/src/bin/pgbench/pgbench.c

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/*
 * pgbench.c
 *
 * A simple benchmark program for PostgreSQL
 * Originally written by Tatsuo Ishii and enhanced by many contributors.
 *
 * src/bin/pgbench/pgbench.c
 * Copyright (c) 2000-2018, PostgreSQL Global Development Group
 * ALL RIGHTS RESERVED;
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without a written agreement
 * is hereby granted, provided that the above copyright notice and this
 * paragraph and the following two paragraphs appear in all copies.
 *
 * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
 * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
 * DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 */

#ifdef WIN32
#define FD_SETSIZE 1024			/* set before winsock2.h is included */
#endif							/* ! WIN32 */

#include "postgres_fe.h"
#include "fe_utils/conditional.h"

#include "getopt_long.h"
#include "libpq-fe.h"
#include "portability/instr_time.h"

#include <ctype.h>
#include <float.h>
#include <limits.h>
#include <math.h>
#include <signal.h>
#include <time.h>
#include <sys/time.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif

#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>		/* for getrlimit */
#endif

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

#include "pgbench.h"

#define ERRCODE_UNDEFINED_TABLE  "42P01"

/*
 * Hashing constants
 */
#define FNV_PRIME			UINT64CONST(0x100000001b3)
#define FNV_OFFSET_BASIS	UINT64CONST(0xcbf29ce484222325)
#define MM2_MUL				UINT64CONST(0xc6a4a7935bd1e995)
#define MM2_MUL_TIMES_8		UINT64CONST(0x35253c9ade8f4ca8)
#define MM2_ROT				47

/*
 * Multi-platform pthread implementations
 */

#ifdef WIN32
/* Use native win32 threads on Windows */
typedef struct win32_pthread *pthread_t;
typedef int pthread_attr_t;

static int	pthread_create(pthread_t *thread, pthread_attr_t *attr, void *(*start_routine) (void *), void *arg);
static int	pthread_join(pthread_t th, void **thread_return);
#elif defined(ENABLE_THREAD_SAFETY)
/* Use platform-dependent pthread capability */
#include <pthread.h>
#else
/* No threads implementation, use none (-j 1) */
#define pthread_t void *
#endif


/********************************************************************
 * some configurable parameters */

/* max number of clients allowed */
#ifdef FD_SETSIZE
#define MAXCLIENTS	(FD_SETSIZE - 10)
#else
#define MAXCLIENTS	1024
#endif

#define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */

#define LOG_STEP_SECONDS	5	/* seconds between log messages */
#define DEFAULT_NXACTS	10		/* default nxacts */

#define ZIPF_CACHE_SIZE	15		/* cache cells number */

#define MIN_GAUSSIAN_PARAM		2.0 /* minimum parameter for gauss */
#define MAX_ZIPFIAN_PARAM		1000	/* maximum parameter for zipfian */

int			nxacts = 0;			/* number of transactions per client */
int			duration = 0;		/* duration in seconds */
int64		end_time = 0;		/* when to stop in micro seconds, under -T */

/*
 * scaling factor. for example, scale = 10 will make 1000000 tuples in
 * pgbench_accounts table.
 */
int			scale = 1;

/*
 * fillfactor. for example, fillfactor = 90 will use only 90 percent
 * space during inserts and leave 10 percent free.
 */
int			fillfactor = 100;

/*
 * use unlogged tables?
 */
bool		unlogged_tables = false;

/*
 * log sampling rate (1.0 = log everything, 0.0 = option not given)
 */
double		sample_rate = 0.0;

/*
 * When threads are throttled to a given rate limit, this is the target delay
 * to reach that rate in usec.  0 is the default and means no throttling.
 */
int64		throttle_delay = 0;

/*
 * Transactions which take longer than this limit (in usec) are counted as
 * late, and reported as such, although they are completed anyway. When
 * throttling is enabled, execution time slots that are more than this late
 * are skipped altogether, and counted separately.
 */
int64		latency_limit = 0;

/*
 * tablespace selection
 */
char	   *tablespace = NULL;
char	   *index_tablespace = NULL;

/* random seed used when calling srandom() */
int64		random_seed = -1;

/*
 * end of configurable parameters
 *********************************************************************/

#define nbranches	1			/* Makes little sense to change this.  Change
								 * -s instead */
#define ntellers	10
#define naccounts	100000

/*
 * The scale factor at/beyond which 32bit integers are incapable of storing
 * 64bit values.
 *
 * Although the actual threshold is 21474, we use 20000 because it is easier to
 * document and remember, and isn't that far away from the real threshold.
 */
#define SCALE_32BIT_THRESHOLD 20000

bool		use_log;			/* log transaction latencies to a file */
bool		use_quiet;			/* quiet logging onto stderr */
int			agg_interval;		/* log aggregates instead of individual
								 * transactions */
bool		per_script_stats = false;	/* whether to collect stats per script */
int			progress = 0;		/* thread progress report every this seconds */
bool		progress_timestamp = false; /* progress report with Unix time */
int			nclients = 1;		/* number of clients */
int			nthreads = 1;		/* number of threads */
bool		is_connect;			/* establish connection for each transaction */
bool		is_latencies;		/* report per-command latencies */
int			main_pid;			/* main process id used in log filename */

char	   *pghost = "";
char	   *pgport = "";
char	   *login = NULL;
char	   *dbName;
char	   *logfile_prefix = NULL;
const char *progname;

#define WSEP '@'				/* weight separator */

volatile bool timer_exceeded = false;	/* flag from signal handler */

/*
 * Variable definitions.
 *
 * If a variable only has a string value, "svalue" is that value, and value is
 * "not set".  If the value is known, "value" contains the value (in any
 * variant).
 *
 * In this case "svalue" contains the string equivalent of the value, if we've
 * had occasion to compute that, or NULL if we haven't.
 */
typedef struct
{
	char	   *name;			/* variable's name */
	char	   *svalue;			/* its value in string form, if known */
	PgBenchValue value;			/* actual variable's value */
} Variable;

#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
#define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */

/*
 * Simple data structure to keep stats about something.
 *
 * XXX probably the first value should be kept and used as an offset for
 * better numerical stability...
 */
typedef struct SimpleStats
{
	int64		count;			/* how many values were encountered */
	double		min;			/* the minimum seen */
	double		max;			/* the maximum seen */
	double		sum;			/* sum of values */
	double		sum2;			/* sum of squared values */
} SimpleStats;

/*
 * Data structure to hold various statistics: per-thread and per-script stats
 * are maintained and merged together.
 */
typedef struct StatsData
{
	time_t		start_time;		/* interval start time, for aggregates */
	int64		cnt;			/* number of transactions, including skipped */
	int64		skipped;		/* number of transactions skipped under --rate
								 * and --latency-limit */
	SimpleStats latency;
	SimpleStats lag;
} StatsData;

/*
 * Connection state machine states.
 */
typedef enum
{
	/*
	 * The client must first choose a script to execute.  Once chosen, it can
	 * either be throttled (state CSTATE_START_THROTTLE under --rate) or start
	 * right away (state CSTATE_START_TX).
	 */
	CSTATE_CHOOSE_SCRIPT,

	/*
	 * In CSTATE_START_THROTTLE state, we calculate when to begin the next
	 * transaction, and advance to CSTATE_THROTTLE.  CSTATE_THROTTLE state
	 * sleeps until that moment.  (If throttling is not enabled, doCustom()
	 * falls directly through from CSTATE_START_THROTTLE to CSTATE_START_TX.)
	 */
	CSTATE_START_THROTTLE,
	CSTATE_THROTTLE,

	/*
	 * CSTATE_START_TX performs start-of-transaction processing.  Establishes
	 * a new connection for the transaction, in --connect mode, and records
	 * the transaction start time.
	 */
	CSTATE_START_TX,

	/*
	 * We loop through these states, to process each command in the script:
	 *
	 * CSTATE_START_COMMAND starts the execution of a command.  On a SQL
	 * command, the command is sent to the server, and we move to
	 * CSTATE_WAIT_RESULT state.  On a \sleep meta-command, the timer is set,
	 * and we enter the CSTATE_SLEEP state to wait for it to expire. Other
	 * meta-commands are executed immediately.
	 *
	 * CSTATE_SKIP_COMMAND for conditional branches which are not executed,
	 * quickly skip commands that do not need any evaluation.
	 *
	 * CSTATE_WAIT_RESULT waits until we get a result set back from the server
	 * for the current command.
	 *
	 * CSTATE_SLEEP waits until the end of \sleep.
	 *
	 * CSTATE_END_COMMAND records the end-of-command timestamp, increments the
	 * command counter, and loops back to CSTATE_START_COMMAND state.
	 */
	CSTATE_START_COMMAND,
	CSTATE_SKIP_COMMAND,
	CSTATE_WAIT_RESULT,
	CSTATE_SLEEP,
	CSTATE_END_COMMAND,

	/*
	 * CSTATE_END_TX performs end-of-transaction processing.  Calculates
	 * latency, and logs the transaction.  In --connect mode, closes the
	 * current connection.  Chooses the next script to execute and starts over
	 * in CSTATE_START_THROTTLE state, or enters CSTATE_FINISHED if we have no
	 * more work to do.
	 */
	CSTATE_END_TX,

	/*
	 * Final states.  CSTATE_ABORTED means that the script execution was
	 * aborted because a command failed, CSTATE_FINISHED means success.
	 */
	CSTATE_ABORTED,
	CSTATE_FINISHED
} ConnectionStateEnum;

/*
 * Connection state.
 */
typedef struct
{
	PGconn	   *con;			/* connection handle to DB */
	int			id;				/* client No. */
	ConnectionStateEnum state;	/* state machine's current state. */
	ConditionalStack cstack;	/* enclosing conditionals state */

	int			use_file;		/* index in sql_script for this client */
	int			command;		/* command number in script */

	/* client variables */
	Variable   *variables;		/* array of variable definitions */
	int			nvariables;		/* number of variables */
	bool		vars_sorted;	/* are variables sorted by name? */

	/* various times about current transaction */
	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
	int64		sleep_until;	/* scheduled start time of next cmd (usec) */
	instr_time	txn_begin;		/* used for measuring schedule lag times */
	instr_time	stmt_begin;		/* used for measuring statement latencies */

	bool		prepared[MAX_SCRIPTS];	/* whether client prepared the script */

	/* per client collected stats */
	int64		cnt;			/* client transaction count, for -t */
	int			ecnt;			/* error count */
} CState;

/*
 * Cache cell for zipfian_random call
 */
typedef struct
{
	/* cell keys */
	double		s;				/* s - parameter of zipfan_random function */
	int64		n;				/* number of elements in range (max - min + 1) */

	double		harmonicn;		/* generalizedHarmonicNumber(n, s) */
	double		alpha;
	double		beta;
	double		eta;

	uint64		last_used;		/* last used logical time */
} ZipfCell;

/*
 * Zipf cache for zeta values
 */
typedef struct
{
	uint64		current;		/* counter for LRU cache replacement algorithm */

	int			nb_cells;		/* number of filled cells */
	int			overflowCount;	/* number of cache overflows */
	ZipfCell	cells[ZIPF_CACHE_SIZE];
} ZipfCache;

/*
 * Thread state
 */
typedef struct
{
	int			tid;			/* thread id */
	pthread_t	thread;			/* thread handle */
	CState	   *state;			/* array of CState */
	int			nstate;			/* length of state[] */
	unsigned short random_state[3]; /* separate randomness for each thread */
	int64		throttle_trigger;	/* previous/next throttling (us) */
	FILE	   *logfile;		/* where to log, or NULL */
	ZipfCache	zipf_cache;		/* for thread-safe  zipfian random number
								 * generation */

	/* per thread collected stats */
	instr_time	start_time;		/* thread start time */
	instr_time	conn_time;
	StatsData	stats;
	int64		latency_late;	/* executed but late transactions */
} TState;

#define INVALID_THREAD		((pthread_t) 0)

/*
 * queries read from files
 */
#define SQL_COMMAND		1
#define META_COMMAND	2
#define MAX_ARGS		10

typedef enum MetaCommand
{
	META_NONE,					/* not a known meta-command */
	META_SET,					/* \set */
	META_SETSHELL,				/* \setshell */
	META_SHELL,					/* \shell */
	META_SLEEP,					/* \sleep */
	META_IF,					/* \if */
	META_ELIF,					/* \elif */
	META_ELSE,					/* \else */
	META_ENDIF					/* \endif */
} MetaCommand;

typedef enum QueryMode
{
	QUERY_SIMPLE,				/* simple query */
	QUERY_EXTENDED,				/* extended query */
	QUERY_PREPARED,				/* extended query with prepared statements */
	NUM_QUERYMODE
} QueryMode;

static QueryMode querymode = QUERY_SIMPLE;
static const char *QUERYMODE[] = {"simple", "extended", "prepared"};

typedef struct
{
	char	   *line;			/* text of command line */
	int			command_num;	/* unique index of this Command struct */
	int			type;			/* command type (SQL_COMMAND or META_COMMAND) */
	MetaCommand meta;			/* meta command identifier, or META_NONE */
	int			argc;			/* number of command words */
	char	   *argv[MAX_ARGS]; /* command word list */
	PgBenchExpr *expr;			/* parsed expression, if needed */
	SimpleStats stats;			/* time spent in this command */
} Command;

typedef struct ParsedScript
{
	const char *desc;			/* script descriptor (eg, file name) */
	int			weight;			/* selection weight */
	Command   **commands;		/* NULL-terminated array of Commands */
	StatsData	stats;			/* total time spent in script */
} ParsedScript;

static ParsedScript sql_script[MAX_SCRIPTS];	/* SQL script files */
static int	num_scripts;		/* number of scripts in sql_script[] */
static int	num_commands = 0;	/* total number of Command structs */
static int64 total_weight = 0;

static int	debug = 0;			/* debug flag */

/* Builtin test scripts */
typedef struct BuiltinScript
{
	const char *name;			/* very short name for -b ... */
	const char *desc;			/* short description */
	const char *script;			/* actual pgbench script */
} BuiltinScript;

static const BuiltinScript builtin_script[] =
{
	{
		"tpcb-like",
		"<builtin: TPC-B (sort of)>",
		"\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
		"\\set bid random(1, " CppAsString2(nbranches) " * :scale)\n"
		"\\set tid random(1, " CppAsString2(ntellers) " * :scale)\n"
		"\\set delta random(-5000, 5000)\n"
		"BEGIN;\n"
		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
		"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
		"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
		"END;\n"
	},
	{
		"simple-update",
		"<builtin: simple update>",
		"\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
		"\\set bid random(1, " CppAsString2(nbranches) " * :scale)\n"
		"\\set tid random(1, " CppAsString2(ntellers) " * :scale)\n"
		"\\set delta random(-5000, 5000)\n"
		"BEGIN;\n"
		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
		"END;\n"
	},
	{
		"select-only",
		"<builtin: select only>",
		"\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
	}
};


/* Function prototypes */
static void setNullValue(PgBenchValue *pv);
static void setBoolValue(PgBenchValue *pv, bool bval);
static void setIntValue(PgBenchValue *pv, int64 ival);
static void setDoubleValue(PgBenchValue *pv, double dval);
static bool evaluateExpr(TState *, CState *, PgBenchExpr *, PgBenchValue *);
static void doLog(TState *thread, CState *st,
	  StatsData *agg, bool skipped, double latency, double lag);
static void processXactStats(TState *thread, CState *st, instr_time *now,
				 bool skipped, StatsData *agg);
static void pgbench_error(const char *fmt,...) pg_attribute_printf(1, 2);
static void addScript(ParsedScript script);
static void *threadRun(void *arg);
static void setalarm(int seconds);
static void finishCon(CState *st);


/* callback functions for our flex lexer */
static const PsqlScanCallbacks pgbench_callbacks = {
	NULL,						/* don't need get_variable functionality */
	pgbench_error
};


static void
usage(void)
{
	printf("%s is a benchmarking tool for PostgreSQL.\n\n"
		   "Usage:\n"
		   "  %s [OPTION]... [DBNAME]\n"
		   "\nInitialization options:\n"
		   "  -i, --initialize         invokes initialization mode\n"
		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
		   "                           run selected initialization steps\n"
		   "  -F, --fillfactor=NUM     set fill factor\n"
		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
		   "  -q, --quiet              quiet logging (one message each 5 seconds)\n"
		   "  -s, --scale=NUM          scaling factor\n"
		   "  --foreign-keys           create foreign key constraints between tables\n"
		   "  --index-tablespace=TABLESPACE\n"
		   "                           create indexes in the specified tablespace\n"
		   "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
		   "  --unlogged-tables        create tables as unlogged tables\n"
		   "\nOptions to select what to run:\n"
		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
		   "                           (use \"-b list\" to list available scripts)\n"
		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
		   "                           (same as \"-b simple-update\")\n"
		   "  -S, --select-only        perform SELECT-only transactions\n"
		   "                           (same as \"-b select-only\")\n"
		   "\nBenchmarking options:\n"
		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
		   "  -C, --connect            establish new connection for each transaction\n"
		   "  -D, --define=VARNAME=VALUE\n"
		   "                           define variable for use by custom script\n"
		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
		   "  -l, --log                write transaction times to log file\n"
		   "  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
		   "  -M, --protocol=simple|extended|prepared\n"
		   "                           protocol for submitting queries (default: simple)\n"
		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
		   "  -r, --report-latencies   report average latency per command\n"
		   "  -R, --rate=NUM           target rate in transactions per second\n"
		   "  -s, --scale=NUM          report this scale factor in output\n"
		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
		   "  -T, --time=NUM           duration of benchmark test in seconds\n"
		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
		   "  --log-prefix=PREFIX      prefix for transaction time log file\n"
		   "                           (default: \"pgbench_log\")\n"
		   "  --progress-timestamp     use Unix epoch timestamps for progress\n"
		   "  --random-seed=SEED       set random seed (\"time\", \"rand\", integer)\n"
		   "  --sampling-rate=NUM      fraction of transactions to log (e.g., 0.01 for 1%%)\n"
		   "\nCommon options:\n"
		   "  -d, --debug              print debugging output\n"
		   "  -h, --host=HOSTNAME      database server host or socket directory\n"
		   "  -p, --port=PORT          database server port number\n"
		   "  -U, --username=USERNAME  connect as specified database user\n"
		   "  -V, --version            output version information, then exit\n"
		   "  -?, --help               show this help, then exit\n"
		   "\n"
		   "Report bugs to <pgsql-bugs@postgresql.org>.\n",
		   progname, progname);
}

/* return whether str matches "^\s*[-+]?[0-9]+$" */
static bool
is_an_int(const char *str)
{
	const char *ptr = str;

	/* skip leading spaces; cast is consistent with strtoint64 */
	while (*ptr && isspace((unsigned char) *ptr))
		ptr++;

	/* skip sign */
	if (*ptr == '+' || *ptr == '-')
		ptr++;

	/* at least one digit */
	if (*ptr && !isdigit((unsigned char) *ptr))
		return false;

	/* eat all digits */
	while (*ptr && isdigit((unsigned char) *ptr))
		ptr++;

	/* must have reached end of string */
	return *ptr == '\0';
}


/*
 * strtoint64 -- convert a string to 64-bit integer
 *
 * This function is a modified version of scanint8() from
 * src/backend/utils/adt/int8.c.
 */
int64
strtoint64(const char *str)
{
	const char *ptr = str;
	int64		result = 0;
	int			sign = 1;

	/*
	 * Do our own scan, rather than relying on sscanf which might be broken
	 * for long long.
	 */

	/* skip leading spaces */
	while (*ptr && isspace((unsigned char) *ptr))
		ptr++;

	/* handle sign */
	if (*ptr == '-')
	{
		ptr++;

		/*
		 * Do an explicit check for INT64_MIN.  Ugly though this is, it's
		 * cleaner than trying to get the loop below to handle it portably.
		 */
		if (strncmp(ptr, "9223372036854775808", 19) == 0)
		{
			result = PG_INT64_MIN;
			ptr += 19;
			goto gotdigits;
		}
		sign = -1;
	}
	else if (*ptr == '+')
		ptr++;

	/* require at least one digit */
	if (!isdigit((unsigned char) *ptr))
		fprintf(stderr, "invalid input syntax for integer: \"%s\"\n", str);

	/* process digits */
	while (*ptr && isdigit((unsigned char) *ptr))
	{
		int64		tmp = result * 10 + (*ptr++ - '0');

		if ((tmp / 10) != result)	/* overflow? */
			fprintf(stderr, "value \"%s\" is out of range for type bigint\n", str);
		result = tmp;
	}

gotdigits:

	/* allow trailing whitespace, but not other trailing chars */
	while (*ptr != '\0' && isspace((unsigned char) *ptr))
		ptr++;

	if (*ptr != '\0')
		fprintf(stderr, "invalid input syntax for integer: \"%s\"\n", str);

	return ((sign < 0) ? -result : result);
}

/* random number generator: uniform distribution from min to max inclusive */
static int64
getrand(TState *thread, int64 min, int64 max)
{
	/*
	 * Odd coding is so that min and max have approximately the same chance of
	 * being selected as do numbers between them.
	 *
	 * pg_erand48() is thread-safe and concurrent, which is why we use it
	 * rather than random(), which in glibc is non-reentrant, and therefore
	 * protected by a mutex, and therefore a bottleneck on machines with many
	 * CPUs.
	 */
	return min + (int64) ((max - min + 1) * pg_erand48(thread->random_state));
}

/*
 * random number generator: exponential distribution from min to max inclusive.
 * the parameter is so that the density of probability for the last cut-off max
 * value is exp(-parameter).
 */
static int64
getExponentialRand(TState *thread, int64 min, int64 max, double parameter)
{
	double		cut,
				uniform,
				rand;

	/* abort if wrong parameter, but must really be checked beforehand */
	Assert(parameter > 0.0);
	cut = exp(-parameter);
	/* erand in [0, 1), uniform in (0, 1] */
	uniform = 1.0 - pg_erand48(thread->random_state);

	/*
	 * inner expression in (cut, 1] (if parameter > 0), rand in [0, 1)
	 */
	Assert((1.0 - cut) != 0.0);
	rand = -log(cut + (1.0 - cut) * uniform) / parameter;
	/* return int64 random number within between min and max */
	return min + (int64) ((max - min + 1) * rand);
}

/* random number generator: gaussian distribution from min to max inclusive */
static int64
getGaussianRand(TState *thread, int64 min, int64 max, double parameter)
{
	double		stdev;
	double		rand;

	/* abort if parameter is too low, but must really be checked beforehand */
	Assert(parameter >= MIN_GAUSSIAN_PARAM);

	/*
	 * Get user specified random number from this loop, with -parameter <
	 * stdev <= parameter
	 *
	 * This loop is executed until the number is in the expected range.
	 *
	 * As the minimum parameter is 2.0, the probability of looping is low:
	 * sqrt(-2 ln(r)) <= 2 => r >= e^{-2} ~ 0.135, then when taking the
	 * average sinus multiplier as 2/pi, we have a 8.6% looping probability in
	 * the worst case. For a parameter value of 5.0, the looping probability
	 * is about e^{-5} * 2 / pi ~ 0.43%.
	 */
	do
	{
		/*
		 * pg_erand48 generates [0,1), but for the basic version of the
		 * Box-Muller transform the two uniformly distributed random numbers
		 * are expected in (0, 1] (see
		 * http://en.wikipedia.org/wiki/Box_muller)
		 */
		double		rand1 = 1.0 - pg_erand48(thread->random_state);
		double		rand2 = 1.0 - pg_erand48(thread->random_state);

		/* Box-Muller basic form transform */
		double		var_sqrt = sqrt(-2.0 * log(rand1));

		stdev = var_sqrt * sin(2.0 * M_PI * rand2);

		/*
		 * we may try with cos, but there may be a bias induced if the
		 * previous value fails the test. To be on the safe side, let us try
		 * over.
		 */
	}
	while (stdev < -parameter || stdev >= parameter);

	/* stdev is in [-parameter, parameter), normalization to [0,1) */
	rand = (stdev + parameter) / (parameter * 2.0);

	/* return int64 random number within between min and max */
	return min + (int64) ((max - min + 1) * rand);
}

/*
 * random number generator: generate a value, such that the series of values
 * will approximate a Poisson distribution centered on the given value.
 */
static int64
getPoissonRand(TState *thread, int64 center)
{
	/*
	 * Use inverse transform sampling to generate a value > 0, such that the
	 * expected (i.e. average) value is the given argument.
	 */
	double		uniform;

	/* erand in [0, 1), uniform in (0, 1] */
	uniform = 1.0 - pg_erand48(thread->random_state);

	return (int64) (-log(uniform) * ((double) center) + 0.5);
}

/* helper function for getZipfianRand */
static double
generalizedHarmonicNumber(int64 n, double s)
{
	int			i;
	double		ans = 0.0;

	for (i = n; i > 1; i--)
		ans += pow(i, -s);
	return ans + 1.0;
}

/* set harmonicn and other parameters to cache cell */
static void
zipfSetCacheCell(ZipfCell *cell, int64 n, double s)
{
	double		harmonic2;

	cell->n = n;
	cell->s = s;

	harmonic2 = generalizedHarmonicNumber(2, s);
	cell->harmonicn = generalizedHarmonicNumber(n, s);

	cell->alpha = 1.0 / (1.0 - s);
	cell->beta = pow(0.5, s);
	cell->eta = (1.0 - pow(2.0 / n, 1.0 - s)) / (1.0 - harmonic2 / cell->harmonicn);
}

/*
 * search for cache cell with keys (n, s)
 * and create new cell if it does not exist
 */
static ZipfCell *
zipfFindOrCreateCacheCell(ZipfCache *cache, int64 n, double s)
{
	int			i,
				least_recently_used = 0;
	ZipfCell   *cell;

	/* search cached cell for given parameters */
	for (i = 0; i < cache->nb_cells; i++)
	{
		cell = &cache->cells[i];
		if (cell->n == n && cell->s == s)
			return &cache->cells[i];

		if (cell->last_used < cache->cells[least_recently_used].last_used)
			least_recently_used = i;
	}

	/* create new one if it does not exist */
	if (cache->nb_cells < ZIPF_CACHE_SIZE)
		i = cache->nb_cells++;
	else
	{
		/* replace LRU cell if cache is full */
		i = least_recently_used;
		cache->overflowCount++;
	}

	zipfSetCacheCell(&cache->cells[i], n, s);

	cache->cells[i].last_used = cache->current++;
	return &cache->cells[i];
}

/*
 * Computing zipfian using rejection method, based on
 * "Non-Uniform Random Variate Generation",
 * Luc Devroye, p. 550-551, Springer 1986.
 */
static int64
computeIterativeZipfian(TState *thread, int64 n, double s)
{
	double		b = pow(2.0, s - 1.0);
	double		x,
				t,
				u,
				v;

	while (true)
	{
		/* random variates */
		u = pg_erand48(thread->random_state);
		v = pg_erand48(thread->random_state);

		x = floor(pow(u, -1.0 / (s - 1.0)));

		t = pow(1.0 + 1.0 / x, s - 1.0);
		/* reject if too large or out of bound */
		if (v * x * (t - 1.0) / (b - 1.0) <= t / b && x <= n)
			break;
	}
	return (int64) x;
}

/*
 * Computing zipfian using harmonic numbers, based on algorithm described in
 * "Quickly Generating Billion-Record Synthetic Databases",
 * Jim Gray et al, SIGMOD 1994
 */
static int64
computeHarmonicZipfian(TState *thread, int64 n, double s)
{
	ZipfCell   *cell = zipfFindOrCreateCacheCell(&thread->zipf_cache, n, s);
	double		uniform = pg_erand48(thread->random_state);
	double		uz = uniform * cell->harmonicn;

	if (uz < 1.0)
		return 1;
	if (uz < 1.0 + cell->beta)
		return 2;
	return 1 + (int64) (cell->n * pow(cell->eta * uniform - cell->eta + 1.0, cell->alpha));
}

/* random number generator: zipfian distribution from min to max inclusive */
static int64
getZipfianRand(TState *thread, int64 min, int64 max, double s)
{
	int64		n = max - min + 1;

	/* abort if parameter is invalid */
	Assert(s > 0.0 && s != 1.0 && s <= MAX_ZIPFIAN_PARAM);


	return min - 1 + ((s > 1)
					  ? computeIterativeZipfian(thread, n, s)
					  : computeHarmonicZipfian(thread, n, s));
}

/*
 * FNV-1a hash function
 */
static int64
getHashFnv1a(int64 val, uint64 seed)
{
	int64		result;
	int			i;

	result = FNV_OFFSET_BASIS ^ seed;
	for (i = 0; i < 8; ++i)
	{
		int32		octet = val & 0xff;

		val = val >> 8;
		result = result ^ octet;
		result = result * FNV_PRIME;
	}

	return result;
}

/*
 * Murmur2 hash function
 *
 * Based on original work of Austin Appleby
 * https://github.com/aappleby/smhasher/blob/master/src/MurmurHash2.cpp
 */
static int64
getHashMurmur2(int64 val, uint64 seed)
{
	uint64		result = seed ^ MM2_MUL_TIMES_8;	/* sizeof(int64) */
	uint64		k = (uint64) val;

	k *= MM2_MUL;
	k ^= k >> MM2_ROT;
	k *= MM2_MUL;

	result ^= k;
	result *= MM2_MUL;

	result ^= result >> MM2_ROT;
	result *= MM2_MUL;
	result ^= result >> MM2_ROT;

	return (int64) result;
}

/*
 * Initialize the given SimpleStats struct to all zeroes
 */
static void
initSimpleStats(SimpleStats *ss)
{
	memset(ss, 0, sizeof(SimpleStats));
}

/*
 * Accumulate one value into a SimpleStats struct.
 */
static void
addToSimpleStats(SimpleStats *ss, double val)
{
	if (ss->count == 0 || val < ss->min)
		ss->min = val;
	if (ss->count == 0 || val > ss->max)
		ss->max = val;
	ss->count++;
	ss->sum += val;
	ss->sum2 += val * val;
}

/*
 * Merge two SimpleStats objects
 */
static void
mergeSimpleStats(SimpleStats *acc, SimpleStats *ss)
{
	if (acc->count == 0 || ss->min < acc->min)
		acc->min = ss->min;
	if (acc->count == 0 || ss->max > acc->max)
		acc->max = ss->max;
	acc->count += ss->count;
	acc->sum += ss->sum;
	acc->sum2 += ss->sum2;
}

/*
 * Initialize a StatsData struct to mostly zeroes, with its start time set to
 * the given value.
 */
static void
initStats(StatsData *sd, time_t start_time)
{
	sd->start_time = start_time;
	sd->cnt = 0;
	sd->skipped = 0;
	initSimpleStats(&sd->latency);
	initSimpleStats(&sd->lag);
}

/*
 * Accumulate one additional item into the given stats object.
 */
static void
accumStats(StatsData *stats, bool skipped, double lat, double lag)
{
	stats->cnt++;

	if (skipped)
	{
		/* no latency to record on skipped transactions */
		stats->skipped++;
	}
	else
	{
		addToSimpleStats(&stats->latency, lat);

		/* and possibly the same for schedule lag */
		if (throttle_delay)
			addToSimpleStats(&stats->lag, lag);
	}
}

/* call PQexec() and exit() on failure */
static void
executeStatement(PGconn *con, const char *sql)
{
	PGresult   *res;

	res = PQexec(con, sql);
	if (PQresultStatus(res) != PGRES_COMMAND_OK)
	{
		fprintf(stderr, "%s", PQerrorMessage(con));
		exit(1);
	}
	PQclear(res);
}

/* call PQexec() and complain, but without exiting, on failure */
static void
tryExecuteStatement(PGconn *con, const char *sql)
{
	PGresult   *res;

	res = PQexec(con, sql);
	if (PQresultStatus(res) != PGRES_COMMAND_OK)
	{
		fprintf(stderr, "%s", PQerrorMessage(con));
		fprintf(stderr, "(ignoring this error and continuing anyway)\n");
	}
	PQclear(res);
}

/* set up a connection to the backend */
static PGconn *
doConnect(void)
{
	PGconn	   *conn;
	bool		new_pass;
	static bool have_password = false;
	static char password[100];

	/*
	 * Start the connection.  Loop until we have a password if requested by
	 * backend.
	 */
	do
	{
#define PARAMS_ARRAY_SIZE	7

		const char *keywords[PARAMS_ARRAY_SIZE];
		const char *values[PARAMS_ARRAY_SIZE];

		keywords[0] = "host";
		values[0] = pghost;
		keywords[1] = "port";
		values[1] = pgport;
		keywords[2] = "user";
		values[2] = login;
		keywords[3] = "password";
		values[3] = have_password ? password : NULL;
		keywords[4] = "dbname";
		values[4] = dbName;
		keywords[5] = "fallback_application_name";
		values[5] = progname;
		keywords[6] = NULL;
		values[6] = NULL;

		new_pass = false;

		conn = PQconnectdbParams(keywords, values, true);

		if (!conn)
		{
			fprintf(stderr, "connection to database \"%s\" failed\n",
					dbName);
			return NULL;
		}

		if (PQstatus(conn) == CONNECTION_BAD &&
			PQconnectionNeedsPassword(conn) &&
			!have_password)
		{
			PQfinish(conn);
			simple_prompt("Password: ", password, sizeof(password), false);
			have_password = true;
			new_pass = true;
		}
	} while (new_pass);

	/* check to see that the backend connection was successfully made */
	if (PQstatus(conn) == CONNECTION_BAD)
	{
		fprintf(stderr, "connection to database \"%s\" failed:\n%s",
				dbName, PQerrorMessage(conn));
		PQfinish(conn);
		return NULL;
	}

	return conn;
}

/* throw away response from backend */
static void
discard_response(CState *state)
{
	PGresult   *res;

	do
	{
		res = PQgetResult(state->con);
		if (res)
			PQclear(res);
	} while (res);
}

/* qsort comparator for Variable array */
static int
compareVariableNames(const void *v1, const void *v2)
{
	return strcmp(((const Variable *) v1)->name,
				  ((const Variable *) v2)->name);
}

/* Locate a variable by name; returns NULL if unknown */
static Variable *
lookupVariable(CState *st, char *name)
{
	Variable	key;

	/* On some versions of Solaris, bsearch of zero items dumps core */
	if (st->nvariables <= 0)
		return NULL;

	/* Sort if we have to */
	if (!st->vars_sorted)
	{
		qsort((void *) st->variables, st->nvariables, sizeof(Variable),
			  compareVariableNames);
		st->vars_sorted = true;
	}

	/* Now we can search */
	key.name = name;
	return (Variable *) bsearch((void *) &key,
								(void *) st->variables,
								st->nvariables,
								sizeof(Variable),
								compareVariableNames);
}

/* Get the value of a variable, in string form; returns NULL if unknown */
static char *
getVariable(CState *st, char *name)
{
	Variable   *var;
	char		stringform[64];

	var = lookupVariable(st, name);
	if (var == NULL)
		return NULL;			/* not found */

	if (var->svalue)
		return var->svalue;		/* we have it in string form */

	/* We need to produce a string equivalent of the value */
	Assert(var->value.type != PGBT_NO_VALUE);
	if (var->value.type == PGBT_NULL)
		snprintf(stringform, sizeof(stringform), "NULL");
	else if (var->value.type == PGBT_BOOLEAN)
		snprintf(stringform, sizeof(stringform),
				 "%s", var->value.u.bval ? "true" : "false");
	else if (var->value.type == PGBT_INT)
		snprintf(stringform, sizeof(stringform),
				 INT64_FORMAT, var->value.u.ival);
	else if (var->value.type == PGBT_DOUBLE)
		snprintf(stringform, sizeof(stringform),
				 "%.*g", DBL_DIG, var->value.u.dval);
	else						/* internal error, unexpected type */
		Assert(0);
	var->svalue = pg_strdup(stringform);
	return var->svalue;
}

/* Try to convert variable to a value; return false on failure */
static bool
makeVariableValue(Variable *var)
{
	size_t		slen;

	if (var->value.type != PGBT_NO_VALUE)
		return true;			/* no work */

	slen = strlen(var->svalue);

	if (slen == 0)
		/* what should it do on ""? */
		return false;

	if (pg_strcasecmp(var->svalue, "null") == 0)
	{
		setNullValue(&var->value);
	}

	/*
	 * accept prefixes such as y, ye, n, no... but not for "o". 0/1 are
	 * recognized later as an int, which is converted to bool if needed.
	 */
	else if (pg_strncasecmp(var->svalue, "true", slen) == 0 ||
			 pg_strncasecmp(var->svalue, "yes", slen) == 0 ||
			 pg_strcasecmp(var->svalue, "on") == 0)
	{
		setBoolValue(&var->value, true);
	}
	else if (pg_strncasecmp(var->svalue, "false", slen) == 0 ||
			 pg_strncasecmp(var->svalue, "no", slen) == 0 ||
			 pg_strcasecmp(var->svalue, "off") == 0 ||
			 pg_strcasecmp(var->svalue, "of") == 0)
	{
		setBoolValue(&var->value, false);
	}
	else if (is_an_int(var->svalue))
	{
		setIntValue(&var->value, strtoint64(var->svalue));
	}
	else						/* type should be double */
	{
		double		dv;
		char		xs;

		if (sscanf(var->svalue, "%lf%c", &dv, &xs) != 1)
		{
			fprintf(stderr,
					"malformed variable \"%s\" value: \"%s\"\n",
					var->name, var->svalue);
			return false;
		}
		setDoubleValue(&var->value, dv);
	}
	return true;
}

/*
 * Check whether a variable's name is allowed.
 *
 * We allow any non-ASCII character, as well as ASCII letters, digits, and
 * underscore.
 *
 * Keep this in sync with the definitions of variable name characters in
 * "src/fe_utils/psqlscan.l", "src/bin/psql/psqlscanslash.l" and
 * "src/bin/pgbench/exprscan.l".  Also see parseVariable(), below.
 *
 * Note: this static function is copied from "src/bin/psql/variables.c"
 */
static bool
valid_variable_name(const char *name)
{
	const unsigned char *ptr = (const unsigned char *) name;

	/* Mustn't be zero-length */
	if (*ptr == '\0')
		return false;

	while (*ptr)
	{
		if (IS_HIGHBIT_SET(*ptr) ||
			strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
				   "_0123456789", *ptr) != NULL)
			ptr++;
		else
			return false;
	}

	return true;
}

/*
 * Lookup a variable by name, creating it if need be.
 * Caller is expected to assign a value to the variable.
 * Returns NULL on failure (bad name).
 */
static Variable *
lookupCreateVariable(CState *st, const char *context, char *name)
{
	Variable   *var;

	var = lookupVariable(st, name);
	if (var == NULL)
	{
		Variable   *newvars;

		/*
		 * Check for the name only when declaring a new variable to avoid
		 * overhead.
		 */
		if (!valid_variable_name(name))
		{
			fprintf(stderr, "%s: invalid variable name: \"%s\"\n",
					context, name);
			return NULL;
		}

		/* Create variable at the end of the array */
		if (st->variables)
			newvars = (Variable *) pg_realloc(st->variables,
											  (st->nvariables + 1) * sizeof(Variable));
		else
			newvars = (Variable *) pg_malloc(sizeof(Variable));

		st->variables = newvars;

		var = &newvars[st->nvariables];

		var->name = pg_strdup(name);
		var->svalue = NULL;
		/* caller is expected to initialize remaining fields */

		st->nvariables++;
		/* we don't re-sort the array till we have to */
		st->vars_sorted = false;
	}

	return var;
}

/* Assign a string value to a variable, creating it if need be */
/* Returns false on failure (bad name) */
static bool
putVariable(CState *st, const char *context, char *name, const char *value)
{
	Variable   *var;
	char	   *val;

	var = lookupCreateVariable(st, context, name);
	if (!var)
		return false;

	/* dup then free, in case value is pointing at this variable */
	val = pg_strdup(value);

	if (var->svalue)
		free(var->svalue);
	var->svalue = val;
	var->value.type = PGBT_NO_VALUE;

	return true;
}

/* Assign a value to a variable, creating it if need be */
/* Returns false on failure (bad name) */
static bool
putVariableValue(CState *st, const char *context, char *name,
				 const PgBenchValue *value)
{
	Variable   *var;

	var = lookupCreateVariable(st, context, name);
	if (!var)
		return false;

	if (var->svalue)
		free(var->svalue);
	var->svalue = NULL;
	var->value = *value;

	return true;
}

/* Assign an integer value to a variable, creating it if need be */
/* Returns false on failure (bad name) */
static bool
putVariableInt(CState *st, const char *context, char *name, int64 value)
{
	PgBenchValue val;

	setIntValue(&val, value);
	return putVariableValue(st, context, name, &val);
}

/*
 * Parse a possible variable reference (:varname).
 *
 * "sql" points at a colon.  If what follows it looks like a valid
 * variable name, return a malloc'd string containing the variable name,
 * and set *eaten to the number of characters consumed.
 * Otherwise, return NULL.
 */
static char *
parseVariable(const char *sql, int *eaten)
{
	int			i = 0;
	char	   *name;

	do
	{
		i++;
	} while (IS_HIGHBIT_SET(sql[i]) ||
			 strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
					"_0123456789", sql[i]) != NULL);
	if (i == 1)
		return NULL;			/* no valid variable name chars */

	name = pg_malloc(i);
	memcpy(name, &sql[1], i - 1);
	name[i - 1] = '\0';

	*eaten = i;
	return name;
}

static char *
replaceVariable(char **sql, char *param, int len, char *value)
{
	int			valueln = strlen(value);

	if (valueln > len)
	{
		size_t		offset = param - *sql;

		*sql = pg_realloc(*sql, strlen(*sql) - len + valueln + 1);
		param = *sql + offset;
	}

	if (valueln != len)
		memmove(param + valueln, param + len, strlen(param + len) + 1);
	memcpy(param, value, valueln);

	return param + valueln;
}

static char *
assignVariables(CState *st, char *sql)
{
	char	   *p,
			   *name,
			   *val;

	p = sql;
	while ((p = strchr(p, ':')) != NULL)
	{
		int			eaten;

		name = parseVariable(p, &eaten);
		if (name == NULL)
		{
			while (*p == ':')
			{
				p++;
			}
			continue;
		}

		val = getVariable(st, name);
		free(name);
		if (val == NULL)
		{
			p++;
			continue;
		}

		p = replaceVariable(&sql, p, eaten, val);
	}

	return sql;
}

static void
getQueryParams(CState *st, const Command *command, const char **params)
{
	int			i;

	for (i = 0; i < command->argc - 1; i++)
		params[i] = getVariable(st, command->argv[i + 1]);
}

static char *
valueTypeName(PgBenchValue *pval)
{
	if (pval->type == PGBT_NO_VALUE)
		return "none";
	else if (pval->type == PGBT_NULL)
		return "null";
	else if (pval->type == PGBT_INT)
		return "int";
	else if (pval->type == PGBT_DOUBLE)
		return "double";
	else if (pval->type == PGBT_BOOLEAN)
		return "boolean";
	else
	{
		/* internal error, should never get there */
		Assert(false);
		return NULL;
	}
}

/* get a value as a boolean, or tell if there is a problem */
static bool
coerceToBool(PgBenchValue *pval, bool *bval)
{
	if (pval->type == PGBT_BOOLEAN)
	{
		*bval = pval->u.bval;
		return true;
	}
	else						/* NULL, INT or DOUBLE */
	{
		fprintf(stderr, "cannot coerce %s to boolean\n", valueTypeName(pval));
		*bval = false;			/* suppress uninitialized-variable warnings */
		return false;
	}
}

/*
 * Return true or false from an expression for conditional purposes.
 * Non zero numerical values are true, zero and NULL are false.
 */
static bool
valueTruth(PgBenchValue *pval)
{
	switch (pval->type)
	{
		case PGBT_NULL:
			return false;
		case PGBT_BOOLEAN:
			return pval->u.bval;
		case PGBT_INT:
			return pval->u.ival != 0;
		case PGBT_DOUBLE:
			return pval->u.dval != 0.0;
		default:
			/* internal error, unexpected type */
			Assert(0);
			return false;
	}
}

/* get a value as an int, tell if there is a problem */
static bool
coerceToInt(PgBenchValue *pval, int64 *ival)
{
	if (pval->type == PGBT_INT)
	{
		*ival = pval->u.ival;
		return true;
	}
	else if (pval->type == PGBT_DOUBLE)
	{
		double		dval = pval->u.dval;

		if (dval < PG_INT64_MIN || PG_INT64_MAX < dval)
		{
			fprintf(stderr, "double to int overflow for %f\n", dval);
			return false;
		}
		*ival = (int64) dval;
		return true;
	}
	else						/* BOOLEAN or NULL */
	{
		fprintf(stderr, "cannot coerce %s to int\n", valueTypeName(pval));
		return false;
	}
}

/* get a value as a double, or tell if there is a problem */
static bool
coerceToDouble(PgBenchValue *pval, double *dval)
{
	if (pval->type == PGBT_DOUBLE)
	{
		*dval = pval->u.dval;
		return true;
	}
	else if (pval->type == PGBT_INT)
	{
		*dval = (double) pval->u.ival;
		return true;
	}
	else						/* BOOLEAN or NULL */
	{
		fprintf(stderr, "cannot coerce %s to double\n", valueTypeName(pval));
		return false;
	}
}

/* assign a null value */
static void
setNullValue(PgBenchValue *pv)
{
	pv->type = PGBT_NULL;
	pv->u.ival = 0;
}

/* assign a boolean value */
static void
setBoolValue(PgBenchValue *pv, bool bval)
{
	pv->type = PGBT_BOOLEAN;
	pv->u.bval = bval;
}

/* assign an integer value */
static void
setIntValue(PgBenchValue *pv, int64 ival)
{
	pv->type = PGBT_INT;
	pv->u.ival = ival;
}

/* assign a double value */
static void
setDoubleValue(PgBenchValue *pv, double dval)
{
	pv->type = PGBT_DOUBLE;
	pv->u.dval = dval;
}

static bool
isLazyFunc(PgBenchFunction func)
{
	return func == PGBENCH_AND || func == PGBENCH_OR || func == PGBENCH_CASE;
}

/* lazy evaluation of some functions */
static bool
evalLazyFunc(TState *thread, CState *st,
			 PgBenchFunction func, PgBenchExprLink *args, PgBenchValue *retval)
{
	PgBenchValue a1,
				a2;
	bool		ba1,
				ba2;

	Assert(isLazyFunc(func) && args != NULL && args->next != NULL);

	/* args points to first condition */
	if (!evaluateExpr(thread, st, args->expr, &a1))
		return false;

	/* second condition for AND/OR and corresponding branch for CASE */
	args = args->next;

	switch (func)
	{
		case PGBENCH_AND:
			if (a1.type == PGBT_NULL)
			{
				setNullValue(retval);
				return true;
			}

			if (!coerceToBool(&a1, &ba1))
				return false;

			if (!ba1)
			{
				setBoolValue(retval, false);
				return true;
			}

			if (!evaluateExpr(thread, st, args->expr, &a2))
				return false;

			if (a2.type == PGBT_NULL)
			{
				setNullValue(retval);
				return true;
			}
			else if (!coerceToBool(&a2, &ba2))
				return false;
			else
			{
				setBoolValue(retval, ba2);
				return true;
			}

			return true;

		case PGBENCH_OR:

			if (a1.type == PGBT_NULL)
			{
				setNullValue(retval);
				return true;
			}

			if (!coerceToBool(&a1, &ba1))
				return false;

			if (ba1)
			{
				setBoolValue(retval, true);
				return true;
			}

			if (!evaluateExpr(thread, st, args->expr, &a2))
				return false;

			if (a2.type == PGBT_NULL)
			{
				setNullValue(retval);
				return true;
			}
			else if (!coerceToBool(&a2, &ba2))
				return false;
			else
			{
				setBoolValue(retval, ba2);
				return true;
			}

		case PGBENCH_CASE:
			/* when true, execute branch */
			if (valueTruth(&a1))
				return evaluateExpr(thread, st, args->expr, retval);

			/* now args contains next condition or final else expression */
			args = args->next;

			/* final else case? */
			if (args->next == NULL)
				return evaluateExpr(thread, st, args->expr, retval);

			/* no, another when, proceed */
			return evalLazyFunc(thread, st, PGBENCH_CASE, args, retval);

		default:
			/* internal error, cannot get here */
			Assert(0);
			break;
	}
	return false;
}

/* maximum number of function arguments */
#define MAX_FARGS 16

/*
 * Recursive evaluation of standard functions,
 * which do not require lazy evaluation.
 */
static bool
evalStandardFunc(TState *thread, CState *st,
				 PgBenchFunction func, PgBenchExprLink *args,
				 PgBenchValue *retval)
{
	/* evaluate all function arguments */
	int			nargs = 0;
	PgBenchValue vargs[MAX_FARGS];
	PgBenchExprLink *l = args;
	bool		has_null = false;

	for (nargs = 0; nargs < MAX_FARGS && l != NULL; nargs++, l = l->next)
	{
		if (!evaluateExpr(thread, st, l->expr, &vargs[nargs]))
			return false;
		has_null |= vargs[nargs].type == PGBT_NULL;
	}

	if (l != NULL)
	{
		fprintf(stderr,
				"too many function arguments, maximum is %d\n", MAX_FARGS);
		return false;
	}

	/* NULL arguments */
	if (has_null && func != PGBENCH_IS && func != PGBENCH_DEBUG)
	{
		setNullValue(retval);
		return true;
	}

	/* then evaluate function */
	switch (func)
	{
			/* overloaded operators */
		case PGBENCH_ADD:
		case PGBENCH_SUB:
		case PGBENCH_MUL:
		case PGBENCH_DIV:
		case PGBENCH_MOD:
		case PGBENCH_EQ:
		case PGBENCH_NE:
		case PGBENCH_LE:
		case PGBENCH_LT:
			{
				PgBenchValue *lval = &vargs[0],
						   *rval = &vargs[1];

				Assert(nargs == 2);

				/* overloaded type management, double if some double */
				if ((lval->type == PGBT_DOUBLE ||
					 rval->type == PGBT_DOUBLE) && func != PGBENCH_MOD)
				{
					double		ld,
								rd;

					if (!coerceToDouble(lval, &ld) ||
						!coerceToDouble(rval, &rd))
						return false;

					switch (func)
					{
						case PGBENCH_ADD:
							setDoubleValue(retval, ld + rd);
							return true;

						case PGBENCH_SUB:
							setDoubleValue(retval, ld - rd);
							return true;

						case PGBENCH_MUL:
							setDoubleValue(retval, ld * rd);
							return true;

						case PGBENCH_DIV:
							setDoubleValue(retval, ld / rd);
							return true;

						case PGBENCH_EQ:
							setBoolValue(retval, ld == rd);
							return true;

						case PGBENCH_NE:
							setBoolValue(retval, ld != rd);
							return true;

						case PGBENCH_LE:
							setBoolValue(retval, ld <= rd);
							return true;

						case PGBENCH_LT:
							setBoolValue(retval, ld < rd);
							return true;

						default:
							/* cannot get here */
							Assert(0);
					}
				}
				else			/* we have integer operands, or % */
				{
					int64		li,
								ri;

					if (!coerceToInt(lval, &li) ||
						!coerceToInt(rval, &ri))
						return false;

					switch (func)
					{
						case PGBENCH_ADD:
							setIntValue(retval, li + ri);
							return true;

						case PGBENCH_SUB:
							setIntValue(retval, li - ri);
							return true;

						case PGBENCH_MUL:
							setIntValue(retval, li * ri);
							return true;

						case PGBENCH_EQ:
							setBoolValue(retval, li == ri);
							return true;

						case PGBENCH_NE:
							setBoolValue(retval, li != ri);
							return true;

						case PGBENCH_LE:
							setBoolValue(retval, li <= ri);
							return true;

						case PGBENCH_LT:
							setBoolValue(retval, li…