[18/51] [partial] incubator-hawq-docs git commit: HAWQ-1254 Fix/remove book branching on incubator-hawq-docs

[yozie]

http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/blob/de1e2e07/markdown/reference/guc/parameter_definitions.html.md.erb
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diff --git a/markdown/reference/guc/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>&lt;format&gt;, &lt;date style&gt;
+<p>where:</p>
+<p>&lt;format&gt; is ISO, Postgres, SQL, or German</p>
+<p>&lt;date style&gt; 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 &gt; 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 &gt; 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 &gt; 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 |
+
+
+## <a name="explain_memory_verbosity"></a>explain\_memory\_verbosity
+Controls the granularity of memory information displayed in `EXPLAIN ANALYZE` 
output.  `explain_memory_verbosity` takes three values:
+
+* SUPPRESS - generate only total memory information for the whole query
+* SUMMARY - generate basic memory information for each executor node
+* DETAIL - generate detailed memory information for each executor node
+
+<table>
+<colgroup>
+<col width="33%" />
+<col width="33%" />
+<col width="34%" />
+</colgroup>
+<thead>
+<tr class="header">
+<th>Value Range</th>
+<th>Default</th>
+<th>Set Classifications</th>
+</tr>
+</thead>
+<tbody>
+<tr class="odd">
+<td>SUPPRESS</p>
+<p>SUMMARY</p>
+<p>DETAIL</p></td>
+<td>SUPPRESS</td>
+<td>master</td>
+</tr>
+</tbody>
+</table>
+
+
+## <a name="explain_pretty_print"></a>explain\_pretty\_print
+
+Determines whether EXPLAIN VERBOSE uses the indented or non-indented format 
for displaying detailed query-tree dumps.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="extra_float_digits"></a>extra\_float\_digits
+
+Adjusts the number of digits displayed for floating-point values, including 
float4, float8, and geometric data types. The parameter value is added to the 
standard number of digits. The value can be set as high as 2, to include 
partially-significant digits; this is especially useful for dumping float data 
that needs to be restored exactly. Or it can be set negative to suppress 
unwanted digits.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 0       | master, session, reload |
+
+## <a name="from_collapse_limit"></a>from\_collapse\_limit
+
+The legacy query optimizer (planner) will merge sub-queries into upper queries 
if the resulting FROM list would have no more than this many items. Smaller 
values reduce planning time but may yield inferior query plans.
+
+| Value Range     | Default | Set Classifications     |
+|-----------------|---------|-------------------------|
+| integer (1-*n*) | 20      | master, session, reload |
+
+## <a 
name="gp_adjust_selectivity_for_outerjoins"></a>gp\_adjust\_selectivity\_for\_outerjoins
+
+Enables the selectivity of NULL tests over outer joins.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_analyze_relative_error"></a>gp\_analyze\_relative\_error
+
+Sets the estimated acceptable error in the cardinality of the table " a value 
of 0.5 is supposed to be equivalent to an acceptable error of 50% (this is the 
default value used in PostgreSQL). If the statistics collected during `ANALYZE` 
are not producing good estimates of cardinality for a particular table 
attribute, decreasing the relative error fraction (accepting less error) tells 
the system to sample more rows.
+
+| Value Range             | Default | Set Classifications     |
+|-------------------------|---------|-------------------------|
+| floating point &lt; 1.0 | 0.25    | master, session, reload |
+
+## <a name="gp_autostats_mode"></a>gp\_autostats\_mode
+
+Specifies the mode for triggering automatic statistics collection with 
`ANALYZE`. The `on_no_stats` option triggers statistics collection for `CREATE 
TABLE AS SELECT`, `INSERT`, or `COPY` operations on any table that has no 
existing statistics.
+
+**Warning:** Depending on the specific nature of your database operations, 
automatic statistics collection can have a negative performance impact. 
Carefully evaluate whether the default value of `on_no_stats` is appropriate 
for your system.
+
+The `on_change` option triggers statistics collection only when the number of 
rows affected exceeds the threshold defined by 
`gp_autostats_on_change_threshold`. Operations that can trigger automatic 
statistics collection with `on_change` are:
+
+`CREATE TABLE AS SELECT`
+
+`INSERT`
+
+`COPY`
+
+Default is `on_no_stats`.
+
+**Note:** For partitioned tables, automatic statistics collection is not 
triggered if data is inserted from the top-level parent table of a partitioned 
table.
+Automatic statistics collection is triggered if data is inserted directly in a 
leaf table (where the data is stored) of the partitioned table. Statistics are 
collected only on the leaf table.
+
+<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>none
+<p>on_change</p>
+<p>on_no_stats</p></td>
+<td>on_no_ stats</td>
+<td>master, session, reload</td>
+</tr>
+</tbody>
+</table>
+
+## <a name="topic_imj_zhf_gw"></a>gp\_autostats\_on\_change\_threshold
+
+Specifies the threshold for automatic statistics collection when 
`gp_autostats_mode` is set to `on_change`. When a triggering table operation 
affects a number of rows exceeding this threshold, `ANALYZE         `is added 
and statistics are collected for the table.
+
+| Value Range | Default    | Set Classifications     |
+|-------------|------------|-------------------------|
+| integer     | 2147483647 | master, session, reload |
+
+## <a name="gp_backup_directIO"></a>gp\_backup\_directIO
+
+Direct I/O allows HAWQ to bypass the buffering of memory within the file 
system cache for backup. When Direct I/O is used for a file, data is 
transferred directly from the disk to the application buffer, without the use 
of the file buffer cache.
+
+Direct I/O is supported only on Red Hat Enterprise Linux, CentOS, and SUSE.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| on, off     | off     | master, session, reload |
+
+## <a 
name="gp_backup_directIO_read_chunk_mb"></a>gp\_backup\_directIO\_read\_chunk\_mb
+
+Sets the chunk size in MB when Direct I/O is enabled with 
[gp\_backup\_directIO](#gp_backup_directIO). The default chunk size is 20MB.
+
+The default value is the optimal setting. Decreasing it will increase the 
backup time and increasing it will result in little change to backup time.
+
+| Value Range | Default | Set Classifications    |
+|-------------|---------|------------------------|
+| 1-200       | 20 MB   | local, session, reload |
+
+## <a 
name="gp_cached_segworkers_threshold"></a>gp\_cached\_segworkers\_threshold
+
+When a user starts a session with HAWQ and issues a query, the system creates 
groups or 'gangs' of worker processes on each segment to do the work. After the 
work is done, the segment worker processes are destroyed except for a cached 
number which is set by this parameter. A lower setting conserves system 
resources on the segment hosts, but a higher setting may improve performance 
for power-users that want to issue many complex queries in a row.
+
+| Value Range    | Default | Set Classifications     |
+|----------------|---------|-------------------------|
+| integer &gt; 0 | 5       | master, session, reload |
+
+## <a name="gp_command_count"></a>gp\_command\_count
+
+Shows how many commands the master has received from the client. Note that a 
single SQL command might actually involve more than one command internally, so 
the counter may increment by more than one for a single query. This counter 
also is shared by all of the segment processes working on the command.
+
+| Value Range    | Default | Set Classifications |
+|----------------|---------|---------------------|
+| integer &gt; 0 | 1       | read only           |
+
+## <a name="gp_connections_per_thread"></a>gp\_connections\_per\_thread
+
+A value larger than or equal to the number of segments means that each slice 
in a query plan will get its own thread when dispatching to the segments. A 
value of 0 indicates that the dispatcher should use a single thread when 
dispatching all query plan slices to a segment. Lower values will use more 
threads, which utilizes more resources on the master. Typically, the default 
does not need to be changed unless there is a known throughput performance 
problem.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 64      | master, session, reload |
+
+## <a name="gp_debug_linger"></a>gp\_debug\_linger
+
+Number of seconds for a HAWQ process to linger after a fatal internal error.
+
+| Value Range                                 | Default | Set Classifications  
   |
+|---------------------------------------------|---------|-------------------------|
+| Any valid time expression (number and unit) | 0       | master, session, 
reload |
+
+## <a name="gp_dynamic_partition_pruning"></a>gp\_dynamic\_partition\_pruning
+
+Enables plans that can dynamically eliminate the scanning of partitions.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| on/off      | on      | master, session, reload |
+
+## <a name="gp_enable_agg_distinct"></a>gp\_enable\_agg\_distinct
+
+Enables or disables two-phase aggregation to compute a single 
distinct-qualified aggregate. This applies only to subqueries that include a 
single distinct-qualified aggregate function.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a 
name="gp_enable_agg_distinct_pruning"></a>gp\_enable\_agg\_distinct\_pruning
+
+Enables or disables three-phase aggregation and join to compute 
distinct-qualified aggregates. This applies only to subqueries that include one 
or more distinct-qualified aggregate functions.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_enable_direct_dispatch"></a>gp\_enable\_direct\_dispatch
+
+Enables or disables the dispatching of targeted query plans for queries that 
access data on a single segment. When on, queries that target rows on a single 
segment will only have their query plan dispatched to that segment (rather than 
to all segments). This significantly reduces the response time of qualifying 
queries as there is no interconnect setup involved. Direct dispatch does 
require more CPU utilization on the master.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, system, restart |
+
+## <a name="gp_enable_fallback_plan"></a>gp\_enable\_fallback\_plan
+
+Allows use of disabled plan types when a query would not be feasible without 
them.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_enable_fast_sri"></a>gp\_enable\_fast\_sri
+
+When set to `on`, the legacy query optimizer (planner) plans single row 
inserts so that they are sent directly to the correct segment instance (no 
motion operation required). This significantly improves performance of 
single-row-insert statements.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a 
name="gp_enable_groupext_distinct_gather"></a>gp\_enable\_groupext\_distinct\_gather
+
+Enables or disables gathering data to a single node to compute 
distinct-qualified aggregates on grouping extension queries. When this 
parameter and `gp_enable_groupext_distinct_pruning` are both enabled, the 
legacy query optimizer (planner) uses the cheaper plan.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a 
name="gp_enable_groupext_distinct_pruning"></a>gp\_enable\_groupext\_distinct\_pruning
+
+Enables or disables three-phase aggregation and join to compute 
distinct-qualified aggregates on grouping extension queries. Usually, enabling 
this parameter generates a cheaper query plan that the legacy query optimizer 
(planner) will use in preference to existing plan.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_enable_multiphase_agg"></a>gp\_enable\_multiphase\_agg
+
+Enables or disables the use of two or three-stage parallel aggregation plans 
legacy query optimizer (planner). This approach applies to any subquery with 
aggregation. If `gp_enable_multiphase_agg` is off, then`           
gp_enable_agg_distinct` and `gp_enable_agg_distinct_pruning` are disabled.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a 
name="gp_enable_predicate_propagation"></a>gp\_enable\_predicate\_propagation
+
+When enabled, the legacy query optimizer (planner) applies query predicates to 
both table expressions in cases where the tables are joined on their 
distribution key column(s). Filtering both tables prior to doing the join (when 
possible) is more efficient.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_enable_preunique"></a>gp\_enable\_preunique
+
+Enables two-phase duplicate removal for `SELECT DISTINCT` queries (not `SELECT 
COUNT(DISTINCT)`). When enabled, it adds an extra `SORT           DISTINCT` set 
of plan nodes before motioning. In cases where the distinct operation greatly 
reduces the number of rows, this extra `SORT DISTINCT` is much cheaper than the 
cost of sending the rows across the Interconnect.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a 
name="gp_enable_sequential_window_plans"></a>gp\_enable\_sequential\_window\_plans
+
+If on, enables non-parallel (sequential) query plans for queries containing 
window function calls. If off, evaluates compatible window functions in 
parallel and rejoins the results. This is an experimental parameter.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_enable_sort_distinct"></a>gp\_enable\_sort\_distinct
+
+Enable duplicates to be removed while sorting.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_enable_sort_limit"></a>gp\_enable\_sort\_limit
+
+Enable `LIMIT` operation to be performed while sorting. Sorts more efficiently 
when the plan requires the first *limit\_number* of rows at most.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_external_enable_exec"></a>gp\_external\_enable\_exec
+
+Enables or disables the use of external tables that execute OS commands or 
scripts on the segment hosts (`CREATE EXTERNAL TABLE EXECUTE` syntax).
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, system, restart |
+
+## <a name="gp_external_grant_privileges"></a>gp\_external\_grant\_privileges
+
+Enables or disables non-superusers to issue a `CREATE EXTERNAL [WEB] TABLE` 
command in cases where the `LOCATION` clause specifies specifies `http` or 
`gpfdist`. The ability to create an external table can be granted to a role 
using `CREATE ROLE` or `ALTER         ROLE`.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | off     | master, system, restart |
+
+## <a name="gp_external_max_segs"></a>gp\_external\_max\_segs
+
+Sets the number of segments that will scan external table data during an 
external table operation, the purpose being not to overload the system with 
scanning data and take away resources from other concurrent operations. This 
only applies to external tables that use the `gpfdist://` protocol to access 
external table data.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 64      | master, session, reload |
+
+## <a 
name="gp_filerep_tcp_keepalives_count"></a>gp\_filerep\_tcp\_keepalives\_count
+
+How many keepalives may be lost before the connection is considered dead. A 
value of 0 uses the system default. If TCP\_KEEPCNT is not supported, this 
parameter must be 0.
+
+| Value Range               | Default | Set Classifications    |
+|---------------------------|---------|------------------------|
+| number of lost keepalives | 2       | local, system, restart |
+
+## <a 
name="gp_filerep_tcp_keepalives_idle"></a>gp\_filerep\_tcp\_keepalives\_idle
+
+Number of seconds between sending keepalives on an otherwise idle connection. 
A value of 0 uses the system default. If TCP\_KEEPIDLE is not supported, this 
parameter must be 0.
+
+| Value Range       | Default | Set Classifications    |
+|-------------------|---------|------------------------|
+| number of seconds | 1 min   | local, system, restart |
+
+## <a 
name="gp_filerep_tcp_keepalives_interval"></a>gp\_filerep\_tcp\_keepalives\_interval
+
+How many seconds to wait for a response to a keepalive before retransmitting. 
A value of 0 uses the system default. If TCP\_KEEPINTVL is not supported, this 
parameter must be 0.
+
+| Value Range       | Default | Set Classifications    |
+|-------------------|---------|------------------------|
+| number of seconds | 30 sec  | local, system, restart |
+
+## <a 
name="gp_hashjoin_tuples_per_bucket"></a>gp\_hashjoin\_tuples\_per\_bucket
+
+Sets the target density of the hash table used by HashJoin operations. A 
smaller value will tend to produce larger hash tables, which can increase join 
performance.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 5       | master, session, reload |
+
+## <a name="gp_idf_deduplicate"></a>gp\_idf\_deduplicate
+
+Changes the strategy to compute and process MEDIAN, and PERCENTILE\_DISC.
+
+<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>auto
+<p>none</p>
+<p>force</p></td>
+<td>auto</td>
+<td>master, session, reload</td>
+</tr>
+</tbody>
+</table>
+
+## <a name="gp_interconnect_fc_method"></a>gp\_interconnect\_fc\_method
+
+Specifies the flow control method used for UDP interconnect when the value of 
[gp\_interconnect\_type](#gp_interconnect_type) is UDPIFC.
+
+For capacity based flow control, senders do not send packets when receivers do 
not have the capacity.
+
+Loss based flow control is based on capacity based flow control, and also 
tunes the sending speed according to packet losses.
+
+<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>CAPACITY
+<p>LOSS</p></td>
+<td>LOSS</td>
+<td>master, session, reload</td>
+</tr>
+</tbody>
+</table>
+
+## <a 
name="gp_interconnect_hash_multiplier"></a>gp\_interconnect\_hash\_multiplier
+
+Sets the size of the hash table used by the UDP interconnect to track 
connections. This number is multiplied by the number of segments to determine 
the number of buckets in the hash table. Increasing the value may increase 
interconnect performance for complex multi-slice queries (while consuming 
slightly more memory on the segment hosts).
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| 2-25        | 2       | master, session, reload |
+
+## <a name="gp_interconnect_queue_depth"></a>gp\_interconnect\_queue\_depth
+
+Sets the amount of data per-peer to be queued by the UDP interconnect on 
receivers (when data is received but no space is available to receive it the 
data will be dropped, and the transmitter will need to resend it). Increasing 
the depth from its default value will cause the system to use more memory; but 
may increase performance. It is reasonable for this to be set between 1 and 10. 
Queries with data skew potentially perform better when this is increased. 
Increasing this may radically increase the amount of memory used by the system.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| 1-2048      | 4       | master, session, reload |
+
+## <a name="gp_interconnect_setup_timeout"></a>gp\_interconnect\_setup\_timeout
+
+When the interconnect type is UDP, the time to wait for the Interconnect to 
complete setup before it times out.
+
+This parameter is used only when 
[gp\_interconnect\_type](#gp_interconnect_type) is set to UDP.
+
+| Value Range                                 | Default | Set Classifications  
   |
+|---------------------------------------------|---------|-------------------------|
+| Any valid time expression (number and unit) | 2 hours | master, session, 
reload |
+
+## <a 
name="gp_interconnect_snd_queue_depth"></a>gp\_interconnect\_snd\_queue\_depth
+
+Sets the amount of data per-peer to be queued by the UDP interconnect on 
senders. Increasing the depth from its default value will cause the system to 
use more memory; but may increase performance. Reasonable values for this 
parameter are between 1 and 4. Increasing the value might radically increase 
the amount of memory used by the system.
+
+This parameter is used only when 
[gp\_interconnect\_type](#gp_interconnect_type) is set to UDPIFC.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| 1 - 4096    | 2       | master, session, reload |
+
+## <a name="gp_interconnect_type"></a>gp\_interconnect\_type
+
+Sets the networking protocol used for Interconnect traffic. With the TCP 
protocol, HAWQ has an upper limit of 1000 segment instances - less than that if 
the query workload involves complex, multi-slice queries.
+
+UDP allows for greater interconnect scalability. Note that the HAWQ software 
does the additional packet verification and checking not performed by UDP, so 
reliability and performance is equivalent to TCP.
+
+UDPIFC specifies using UDP with flow control for interconnect traffic. Specify 
the interconnect flow control method with 
[gp\_interconnect\_fc\_method](#gp_interconnect_fc_method).
+
+<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>TCP
+<p>UDP</p>
+<p>UDPIFC</p></td>
+<td>UDPIFC</td>
+<td>local, system, restart</td>
+</tr>
+</tbody>
+</table>
+
+## <a name="gp_log_format"></a>gp\_log\_format
+
+Specifies the format of the server log files. If using *hawq\_toolkit* 
administrative schema, the log files must be in CSV format.
+
+<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>csv
+<p>text</p></td>
+<td>csv</td>
+<td>local, system, restart</td>
+</tr>
+</tbody>
+</table>
+
+## <a name="gp_max_csv_line_length"></a>gp\_max\_csv\_line\_length
+
+The maximum length of a line in a CSV formatted file that will be imported 
into the system. The default is 1MB (1048576 bytes). Maximum allowed is 4MB 
(4194184 bytes). The default may need to be increased if using the 
*hawq\_toolkit* administrative schema to read HAWQ log files.
+
+| Value Range     | Default | Set Classifications    |
+|-----------------|---------|------------------------|
+| number of bytes | 1048576 | local, system, restart |
+
+## <a name="gp_max_databases"></a>gp\_max\_databases
+
+The maximum number of databases allowed in a HAWQ system.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 16      | master, system, restart |
+
+## <a name="gp_max_filespaces"></a>gp\_max\_filespaces
+
+The maximum number of filespaces allowed in a HAWQ system.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 8       | master, system, restart |
+
+## <a name="gp_max_packet_size"></a>gp\_max\_packet\_size
+
+Sets the size (in bytes) of messages sent by the UDP interconnect, and sets 
the tuple-serialization chunk size for both the UDP and TCP interconnect.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| 512-65536   | 8192    | master, system, restart |
+
+## <a name="gp_max_plan_size"></a>gp\_max\_plan\_size
+
+Specifies the total maximum uncompressed size of a query execution plan 
multiplied by the number of Motion operators (slices) in the plan. If the size 
of the query plan exceeds the value, the query is cancelled and an error is 
returned. A value of 0 means that the size of the plan is not monitored.
+
+You can specify a value in KB,MB, or GB. The default unit is KB. For example, 
a value of 200 is 200KB. A value of 1GB is the same as 1024MB or 1048576KB.
+
+| Value Range | Default | Set Classifications        |
+|-------------|---------|----------------------------|
+| integer     | 0       | master, superuser, session |
+
+## <a name="gp_max_tablespaces"></a>gp\_max\_tablespaces
+
+The maximum number of tablespaces allowed in a HAWQ system.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 16      | master, system, restart |
+
+## <a name="gp_motion_cost_per_row"></a>gp\_motion\_cost\_per\_row
+
+Sets the legacy query optimizer (planner) cost estimate for a Motion operator 
to transfer a row from one segment to another, measured as a fraction of the 
cost of a sequential page fetch. If 0, then the value used is two times the 
value of *cpu\_tuple\_cost*.
+
+| Value Range    | Default | Set Classifications     |
+|----------------|---------|-------------------------|
+| floating point | 0       | master, session, reload |
+
+## <a name="gp_reject_percent_threshold"></a>gp\_reject\_percent\_threshold
+
+For single row error handling on COPY and external table SELECTs, sets the 
number of rows processed before SEGMENT REJECT LIMIT *n* PERCENT starts 
calculating.
+
+| Value Range     | Default | Set Classifications     |
+|-----------------|---------|-------------------------|
+| integer (1-*n*) | 300     | master, session, reload |
+
+## <a name="gp_reraise_signal"></a>gp\_reraise\_signal
+
+If enabled, will attempt to dump core if a fatal server error occurs.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_role"></a>gp\_role
+
+The role of this server process " set to *dispatch* for the master and 
*execute* for a segment.
+
+<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>dispatch
+<p>execute</p>
+<p>utility</p></td>
+<td> </td>
+<td>read only</td>
+</tr>
+</tbody>
+</table>
+
+## <a name="gp_safefswritesize"></a>gp\_safefswritesize
+
+Specifies a minimum size for safe write operations to append-only tables in a 
non-mature file system. When a number of bytes greater than zero is specified, 
the append-only writer adds padding data up to that number in order to prevent 
data corruption due to file system errors. Each non-mature file system has a 
known safe write size that must be specified here when using HAWQ with that 
type of file system. This is commonly set to a multiple of the extent size of 
the file system; for example, Linux ext3 is 4096 bytes, so a value of 32768 is 
commonly used.
+
+| Value Range | Default | Set Classifications    |
+|-------------|---------|------------------------|
+| integer     | 0       | local, system, restart |
+
+## <a name="gp_segment_connect_timeout"></a>gp\_segment\_connect\_timeout
+
+Time that the HAWQ interconnect will try to connect to a segment instance over 
the network before timing out. Controls the network connection timeout between 
master and segment replication processes.
+
+| Value Range                                 | Default | Set Classifications  
 |
+|---------------------------------------------|---------|-----------------------|
+| Any valid time expression (number and unit) | 10min   | local, system, 
reload |
+
+## <a name="gp_segments_for_planner"></a>gp\_segments\_for\_planner
+
+Sets the number of segment instances for the legacy query optimizer (planner) 
to assume in its cost and size estimates. If 0, then the value used is the 
actual number of segments. This variable affects the legacy optimizer's 
estimates of the number of rows handled by each sending and receiving process 
in Motion operators.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 0       | master, session, reload |
+
+## <a name="gp_session_id"></a>gp\_session\_id
+
+A system assigned ID number for a client session. Starts counting from 1 when 
the master instance is first started.
+
+| Value Range     | Default | Set Classifications |
+|-----------------|---------|---------------------|
+| integer (1-*n*) | 14      | read only           |
+
+## <a name="gp_set_proc_affinity"></a>gp\_set\_proc\_affinity
+
+If enabled, when a HAWQ server process (postmaster) is started it will bind to 
a CPU.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | off     | master, system, restart |
+
+## <a name="gp_set_read_only"></a>gp\_set\_read\_only
+
+Set to on to disable writes to the database. Any in progress transactions must 
finish before read-only mode takes affect.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | off     | master, session, reload |
+
+## <a 
name="gp_statistics_pullup_from_child_partition"></a>gp\_statistics\_pullup\_from\_child\_partition
+
+Enables the use of statistics from child tables when planning queries on the 
parent table by the legacy query optimizer (planner).
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="gp_statistics_use_fkeys"></a>gp\_statistics\_use\_fkeys
+
+When enabled, allows the legacy query optimizer (planner) to use foreign key 
information stored in the system catalog to optimize joins between foreign keys 
and primary keys.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a 
name="gp_vmem_idle_resource_timeout"></a>gp\_vmem\_idle\_resource\_timeout
+
+Sets the time in milliseconds a session can be idle before gangs on the 
segment databases are released to free up resources.
+
+| Value Range    | Default | Set Classifications     |
+|----------------|---------|-------------------------|
+| number of milliseconds | 18000  | master, system, restart |
+
+
+## <a 
name="gp_vmem_protect_segworker_cache_limit"></a>gp\_vmem\_protect\_segworker\_cache\_limit
+
+If a query executor process consumes more than this configured amount, then 
the process will not be cached for use in subsequent queries after the process 
completes. Systems with lots of connections or idle processes may want to 
reduce this number to free more memory on the segments. Note that this is a 
local parameter and must be set for every segment.
+
+| Value Range         | Default | Set Classifications    |
+|---------------------|---------|------------------------|
+| number of megabytes | 500     | local, system, restart |
+
+## <a name="gp_workfile_checksumming"></a>gp\_workfile\_checksumming
+
+Adds a checksum value to each block of a work file (or spill file) used by 
`HashAgg` and `HashJoin` query operators. This adds an additional safeguard 
from faulty OS disk drivers writing corrupted blocks to disk. When a checksum 
operation fails, the query will cancel and rollback rather than potentially 
writing bad data to disk.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a 
name="gp_workfile_compress_algorithm"></a>gp\_workfile\_compress\_algorithm
+
+When a hash aggregation or hash join operation spills to disk during query 
processing, specifies the compression algorithm to use on the spill files. If 
using zlib, it must be in your $PATH on all segments.
+
+If your HAWQ database installation uses serial ATA (SATA) disk drives, setting 
the value of this parameter to `zlib` might help to avoid overloading the disk 
subsystem with IO operations.
+
+<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>none
+<p>zlib</p></td>
+<td>none</td>
+<td>master, session, reload</td>
+</tr>
+</tbody>
+</table>
+
+## <a 
name="gp_workfile_limit_files_per_query"></a>gp\_workfile\_limit\_files\_per\_query
+
+Sets the maximum number of temporary spill files (also known as workfiles) 
allowed per query per segment. Spill files are created when executing a query 
that requires more memory than it is allocated. The current query is terminated 
when the limit is exceeded.
+
+Set the value to 0 (zero) to allow an unlimited number of spill files. master 
session reload
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 3000000 | master, session, reload |
+
+## <a name="gp_workfile_limit_per_query"></a>gp\_workfile\_limit\_per\_query
+
+Sets the maximum disk size an individual query is allowed to use for creating 
temporary spill files at each segment. The default value is 0, which means a 
limit is not enforced.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| kilobytes   | 0       | master, session, reload |
+
+## <a 
name="gp_workfile_limit_per_segment"></a>gp\_workfile\_limit\_per\_segment
+
+Sets the maximum total disk size that all running queries are allowed to use 
for creating temporary spill files at each segment. The default value is 0, 
which means a limit is not enforced.
+
+| Value Range | Default | Set Classifications    |
+|-------------|---------|------------------------|
+| kilobytes   | 0       | local, system, restart |
+
+## <a name="hawq_dfs_url"></a>hawq\_dfs\_url
+
+URL for HAWQ data directories on HDFS. The directory that you specify must be 
writeable by the `gpadmin` user. For example 'localhost:8020/hawq\_default'. If 
you have high availability enabled for your HDFS NameNodes, then this 
configuration parameter must be set to the service ID you configured in HDFS. 
See "HAWQ Filespaces and High Availability Enabled HDFS" for more information.
+
+| Value Range                                                             | 
Default             | Set Classifications     |
+|-------------------------------------------------------------------------|---------------------|-------------------------|
+| URL in the form of *NameNode\_host name*:*port*/*data\_directory\_name* | 
localhost:8020/hawq | master, session, reload |
+
+## <a name="hawq_global_rm_type"></a>hawq\_global\_rm\_type
+
+HAWQ global resource manager type. Valid values are `yarn` and `none`. Setting 
this parameter to `none` indicates that the HAWQ resource manager will manages 
its own resources. Setting the value to `yarn` means that HAWQ will negotiate 
with YARN for resources.
+
+| Value Range  | Default | Set Classifications     |
+|--------------|---------|-------------------------|
+| yarn or none | none    | master, system, restart |
+
+## <a name="hawq_master_address_host"></a>hawq\_master\_address\_host
+
+Address or hostname of HAWQ master.
+
+| Value Range     | Default   | Set Classifications     |
+|-----------------|-----------|-------------------------|
+| master hostname | localhost | master, session, reload |
+
+## <a name="hawq_master_address_port"></a>hawq\_master\_address\_port
+
+Port of the HAWQ master.
+
+| Value Range       | Default | Set Classifications     |
+|-------------------|---------|-------------------------|
+| valid port number |         | master, session, reload |
+
+## <a name="hawq_master_directory"></a>hawq\_master\_directory
+
+Master server data directory.
+
+| Value Range    | Default | Set Classifications     |
+|----------------|---------|-------------------------|
+| directory name |         | master, session, reload |
+
+## <a name="hawq_master_temp_directory"></a>hawq\_master\_temp\_directory
+
+One or more temporary directories for the HAWQ master. Separate multiple 
entries with commas.
+
+| Value Range                                               | Default | Set 
Classifications     |
+|-----------------------------------------------------------|---------|-------------------------|
+| directory name or comma-separated list of directory names | /tmp    | 
master, session, reload |
+
+## <a 
name="hawq_re_memory_overcommit_max"></a>hawq\_re\_memory\_overcommit\_max
+
+Sets the maximum quota of memory overcommit (in MB) per physical segment for 
resource enforcement. This parameter sets the memory quota that can be 
overcommited beyond the memory quota dynamically assigned by the resource 
manager.
+
+Specify a larger value to prevent out of memory errors in YARN mode.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| integer     | 8192    | master, system, restart |
+
+## <a name="hawq_rm_cluster_report"></a>hawq\_rm\_cluster\_report\_period
+
+Defines the time period, in seconds, for refreshing the global resource 
manager’s cluster report.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| 10-100      | 60      | master, session, reload |
+
+## <a 
name="hawq_rm_force_alterqueue_cancel_queued_request"></a>hawq\_rm\_force\_alterqueue\_cancel\_queued\_request
+
+Instructs HAWQ to cancel by all resource requests that are in conflict with 
the new resource queue definitions supplied in a ALTER RESOURCE QUEUE statement.
+
+If you set this parameter to false, the actions specified in ALTER RESOURCE 
QUEUE are canceled if the resource manager finds at least one resource request 
that is in conflict with the new resource definitions supplied in the altering 
command.
+
+| Value Range | Default | Set Classifications     |
+|-------------|---------|-------------------------|
+| Boolean     | on      | master, session, reload |
+
+## <a name="hawq_rm_master_port"></a>hawq\_rm\_master\_port
+
+HAWQ resource manager master port number.
+
+| Value Range       | Default | Set Classifications     |
+|-------------------|---------|-------------------------|
+| valid port number | 5437    | master, session, reload |
+
+## <a name="hawq_rm_memory_limit_perseg"></a>hawq\_rm\_memory\_limit\_perseg
+
+Limit of memory usage by a HAWQ segment when `hawq_global_rm_type` is set to 
`none`. For example, `8GB`.
+
+| V

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