guc.h

/*--------------------------------------------------------------------
 * guc.h
 *
 * External declarations pertaining to backend/utils/misc/guc.c and
 * backend/utils/misc/guc-file.l
 *
 * Portions Copyright (c) 2007-2010, Greenplum inc
 * Portions Copyright (c) 2012-Present Pivotal Software, Inc.
 * Copyright (c) 2000-2009, PostgreSQL Global Development Group
 * Written by Peter Eisentraut <peter_e@gmx.net>.
 *
 * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.102 2009/06/11 14:49:13 momjian Exp $
 *--------------------------------------------------------------------
 */
#ifndef GUC_H
#define GUC_H

#include "nodes/parsenodes.h"
#include "tcop/dest.h"
#include "utils/array.h"

#define MAX_MAX_BACKENDS (INT_MAX / BLCKSZ)
#define MAX_AUTHENTICATION_TIMEOUT (600)
#define MAX_PRE_AUTH_DELAY (60)
/*
 * One connection must be reserved for FTS to always able to probe
 * primary. So, this acts as lower limit on reserved superuser connections.
*/
#define RESERVED_FTS_CONNECTIONS (1)

struct StringInfoData;                  /* #include "lib/stringinfo.h" */


/*
 * Certain options can only be set at certain times. The rules are
 * like this:
 *
 * INTERNAL options cannot be set by the user at all, but only through
 * internal processes ("server_version" is an example).  These are GUC
 * variables only so they can be shown by SHOW, etc.
 *
 * POSTMASTER options can only be set when the postmaster starts,
 * either from the configuration file or the command line.
 *
 * SIGHUP options can only be set at postmaster startup or by changing
 * the configuration file and sending the HUP signal to the postmaster
 * or a backend process. (Notice that the signal receipt will not be
 * evaluated immediately. The postmaster and the backend check it at a
 * certain point in their main loop. It's safer to wait than to read a
 * file asynchronously.)
 *
 * BACKEND options can only be set at postmaster startup, from the
 * configuration file, or by client request in the connection startup
 * packet (e.g., from libpq's PGOPTIONS variable).  Furthermore, an
 * already-started backend will ignore changes to such an option in the
 * configuration file.	The idea is that these options are fixed for a
 * given backend once it's started, but they can vary across backends.
 *
 * SUSET options can be set at postmaster startup, with the SIGHUP
 * mechanism, or from SQL if you're a superuser.
 *
 * USERSET options can be set by anyone any time.
 */
typedef enum
{
	PGC_INTERNAL,
	PGC_POSTMASTER,
	PGC_SIGHUP,
	PGC_BACKEND,
	PGC_SUSET,
	PGC_USERSET
} GucContext;

/*
 * The following type records the source of the current setting.  A
 * new setting can only take effect if the previous setting had the
 * same or lower level.  (E.g, changing the config file doesn't
 * override the postmaster command line.)  Tracking the source allows us
 * to process sources in any convenient order without affecting results.
 * Sources <= PGC_S_OVERRIDE will set the default used by RESET, as well
 * as the current value.  Note that source == PGC_S_OVERRIDE should be
 * used when setting a PGC_INTERNAL option.
 *
 * PGC_S_INTERACTIVE isn't actually a source value, but is the
 * dividing line between "interactive" and "non-interactive" sources for
 * error reporting purposes.
 *
 * PGC_S_TEST is used when testing values to be stored as per-database or
 * per-user defaults ("doit" will always be false, so this never gets stored
 * as the actual source of any value).	This is an interactive case, but
 * it needs its own source value because some assign hooks need to make
 * different validity checks in this case.
 *
 * NB: see GucSource_Names in guc.c if you change this.
 */
typedef enum
{
	PGC_S_DEFAULT,				/* wired-in default */
	PGC_S_ENV_VAR,				/* postmaster environment variable */
	PGC_S_FILE,					/* postgresql.conf */
	PGC_S_ARGV,					/* postmaster command line */
	PGC_S_DATABASE,				/* per-database setting */
	PGC_S_USER,					/* per-user setting */
	PGC_S_CLIENT,				/* from client connection request */
	PGC_S_RESGROUP,				/* per-resgroup setting */
	PGC_S_OVERRIDE,				/* special case to forcibly set default */
	PGC_S_INTERACTIVE,			/* dividing line for error reporting */
	PGC_S_TEST,					/* test per-database or per-user setting */
	PGC_S_SESSION				/* SET command */
} GucSource;

/*
 * Parsing the configuation file will return a list of name-value pairs
 */
typedef struct ConfigVariable
{
	char       *name;
	char       *value;
	char	   *filename;
	int			sourceline;
	struct ConfigVariable  *next;
} ConfigVariable;

extern bool ParseConfigFile(const char *config_file, const char *calling_file,
				int depth, int elevel,
				ConfigVariable **head_p, ConfigVariable **tail_p);
extern bool ParseConfigFp(FILE *fp, const char *config_file,
			  int depth, int elevel,
			  ConfigVariable **head_p, ConfigVariable **tail_p);
extern void FreeConfigVariables(ConfigVariable *list);

/*
 * Enum values are made up of an array of name-value pairs
 */
struct config_enum_entry
{
	const char *name;
	int			val;
	bool		hidden;
};

typedef const char *(*GucStringAssignHook) (const char *newval, bool doit, GucSource source);
typedef bool (*GucBoolAssignHook) (bool newval, bool doit, GucSource source);
typedef bool (*GucIntAssignHook) (int newval, bool doit, GucSource source);
typedef bool (*GucRealAssignHook) (double newval, bool doit, GucSource source);
typedef bool (*GucEnumAssignHook) (int newval, bool doit, GucSource source);

typedef const char *(*GucShowHook) (void);

typedef enum
{
	/* Types of set_config_option actions */
	GUC_ACTION_SET,				/* regular SET command */
	GUC_ACTION_LOCAL,			/* SET LOCAL command */
	GUC_ACTION_SAVE				/* function SET option */
} GucAction;

#define GUC_QUALIFIER_SEPARATOR '.'

/*
 * bit values in "flags" of a GUC variable
 */
#define GUC_LIST_INPUT			0x0001	/* input can be list format */
#define GUC_LIST_QUOTE			0x0002	/* double-quote list elements */
#define GUC_NO_SHOW_ALL			0x0004	/* exclude from SHOW ALL */
#define GUC_NO_RESET_ALL		0x0008	/* exclude from RESET ALL */
#define GUC_REPORT				0x0010	/* auto-report changes to client */
#define GUC_NOT_IN_SAMPLE		0x0020	/* not in postgresql.conf.sample */
#define GUC_DISALLOW_IN_FILE	0x0040	/* can't set in postgresql.conf */
#define GUC_CUSTOM_PLACEHOLDER	0x0080	/* placeholder for custom variable */
#define GUC_SUPERUSER_ONLY		0x0100	/* show only to superusers */
#define GUC_IS_NAME				0x0200	/* limit string to NAMEDATALEN-1 */

#define GUC_UNIT_KB				0x0400	/* value is in kilobytes */
#define GUC_UNIT_BLOCKS			0x0800	/* value is in blocks */
#define GUC_UNIT_XBLOCKS		0x0C00	/* value is in xlog blocks */
#define GUC_UNIT_MEMORY			0x0C00	/* mask for KB, BLOCKS, XBLOCKS */

#define GUC_UNIT_MS				0x1000	/* value is in milliseconds */
#define GUC_UNIT_S				0x2000	/* value is in seconds */
#define GUC_UNIT_MIN			0x4000	/* value is in minutes */
#define GUC_UNIT_TIME			0x7000	/* mask for MS, S, MIN */

/* GUC lists for gp_guc_list_show().  (List of struct config_generic) */
extern List    *gp_guc_list_for_explain;
extern List    *gp_guc_list_for_no_plan;

/* GUC vars that are actually declared in guc.c, rather than elsewhere */
extern bool log_duration;
extern bool Debug_print_plan;
extern bool Debug_print_parse;
extern bool Debug_print_rewritten;
extern bool Debug_pretty_print;

extern bool	Debug_print_full_dtm;
extern bool	Debug_print_snapshot_dtm;
extern bool	Debug_print_qd_mirroring;
extern bool Debug_disable_distributed_snapshot;
extern bool Debug_abort_after_distributed_prepared;
extern bool Debug_abort_after_segment_prepared;
extern bool Debug_appendonly_print_insert;
extern bool Debug_appendonly_print_insert_tuple;
extern bool Debug_appendonly_print_scan;
extern bool Debug_appendonly_print_scan_tuple;
extern bool Debug_appendonly_print_delete;
extern bool Debug_appendonly_print_storage_headers;
extern bool Debug_appendonly_print_verify_write_block;
extern bool Debug_appendonly_use_no_toast;
extern bool Debug_appendonly_print_blockdirectory;
extern bool Debug_appendonly_print_read_block;
extern bool Debug_appendonly_print_append_block;
extern bool Debug_appendonly_print_segfile_choice;
extern bool test_AppendOnlyHash_eviction_vs_just_marking_not_inuse;
extern int  Debug_appendonly_bad_header_print_level;
extern bool Debug_appendonly_print_datumstream;
extern bool Debug_appendonly_print_visimap;
extern bool Debug_appendonly_print_compaction;
extern bool gp_crash_recovery_abort_suppress_fatal;
extern bool Debug_bitmap_print_insert;
extern bool Test_appendonly_override;
extern bool enable_checksum_on_tables;
extern int  Test_compresslevel_override;
extern int  gp_max_local_distributed_cache;
extern bool gp_local_distributed_cache_stats;
extern bool gp_appendonly_verify_block_checksums;
extern bool gp_appendonly_verify_write_block;
extern bool gp_appendonly_compaction;

/*
 * Threshold of the ratio of dirty data in a segment file
 * over which the segment file will be compacted during
 * lazy vacuum.
 * 0 indicates compact whenever there is hidden data.
 * 10 indicates that a segment should be compacted when more than
 * 10% of the tuples are hidden.
 */ 
extern int  gp_appendonly_compaction_threshold;
extern bool gp_heap_require_relhasoids_match;
extern bool	Debug_appendonly_rezero_quicklz_compress_scratch;
extern bool	Debug_appendonly_rezero_quicklz_decompress_scratch;
extern bool	Debug_appendonly_guard_end_quicklz_scratch;
extern bool	Debug_xlog_insert_print;
extern bool	debug_xlog_record_read;
extern bool Debug_cancel_print;
extern bool Debug_datumstream_write_print_small_varlena_info;
extern bool Debug_datumstream_write_print_large_varlena_info;
extern bool Debug_datumstream_read_check_large_varlena_integrity;
extern bool Debug_datumstream_block_read_check_integrity;
extern bool Debug_datumstream_block_write_check_integrity;
extern bool Debug_datumstream_read_print_varlena_info;
extern bool Debug_datumstream_write_use_small_initial_buffers;
extern bool	Debug_database_command_print;
extern bool gp_startup_integrity_checks;
extern bool Debug_resource_group;
extern bool gp_crash_recovery_suppress_ao_eof;
extern bool gp_create_table_random_default_distribution;
extern bool gp_allow_non_uniform_partitioning_ddl;
extern bool gp_enable_exchange_default_partition;
extern int  dtx_phase2_retry_count;

/* WAL replication debug gucs */
extern bool debug_walrepl_snd;
extern bool debug_walrepl_syncrep;
extern bool debug_walrepl_rcv;
extern bool debug_basebackup;

/* Latch mechanism debug GUCs */
extern bool debug_latch;

extern bool gp_upgrade_mode;
extern bool gp_maintenance_mode;
extern bool gp_maintenance_conn;
extern bool allow_segment_DML;
extern bool gp_allow_rename_relation_without_lock;

extern bool gp_ignore_window_exclude;

extern bool rle_type_compression_stats;

extern bool	Debug_print_server_processes;
extern bool Debug_print_control_checkpoints;
extern bool	Debug_dtm_action_primary;

extern bool gp_log_optimization_time;
extern bool log_parser_stats;
extern bool log_planner_stats;
extern bool log_executor_stats;
extern bool log_statement_stats;
extern bool log_dispatch_stats;
extern bool log_btree_build_stats;

extern PGDLLIMPORT bool check_function_bodies;
extern bool default_with_oids;
extern bool SQL_inheritance;

extern int	log_min_error_statement;
extern int	log_min_messages;
extern int	client_min_messages;
extern int	log_min_duration_statement;
extern int	log_temp_files;

extern int	num_temp_buffers;

extern bool gp_cancel_query_print_log;
extern int gp_cancel_query_delay_time;
extern bool vmem_process_interrupt;
extern bool execute_pruned_plan;

extern bool gp_partitioning_dynamic_selection_log;
extern int gp_max_partition_level;

extern bool gp_perfmon_print_packet_info;

extern bool gp_enable_relsize_collection;

/* Debug DTM Action */
typedef enum
{
	DEBUG_DTM_ACTION_NONE = 0,
	DEBUG_DTM_ACTION_DELAY = 1,
	DEBUG_DTM_ACTION_FAIL_BEGIN_COMMAND = 2,
	DEBUG_DTM_ACTION_FAIL_END_COMMAND = 3,
	DEBUG_DTM_ACTION_PANIC_BEGIN_COMMAND = 4,

	DEBUG_DTM_ACTION_LAST = 4
}	DebugDtmAction;

/* Debug DTM Action */
typedef enum
{
	DEBUG_DTM_ACTION_TARGET_NONE = 0,
	DEBUG_DTM_ACTION_TARGET_PROTOCOL = 1,
	DEBUG_DTM_ACTION_TARGET_SQL = 2,

	DEBUG_DTM_ACTION_TARGET_LAST = 2
}	DebugDtmActionTarget;

extern int Debug_dtm_action;
extern int Debug_dtm_action_target;
extern int Debug_dtm_action_protocol;
extern int Debug_dtm_action_segment;
extern int Debug_dtm_action_nestinglevel;

extern char *data_directory;
extern char *ConfigFileName;
extern char *HbaFileName;
extern char *IdentFileName;
extern char *external_pid_file;

extern char *application_name;

extern char *Debug_dtm_action_sql_command_tag;
extern char *Debug_dtm_action_str;
extern char *Debug_dtm_action_target_str;

/* Enable check for compatibility of encoding and locale in createdb */
extern bool gp_encoding_check_locale_compatibility;

extern int	tcp_keepalives_idle;
extern int	tcp_keepalives_interval;
extern int	tcp_keepalives_count;

extern int	gp_connection_send_timeout;

extern int  WalSendClientTimeout;

extern char  *data_directory;

/* ORCA related definitions */
#define OPTIMIZER_XFORMS_COUNT 400 /* number of transformation rules */

/* types of optimizer failures */
#define OPTIMIZER_ALL_FAIL 			0  /* all failures */
#define OPTIMIZER_UNEXPECTED_FAIL 	1  /* unexpected failures */
#define OPTIMIZER_EXPECTED_FAIL 	2 /* expected failures */

/* optimizer minidump mode */
#define OPTIMIZER_MINIDUMP_FAIL  	0  /* create optimizer minidump on failure */
#define OPTIMIZER_MINIDUMP_ALWAYS 	1  /* always create optimizer minidump */

/* optimizer cost model */
#define OPTIMIZER_GPDB_LEGACY           0       /* GPDB's legacy cost model */
#define OPTIMIZER_GPDB_CALIBRATED       1       /* GPDB's calibrated cost model */

/* Optimizer related gucs */
extern bool	optimizer;
extern bool optimizer_control;	/* controls whether the user can change the setting of the "optimizer" guc */
extern bool	optimizer_log;
extern int  optimizer_log_failure;
extern bool	optimizer_trace_fallback;
extern bool optimizer_minidump;
extern int  optimizer_cost_model;
extern bool optimizer_metadata_caching;
extern int	optimizer_mdcache_size;

/* Optimizer debugging GUCs */
extern bool optimizer_print_query;
extern bool optimizer_print_plan;
extern bool optimizer_print_xform;
extern bool	optimizer_print_memo_after_exploration;
extern bool	optimizer_print_memo_after_implementation;
extern bool	optimizer_print_memo_after_optimization;
extern bool	optimizer_print_job_scheduler;
extern bool	optimizer_print_expression_properties;
extern bool	optimizer_print_group_properties;
extern bool	optimizer_print_optimization_context;
extern bool optimizer_print_optimization_stats;
extern bool optimizer_print_xform_results;

/* array of xforms disable flags */
extern bool optimizer_xforms[OPTIMIZER_XFORMS_COUNT];
extern char *optimizer_search_strategy_path;

/* GUCs to tell Optimizer to enable a physical operator */
extern bool optimizer_enable_indexjoin;
extern bool optimizer_enable_motions_masteronly_queries;
extern bool optimizer_enable_motions;
extern bool optimizer_enable_motion_broadcast;
extern bool optimizer_enable_motion_gather;
extern bool optimizer_enable_motion_redistribute;
extern bool optimizer_enable_sort;
extern bool optimizer_enable_materialize;
extern bool optimizer_enable_partition_propagation;
extern bool optimizer_enable_partition_selection;
extern bool optimizer_enable_outerjoin_rewrite;
extern bool optimizer_enable_multiple_distinct_aggs;
extern bool optimizer_enable_hashjoin_redistribute_broadcast_children;
extern bool optimizer_enable_broadcast_nestloop_outer_child;
extern bool optimizer_enable_assert_maxonerow;
extern bool optimizer_enable_constant_expression_evaluation;
extern bool optimizer_enable_bitmapscan;
extern bool optimizer_enable_outerjoin_to_unionall_rewrite;
extern bool optimizer_enable_ctas;
extern bool optimizer_enable_partial_index;
extern bool optimizer_enable_dml_triggers;
extern bool	optimizer_enable_dml_constraints;
extern bool optimizer_enable_direct_dispatch;
extern bool optimizer_enable_master_only_queries;
extern bool optimizer_enable_hashjoin;
extern bool optimizer_enable_dynamictablescan;
extern bool optimizer_enable_indexscan;
extern bool optimizer_enable_tablescan;

/* Optimizer plan enumeration related GUCs */
extern bool optimizer_enumerate_plans;
extern bool optimizer_sample_plans;
extern int	optimizer_plan_id;
extern int	optimizer_samples_number;

/* Cardinality estimation related GUCs used by the Optimizer */
extern bool optimizer_extract_dxl_stats;
extern bool optimizer_extract_dxl_stats_all_nodes;
extern bool optimizer_print_missing_stats;
extern double optimizer_damping_factor_filter;
extern double optimizer_damping_factor_join;
extern double optimizer_damping_factor_groupby;
extern bool optimizer_dpe_stats;
extern bool optimizer_enable_derive_stats_all_groups;

/* Costing or tuning related GUCs used by the Optimizer */
extern int optimizer_segments;
extern int optimizer_penalize_broadcast_threshold;
extern double optimizer_cost_threshold;
extern double optimizer_nestloop_factor;
extern double optimizer_sort_factor;

/* Optimizer hints */
extern int optimizer_array_expansion_threshold;
extern int optimizer_join_order_threshold;
extern int optimizer_join_order;
extern int optimizer_join_arity_for_associativity_commutativity;
extern int optimizer_cte_inlining_bound;
extern bool optimizer_force_multistage_agg;
extern bool optimizer_force_three_stage_scalar_dqa;
extern bool optimizer_force_expanded_distinct_aggs;
extern bool optimizer_prune_computed_columns;
extern bool optimizer_push_requirements_from_consumer_to_producer;
extern bool optimizer_enforce_subplans;
extern bool optimizer_apply_left_outer_to_union_all_disregarding_stats;
extern bool optimizer_use_external_constant_expression_evaluation_for_ints;
extern bool optimizer_remove_order_below_dml;
extern bool optimizer_multilevel_partitioning;
extern bool optimizer_parallel_union;
extern bool optimizer_array_constraints;
extern bool optimizer_cte_inlining;
extern bool optimizer_enable_space_pruning;

/* Analyze related GUCs for Optimizer */
extern bool optimizer_analyze_root_partition;
extern bool optimizer_analyze_midlevel_partition;

extern bool optimizer_use_gpdb_allocators;


/**
 * Enable logging of DPE match in optimizer.
 */
extern bool	optimizer_partition_selection_log;

/* optimizer join heuristic models */
#define JOIN_ORDER_IN_QUERY                 0
#define JOIN_ORDER_GREEDY_SEARCH            1
#define JOIN_ORDER_EXHAUSTIVE_SEARCH        2

extern char  *gp_email_smtp_server;
extern char  *gp_email_smtp_userid;
extern char  *gp_email_smtp_password;
extern char  *gp_email_from;
extern char  *gp_email_to;
extern int   gp_email_connect_timeout;
extern int   gp_email_connect_failures;
extern int   gp_email_connect_avoid_duration; 

#if USE_SNMP
extern char   *gp_snmp_community;
extern char   *gp_snmp_monitor_address;
extern char   *gp_snmp_use_inform_or_trap;
extern char   *gp_snmp_debug_log;
#endif

/* Hadoop Integration GUCs */
extern char  *gp_hadoop_connector_jardir;  /* relative dir on $GPHOME of the Hadoop connector jar is located */
extern char  *gp_hadoop_connector_version; /* connector version (internal use only) */
extern char  *gp_hadoop_target_version; /* the target hadoop distro/version */
extern char  *gp_hadoop_home;    /* $HADOOP_HOME on all segments */

/* Time based authentication GUC */
extern char  *gp_auth_time_override_str;

extern char  *gp_default_storage_options;

/* copy GUC */
extern bool gp_enable_segment_copy_checking;

extern int writable_external_table_bufsize;

typedef enum
{
	INDEX_CHECK_NONE,
	INDEX_CHECK_SYSTEM,
	INDEX_CHECK_ALL
} IndexCheckType;

extern IndexCheckType gp_indexcheck_insert;
extern IndexCheckType gp_indexcheck_vacuum;

/* Storage option names */
#define SOPT_FILLFACTOR    "fillfactor"
#define SOPT_APPENDONLY    "appendonly"
#define SOPT_BLOCKSIZE     "blocksize"
#define SOPT_COMPTYPE      "compresstype"
#define SOPT_COMPLEVEL     "compresslevel"
#define SOPT_CHECKSUM      "checksum"
#define SOPT_ORIENTATION   "orientation"
/* Max number of chars needed to hold value of a storage option. */
#define MAX_SOPT_VALUE_LEN 15

extern void SetConfigOption(const char *name, const char *value,
				GucContext context, GucSource source);

extern void DefineCustomBoolVariable(
						 const char *name,
						 const char *short_desc,
						 const char *long_desc,
						 bool *valueAddr,
						 bool bootValue,
						 GucContext context,
						 int flags,
						 GucBoolAssignHook assign_hook,
						 GucShowHook show_hook);

extern void DefineCustomIntVariable(
						const char *name,
						const char *short_desc,
						const char *long_desc,
						int *valueAddr,
						int bootValue,
						int minValue,
						int maxValue,
						GucContext context,
						int flags,
						GucIntAssignHook assign_hook,
						GucShowHook show_hook);

extern void DefineCustomRealVariable(
						 const char *name,
						 const char *short_desc,
						 const char *long_desc,
						 double *valueAddr,
						 double bootValue,
						 double minValue,
						 double maxValue,
						 GucContext context,
						 int flags,
						 GucRealAssignHook assign_hook,
						 GucShowHook show_hook);

extern void DefineCustomStringVariable(
						   const char *name,
						   const char *short_desc,
						   const char *long_desc,
						   char **valueAddr,
						   const char *bootValue,
						   GucContext context,
						   int flags,
						   GucStringAssignHook assign_hook,
						   GucShowHook show_hook);

extern void DefineCustomEnumVariable(
						 const char *name,
						 const char *short_desc,
						 const char *long_desc,
						 int *valueAddr,
						 int bootValue,
						 const struct config_enum_entry * options,
						 GucContext context,
						 int flags,
						 GucEnumAssignHook assign_hook,
						 GucShowHook show_hook);

extern void EmitWarningsOnPlaceholders(const char *className);

extern const char *GetConfigOption(const char *name);
extern const char *GetConfigOptionResetString(const char *name);
extern bool IsSuperuserConfigOption(const char *name);
extern void ProcessConfigFile(GucContext context);
extern void InitializeGUCOptions(void);
extern bool SelectConfigFiles(const char *userDoption, const char *progname);
extern void ResetAllOptions(void);
extern void AtStart_GUC(void);
extern int	NewGUCNestLevel(void);
extern void AtEOXact_GUC(bool isCommit, int nestLevel);
extern void BeginReportingGUCOptions(void);
extern void ParseLongOption(const char *string, char **name, char **value);
extern bool parse_int(const char *value, int *result, int flags,
		  const char **hintmsg);
extern bool parse_real(const char *value, double *result);
extern bool set_config_option(const char *name, const char *value,
				  GucContext context, GucSource source,
				  GucAction action, bool changeVal);
extern char *GetConfigOptionByName(const char *name, const char **varname);
extern void GetConfigOptionByNum(int varnum, const char **values, bool *noshow);
extern int	GetNumConfigOptions(void);

extern void SetPGVariable(const char *name, List *args, bool is_local);
extern void SetPGVariableOptDispatch(const char *name, List *args, bool is_local, bool gp_dispatch);
extern void GetPGVariable(const char *name, DestReceiver *dest);
extern TupleDesc GetPGVariableResultDesc(const char *name);

extern void ExecSetVariableStmt(VariableSetStmt *stmt);
extern char *ExtractSetVariableArgs(VariableSetStmt *stmt);

extern void ProcessGUCArray(ArrayType *array,
				GucContext context, GucSource source, GucAction action);
extern ArrayType *GUCArrayAdd(ArrayType *array, const char *name, const char *value);
extern ArrayType *GUCArrayDelete(ArrayType *array, const char *name);
extern ArrayType *GUCArrayReset(ArrayType *array);

extern int	GUC_complaint_elevel(GucSource source);

extern void pg_timezone_abbrev_initialize(void);

extern char *gp_guc_list_show(GucSource excluding, List *guclist);

extern struct config_generic *find_option(const char *name,
				bool create_placeholders, int elevel);

extern char  *gp_replication_config_filename;

extern bool select_gp_replication_config_files(const char *configdir, const char *progname);

extern void set_gp_replication_config(const char *name, const char *value);

extern bool parse_real(const char *value, double *result);

#ifdef EXEC_BACKEND
extern void write_nondefault_variables(GucContext context);
extern void read_nondefault_variables(void);
#endif

/*
 * The following functions are not in guc.c, but are declared here to avoid
 * having to include guc.h in some widely used headers that it really doesn't
 * belong in.
 */

/* in commands/tablespace.c */
extern const char *assign_default_tablespace(const char *newval,
						  bool doit, GucSource source);
extern const char *assign_temp_tablespaces(const char *newval,
						bool doit, GucSource source);

/* in catalog/namespace.c */
extern const char *assign_search_path(const char *newval,
				   bool doit, GucSource source);

/* in access/transam/xlog.c */
extern bool assign_xlog_sync_method(int newval,
						bool doit, GucSource source);

extern StdRdOptions *defaultStdRdOptions(char relkind);

#endif   /* GUC_H */