>deadlock\_timeout
The time, in milliseconds, to wait on a lock before checking to see if there is a deadlock condition. On a heavily loaded server you might want to raise this value. Ideally the setting should exceed your typical transaction time, so as to improve the odds that a lock will be released before the waiter decides to check for deadlock.
| Value Range | Default | Set Classifications |
|------------------------|---------|------------------------|
| integer (milliseconds) | 1000 | local, system, restart |
## <a name="debug_assertions"></a>debug\_assertions
Turns on various assertion checks.
| Value Range | Default | Set Classifications |
|-------------|---------|------------------------|
| Boolean | off | local, system, restart |
## <a name="debug_pretty_print"></a>debug\_pretty\_print
Indents debug output to produce a more readable but much longer output format. *client\_min\_messages* or *log\_min\_messages* must be DEBUG1 or lower.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="debug_print_parse"></a>debug\_print\_parse
For each executed query, prints the resulting parse tree. *client\_min\_messages* or *log\_min\_messages* must be DEBUG1 or lower.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="debug_print_plan"></a>debug\_print\_plan
For each executed query, prints the HAWQ parallel query execution plan. *client\_min\_messages* or *log\_min\_messages* must be DEBUG1 or lower.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="debug_print_prelim_plan"></a>debug\_print\_prelim\_plan
For each executed query, prints the preliminary query plan. *client\_min\_messages* or *log\_min\_messages* must be DEBUG1 or lower.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="debug_print_rewritten"></a>debug\_print\_rewritten
For each executed query, prints the query rewriter output. *client\_min\_messages* or *log\_min\_messages* must be DEBUG1 or lower.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="debug_print_slice_table"></a>debug\_print\_slice\_table
For each executed query, prints the HAWQ query slice plan. *client\_min\_messages* or *log\_min\_messages* must be DEBUG1 or lower.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="topic_fqj_4fd_kv"></a>default\_hash\_table\_bucket\_number
The default number of hash buckets to use when executing a query statement on a hash table. Due to dynamic allocation, when the query is actually executed, the number of virtual segments may differ from this number depending on the query's needs. The total number of segments should never exceed the maximum set in `hawq_rm_nvseg_perquery_limit`.
When expanding the cluster, you should adjust this number to reflect the number of nodes in the new cluster times the number of virtual segments per node. See [Expanding a Cluster](../../admin/ClusterExpansion.html) and [Creating and Managing Tables](../../ddl/ddl-table.html) for more details on modifying this parameter.
| Value Range | Default | Set Classifications |
|----------------|-----------------|-------------------------|
| integer > 0 | 6\*SegmentCount | master, session, reload |
## <a name="default_statement_mem"></a>default\_statement\_mem
The default amount of memory, in KB, to allocate to query statements that do not require any segment resources and are executed only on the master host. This type of query execution is rare in HAWQ.
The default value of this configuration parameter is acceptable for most deployments. Modify this value only if you are using an advanced configuration.
| Value Range | Default | Set Classifications |
|----------------|-----------------|-------------------------|
| integer > 1000 |128000 | master, session, reload |
## <a name="default_statistics_target"></a>default\_statistics\_target
Sets the default statistics target for table columns that have not had a column-specific target set via `ALTER TABLE SET STATISTICS`. Larger values increase the time needed to do `ANALYZE`, but may improve the quality of the legacy query optimizer (planner) estimates.
| Value Range | Default | Set Classifications |
|----------------|---------|-------------------------|
| integer > 0 | 25 | master, session, reload |
## <a name="default_tablespace"></a>default\_tablespace
The default tablespace in which to create objects (tables and indexes) when a `CREATE` command does not explicitly specify a tablespace.
| Value Range | Default | Set Classifications |
|----------------------|---------|-------------------------|
| name of a tablespace | unset | master, session, reload |
## <a name="default_transaction_isolation"></a>default\_transaction\_isolation
Controls the default isolation level of each new transaction.
<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th>Value Range</th>
<th>Default</th>
<th>Set Classifications</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td>read committed
<p>read uncommitted</p>
<p>repeatable read</p>
<p>serializable</p></td>
<td>read committed</td>
<td>master, session, reload</td>
</tr>
</tbody>
</table>
## <a name="default_transaction_read_only"></a>default\_transaction\_read\_only
Controls the default read-only status of each new transaction. A read-only SQL transaction cannot alter non-temporary tables.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="dfs_url"></a>dfs\_url
See [hawq\_dfs\_url](#hawq_dfs_url).
## <a name="dynamic_library_path"></a>dynamic\_library\_path
If a dynamically loadable module needs to be opened and the file name specified in the `CREATE FUNCTION` or `LOAD` command does not have a directory component (i.e. the name does not contain a slash), the system will search this path for the required file. The compiled-in PostgreSQL package library directory is substituted for $libdir. This is where the modules provided by the standard PostgreSQL distribution are installed.
| Value Range | Default | Set Classifications |
|--------------------------------------------------------|---------|-------------------------|
| a list of absolute directory paths separated by colons | $libdir | master, session, reload |
## <a name="effective_cache_size"></a>effective\_cache\_size
Sets the assumption about the effective size of the disk cache that is available to a single query for the legacy query optimizer (planner). This is factored into estimates of the cost of using an index; a higher value makes it more likely index scans will be used, a lower value makes it more likely sequential scans will be used. This parameter has no effect on the size of shared memory allocated by a HAWQ server instance, nor does it reserve kernel disk cache; it is used only for estimation purposes.
| Value Range | Default | Set Classifications |
|----------------|---------|-------------------------|
| floating point | 512MB | master, session, reload |
## <a name="enable_bitmapscan"></a>enable\_bitmapscan
Enables or disables the use of bitmap-scan plan types by the legacy query optimizer (planner). Note that this is different than a Bitmap Index Scan. A Bitmap Scan means that indexes will be dynamically converted to bitmaps in memory when appropriate, giving faster index performance on complex queries against very large tables. It is used when there are multiple predicates on different indexed columns. Each bitmap per column can be compared to create a final list of selected tuples.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="enable_groupagg"></a>enable\_groupagg
Enables or disables the use of group aggregation plan types by the legacy query optimizer (planner).
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="enable_hashagg"></a>enable\_hashagg
Enables or disables the use of hash aggregation plan types by the legacy query optimizer (planner).
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="enable_hashjoin"></a>enable\_hashjoin
Enables or disables the use of hash-join plan types by the legacy query optimizer (planner).
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="enable_indexscan"></a>enable\_indexscan
Enables or disables the use of index-scan plan types by the legacy query optimizer (planner).
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="enable_mergejoin"></a>enable\_mergejoin
Enables or disables the use of merge-join plan types by the legacy query optimizer (planner). Merge join is based on the idea of sorting the left- and right-hand tables into order and then scanning them in parallel. So, both data types must be capable of being fully ordered, and the join operator must be one that can only succeed for pairs of values that fall at the 'same place' in the sort order. In practice this means that the join operator must behave like equality.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="enable_nestloop"></a>enable\_nestloop
Enables or disables the use of nested-loop join plans by the legacy query optimizer (planner). It's not possible to suppress nested-loop joins entirely, but turning this variable off discourages the legacy optimizer from using one if there are other methods available.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, session, reload |
## <a name="enable_secure_filesystem"></a>enable\_secure\_filesystem
Enables or disables access to a secure HDFS file system. To enable Kerberos security for HDFS, set this configuration parameter to `on` before starting HAWQ.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | off | master, system, superuser |
## <a name="enable_seqscan"></a>enable\_seqscan
Enables or disables the use of sequential scan plan types by the legacy query optimizer (planner). It's not possible to suppress sequential scans entirely, but turning this variable off discourages the legacy optimizer from using one if there are other methods available.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="enable_sort"></a>enable\_sort
Enables or disables the use of explicit sort steps by the legacy query optimizer (planner). It's not possible to suppress explicit sorts entirely, but turning this variable off discourages the legacy optimizer from using one if there are other methods available.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="enable_tidscan"></a>enable\_tidscan
Enables or disables the use of tuple identifier (TID) scan plan types by the legacy query optimizer (planner).
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |
## <a name="escape_string_warning"></a>escape\_string\_warning
When on, a warning is issued if a backslash (\\) appears in an ordinary string literal ('...' syntax). Escape string syntax (E'...') should be used for escapes, because in future versions, ordinary strings will have the SQL standard-conforming behavior of treating backslashes literally.
| Value Range | Default | Set Classifications |
|-------------|---------|-------------------------|
| Boolean | on | master, session, reload |