Server Configuration Changes from Greenplum 5 to 6

This GUC list is copied from an open PR and may be incomplete or contain inaccuracies.

Greenplum 6 includes new server configuration parameters, and removes or updates the default values of certain server configuration parameters as described below.

New Parameters

The following new server configuration parameters are available in Greenplum 6:

  • default_text_search_config selects the text search configuration.
  • default_transaction_deferrable controls the default deferrable status of each new transaction.
  • gp_enable_global_deadlock_detector controls whether the Greenplum Database global deadlock detector is enabled.
  • gp_global_deadlock_detector_period is the timeout period for the Greenplum Database global deadlock detector.
  • gp_use_legacy_hashops controls whether the legacy or default hash functions are used when creating tables that are defined with a distribution column.
  • lock_timeout identifies the amount of time for Greenplum Database to wait to acquire a lock.
  • optimizer_enable_dml controls DML operations executed by GPORCA.
  • temp_tablespaces specifies the tablespace in which Greenplum Database creates temporary objects.

Removed Parameters

The following server configuration parameters are removed in Greenplum 6:

  • add_missing_from
  • custom_variable_classes
  • filerep_mirrorvalidation_during_resync
  • gp_analyze_relative_error
  • gp_backup_directIO
  • gp_backup_directIO_read_chunk_mb
  • gp_cancel_query_delay_time (undocumented)
  • gp_cancel_query_print_log (undocumented)
  • gp_connections_per_thread
  • gp_email_from
  • gp_email_smtp_password
  • gp_email_smtp_server
  • gp_email_smtp_userid
  • gp_email_to
  • gp_enable_fallback_plan
  • gp_enable_sequential_window_plans
  • gp_filerep_tcp_keepalives_count
  • gp_filerep_tcp_keepalives_idle
  • gp_filerep_tcp_keepalives_interval
  • gp_fts_probe_threadcount
  • gp_hadoop_home
  • gp_hadoop_target_version
  • gp_idf_deduplicate
  • gp_interconnect_hash_multiplier
  • gp_max_csv_line_length
  • gp_max_databases
  • gp_max_filespaces
  • gp_max_tablespaces
  • gp_num_contents_in_cluster
  • gp_snmp_community
  • gp_snmp_monitor_address
  • gp_snmp_use_inform_or_trap
  • gp_workfile_checksumming
  • krb_srvname
  • max_fsm_pages
  • max_fsm_relations

Changed Parameters

These server configuration parameters are changed in Greenplum 6:

  • These configuration parameter values are changed from strings to enums:
    • backslash_quote
    • client_min_messages
    • default_transaction_isolation
    • IntervalStyle
    • log_error_verbosity
    • log_min_messages
    • log_statement
  • The debug_pretty_print parameter default value is changed from off to on.
  • The effective_cache_size parameter default value is changed from 16384 pages to 524288 pages.
  • The gp_cached_segworkers_threshold parameter minimum value is changed from 0 to 1.
  • The gp_recursive_cte_prototype configuration parameter name is changed to gp_recursive_cte and deprecated.
  • The gp_workfile_limit_per_query parameter maximum value is changed from SIZE_MAX/1024 to INT_MAX.
  • The gp_workfile_limit_per_segment parameter maximum value is changed from SIZE_MAX/1024 to INT_MAX.
  • The gp_workfile_compress_algorithm configuration parameter name is changed to gp_workfile_compression. This server configuration parameter now enables or disables compression of temporary files. When workfile compression is enabled, Greenplum Database uses Zstandard compression.
  • The default value of the log_rotation_size parameter is changed from 0 to 1GB. This changes the default log rotation behavior so that a new log file is opened when more than 1GB has been written to the current log file, or when the current log file has been open for 24 hours.
  • The optimizer_force_multistage_agg parameter default is changed from true to false. GPORCA will now by default choose between a one-stage or two-stage aggregate plan for a scalar distinct qualified aggregate based on cost.

  • The optimizer_penalize_skew parameter default is changed from false to true. GPORCA will now by default choose between a one-stage or two-stage aggregate plan for a scalar distinct qualified aggregate based on cost.

  • The pgstat_track_activity_query_size configuration parameter name is changed to track_activity_query_size and deprecated.

  • The server_version parameter value is changed from 8.3.23 to 9.4.20.

  • The server_version_num parameter value is changed from 80323 to 90420.

  • When the resource group resource management scheme is enabled and you configure MEMORY_SPILL_RATIO=0 for a resource group, Greenplum Database uses the statement_mem parameter setting to identify the initial amount of query operator memory.

  • The unix_socket_directory configuration parameter name is changed to unix_socket_directories and now references one or more directories where Greenplum Database creates Unix-domain sockets.

  • The bytea representation changed to a hexadecimal format, by default. Use the server parameter bytea_output to select the 5.x output format for backward compatibility. Perform the following sequence to reset it:

    • run gpupgrade initialize
    • run gpupgrade execute
    • run gpugrade finalize
    • against target cluster, run gpconfig -c bytea_output -v escape
    • run gpstop -a
    • run gpstart -a
    • run psql with a query, to verify the change