cdbvars.c

/*-------------------------------------------------------------------------
 *
 * cdbvars.c
 *	  Provides storage areas and processing routines for Greenplum Database variables
 *	  managed by GUC.
 *
 * Copyright (c) 2003-2010, Greenplum inc
 *
 *
 * NOTES
 *	  See src/backend/utils/misc/guc.c for variable external specification.
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"
#include "miscadmin.h"
#include "utils/guc.h"
#include "catalog/gp_segment_config.h"
#include "cdb/cdbvars.h"
#include "cdb/cdbfts.h"
#include "cdb/cdbdisp.h"
#include "cdb/cdbutil.h"
#include "cdb/cdbdisp.h"
#include "lib/stringinfo.h"
#include "libpq/libpq-be.h"
#include "utils/memutils.h"
#include "storage/bfz.h"
#include "storage/proc.h"
#include "cdb/memquota.h"

/*
 * ----------------
 *		GUC/global variables
 *
 *	Initial values are set by guc.c function "InitializeGUCOptions" called
 *	*very* early during postmaster, postgres, or bootstrap initialization.
 * ----------------
 */



GpRoleValue Gp_role;			/* Role paid by this Greenplum Database
								 * backend */
char	   *gp_role_string;		/* Staging area for guc.c */
char	   *gp_fault_action_string;		/* Staging area for guc.c */
bool		gp_set_read_only;	/* Staging area for guc.c */

GpRoleValue Gp_session_role;	/* Role paid by this Greenplum Database
								 * backend */
char	   *gp_session_role_string;		/* Staging area for guc.c */

bool		Gp_is_writer;		/* is this qExec a "writer" process. */

int			gp_session_id;		/* global unique id for session. */

char	   *qdHostname;			/* QD hostname */
int			qdPostmasterPort;	/* Master Segment Postmaster port. */

int			gp_command_count;	/* num of commands from client */

bool		gp_debug_pgproc;	/* print debug info for PGPROC */
bool		Debug_print_prelim_plan;	/* Shall we log argument of
										 * cdbparallelize? */

bool		Debug_print_slice_table;	/* Shall we log the slice table? */

bool		gp_backup_directIO = false; /* disable\enable direct I/O dump */

int			gp_backup_directIO_read_chunk_mb = 20;		/* size of readChunk
														 * buffer for directIO
														 * dump */

bool		gp_external_enable_exec = true;		/* allow ext tables with
												 * EXECUTE */

bool		gp_external_grant_privileges = false;		/* allow creating
														 * http/gpfdist/gpfdists
														 * for non-su */

int			gp_external_max_segs;		/* max segdbs per gpfdist/gpfdists URI */

int			gp_safefswritesize; /* set for safe AO writes in non-mature fs */

int			gp_connections_per_thread;	/* How many libpq connections are
										 * handled in each thread */

int			gp_cached_gang_threshold;	/* How many gangs to keep around from
										 * stmt to stmt. */

int			Gp_segment = UNDEF_SEGMENT; /* What content this QE is handling. */

bool		Gp_write_shared_snapshot;	/* tell the writer QE to write the
										 * shared snapshot */

bool		gp_reraise_signal = false;	/* try to dump core when we get
										 * SIGABRT & SIGSEGV */

bool		gp_set_proc_affinity = false;		/* set processor affinity (if
												 * platform supports it) */

int			gp_reject_percent_threshold;		/* SREH reject % kicks off
												 * only after * <num> records
												 * have been processed	*/

int			gp_max_csv_line_length;		/* max allowed len for csv data line
										 * in bytes */

bool		gp_select_invisible = false;		/* debug mode to allow select
												 * to see "invisible" rows */

int			pgstat_track_activity_query_size = INT_MAX; /* max allowed len for
														 * displaying the query
														 * in pg_stat_activity
														 * table */

/*
 * Configurable timeout for snapshot add: exceptionally busy systems may take
 * longer than our old hard-coded version -- so here is a tuneable version.
 */
int			gp_snapshotadd_timeout = 10;


/*
 * Probe retry count for fts prober.
 */
int			gp_fts_probe_retries = 5;

/*
 * Probe timeout for fts prober.
 */
int			gp_fts_probe_timeout = 20;

/*
 * Polling interval for the fts prober. A scan of the entire system starts
 * every time this expires.
 */
int			gp_fts_probe_interval = 60;

/*
 * Number of threads to use for probe of segments (it is a good idea to have this
 * larger than the number of segments per host.
 */
int			gp_fts_probe_threadcount = 16;

/*
 * Controls parallel segment transition (failover).
 */
bool		gp_fts_transition_parallel = true;

/* The number of retries to request a segment state transition. */
int			gp_fts_transition_retries = 5;

/* Timeout to request a segment state transition. */
int			gp_fts_transition_timeout = 3600;


/*
 * When we have certain types of failures during gang creation which indicate
 * that a segment is in recovery mode we may be able to retry.
 */
int			gp_gang_creation_retry_count = 5;	/* disable by default */
int			gp_gang_creation_retry_timer = 2000;		/* 2000ms */

/*
 * gp_enable_slow_writer_testmode
 *
 * In order facilitate testing of reader-gang/writer-gang synchronization,
 * this inserts a pg_usleep call at the start of writer-gang processing.
 */
bool		gp_enable_slow_writer_testmode = false;

/*
 * gp_enable_slow_cursor_testmode
 *
 * In order facilitate testing of reader-gang/writer-gang synchronization,
 * this inserts a pg_usleep call at the start of cursor-gang processing.
 */
bool		gp_enable_slow_cursor_testmode = false;

/**
 * Hash-join node releases hash table when it returns last tuple.
 */
bool		gp_eager_hashtable_release = true;

int			Gp_max_packet_size; /* max Interconnect packet size */

int			Gp_interconnect_queue_depth = 4;	/* max number of messages
												 * waiting in rx-queue before
												 * we drop. */
int			Gp_interconnect_snd_queue_depth = 2;
int			Gp_interconnect_timer_period = 5;
int			Gp_interconnect_timer_checking_period = 20;
int			Gp_interconnect_default_rtt = 20;
int			Gp_interconnect_min_rto = 20;
int			Gp_interconnect_fc_method = INTERCONNECT_FC_METHOD_LOSS;
int			Gp_interconnect_transmit_timeout = 3600;
int			Gp_interconnect_min_retries_before_timeout = 100;

int			Gp_interconnect_hash_multiplier = 2;		/* sets the size of the
														 * hash table used by
														 * the UDP-IC */

int			interconnect_setup_timeout = 7200;

int			Gp_interconnect_type = INTERCONNECT_TYPE_UDPIFC;

bool		gp_interconnect_full_crc = false;	/* sanity check UDP data. */

bool		gp_interconnect_log_stats = false;	/* emit stats at log-level */

bool		gp_interconnect_cache_future_packets = true;

int			Gp_udp_bufsize_k;	/* UPD recv buf size, in KB */

#ifdef USE_ASSERT_CHECKING
/*
 * UDP-IC Test hooks (for fault injection).
 *
 * Dropseg: specifies which segment to apply the drop_percent to.
 */
int			gp_udpic_dropseg = UNDEF_SEGMENT;
int			gp_udpic_dropxmit_percent = 0;
int			gp_udpic_dropacks_percent = 0;
int			gp_udpic_fault_inject_percent = 0;
int			gp_udpic_fault_inject_bitmap = 0;
int			gp_udpic_network_disable_ipv6 = 0;
#endif

/*
 * Each slice table has a unique ID (certain commands like "vacuum analyze"
 * run many many slice-tables for each gp_command_id).
 */
uint32		gp_interconnect_id = 0;

/* --------------------------------------------------------------------------------------------------
 * Resource management
 */

double		gp_hashagg_respill_bias = 1;

/* --------------------------------------------------------------------------------------------------
 * Greenplum Optimizer GUCs
 */

double		gp_motion_cost_per_row = 0;
int			gp_segments_for_planner = 0;

int			gp_hashagg_default_nbatches = 32;

bool		gp_adjust_selectivity_for_outerjoins = TRUE;
bool		gp_selectivity_damping_for_scans = false;
bool		gp_selectivity_damping_for_joins = false;
double		gp_selectivity_damping_factor = 1;
bool		gp_selectivity_damping_sigsort = true;

int			gp_hashjoin_tuples_per_bucket = 5;
int			gp_hashagg_groups_per_bucket = 5;
int			gp_hashjoin_metadata_memory_percent = 20;


/* default value to 0, which means we do not try to control number of spill batches */
int			gp_hashagg_spillbatch_min = 0;
int			gp_hashagg_spillbatch_max = 0;

/* hash join to use bloom filter: default to 0, means not used */
int			gp_hashjoin_bloomfilter = 0;

/* Analyzing aid */
int			gp_motion_slice_noop = 0;
#ifdef ENABLE_LTRACE
int			gp_ltrace_flag = 0;
#endif

/* Internal Features */
bool		gp_enable_alter_table_inherit_cols = false;

/* During insertion in a table with parquet partitions, require tuples to be sorted by partition key */
bool		gp_parquet_insert_sort = true;

/* Greenplum Database Experimental Feature GUCs */
int			gp_distinct_grouping_sets_threshold = 32;
bool		gp_enable_explain_allstat = FALSE;
bool		gp_enable_motion_deadlock_sanity = FALSE;	/* planning time sanity
														 * check */

#ifdef USE_ASSERT_CHECKING
bool		gp_mk_sort_check = false;
#endif
int			gp_sort_flags = 0;
int			gp_dbg_flags = 0;
int			gp_sort_max_distinct = 20000;

bool		gp_enable_hash_partitioned_tables = FALSE;
bool		gp_setwith_alter_storage = FALSE;

bool		gp_enable_tablespace_auto_mkdir = FALSE;

/* MPP-9772, MPP-9773: remove support for CREATE INDEX CONCURRENTLY */
bool		gp_create_index_concurrently = FALSE;

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

/* Priority for the segworkers relative to the postmaster's priority */
int			gp_segworker_relative_priority = PRIO_MAX;

/* Max size of dispatched plans; 0 if no limit */
int			gp_max_plan_size = 0;

/* Disable setting of tuple hints while reading */
bool		gp_disable_tuple_hints = false;
int			gp_hashagg_compress_spill_files = 0;

int			gp_workfile_compress_algorithm = 0;
bool		gp_workfile_checksumming = false;
int			gp_workfile_caching_loglevel = DEBUG1;
int			gp_sessionstate_loglevel = DEBUG1;

/* Maximum disk space to use for workfiles on a segment, in kilobytes */
double		gp_workfile_limit_per_segment = 0;

/* Maximum disk space to use for workfiles per query on a segment, in kilobytes */
double		gp_workfile_limit_per_query = 0;

/* Maximum number of workfiles to be created by a query */
int			gp_workfile_limit_files_per_query = 0;
bool		gp_workfile_faultinject = false;
int			gp_workfile_bytes_to_checksum = 16;

/* The type of work files that HashJoin should use */
int			gp_workfile_type_hashjoin = 0;

/* Gpmon */
bool		gp_enable_gpperfmon = false;
int			gp_gpperfmon_send_interval = 1;
GpperfmonLogAlertLevel gpperfmon_log_alert_level = GPPERFMON_LOG_ALERT_LEVEL_NONE;

/* Enable single-slice single-row inserts ?*/
bool		gp_enable_fast_sri = true;

/* Enable single-mirror pair dispatch. */
bool		gp_enable_direct_dispatch = true;

/* Disable logging while creating mapreduce objects */
bool		gp_mapreduce_define = false;

/* request fault-prober pause */
bool		gp_fts_probe_pause = false;

/* Force core dump on memory context error */
bool		coredump_on_memerror = false;

/* Experimental feature for MPP-4082. Please read doc before setting this guc */
GpAutoStatsModeValue gp_autostats_mode;
char	   *gp_autostats_mode_string;
GpAutoStatsModeValue gp_autostats_mode_in_functions;
char	   *gp_autostats_mode_in_functions_string;
int			gp_autostats_on_change_threshold = 100000;
bool		log_autostats = true;

/* --------------------------------------------------------------------------------------------------
 * Miscellaneous developer use
 */

bool		gp_dev_notice_agg_cost = false;

/* --------------------------------------------------------------------------------------------------
 * Server debugging
 */

/*
 * gp_debug_linger (integer)
 *
 * Upon an error with severity FATAL and error code ERRCODE_INTERNAL_ERROR,
 * errfinish() will sleep() for the specified number of seconds before
 * termination, to let the user attach a debugger.
 */
int			gp_debug_linger = 30;

/* ----------------
 * Non-GUC globals
 */

int			currentSliceId = UNSET_SLICE_ID;	/* used by elog to show the
												 * current slice the process
												 * is executing. */
SeqServerControlBlock *seqServerCtl;

/* Segment id where singleton gangs are to be dispatched. */
int			gp_singleton_segindex;

bool		gp_cost_hashjoin_chainwalk = false;

/* ----------------
 * This variable is initialized by the postmaster from command line arguments
 *
 * Any code needing the "numsegments"
 * can simply #include cdbvars.h, and use GpIdentity.numsegments
 */
GpId		GpIdentity = {UNINITIALIZED_GP_IDENTITY_VALUE, UNINITIALIZED_GP_IDENTITY_VALUE, UNINITIALIZED_GP_IDENTITY_VALUE};

/*
 * This has to be int because of guc.c stupidity :(
 * The value is supposed to be passed through postmaster command line
 * and go to XLogCtlData for mmxlog purpose.  We'd like to fetch the value
 * from the catalog but the value is too fundamental and accessed too early
 * to fetch it from catalog.
 */
int			GpStandbyDbid = InvalidDbid;

void
verifyGpIdentityIsSet(void)
{
	if (GpIdentity.numsegments == UNINITIALIZED_GP_IDENTITY_VALUE ||
		GpIdentity.dbid == UNINITIALIZED_GP_IDENTITY_VALUE ||
		GpIdentity.segindex == UNINITIALIZED_GP_IDENTITY_VALUE)
	{
		elog(ERROR, "GpIdentity is not set");
	}
}

/*
 * Keep track of a few dispatch-related  statistics:
 */
int			cdb_total_slices = 0;
int			cdb_total_plans = 0;
int			cdb_max_slices = 0;

/*
 * Local macro to provide string values of numeric defines.
 */
#define CppNumericAsString(s) CppAsString(s)

/*
 *	Forward declarations of local function.
 */
GpRoleValue string_to_role(const char *string);
const char *role_to_string(GpRoleValue role);


/*
 * Convert a Greenplum Database role string (as for gp_session_role or gp_role) to an
 * enum value of type GpRoleValue. Return GP_ROLE_UNDEFINED in case the
 * string is unrecognized.
 */
GpRoleValue
string_to_role(const char *string)
{
	GpRoleValue role = GP_ROLE_UNDEFINED;

	if (pg_strcasecmp(string, "dispatch") == 0 || pg_strcasecmp(string, "") == 0)
	{
		role = GP_ROLE_DISPATCH;
	}
	else if (pg_strcasecmp(string, "execute") == 0)
	{
		role = GP_ROLE_EXECUTE;
	}
	else if (pg_strcasecmp(string, "utility") == 0)
	{
		role = GP_ROLE_UTILITY;
	}

	return role;
}

/*
 * Convert a GpRoleValue to a role string (as for gp_session_role or
 * gp_role).  Return eyecatcher in the unexpected event that the value
 * is unknown or undefined.
 */
const char *
role_to_string(GpRoleValue role)
{
	switch (role)
	{
		case GP_ROLE_DISPATCH:
			return "dispatch";
		case GP_ROLE_EXECUTE:
			return "execute";
		case GP_ROLE_UTILITY:
			return "utility";
		case GP_ROLE_UNDEFINED:
		default:
			return "*undefined*";
	}
}


/*
 * Assign hook routine for "gp_session_role" option.  Because this variable
 * has context PGC_BACKEND, we expect this assigment to happen only during
 * setup of a BACKEND, e.g., based on the role value specified on the connect
 * request.
 *
 * See src/backend/util/misc/guc.c for option definition.
 */
const char *
assign_gp_session_role(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
#if FALSE
	elog(DEBUG1, "assign_gp_session_role: gp_session_role=%s, newval=%s, doit=%s",
		 show_gp_session_role(), newval, (doit ? "true" : "false"));
#endif

	GpRoleValue newrole = string_to_role(newval);

	if (newrole == GP_ROLE_UNDEFINED)
	{
		return NULL;
	}

	if (doit)
	{
		Gp_session_role = newrole;
		Gp_role = Gp_session_role;

		if (Gp_role == GP_ROLE_DISPATCH)
			Gp_segment = -1;

		if (Gp_role == GP_ROLE_UTILITY && MyProc != NULL)
			MyProc->mppIsWriter = false;
	}
	return newval;
}



/*
 * Assign hook routine for "gp_role" option.  This variable has context
 * PGC_SUSET so that is can only be set by a superuser via the SET command.
 * (It can also be set using an option on postmaster start, but this isn't
 * interesting beccause the derived global CdbRole is always set (along with
 * CdbSessionRole) on backend startup for a new connection.
 *
 * See src/backend/util/misc/guc.c for option definition.
 */
const char *
assign_gp_role(const char *newval, bool doit, GucSource source)
{
#if FALSE
	elog(DEBUG1, "assign_gp_role: gp_role=%s, newval=%s, doit=%s",
		 show_gp_role(), newval, (doit ? "true" : "false"));
#endif


	GpRoleValue newrole = string_to_role(newval);
	GpRoleValue oldrole = Gp_role;

	if (newrole == GP_ROLE_UNDEFINED)
	{
		return NULL;
	}

	if (doit)
	{
		/*
		 * When changing between roles, we must call cdb_cleanup and then
		 * cdb_setup to get setup and connections appropriate to the new role.
		 */
		bool		do_disconnect = false;
		bool		do_connect = false;

		if (Gp_role != newrole && IsUnderPostmaster)
		{
			if (Gp_role != GP_ROLE_UTILITY)
				do_disconnect = true;

			if (newrole != GP_ROLE_UTILITY)
				do_connect = true;
		}

		if (do_disconnect)
			cdb_cleanup(0, 0);

		Gp_role = newrole;

		if (source != PGC_S_DEFAULT)
		{
			if (do_connect)
			{
				/*
				 * In case there are problems with the Greenplum Database
				 * tables or data, we catch any error coming out of
				 * cdblink_setup so we can set the gp_role back to what it
				 * was.  Otherwise we may be left with inappropriate
				 * connections for the new role.
				 */
				PG_TRY();
				{
					cdb_setup();
				}
				PG_CATCH();
				{
					cdb_cleanup(0, 0);
					Gp_role = oldrole;
					if (Gp_role != GP_ROLE_UTILITY)
						cdb_setup();
					PG_RE_THROW();
				}
				PG_END_TRY();
			}
		}
	}

	return newval;
}


/*
 * Assign hook routine for "gp_connections_per_thread" option.  This variable has context
 * PGC_SUSET so that is can only be set by a superuser via the SET command.
 * (It can also be set in config file, but not inside of PGOPTIONS.)
 *
 * See src/backend/util/misc/guc.c for option definition.
 */
bool
assign_gp_connections_per_thread(int newval, bool doit, GucSource source __attribute__((unused)))
{
#if FALSE
	elog(DEBUG1, "assign_gp_connections_per_thread: gp_connections_per_thread=%s, newval=%d, doit=%s",
		 show_gp_connections_per_thread(), newval, (doit ? "true" : "false"));
#endif

	if (doit)
	{
		if (newval < 0)
			return false;

		cdbdisp_setAsync(newval == 0);
		cdbgang_setAsync(newval == 0);
		gp_connections_per_thread = newval;
	}

	return true;
}

/*
 * Show hook routine for "gp_session_role" option.
 *
 * See src/backend/util/misc/guc.c for option definition.
 */
const char *
show_gp_session_role(void)
{
	return role_to_string(Gp_session_role);
}


/*
 * Show hook routine for "gp_role" option.
 *
 * See src/backend/util/misc/guc.c for option definition.
 */
const char *
show_gp_role(void)
{
	return role_to_string(Gp_role);
}

/*
 * Show hook routine for "gp_connections_per_thread" option.
 *
 * See src/backend/util/misc/guc.c for option definition.
 */
const char *
show_gp_connections_per_thread(void)
{
	/*
	 * We rely on the fact that the memory context will clean up the memory
	 * for the buffer.data.
	 */
	StringInfoData buffer;

	initStringInfo(&buffer);

	appendStringInfo(&buffer, "%d", gp_connections_per_thread);

	return buffer.data;
}



/* --------------------------------------------------------------------------------------------------
 * Logging
 */


/*
 * gp_log_gangs (string)
 *
 * Should creation, reallocation and cleanup of gangs of QE processes be logged?
 * "OFF"	 -> only errors are logged
 * "TERSE"	 -> terse logging of routine events, e.g. creation of new qExecs
 * "VERBOSE" -> gang allocation per command is logged
 * "DEBUG"	 -> additional events are logged at severity level DEBUG1 to DEBUG5
 *
 * The messages that are enabled by the TERSE and VERBOSE settings are
 * written with a severity level of LOG.
 */
GpVars_Verbosity gp_log_gang;

/*
 * gp_log_fts (string)
 *
 * What kind of messages should the fault-prober log ?
 * "OFF"	 -> only errors are logged
 * "TERSE"	 -> terse logging of routine events
 * "VERBOSE" -> gang allocation per command is logged
 * "DEBUG"	 -> additional events are logged at severity level DEBUG1 to DEBUG5
 *
 * The messages that are enabled by the TERSE and VERBOSE settings are
 * written with a severity level of LOG.
 */
GpVars_Verbosity gp_log_fts;

/*
 * gp_log_interconnect (string)
 *
 * Should connections between internal processes be logged?  (qDisp/qExec/etc)
 * "OFF"	 -> connection errors are logged
 * "TERSE"	 -> terse logging of routine events, e.g. successful connections
 * "VERBOSE" -> most interconnect setup events are logged
 * "DEBUG"	 -> additional events are logged at severity level DEBUG1 to DEBUG5.
 *
 * The messages that are enabled by the TERSE and VERBOSE settings are
 * written with a severity level of LOG.
 */
GpVars_Verbosity gp_log_interconnect;

/*
 * gpvars_string_to_verbosity
 */
static GpVars_Verbosity
gpvars_string_to_verbosity(const char *s)
{
	GpVars_Verbosity result;

	if (!s ||
		!s[0] ||
		!pg_strcasecmp("terse", s))
		result = GPVARS_VERBOSITY_TERSE;
	else if (!pg_strcasecmp("off", s))
		result = GPVARS_VERBOSITY_OFF;
	else if (!pg_strcasecmp("verbose", s))
		result = GPVARS_VERBOSITY_VERBOSE;
	else if (!pg_strcasecmp("debug", s))
		result = GPVARS_VERBOSITY_DEBUG;
	else
		result = GPVARS_VERBOSITY_UNDEFINED;
	return result;
}	/* gpvars_string_to_verbosity */

/*
 * gpvars_verbosity_to_string
 */
static const char *
gpvars_verbosity_to_string(GpVars_Verbosity verbosity)
{
	switch (verbosity)
	{
		case GPVARS_VERBOSITY_OFF:
			return "off";
		case GPVARS_VERBOSITY_TERSE:
			return "terse";
		case GPVARS_VERBOSITY_VERBOSE:
			return "verbose";
		case GPVARS_VERBOSITY_DEBUG:
			return "debug";
		default:
			return "*undefined*";
	}
}	/* gpvars_verbosity_to_string */

/*
 * gpperfmon_log_alert_level_to_string
 */
const char *
gpperfmon_log_alert_level_to_string(GpperfmonLogAlertLevel level)
{
	switch (level)
	{
		case GPPERFMON_LOG_ALERT_LEVEL_NONE:
			return "none";
		case GPPERFMON_LOG_ALERT_LEVEL_WARNING:
			return "warning";
		case GPPERFMON_LOG_ALERT_LEVEL_ERROR:
			return "error";
		case GPPERFMON_LOG_ALERT_LEVEL_FATAL:
			return "fatal";
		case GPPERFMON_LOG_ALERT_LEVEL_PANIC:
			return "panic";
		default:
			return "*undefined*";
	}
}

/*
 * gpperfmon_log_alert_level_from_string
 */
GpperfmonLogAlertLevel
gpperfmon_log_alert_level_from_string(const char *level_string)
{
	if (strcasecmp(level_string, "warning") == 0)
	{
		return GPPERFMON_LOG_ALERT_LEVEL_WARNING;
	}
	if (strcasecmp(level_string, "error") == 0)
	{
		return GPPERFMON_LOG_ALERT_LEVEL_ERROR;
	}
	if (strcasecmp(level_string, "fatal") == 0)
	{
		return GPPERFMON_LOG_ALERT_LEVEL_FATAL;
	}
	if (strcasecmp(level_string, "panic") == 0)
	{
		return GPPERFMON_LOG_ALERT_LEVEL_PANIC;
	}
	return GPPERFMON_LOG_ALERT_LEVEL_NONE;
}

/*
 * gpvars_assign_gp_log_gangs
 * gpvars_show_gp_log_gangs
 */
const char *
gpvars_assign_gp_log_gang(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	GpVars_Verbosity v = gpvars_string_to_verbosity(newval);

	if (v == GPVARS_VERBOSITY_UNDEFINED)
		return NULL;
	if (doit)
		gp_log_gang = v;
	return newval;
}	/* gpvars_assign_gp_log_gangs */

const char *
gpvars_show_gp_log_gang(void)
{
	return gpvars_verbosity_to_string(gp_log_gang);
}	/* gpvars_show_gp_log_gangs */

/*
 * gpvars_assign_gp_log_fts
 * gpvars_show_gp_log_fts
 */
const char *
gpvars_assign_gp_log_fts(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	GpVars_Verbosity v = gpvars_string_to_verbosity(newval);

	if (v == GPVARS_VERBOSITY_UNDEFINED)
		return NULL;
	if (doit)
		gp_log_fts = v;
	return newval;
}	/* gpvars_assign_gp_log_fts */

const char *
gpvars_show_gp_log_fts(void)
{
	return gpvars_verbosity_to_string(gp_log_fts);
}	/* gpvars_show_gp_log_fts */

/*
 * gpvars_assign_gp_log_interconnect
 * gpvars_show_gp_log_interconnect
 */
const char *
gpvars_assign_gp_log_interconnect(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	GpVars_Verbosity v = gpvars_string_to_verbosity(newval);

	if (v == GPVARS_VERBOSITY_UNDEFINED)
		return NULL;
	if (doit)
		gp_log_interconnect = v;
	return newval;
}	/* gpvars_assign_gp_log_interconnect */

const char *
gpvars_show_gp_log_interconnect(void)
{
	return gpvars_verbosity_to_string(gp_log_interconnect);
}	/* gpvars_show_gp_log_interconnect */


/*
 * gpvars_assign_gp_interconnect_type
 * gpvars_show_gp_interconnect_type
 */
const char *
gpvars_assign_gp_interconnect_type(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	int			newtype = 0;

	if (newval == NULL || newval[0] == 0)
		newtype = INTERCONNECT_TYPE_UDPIFC;
	else if (!pg_strcasecmp("udpifc", newval))
		newtype = INTERCONNECT_TYPE_UDPIFC;
	else
		elog(ERROR, "Only support UDPIFC, (current type is '%s')", gpvars_show_gp_interconnect_type());

	if (doit)
	{
		Gp_interconnect_type = newtype;
	}

	return newval;
}	/* gpvars_assign_gp_log_interconnect */

const char *
gpvars_show_gp_interconnect_type(void)
{
	return "UDPIFC";
}	/* gpvars_show_gp_log_interconnect */

/*
 * gpvars_assign_gp_interconnect_fc_method
 * gpvars_show_gp_interconnect_fc_method
 */
const char *
gpvars_assign_gp_interconnect_fc_method(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	int			newmethod = 0;

	if (newval == NULL || newval[0] == 0 ||
		!pg_strcasecmp("capacity", newval))
		newmethod = INTERCONNECT_FC_METHOD_CAPACITY;
	else if (!pg_strcasecmp("loss", newval))
		newmethod = INTERCONNECT_FC_METHOD_LOSS;
	else
		elog(ERROR, "Unknown interconnect flow control method. (current method is '%s')", gpvars_show_gp_interconnect_fc_method());

	if (doit)
	{
		Gp_interconnect_fc_method = newmethod;
	}

	return newval;
}	/* gpvars_assign_gp_interconnect_fc_method */

const char *
gpvars_show_gp_interconnect_fc_method(void)
{
	switch (Gp_interconnect_fc_method)
	{
		case INTERCONNECT_FC_METHOD_CAPACITY:
			return "CAPACITY";
		case INTERCONNECT_FC_METHOD_LOSS:
			return "LOSS";
		default:
			return "CAPACITY";
	}
}	/* gpvars_show_gp_interconnect_fc_method */

/*
 * Parse the string value of gp_autostats_mode and gp_autostats_mode_in_functions
 */
static int
gpvars_parse_gp_autostats_mode(const char *newval, bool inFunctions)
{
	int			newtype = 0;

	if (newval == NULL || newval[0] == 0 ||
		!pg_strcasecmp("none", newval))
	{
		newtype = GP_AUTOSTATS_NONE;
	}
	else if (!pg_strcasecmp("on_change", newval) || !pg_strcasecmp("onchange", newval))
	{
		newtype = GP_AUTOSTATS_ON_CHANGE;
	}
	else if (!pg_strcasecmp("on_no_stats", newval))
	{
		newtype = GP_AUTOSTATS_ON_NO_STATS;
	}
	else
	{
		const char *autostats_mode_string;

		if (inFunctions)
		{
			autostats_mode_string = gpvars_show_gp_autostats_mode_in_functions();
		}
		else
		{
			autostats_mode_string = gpvars_show_gp_autostats_mode();
		}
		elog(ERROR, "Unknown autostats mode. (current type is '%s')", autostats_mode_string);
	}

	return newtype;
}

/*
 * gpvars_assign_gp_autostats_mode
 * gpvars_show_gp_autostats_mode
 */
const char *
gpvars_assign_gp_autostats_mode(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	int			newtype = gpvars_parse_gp_autostats_mode(newval, false /* inFunctions */ );

	if (doit)
	{
		gp_autostats_mode = newtype;
	}

	return newval;
}

/*
 * Common function to show the value of the gp_autostats_mode
 * and gp_autostats_mode_in_functions GUCs
 */
static const char *
gpvars_show_gp_autostats_mode_common(bool inFunctions)
{
	GpAutoStatsModeValue autostats_mode;

	if (inFunctions)
	{
		autostats_mode = gp_autostats_mode_in_functions;
	}
	else
	{
		autostats_mode = gp_autostats_mode;
	}
	switch (autostats_mode)
	{
		case GP_AUTOSTATS_NONE:
			return "NONE";
		case GP_AUTOSTATS_ON_CHANGE:
			return "ON_CHANGE";
		case GP_AUTOSTATS_ON_NO_STATS:
			return "ON_NO_STATS";
		default:
			return "NONE";
	}
}

const char *
gpvars_show_gp_autostats_mode(void)
{
	return gpvars_show_gp_autostats_mode_common(false /* inFunctions */ );
}

/*
 * gpvars_assign_gp_autostats_mode_in_functions
 * gpvars_show_gp_autostats_mode_in_functions
 */

const char *
gpvars_assign_gp_autostats_mode_in_functions(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	bool		inFunctions = true;
	int			newtype = gpvars_parse_gp_autostats_mode(newval, inFunctions);

	if (doit)
	{
		gp_autostats_mode_in_functions = newtype;
	}

	return newval;
}


const char *
gpvars_show_gp_autostats_mode_in_functions(void)
{
	return gpvars_show_gp_autostats_mode_common(true /* inFunctions */ );
}

/* gp_enable_gpperfmon and gp_gpperfmon_send_interval are GUCs that we'd like
 * to have propagate from master to segments but we don't want non-super users
 * to be able to set it.  Unfortunately, as long as we use libpq to connect to
 * the segments its hard to create a clean way of doing this.
 *
 * Here we check and enforce that if the value is being set on the master its being
 * done as superuser and not a regular user.
 *
 */
bool
gpvars_assign_gp_enable_gpperfmon(bool newval, bool doit, GucSource source)
{
	if (doit)
	{

		if (Gp_role == GP_ROLE_DISPATCH && IsUnderPostmaster && GetCurrentRoleId() != InvalidOid && !superuser())
		{
			ereport(ERROR,
					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
					 errmsg("must be superuser to set gp_enable_gpperfmon")));
		}
		else
		{
			gp_enable_gpperfmon = newval;
		}
	}

	return true;
}

bool
gpvars_assign_gp_gpperfmon_send_interval(int newval, bool doit, GucSource source)
{
	if (doit)
	{
		if (Gp_role == GP_ROLE_DISPATCH && IsUnderPostmaster && GetCurrentRoleId() != InvalidOid && !superuser())
		{
			ereport(ERROR,
					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
			 errmsg("must be superuser to set gp_gpperfmon_send_interval")));
		}
		else
		{
			gp_gpperfmon_send_interval = newval;
		}
	}

	return true;
}

const char *
gpvars_assign_gp_gpperfmon_log_alert_level(const char *newval, bool doit, GucSource source)
{
	if (doit)
	{
		if (!pg_strcasecmp(newval, "none"))
		{
			gpperfmon_log_alert_level = GPPERFMON_LOG_ALERT_LEVEL_NONE;
		}
		else if (!pg_strcasecmp(newval, "warning"))
		{
			gpperfmon_log_alert_level = GPPERFMON_LOG_ALERT_LEVEL_WARNING;
		}
		else if (!pg_strcasecmp(newval, "error"))
		{
			gpperfmon_log_alert_level = GPPERFMON_LOG_ALERT_LEVEL_ERROR;
		}
		else if (!pg_strcasecmp(newval, "fatal"))
		{
			gpperfmon_log_alert_level = GPPERFMON_LOG_ALERT_LEVEL_FATAL;
		}
		else if (!pg_strcasecmp(newval, "panic"))
		{
			gpperfmon_log_alert_level = GPPERFMON_LOG_ALERT_LEVEL_PANIC;
		}
		else
		{
			elog(ERROR, "Unknown log alert level '%s'. (current value is '%s')", newval, gpperfmon_log_alert_level_to_string(gpperfmon_log_alert_level));
		}
	}

	return newval;
}

const char *
gpvars_show_gp_gpperfmon_log_alert_level(void)
{
	return gpperfmon_log_alert_level_to_string(gpperfmon_log_alert_level);
}

/*
 * Request the fault-prober to suspend probes -- no fault actions will
 * be taken based on in-flight probes until the prober is unpaused.
 */
bool
gpvars_assign_gp_fts_probe_pause(bool newval, bool doit, GucSource source)
{
	if (doit)
	{
		/*
		 * We only want to do fancy stuff on the master (where we have a
		 * prober).
		 */
		if (ftsProbeInfo && Gp_segment == -1)
		{
			/*
			 * fts_pauseProbes is externally set/cleared; fts_cancelProbes is
			 * externally set and cleared by FTS
			 */
			ftsLock();
			ftsProbeInfo->fts_pauseProbes = newval;
			ftsProbeInfo->fts_discardResults = ftsProbeInfo->fts_discardResults || newval;
			ftsUnlock();

			/*
			 * If we're unpausing, we want to force the prober to re-read
			 * everything. (we want FtsNotifyProber()).
			 */
			if (!newval)
			{
				FtsNotifyProber();
			}
		}
		gp_fts_probe_pause = newval;
	}

	return true;
}

/*
 * gpvars_assign_gp_resqueue_memory_policy
 * gpvars_show_gp_resqueue_memory_policy
 */
const char *
gpvars_assign_gp_resqueue_memory_policy(const char *newval, bool doit, GucSource source __attribute__((unused)))
{
	ResQueueMemoryPolicy newtype = RESQUEUE_MEMORY_POLICY_NONE;

	if (newval == NULL || newval[0] == 0 ||
		!pg_strcasecmp("none", newval))
		newtype = RESQUEUE_MEMORY_POLICY_NONE;
	else if (!pg_strcasecmp("auto", newval))
		newtype = RESQUEUE_MEMORY_POLICY_AUTO;
	else if (!pg_strcasecmp("eager_free", newval))
		newtype = RESQUEUE_MEMORY_POLICY_EAGER_FREE;
	else
		elog(ERROR, "unknown resource queue memory policy: current policy is '%s'", gpvars_show_gp_resqueue_memory_policy());

	if (doit)
	{
		gp_resqueue_memory_policy = newtype;
	}

	return newval;
}

const char *
gpvars_show_gp_resqueue_memory_policy(void)
{
	switch (gp_resqueue_memory_policy)
	{
		case RESQUEUE_MEMORY_POLICY_NONE:
			return "none";
		case RESQUEUE_MEMORY_POLICY_AUTO:
			return "auto";
		case RESQUEUE_MEMORY_POLICY_EAGER_FREE:
			return "eager_free";
		default:
			return "none";
	}
}

/*
 * gpvars_assign_statement_mem
 */
bool
gpvars_assign_statement_mem(int newval, bool doit, GucSource source __attribute__((unused)))
{
	if (newval >= max_statement_mem)
	{
		elog(ERROR, "Invalid input for statement_mem. Must be less than max_statement_mem (%d kB).", max_statement_mem);
	}

	if (doit)
	{
		statement_mem = newval;
	}

	return true;
}

/*
 * increment_command_count
 *	  Increment gp_command_count. If the new command count is 0 or a negative number, reset it to 1.
 */
void
increment_command_count()
{
	if (gp_cancel_query_print_log)
	{
		ereport(LOG,
				(errmsg("Incrementing command count from %d to %d",
						gp_command_count, gp_command_count + 1),
				 errprintstack(true)));
	}

	gp_command_count++;
	if (gp_command_count <= 0)
	{
		gp_command_count = 1;
	}
}