/* pg_autovacuum.c
 * All the code for the pg_autovacuum program
 * (c) 2003 Matthew T. O'Connor
 * Revisions by Christopher B. Browne, Liberty RMS
 * Win32 Service code added by Dave Page
 *
 * $PostgreSQL: pgsql/contrib/pg_autovacuum/pg_autovacuum.c,v 1.33 2005/05/11 17:57:56 momjian Exp $
 */

#include "postgres_fe.h"

#include <unistd.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#include <time.h>
#include <sys/time.h>
#ifdef WIN32
#include <windows.h>
#endif
#include <sys/stat.h>
#include <fcntl.h>

#include "pg_autovacuum.h"

#ifdef WIN32
SERVICE_STATUS ServiceStatus;
SERVICE_STATUS_HANDLE hStatus;
int			appMode = 0;
char       deps[255];
#endif

/* define atooid */
#define atooid(x)  ((Oid) strtoul((x), NULL, 10))


static cmd_args *args;
static FILE	   *LOGOUTPUT;
static char		logbuffer[4096];


/* The main program loop function */
static int	VacuumLoop(int argc, char **argv);

/* Functions for dealing with command line arguements */
static cmd_args *get_cmd_args(int argc, char *argv[]);
static void print_cmd_args(void);
static void free_cmd_args(void);
static void usage(void);

/* Functions for managing database lists */
static Dllist *init_db_list(void);
static db_info *init_dbinfo(char *dbname, Oid oid, long age);
static void update_db_list(Dllist *db_list);
static void remove_db_from_list(Dlelem *db_to_remove);
static void print_db_info(db_info * dbi, int print_table_list);
static void print_db_list(Dllist *db_list, int print_table_lists);
static int	xid_wraparound_check(db_info * dbi);
static void free_db_list(Dllist *db_list);

/* Functions for managing table lists */
static tbl_info *init_table_info(PGresult *conn, int row, db_info * dbi);
static void update_table_list(db_info * dbi);
static void remove_table_from_list(Dlelem *tbl_to_remove);
static void print_table_list(Dllist *tbl_node);
static void print_table_info(tbl_info * tbl);
static void update_table_thresholds(db_info * dbi, tbl_info * tbl, int vacuum_type);
static void free_tbl_list(Dllist *tbl_list);

/* A few database helper functions */
static int	check_stats_enabled(db_info * dbi);
static PGconn *db_connect(db_info * dbi);
static void db_disconnect(db_info * dbi);
static PGresult *send_query(const char *query, db_info * dbi);

/* Other Generally needed Functions */
#ifndef WIN32
static void daemonize(void);
#endif
static void log_entry(const char *logentry, int level);

#ifdef WIN32
/* Windows Service related functions */
static void ControlHandler(DWORD request);
static int	InstallService();
static int	RemoveService();
#endif


static void
log_entry(const char *logentry, int level)
{
	/*
	 * Note: Under Windows we dump the log entries to the normal
	 * stderr/logfile as well, otherwise it can be a pain to debug
	 * service install failures etc.
	 */

	time_t		curtime;
	struct tm  *loctime;
	char		timebuffer[128],
				slevel[10];


#ifdef WIN32
	static HANDLE evtHandle = INVALID_HANDLE_VALUE;
	static int	last_level;
	WORD		elevel;
#endif

	switch (level)
	{
		case LVL_DEBUG:
			sprintf(slevel, "DEBUG:   ");
			break;

		case LVL_INFO:
			sprintf(slevel, "INFO:    ");
			break;

		case LVL_WARNING:
			sprintf(slevel, "WARNING: ");
			break;

		case LVL_ERROR:
			sprintf(slevel, "ERROR:   ");
			break;

		case LVL_EXTRA:
			sprintf(slevel, "         ");
			break;

		default:
			sprintf(slevel, "         ");
			break;
	}

	curtime = time(NULL);
	loctime = localtime(&curtime);
	strftime(timebuffer, sizeof(timebuffer), "%Y-%m-%d %H:%M:%S %Z", loctime);
	fprintf(LOGOUTPUT, "[%s] %s%s\n", timebuffer, slevel, logentry);

#ifdef WIN32

	/* Restore the previous level if this is extra info */
	if (level == LVL_EXTRA)
		level = last_level;
	last_level = level;

	switch (level)
	{
		case LVL_DEBUG:
			elevel = EVENTLOG_INFORMATION_TYPE;
			break;

		case LVL_INFO:
			elevel = EVENTLOG_SUCCESS;
			break;

		case LVL_WARNING:
			elevel = EVENTLOG_WARNING_TYPE;
			break;

		case LVL_ERROR:
			elevel = EVENTLOG_ERROR_TYPE;
			break;

		default:
			elevel = EVENTLOG_SUCCESS;
			break;
	}

	if (evtHandle == INVALID_HANDLE_VALUE)
	{
		evtHandle = RegisterEventSource(NULL, "PostgreSQL Auto Vacuum");
		if (evtHandle == NULL)
		{
			evtHandle = INVALID_HANDLE_VALUE;
			return;
		}
	}

	ReportEvent(evtHandle, elevel, 0, 0, NULL, 1, 0, &logentry, NULL);
#endif
}

/*
 * Function used to detach the pg_autovacuum daemon from the tty and go into
 * the background.
 *
 * This code is ripped directly from pmdaemonize in postmaster.c.
 */
#ifndef WIN32
static void
daemonize(void)
{
	int			i;
	pid_t		pid;

	pid = fork();
	if (pid == (pid_t) -1)
	{
		log_entry("cannot disassociate from controlling TTY", LVL_ERROR);
		fflush(LOGOUTPUT);
		_exit(1);
	}
	else if (pid)
	{							/* parent */
		/* Parent should just exit, without doing any atexit cleanup */
		_exit(0);
	}

/* GH: If there's no setsid(), we hopefully don't need silent mode.
 * Until there's a better solution.
 */
#ifdef HAVE_SETSID
	if (setsid() < 0)
	{
		log_entry("cannot disassociate from controlling TTY", LVL_ERROR);
		fflush(LOGOUTPUT);
		_exit(1);
	}
#endif
	i = open(NULL_DEV, O_RDWR);
	dup2(i, 0);
	dup2(i, 1);
	dup2(i, 2);
	close(i);
}
#endif   /* WIN32 */

/* Create and return tbl_info struct with initialized to values from row or res */
static tbl_info *
init_table_info(PGresult *res, int row, db_info * dbi)
{
	tbl_info   *new_tbl = (tbl_info *) malloc(sizeof(tbl_info));

	if (!new_tbl)
	{
		log_entry("init_table_info: Cannot get memory", LVL_ERROR);
		fflush(LOGOUTPUT);
		return NULL;
	}

	if (res == NULL)
		return NULL;

	new_tbl->dbi = dbi;			/* set pointer to db */

	new_tbl->schema_name = (char *)
		malloc(strlen(PQgetvalue(res, row, PQfnumber(res, "schemaname"))) + 1);
	if (!new_tbl->schema_name)
	{
		log_entry("init_table_info: malloc failed on new_tbl->schema_name", LVL_ERROR);
		fflush(LOGOUTPUT);
		return NULL;
	}
	strcpy(new_tbl->schema_name,
		   PQgetvalue(res, row, PQfnumber(res, "schemaname")));

	new_tbl->table_name = (char *)
		malloc(strlen(PQgetvalue(res, row, PQfnumber(res, "relname"))) +
			   strlen(new_tbl->schema_name) + 6);
	if (!new_tbl->table_name)
	{
		log_entry("init_table_info: malloc failed on new_tbl->table_name", LVL_ERROR);
		fflush(LOGOUTPUT);
		return NULL;
	}

	/*
	 * Put both the schema and table name in quotes so that we can work
	 * with mixed case table names
	 */
	strcpy(new_tbl->table_name, "\"");
	strcat(new_tbl->table_name, new_tbl->schema_name);
	strcat(new_tbl->table_name, "\".\"");
	strcat(new_tbl->table_name, PQgetvalue(res, row, PQfnumber(res, "relname")));
	strcat(new_tbl->table_name, "\"");

	new_tbl->CountAtLastAnalyze =
		(atol(PQgetvalue(res, row, PQfnumber(res, "n_tup_ins"))) +
		 atol(PQgetvalue(res, row, PQfnumber(res, "n_tup_upd"))) +
		 atol(PQgetvalue(res, row, PQfnumber(res, "n_tup_del"))));
	new_tbl->curr_analyze_count = new_tbl->CountAtLastAnalyze;

	new_tbl->CountAtLastVacuum =
		(atol(PQgetvalue(res, row, PQfnumber(res, "n_tup_del"))) +
		 atol(PQgetvalue(res, row, PQfnumber(res, "n_tup_upd"))));
	new_tbl->curr_vacuum_count = new_tbl->CountAtLastVacuum;

	new_tbl->relid = atooid(PQgetvalue(res, row, PQfnumber(res, "oid")));
	new_tbl->reltuples = atof(PQgetvalue(res, row, PQfnumber(res, "reltuples")));
	new_tbl->relpages = atooid(PQgetvalue(res, row, PQfnumber(res, "relpages")));

	if (strcmp("t", PQgetvalue(res, row, PQfnumber(res, "relisshared"))))
		new_tbl->relisshared = 0;
	else
		new_tbl->relisshared = 1;

	new_tbl->analyze_threshold =
		args->analyze_base_threshold + args->analyze_scaling_factor * new_tbl->reltuples;
	new_tbl->vacuum_threshold =
		args->vacuum_base_threshold + args->vacuum_scaling_factor * new_tbl->reltuples;

	if (args->debug >= 2)
		print_table_info(new_tbl);

	return new_tbl;
}

/* Set thresholds = base_value + scaling_factor * reltuples
   Should be called after a vacuum since vacuum updates values in pg_class */
static void
update_table_thresholds(db_info * dbi, tbl_info * tbl, int vacuum_type)
{
	PGresult   *res = NULL;
	int			disconnect = 0;
	char		query[128];

	if (dbi->conn == NULL)
	{
		dbi->conn = db_connect(dbi);
		disconnect = 1;
	}

	if (dbi->conn != NULL)
	{
		snprintf(query, sizeof(query), PAGES_QUERY, tbl->relid);
		res = send_query(query, dbi);
		if (res != NULL)
		{
			tbl->reltuples =
				atof(PQgetvalue(res, 0, PQfnumber(res, "reltuples")));
			tbl->relpages = atooid(PQgetvalue(res, 0, PQfnumber(res, "relpages")));

			/*
			 * update vacuum thresholds only of we just did a vacuum
			 * analyze
			 */
			if (vacuum_type == VACUUM_ANALYZE)
			{
				tbl->vacuum_threshold =
					(args->vacuum_base_threshold + args->vacuum_scaling_factor * tbl->reltuples);
				tbl->CountAtLastVacuum = tbl->curr_vacuum_count;
			}

			/* update analyze thresholds */
			tbl->analyze_threshold =
				(args->analyze_base_threshold + args->analyze_scaling_factor * tbl->reltuples);
			tbl->CountAtLastAnalyze = tbl->curr_analyze_count;

			PQclear(res);

			/*
			 * If the stats collector is reporting fewer updates then we
			 * have on record then the stats were probably reset, so we
			 * need to reset also
			 */
			if ((tbl->curr_analyze_count < tbl->CountAtLastAnalyze) ||
				(tbl->curr_vacuum_count < tbl->CountAtLastVacuum))
			{
				tbl->CountAtLastAnalyze = tbl->curr_analyze_count;
				tbl->CountAtLastVacuum = tbl->curr_vacuum_count;
			}
		}
	}
	if (disconnect)
		db_disconnect(dbi);
}

static void
update_table_list(db_info * dbi)
{
	int			disconnect = 0;
	PGresult   *res = NULL;
	tbl_info   *tbl = NULL;
	Dlelem	   *tbl_elem = DLGetHead(dbi->table_list);
	int			i = 0,
				t = 0,
				found_match = 0;

	if (dbi->conn == NULL)
	{
		dbi->conn = db_connect(dbi);
		disconnect = 1;
	}

	if (dbi->conn != NULL)
	{
		/*
		 * Get a result set that has all the information we will need to
		 * both remove tables from the list that no longer exist and add
		 * tables to the list that are new
		 */
		res = send_query((char *) TABLE_STATS_QUERY, dbi);
		if (res != NULL)
		{
			t = PQntuples(res);

			/*
			 * First: use the tbl_list as the outer loop and the result
			 * set as the inner loop, this will determine what tables
			 * should be removed
			 */
			while (tbl_elem != NULL)
			{
				tbl = ((tbl_info *) DLE_VAL(tbl_elem));
				found_match = 0;

				for (i = 0; i < t; i++)
				{				/* loop through result set looking for a
								 * match */
					if (tbl->relid == atooid(PQgetvalue(res, i, PQfnumber(res, "oid"))))
					{
						found_match = 1;
						break;
					}
				}
				if (found_match == 0)
				{				/* then we didn't find this tbl_elem in
								 * the result set */
					Dlelem	   *elem_to_remove = tbl_elem;

					tbl_elem = DLGetSucc(tbl_elem);
					remove_table_from_list(elem_to_remove);
				}
				else
					tbl_elem = DLGetSucc(tbl_elem);
			}					/* Done removing dropped tables from the
								 * table_list */

			/*
			 * Then loop use result set as outer loop and tbl_list as the
			 * inner loop to determine what tables are new
			 */
			for (i = 0; i < t; i++)
			{
				tbl_elem = DLGetHead(dbi->table_list);
				found_match = 0;
				while (tbl_elem != NULL)
				{
					tbl = ((tbl_info *) DLE_VAL(tbl_elem));
					if (tbl->relid == atooid(PQgetvalue(res, i, PQfnumber(res, "oid"))))
					{
						found_match = 1;
						break;
					}
					tbl_elem = DLGetSucc(tbl_elem);
				}
				if (found_match == 0)	/* then we didn't find this result
										 * now in the tbl_list */
				{
					DLAddTail(dbi->table_list, DLNewElem(init_table_info(res, i, dbi)));
					if (args->debug >= 1)
					{
						sprintf(logbuffer, "added table: %s.%s", dbi->dbname,
								((tbl_info *) DLE_VAL(DLGetTail(dbi->table_list)))->table_name);
						log_entry(logbuffer, LVL_DEBUG);
					}
				}
			}					/* end of for loop that adds tables */
		}
		fflush(LOGOUTPUT);
		PQclear(res);
		res = NULL;
		if (args->debug >= 3)
			print_table_list(dbi->table_list);
		if (disconnect)
			db_disconnect(dbi);
	}
}

/* Free memory, and remove the node from the list */
static void
remove_table_from_list(Dlelem *tbl_to_remove)
{
	tbl_info   *tbl = ((tbl_info *) DLE_VAL(tbl_to_remove));

	if (args->debug >= 1)
	{
		sprintf(logbuffer, "Removing table: %s from list.", tbl->table_name);
		log_entry(logbuffer, LVL_DEBUG);
		fflush(LOGOUTPUT);
	}
	DLRemove(tbl_to_remove);

	if (tbl->schema_name)
	{
		free(tbl->schema_name);
		tbl->schema_name = NULL;
	}
	if (tbl->table_name)
	{
		free(tbl->table_name);
		tbl->table_name = NULL;
	}
	if (tbl)
	{
		free(tbl);
		tbl = NULL;
	}
	DLFreeElem(tbl_to_remove);
}

/* Free the entire table list */
static void
free_tbl_list(Dllist *tbl_list)
{
	Dlelem	   *tbl_elem = DLGetHead(tbl_list);
	Dlelem	   *tbl_elem_to_remove = NULL;

	while (tbl_elem != NULL)
	{
		tbl_elem_to_remove = tbl_elem;
		tbl_elem = DLGetSucc(tbl_elem);
		remove_table_from_list(tbl_elem_to_remove);
	}
	DLFreeList(tbl_list);
}

static void
print_table_list(Dllist *table_list)
{
	Dlelem	   *table_elem = DLGetHead(table_list);

	while (table_elem != NULL)
	{
		print_table_info(((tbl_info *) DLE_VAL(table_elem)));
		table_elem = DLGetSucc(table_elem);
	}
}

static void
print_table_info(tbl_info * tbl)
{
	sprintf(logbuffer, "  table name: %s.%s", tbl->dbi->dbname, tbl->table_name);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "     relid: %u;   relisshared: %d", tbl->relid, tbl->relisshared);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "     reltuples: %f;  relpages: %u", tbl->reltuples, tbl->relpages);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "     curr_analyze_count: %li; curr_vacuum_count: %li",
			tbl->curr_analyze_count, tbl->curr_vacuum_count);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "     last_analyze_count: %li; last_vacuum_count: %li",
			tbl->CountAtLastAnalyze, tbl->CountAtLastVacuum);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "     analyze_threshold: %li; vacuum_threshold: %li",
			tbl->analyze_threshold, tbl->vacuum_threshold);
	log_entry(logbuffer, LVL_INFO);
	fflush(LOGOUTPUT);
}

/* End of table Management Functions */

/* Beginning of DB Management Functions */

/* init_db_list() creates the db_list and initalizes template1 */
static Dllist *
init_db_list(void)
{
	Dllist	   *db_list = DLNewList();
	db_info    *dbs = NULL;
	PGresult   *res = NULL;
#ifdef WIN32
	int			k = 0;
#endif

	DLAddHead(db_list, DLNewElem(init_dbinfo((char *) "template1", 0, 0)));
	if (DLGetHead(db_list) == NULL)
	{							/* Make sure init_dbinfo was successful */
		log_entry("init_db_list(): Error creating db_list for db: template1.", LVL_ERROR);
		fflush(LOGOUTPUT);
		return NULL;
	}

	/*
	 * We do this just so we can set the proper oid for the template1
	 * database
	 */
	dbs = ((db_info *) DLE_VAL(DLGetHead(db_list)));
	dbs->conn = db_connect(dbs);

#ifdef WIN32
	while (dbs->conn == NULL && !appMode && k < 10)
	{
		int        j;

		/* Pause for 30 seconds to allow the database to start up */
		log_entry("Pausing 30 seconds to allow the database to startup completely", LVL_INFO);
		fflush(LOGOUTPUT);
		ServiceStatus.dwWaitHint = 10;
		for (j=0; j<6; j++)
		{
			pg_usleep(5000000);
			ServiceStatus.dwCheckPoint++;
			SetServiceStatus(hStatus, &ServiceStatus);
			fflush(LOGOUTPUT);
		}

		/* now try again */
		log_entry("Attempting to connect again.", LVL_INFO);
		dbs->conn = db_connect(dbs);
		k++;
	}
#endif

	if (dbs->conn != NULL)
	{
		res = send_query(FROZENOID_QUERY, dbs);
		if (res != NULL)
		{
			dbs->oid = atooid(PQgetvalue(res, 0, PQfnumber(res, "oid")));
			dbs->age = atol(PQgetvalue(res, 0, PQfnumber(res, "age")));
			if (res)
				PQclear(res);

			if (args->debug >= 2)
				print_db_list(db_list, 0);
		}
		else
			return NULL;
	}
	return db_list;
}

/* Simple function to create an instance of the dbinfo struct
	Initalizes all the pointers and connects to the database  */
static db_info *
init_dbinfo(char *dbname, Oid oid, long age)
{
	db_info    *newdbinfo = (db_info *) malloc(sizeof(db_info));

	newdbinfo->analyze_threshold = args->vacuum_base_threshold;
	newdbinfo->vacuum_threshold = args->analyze_base_threshold;
	newdbinfo->dbname = (char *) malloc(strlen(dbname) + 1);
	strcpy(newdbinfo->dbname, dbname);
	newdbinfo->username = NULL;
	if (args->user != NULL)
	{
		newdbinfo->username = (char *) malloc(strlen(args->user) + 1);
		strcpy(newdbinfo->username, args->user);
	}
	newdbinfo->password = NULL;
	if (args->password != NULL)
	{
		newdbinfo->password = (char *) malloc(strlen(args->password) + 1);
		strcpy(newdbinfo->password, args->password);
	}
	newdbinfo->oid = oid;
	newdbinfo->age = age;
	newdbinfo->table_list = DLNewList();
	newdbinfo->conn = NULL;

	if (args->debug >= 2)
		print_table_list(newdbinfo->table_list);

	return newdbinfo;
}

/* Function adds and removes databases from the db_list as appropriate */
static void
update_db_list(Dllist *db_list)
{
	int			disconnect = 0;
	PGresult   *res = NULL;
	Dlelem	   *db_elem = DLGetHead(db_list);
	db_info    *dbi = NULL;
	db_info    *dbi_template1 = DLE_VAL(db_elem);
	int			i = 0,
				t = 0,
				found_match = 0;

	if (args->debug >= 2)
	{
		log_entry("updating the database list", LVL_DEBUG);
		fflush(LOGOUTPUT);
	}

	if (dbi_template1->conn == NULL)
	{
		dbi_template1->conn = db_connect(dbi_template1);
		disconnect = 1;
	}

	if (dbi_template1->conn != NULL)
	{
		/*
		 * Get a result set that has all the information we will need to
		 * both remove databasews from the list that no longer exist and
		 * add databases to the list that are new
		 */
		res = send_query(FROZENOID_QUERY2, dbi_template1);
		if (res != NULL)
		{
			t = PQntuples(res);

			/*
			 * First: use the db_list as the outer loop and the result set
			 * as the inner loop, this will determine what databases
			 * should be removed
			 */
			while (db_elem != NULL)
			{
				dbi = ((db_info *) DLE_VAL(db_elem));
				found_match = 0;

				for (i = 0; i < t; i++)
				{				/* loop through result set looking for a
								 * match */
					if (dbi->oid == atooid(PQgetvalue(res, i, PQfnumber(res, "oid"))))
					{
						found_match = 1;

						/*
						 * update the dbi->age so that we ensure
						 * xid_wraparound won't happen
						 */
						dbi->age = atol(PQgetvalue(res, i, PQfnumber(res, "age")));
						break;
					}
				}
				if (found_match == 0)
				{				/* then we didn't find this db_elem in the
								 * result set */
					Dlelem	   *elem_to_remove = db_elem;

					db_elem = DLGetSucc(db_elem);
					remove_db_from_list(elem_to_remove);
				}
				else
					db_elem = DLGetSucc(db_elem);
			}					/* Done removing dropped databases from
								 * the table_list */

			/*
			 * Then loop use result set as outer loop and db_list as the
			 * inner loop to determine what databases are new
			 */
			for (i = 0; i < t; i++)
			{
				db_elem = DLGetHead(db_list);
				found_match = 0;
				while (db_elem != NULL)
				{
					dbi = ((db_info *) DLE_VAL(db_elem));
					if (dbi->oid == atooid(PQgetvalue(res, i, PQfnumber(res, "oid"))))
					{
						found_match = 1;
						break;
					}
					db_elem = DLGetSucc(db_elem);
				}
				if (found_match == 0)	/* then we didn't find this result
										 * now in the tbl_list */
				{
					DLAddTail(db_list, DLNewElem(init_dbinfo
						  (PQgetvalue(res, i, PQfnumber(res, "datname")),
					   atooid(PQgetvalue(res, i, PQfnumber(res, "oid"))),
					  atol(PQgetvalue(res, i, PQfnumber(res, "age"))))));
					if (args->debug >= 1)
					{
						sprintf(logbuffer, "added database: %s", ((db_info *) DLE_VAL(DLGetTail(db_list)))->dbname);
						log_entry(logbuffer, LVL_DEBUG);
					}
				}
			}					/* end of for loop that adds tables */
		}
		fflush(LOGOUTPUT);
		PQclear(res);
		res = NULL;
		if (args->debug >= 3)
			print_db_list(db_list, 0);
		if (disconnect)
			db_disconnect(dbi_template1);
	}
}

/* xid_wraparound_check

From the docs:

With the standard freezing policy, the age column will start at one billion for a
freshly-vacuumed database. When the age approaches two billion, the database must
be vacuumed again to avoid risk of wraparound failures. Recommended practice is
to vacuum each database at least once every half-a-billion (500 million) transactions,
so as to provide plenty of safety margin.

So we do a full database vacuum if age > 1.5billion
return 0 if nothing happened,
return 1 if the database needed a database wide vacuum
*/
static int
xid_wraparound_check(db_info * dbi)
{
	/*
	 * FIXME: should probably do something better here so that we don't
	 * vacuum all the databases on the server at the same time.  We have
	 * 500million xacts to work with so we should be able to spread the
	 * load of full database vacuums a bit
	 */
	if (dbi->age > 1500000000)
	{
		PGresult   *res = NULL;

		res = send_query("VACUUM", dbi);
		/* FIXME: Perhaps should add a check for PQ_COMMAND_OK */
		if (res != NULL)
			PQclear(res);
		return 1;
	}
	return 0;
}

/* Close DB connection, free memory, and remove the node from the list */
static void
remove_db_from_list(Dlelem *db_to_remove)
{
	db_info    *dbi = ((db_info *) DLE_VAL(db_to_remove));

	if (args->debug >= 1)
	{
		sprintf(logbuffer, "Removing db: %s from list.", dbi->dbname);
		log_entry(logbuffer, LVL_DEBUG);
		fflush(LOGOUTPUT);
	}
	DLRemove(db_to_remove);
	if (dbi->conn)
		db_disconnect(dbi);
	if (dbi->dbname)
	{
		free(dbi->dbname);
		dbi->dbname = NULL;
	}
	if (dbi->username)
	{
		free(dbi->username);
		dbi->username = NULL;
	}
	if (dbi->password)
	{
		free(dbi->password);
		dbi->password = NULL;
	}
	if (dbi->table_list)
	{
		free_tbl_list(dbi->table_list);
		dbi->table_list = NULL;
	}
	if (dbi)
	{
		free(dbi);
		dbi = NULL;
	}
	DLFreeElem(db_to_remove);
}

/* Function is called before program exit to free all memory
		mostly it's just to keep valgrind happy */
static void
free_db_list(Dllist *db_list)
{
	Dlelem	   *db_elem = DLGetHead(db_list);
	Dlelem	   *db_elem_to_remove = NULL;

	while (db_elem != NULL)
	{
		db_elem_to_remove = db_elem;
		db_elem = DLGetSucc(db_elem);
		remove_db_from_list(db_elem_to_remove);
		db_elem_to_remove = NULL;
	}
	DLFreeList(db_list);
}

static void
print_db_list(Dllist *db_list, int print_table_lists)
{
	Dlelem	   *db_elem = DLGetHead(db_list);

	while (db_elem != NULL)
	{
		print_db_info(((db_info *) DLE_VAL(db_elem)), print_table_lists);
		db_elem = DLGetSucc(db_elem);
	}
}

static void
print_db_info(db_info * dbi, int print_tbl_list)
{
	sprintf(logbuffer, "dbname: %s", (dbi->dbname) ? dbi->dbname : "(null)");
	log_entry(logbuffer, LVL_INFO);

	sprintf(logbuffer, "  oid: %u", dbi->oid);
	log_entry(logbuffer, LVL_INFO);

	sprintf(logbuffer, "  username: %s", (dbi->username) ? dbi->username : "(null)");
	log_entry(logbuffer, LVL_INFO);

	sprintf(logbuffer, "  password: %s", (dbi->password) ? dbi->password : "(null)");
	log_entry(logbuffer, LVL_INFO);

	if (dbi->conn != NULL)
		log_entry("  conn is valid, (connected)", LVL_INFO);
	else
		log_entry("  conn is null, (not connected)", LVL_INFO);

	sprintf(logbuffer, "  default_analyze_threshold: %li", dbi->analyze_threshold);
	log_entry(logbuffer, LVL_INFO);

	sprintf(logbuffer, "  default_vacuum_threshold: %li", dbi->vacuum_threshold);
	log_entry(logbuffer, LVL_INFO);

	fflush(LOGOUTPUT);
	if (print_tbl_list > 0)
		print_table_list(dbi->table_list);
}

/* End of DB List Management Function */

/* Beginning of misc Functions */

/* Perhaps add some test to this function to make sure that the stats we need are available */
static PGconn *
db_connect(db_info * dbi)
{
	PGconn	   *db_conn =
	PQsetdbLogin(args->host, args->port, NULL, NULL, dbi->dbname,
				 dbi->username, dbi->password);

	if (PQstatus(db_conn) != CONNECTION_OK)
	{
		sprintf(logbuffer, "Failed connection to database %s with error: %s.",
				dbi->dbname, PQerrorMessage(db_conn));
		log_entry(logbuffer, LVL_ERROR);
		fflush(LOGOUTPUT);
		PQfinish(db_conn);
		db_conn = NULL;
	}

	return db_conn;
}	/* end of db_connect() */

static void
db_disconnect(db_info * dbi)
{
	if (dbi->conn != NULL)
	{
		PQfinish(dbi->conn);
		dbi->conn = NULL;
	}
}

static int
check_stats_enabled(db_info * dbi)
{
	PGresult   *res;
	int			ret = 0;

	res = send_query("SHOW stats_row_level", dbi);
	if (res != NULL)
	{
		ret = strcmp("on", PQgetvalue(res, 0, PQfnumber(res, "stats_row_level")));
		PQclear(res);
	}
	return ret;
}

static PGresult *
send_query(const char *query, db_info * dbi)
{
	PGresult   *res;

	if (dbi->conn == NULL)
		return NULL;

	if (args->debug >= 4)
		log_entry(query, LVL_DEBUG);

	res = PQexec(dbi->conn, query);

	if (!res)
	{
		sprintf(logbuffer,
		   "Fatal error occured while sending query (%s) to database %s",
				query, dbi->dbname);
		log_entry(logbuffer, LVL_ERROR);
		sprintf(logbuffer, "The error is [%s]", PQresultErrorMessage(res));
		log_entry(logbuffer, LVL_EXTRA);
		fflush(LOGOUTPUT);
		return NULL;
	}
	if (PQresultStatus(res) != PGRES_TUPLES_OK &&
		PQresultStatus(res) != PGRES_COMMAND_OK)
	{
		sprintf(logbuffer,
		  "Can not refresh statistics information from the database %s.",
				dbi->dbname);
		log_entry(logbuffer, LVL_ERROR);
		sprintf(logbuffer, "The error is [%s]", PQresultErrorMessage(res));
		log_entry(logbuffer, LVL_EXTRA);
		fflush(LOGOUTPUT);
		PQclear(res);
		return NULL;
	}
	return res;
}	/* End of send_query() */

/*
 * Perform either a vacuum or a vacuum analyze
 */
static void
perform_maintenance_command(db_info * dbi, tbl_info * tbl, int operation)
{
	char		buf[256];

	/*
	 * Set the vacuum_cost variables if supplied on command line
	 */
	if (args->av_vacuum_cost_delay != -1)
	{
		snprintf(buf, sizeof(buf), "set vacuum_cost_delay = %d",
				 args->av_vacuum_cost_delay);
		send_query(buf, dbi);
	}
	if (args->av_vacuum_cost_page_hit != -1)
	{
		snprintf(buf, sizeof(buf), "set vacuum_cost_page_hit = %d",
				 args->av_vacuum_cost_page_hit);
		send_query(buf, dbi);
	}
	if (args->av_vacuum_cost_page_miss != -1)
	{
		snprintf(buf, sizeof(buf), "set vacuum_cost_page_miss = %d",
				 args->av_vacuum_cost_page_miss);
		send_query(buf, dbi);
	}
	if (args->av_vacuum_cost_page_dirty != -1)
	{
		snprintf(buf, sizeof(buf), "set vacuum_cost_page_dirty = %d",
				 args->av_vacuum_cost_page_dirty);
		send_query(buf, dbi);
	}
	if (args->av_vacuum_cost_limit != -1)
	{
		snprintf(buf, sizeof(buf), "set vacuum_cost_limit = %d",
				 args->av_vacuum_cost_limit);
		send_query(buf, dbi);
	}

	/*
	 * if ((relisshared = t and database != template1) or
	 * if operation = ANALYZE_ONLY)
	 * then only do an analyze
	 */
	if ((tbl->relisshared > 0 && strcmp("template1", dbi->dbname) != 0) ||
		(operation == ANALYZE_ONLY))
		snprintf(buf, sizeof(buf), "ANALYZE %s", tbl->table_name);
	else if (operation == VACUUM_ANALYZE)
		snprintf(buf, sizeof(buf), "VACUUM ANALYZE %s", tbl->table_name);
	else
		return;

	if (args->debug >= 1)
	{
		sprintf(logbuffer, "Performing: %s", buf);
		log_entry(logbuffer, LVL_DEBUG);
		fflush(LOGOUTPUT);
	}

	send_query(buf, dbi);

	update_table_thresholds(dbi, tbl, operation);

	if (args->debug >= 2)
		print_table_info(tbl);
}

static void
free_cmd_args(void)
{
	if (args != NULL)
	{
		if (args->user != NULL)
			free(args->user);
		if (args->password != NULL)
			free(args->password);
		free(args);
	}
}

static cmd_args *
get_cmd_args(int argc, char *argv[])
{
	int			c;

	args = (cmd_args *) malloc(sizeof(cmd_args));
	args->sleep_base_value = SLEEPBASEVALUE;
	args->sleep_scaling_factor = SLEEPSCALINGFACTOR;
	args->vacuum_base_threshold = VACBASETHRESHOLD;
	args->vacuum_scaling_factor = VACSCALINGFACTOR;
	args->analyze_base_threshold = -1;
	args->analyze_scaling_factor = -1;
	args->debug = AUTOVACUUM_DEBUG;
	args->update_interval = UPDATE_INTERVAL;
#ifndef WIN32
	args->daemonize = 0;
#else
    args->service_dependencies = 0;
	args->install_as_service = 0;
	args->remove_as_service = 0;
	args->service_user = 0;
	args->service_password = 0;
#endif
	args->user = 0;
	args->password = 0;
	args->host = 0;
	args->logfile = 0;
	args->port = 0;

	/*
	 * Cost-Based Vacuum Delay Settings for pg_autovacuum
	 */
	args->av_vacuum_cost_delay = -1;
	args->av_vacuum_cost_page_hit = -1;
	args->av_vacuum_cost_page_miss = -1;
	args->av_vacuum_cost_page_dirty = -1;
	args->av_vacuum_cost_limit = -1;

	/*
	 * Fixme: Should add some sanity checking such as positive integer
	 * values etc
	 */
#ifndef WIN32
	while ((c = getopt(argc, argv, "s:S:v:V:a:A:d:U:P:H:L:p:hDc:C:m:n:l:")) != -1)
#else
	while ((c = getopt(argc, argv, "s:S:v:V:a:A:d:U:P:H:L:p:hIRN:W:E:c:C:m:n:l:")) != -1)
#endif
	{
		switch (c)
		{
			case 's':
				args->sleep_base_value = atoi(optarg);
				break;
			case 'S':
				args->sleep_scaling_factor = atof(optarg);
				break;
			case 'v':
				args->vacuum_base_threshold = atoi(optarg);
				break;
			case 'V':
				args->vacuum_scaling_factor = atof(optarg);
				break;
			case 'a':
				args->analyze_base_threshold = atoi(optarg);
				break;
			case 'A':
				args->analyze_scaling_factor = atof(optarg);
				break;
			case 'i':
				args->update_interval = atoi(optarg);
				break;
			case 'c':
				args->av_vacuum_cost_delay = atoi(optarg);
				break;
			case 'C':
				args->av_vacuum_cost_page_hit = atoi(optarg);
				break;
			case 'm':
				args->av_vacuum_cost_page_miss = atoi(optarg);
				break;
			case 'n':
				args->av_vacuum_cost_page_dirty = atoi(optarg);
				break;
			case 'l':
				args->av_vacuum_cost_limit = atoi(optarg);
				break;
#ifndef WIN32
			case 'D':
				args->daemonize++;
				break;
#endif
			case 'd':
				args->debug = atoi(optarg);
				break;
			case 'U':
				args->user = optarg;
				break;
			case 'P':
				args->password = optarg;
				break;
			case 'H':
				args->host = optarg;
				break;
			case 'L':
				args->logfile = optarg;
				break;
			case 'p':
				args->port = optarg;
				break;
			case 'h':
				usage();
				exit(0);
#ifdef WIN32
			case 'E':
				/*
				 * CreateService() expects a list of service
				 * dependencies as a NUL-separated, double-NUL
				 * terminated list (although we only allow the user to
				 * specify a single dependency). So we zero out the
				 * list first, and make sure to leave room for two NUL
				 * terminators.
				 */
				ZeroMemory(deps, sizeof(deps));
				snprintf(deps, sizeof(deps) - 2, "%s", optarg);
				args->service_dependencies = deps;
				break;
			case 'I':
				args->install_as_service++;
				break;
			case 'R':
				args->remove_as_service++;
				break;
			case 'N':
				args->service_user = optarg;
				break;
			case 'W':
				args->service_password = optarg;
				break;
#endif
			default:

				/*
				 * It's here that we know that things are invalid... It is
				 * not forcibly an error to call usage
				 */
				fprintf(stderr, "Error: Invalid Command Line Options.\n");
				usage();
				exit(1);
				break;
		}

		/*
		 * if values for insert thresholds are not specified, then they
		 * default to 1/2 of the delete values
		 */
		if (args->analyze_base_threshold == -1)
			args->analyze_base_threshold = args->vacuum_base_threshold / 2;
		if (args->analyze_scaling_factor == -1)
			args->analyze_scaling_factor = args->vacuum_scaling_factor / 2;
	}
	return args;
}

static void
usage(void)
{
	int			i = 0;
	float		f = 0;

	fprintf(stderr, "usage: pg_autovacuum \n");
#ifndef WIN32
	fprintf(stderr, "   [-D] Daemonize (Detach from tty and run in the background)\n");
#else
	fprintf(stderr, "   [-I] Install as a Windows service\n");
	fprintf(stderr, "   [-R] Remove as a Windows service (all other options will be ignored)\n");
	fprintf(stderr, "   [-N] Username to run service as (only useful when installing as a Windows service)\n");
	fprintf(stderr, "   [-W] Password to run service with (only useful when installing as a Windows service)\n");
	fprintf(stderr, "   [-E] Dependent service that must start before this service (only useful when installing as a Windows service)\n");
#endif
	i = AUTOVACUUM_DEBUG;
	fprintf(stderr, "   [-d] debug (debug level=0,1,2,3; default=%d)\n", i);

	i = SLEEPBASEVALUE;
	fprintf(stderr, "   [-s] sleep base value (default=%d)\n", i);
	f = SLEEPSCALINGFACTOR;
	fprintf(stderr, "   [-S] sleep scaling factor (default=%f)\n", f);

	i = VACBASETHRESHOLD;
	fprintf(stderr, "   [-v] vacuum base threshold (default=%d)\n", i);
	f = VACSCALINGFACTOR;
	fprintf(stderr, "   [-V] vacuum scaling factor (default=%f)\n", f);
	i = i / 2;
	fprintf(stderr, "   [-a] analyze base threshold (default=%d)\n", i);
	f = f / 2;
	fprintf(stderr, "   [-A] analyze scaling factor (default=%f)\n", f);

	fprintf(stderr, "   [-L] logfile (default=none)\n");

	fprintf(stderr, "   [-c] vacuum_cost_delay (default=none)\n");
	fprintf(stderr, "   [-C] vacuum_cost_page_hit (default=none)\n");
	fprintf(stderr, "   [-m] vacuum_cost_page_miss (default=none)\n");
	fprintf(stderr, "   [-n] vacuum_cost_page_dirty (default=none)\n");
	fprintf(stderr, "   [-l] vacuum_cost_limit (default=none)\n");

	fprintf(stderr, "   [-U] username (libpq default)\n");
	fprintf(stderr, "   [-P] password (libpq default)\n");
	fprintf(stderr, "   [-H] host (libpq default)\n");
	fprintf(stderr, "   [-p] port (libpq default)\n");

	fprintf(stderr, "   [-h] help (Show this output)\n");
}

static void
print_cmd_args(void)
{
	sprintf(logbuffer, "Printing command_args");
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->host=%s", (args->host) ? args->host : "(null)");
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->port=%s", (args->port) ? args->port : "(null)");
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->username=%s", (args->user) ? args->user : "(null)");
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->password=%s", (args->password) ? args->password : "(null)");
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->logfile=%s", (args->logfile) ? args->logfile : "(null)");
	log_entry(logbuffer, LVL_INFO);
#ifndef WIN32
	sprintf(logbuffer, "  args->daemonize=%d", args->daemonize);
	log_entry(logbuffer, LVL_INFO);
#else
	sprintf(logbuffer, "  args->install_as_service=%d", args->install_as_service);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->remove_as_service=%d", args->remove_as_service);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->service_dependencies=%s", (args->service_dependencies) ? args->service_dependencies : "(null)");
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->service_user=%s", (args->service_user) ? args->service_user : "(null)");
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->service_password=%s", (args->service_password) ? args->service_password : "(null)");
	log_entry(logbuffer, LVL_INFO);
#endif

	sprintf(logbuffer, "  args->sleep_base_value=%d", args->sleep_base_value);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->sleep_scaling_factor=%f", args->sleep_scaling_factor);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->vacuum_base_threshold=%d", args->vacuum_base_threshold);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->vacuum_scaling_factor=%f", args->vacuum_scaling_factor);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->analyze_base_threshold=%d", args->analyze_base_threshold);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->analyze_scaling_factor=%f", args->analyze_scaling_factor);
	log_entry(logbuffer, LVL_INFO);
	sprintf(logbuffer, "  args->update_interval=%i", args->update_interval);
	log_entry(logbuffer, LVL_INFO);

	if (args->av_vacuum_cost_delay != -1)
		sprintf(logbuffer, "  args->av_vacuum_cost_delay=%d", args->av_vacuum_cost_delay);
	else
		sprintf(logbuffer, "  args->av_vacuum_cost_delay=(default)");
	log_entry(logbuffer, LVL_INFO);
	if (args->av_vacuum_cost_page_hit != -1)
		sprintf(logbuffer, "  args->av_vacuum_cost_page_hit=%d", args->av_vacuum_cost_page_hit);
	else
		sprintf(logbuffer, "  args->av_vacuum_cost_page_hit=(default)");
	log_entry(logbuffer, LVL_INFO);
	if (args->av_vacuum_cost_page_miss != -1)
		sprintf(logbuffer, "  args->av_vacuum_cost_page_miss=%d", args->av_vacuum_cost_page_miss);
	else
		sprintf(logbuffer, "  args->av_vacuum_cost_page_miss=(default)");
	log_entry(logbuffer, LVL_INFO);
	if (args->av_vacuum_cost_page_dirty != -1)
		sprintf(logbuffer, "  args->av_vacuum_cost_page_dirty=%d", args->av_vacuum_cost_page_dirty);
	else
		sprintf(logbuffer, "  args->av_vacuum_cost_page_dirty=(default)");
	log_entry(logbuffer, LVL_INFO);
	if (args->av_vacuum_cost_limit != -1)
		sprintf(logbuffer, "  args->av_vacuum_cost_limit=%d", args->av_vacuum_cost_limit);
	else
		sprintf(logbuffer, "  args->av_vacuum_cost_limit=(default)");
	log_entry(logbuffer, LVL_INFO);

	sprintf(logbuffer, "  args->debug=%d", args->debug);
	log_entry(logbuffer, LVL_INFO);

	fflush(LOGOUTPUT);
}

#ifdef WIN32

/* Handle control requests from the Service Control Manager */
static void
ControlHandler(DWORD request)
{
	switch (request)
	{
		case SERVICE_CONTROL_STOP:
		case SERVICE_CONTROL_SHUTDOWN:
			log_entry("pg_autovacuum service stopping...", LVL_INFO);
			fflush(LOGOUTPUT);
			ServiceStatus.dwWin32ExitCode = 0;
			ServiceStatus.dwCurrentState = SERVICE_STOPPED;
			SetServiceStatus(hStatus, &ServiceStatus);
			return;

		default:
			break;
	}

	/* Report current status */
	SetServiceStatus(hStatus, &ServiceStatus);

	return;
}

/* Register with the Service Control Manager */
static int
InstallService(void)
{
	SC_HANDLE	schService = NULL;
	SC_HANDLE	schSCManager = NULL;
	char		szFilename[MAX_PATH],
				szKey[MAX_PATH],
				szCommand[MAX_PATH + 1024],
				szMsgDLL[MAX_PATH];
	HKEY		hk = NULL;
	DWORD		dwData = 0;

	/*
	 * Register the service with the SCM
	 */
	GetModuleFileName(NULL, szFilename, MAX_PATH);

	/* Open the Service Control Manager on the local computer. */
	schSCManager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
	if (!schSCManager)
		return -1;

	schService = CreateService(
							   schSCManager,	/* SCManager database */
							   TEXT("pg_autovacuum"),	/* Name of service */
							   TEXT("PostgreSQL Auto Vacuum"),	/* Name to display */
							   SERVICE_ALL_ACCESS,		/* Desired access */
							   SERVICE_WIN32_OWN_PROCESS,		/* Service type */
							   SERVICE_AUTO_START,		/* Start type */
							   SERVICE_ERROR_NORMAL,	/* Error control type */
							   szFilename,		/* Service binary */
							   NULL,	/* No load ordering group */
							   NULL,	/* No tag identifier */
							   args->service_dependencies,	/* Dependencies */
							   args->service_user,		/* Service account */
							   args->service_password); /* Account password */

	if (!schService)
		return -2;

	/*
	 * Rewrite the command line for the service
	 */
	sprintf(szKey, "SYSTEM\\CurrentControlSet\\Services\\pg_autovacuum");
	if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, szKey, 0, KEY_ALL_ACCESS, &hk))
		return -3;

	/* Build the command line */
	sprintf(szCommand, "\"%s\"", szFilename);
	if (args->host)
		sprintf(szCommand, "%s -H %s", szCommand, args->host);
	if (args->port)
		sprintf(szCommand, "%s -p %s", szCommand, args->port);
	if (args->user)
		sprintf(szCommand, "%s -U \"%s\"", szCommand, args->user);
	if (args->password)
		sprintf(szCommand, "%s -P \"%s\"", szCommand, args->password);
	if (args->logfile)
		sprintf(szCommand, "%s -L \"%s\"", szCommand, args->logfile);
	if (args->sleep_base_value != (int) SLEEPBASEVALUE)
		sprintf(szCommand, "%s -s %d", szCommand, args->sleep_base_value);
	if (args->sleep_scaling_factor != (float) SLEEPSCALINGFACTOR)
		sprintf(szCommand, "%s -S %f", szCommand, args->sleep_scaling_factor);
	if (args->vacuum_base_threshold != (int) VACBASETHRESHOLD)
		sprintf(szCommand, "%s -v %d", szCommand, args->vacuum_base_threshold);
	if (args->vacuum_scaling_factor != (float) VACSCALINGFACTOR)
		sprintf(szCommand, "%s -V %f", szCommand, args->vacuum_scaling_factor);
	if (args->analyze_base_threshold != (int) (VACBASETHRESHOLD / 2))
		sprintf(szCommand, "%s -a %d", szCommand, args->analyze_base_threshold);
	if (args->analyze_scaling_factor != (float) (VACSCALINGFACTOR / 2))
		sprintf(szCommand, "%s -A %f", szCommand, args->analyze_scaling_factor);
	if (args->debug != (int) AUTOVACUUM_DEBUG)
		sprintf(szCommand, "%s -d %d", szCommand, args->debug);
	if (args->av_vacuum_cost_delay != -1)
		sprintf(szCommand, "%s -d %d", szCommand, args->av_vacuum_cost_delay);
	if (args->av_vacuum_cost_page_hit != -1)
		sprintf(szCommand, "%s -d %d", szCommand, args->av_vacuum_cost_page_hit);
	if (args->av_vacuum_cost_page_miss != -1)
		sprintf(szCommand, "%s -d %d", szCommand, args->av_vacuum_cost_page_miss);
	if (args->av_vacuum_cost_page_dirty != -1)
		sprintf(szCommand, "%s -d %d", szCommand, args->av_vacuum_cost_page_dirty);
	if (args->av_vacuum_cost_limit != -1)
		sprintf(szCommand, "%s -d %d", szCommand, args->av_vacuum_cost_limit);

	/* And write the new value */
	if (RegSetValueEx(hk, "ImagePath", 0, REG_EXPAND_SZ, (LPBYTE) szCommand, (DWORD) strlen(szCommand) + 1))
		return -4;
	RegCloseKey(hk);

	/*
	 * Set the Event source for the application log
	 */
	sprintf(szKey, "SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\PostgreSQL Auto Vacuum");
	if (RegCreateKeyEx(HKEY_LOCAL_MACHINE, szKey, 0, NULL, REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, NULL, &hk, NULL))
		return -5;

	/* TODO Try to find pgevent.dll, rather than hope it's in the path. ! */
	/* Message DLL */
	sprintf(szMsgDLL, "pgevent.dll");
	if (RegSetValueEx(hk, "EventMessageFile", 0, REG_EXPAND_SZ, (LPBYTE) szMsgDLL, (DWORD) strlen(szMsgDLL) + 1))
		return -6;

	/* Set the event types supported */
	dwData = EVENTLOG_ERROR_TYPE | EVENTLOG_WARNING_TYPE | EVENTLOG_INFORMATION_TYPE | EVENTLOG_SUCCESS;
	if (RegSetValueEx(hk, "TypesSupported", 0, REG_DWORD, (LPBYTE) & dwData, sizeof(DWORD)))
		return -9;

	RegCloseKey(hk);
	return 0;
}

/* Unregister from the Service Control Manager */
static int
RemoveService(void)
{
	SC_HANDLE	schService = NULL;
	SC_HANDLE	schSCManager = NULL;
	char		szKey[MAX_PATH];
	HKEY		hk = NULL;

	/* Open the SCM */
	schSCManager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
	if (!schSCManager)
		return -1;

	/* Open the service */
	schService = OpenService(schSCManager, TEXT("pg_autovacuum"), SC_MANAGER_ALL_ACCESS);
	if (!schService)
		return -2;

	/* Now delete the service */
	if (!DeleteService(schService))
		return -3;

	/*
	 * Remove the Event source from the application log
	 */
	sprintf(szKey, "SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application");
	if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, szKey, 0, KEY_ALL_ACCESS, &hk))
		return -4;
	if (RegDeleteKey(hk, "PostgreSQL Auto Vacuum"))
		return -5;

	return 0;
}
#endif   /* WIN32 */

static
int
VacuumLoop(int argc, char **argv)
{
	int			j = 0,
				loops = 0;

	/* int numInserts, numDeletes, */
	int			sleep_secs;
	Dllist	   *db_list;
	Dlelem	   *db_elem,
			   *tbl_elem;
	db_info    *dbs;
	tbl_info   *tbl;
	PGresult   *res = NULL;
	double		diff;

	struct timeval now,
				then;

#ifdef WIN32

	if (appMode)
		log_entry("pg_autovacuum starting in Windows Application mode", LVL_INFO);
	else
		log_entry("pg_autovacuum starting in Windows Service mode", LVL_INFO);

	ServiceStatus.dwServiceType = SERVICE_WIN32;
	ServiceStatus.dwCurrentState = SERVICE_START_PENDING;
	ServiceStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
	ServiceStatus.dwWin32ExitCode = 0;
	ServiceStatus.dwServiceSpecificExitCode = 0;
	ServiceStatus.dwCheckPoint = 0;
	ServiceStatus.dwWaitHint = 0;

	if (!appMode)
	{
		hStatus = RegisterServiceCtrlHandler("pg_autovacuum", (LPHANDLER_FUNCTION) ControlHandler);
		if (hStatus == (SERVICE_STATUS_HANDLE) 0)
			return -1;
	}
#endif   /* WIN32 */

	/* Init the db list with template1 */
	db_list = init_db_list();
	if (db_list == NULL)
		return 1;

	if (check_stats_enabled(((db_info *) DLE_VAL(DLGetHead(db_list)))) != 0)
	{
		log_entry("GUC variable stats_row_level must be enabled.", LVL_ERROR);
		log_entry("       Please fix the problems and try again.", LVL_EXTRA);
		fflush(LOGOUTPUT);

		exit(1);
	}

	gettimeofday(&then, 0);		/* for use later to caluculate sleep time */

#ifndef WIN32
	while (1)
#else
	/* We can now report the running status to SCM. */
	ServiceStatus.dwCurrentState = SERVICE_RUNNING;
	if (!appMode)
		SetServiceStatus(hStatus, &ServiceStatus);

	while (ServiceStatus.dwCurrentState == SERVICE_RUNNING)
#endif
	{
		/* Main Loop */

		db_elem = DLGetHead(db_list);	/* Reset cur_db_node to the
										 * beginning of the db_list */

		dbs = ((db_info *) DLE_VAL(db_elem));	/* get pointer to cur_db's
												 * db_info struct */
		if (dbs->conn == NULL)
		{
			dbs->conn = db_connect(dbs);
			if (dbs->conn == NULL)
			{					/* Serious problem: We can't connect to
								 * template1 */
				log_entry("Cannot connect to template1, exiting.", LVL_ERROR);
				fflush(LOGOUTPUT);
				fclose(LOGOUTPUT);
#ifdef WIN32
				ServiceStatus.dwCurrentState = SERVICE_STOPPED;
				ServiceStatus.dwWin32ExitCode = ERROR_SERVICE_SPECIFIC_ERROR;
				ServiceStatus.dwServiceSpecificExitCode = -1;
				if (!appMode)
					SetServiceStatus(hStatus, &ServiceStatus);
#endif
				exit(1);
			}
		}

		if (loops % args->update_interval == 0)		/* Update the list if it's
													 * time */
			update_db_list(db_list);	/* Add and remove databases from
										 * the list */

		while (db_elem != NULL)
		{						/* Loop through databases in list */
			dbs = ((db_info *) DLE_VAL(db_elem));		/* get pointer to
														 * cur_db's db_info
														 * struct */
			if (dbs->conn == NULL)
				dbs->conn = db_connect(dbs);

			if (dbs->conn != NULL)
			{
				if (loops % args->update_interval == 0)		/* Update the list if
															 * it's time */
					update_table_list(dbs);		/* Add and remove tables
												 * from the list */

				if (xid_wraparound_check(dbs) == 0)
				{
					res = send_query(TABLE_STATS_QUERY, dbs);	/* Get an updated
																 * snapshot of this dbs
																 * table stats */
					if (res != NULL)
					{
						for (j = 0; j < PQntuples(res); j++)
						{		/* loop through result set */
							tbl_elem = DLGetHead(dbs->table_list);		/* Reset tbl_elem to top
																		 * of dbs->table_list */
							while (tbl_elem != NULL)
							{	/* Loop through tables in list */
								tbl = ((tbl_info *) DLE_VAL(tbl_elem)); /* set tbl_info =
																		 * current_table */
								if (tbl->relid == atooid(PQgetvalue(res, j, PQfnumber(res, "oid"))))
								{
									tbl->curr_analyze_count =
										(atol(PQgetvalue(res, j, PQfnumber(res, "n_tup_ins"))) +
										 atol(PQgetvalue(res, j, PQfnumber(res, "n_tup_upd"))) +
										 atol(PQgetvalue(res, j, PQfnumber(res, "n_tup_del"))));
									tbl->curr_vacuum_count =
										(atol(PQgetvalue(res, j, PQfnumber(res, "n_tup_del"))) +
										 atol(PQgetvalue(res, j, PQfnumber(res, "n_tup_upd"))));

									/*
									 * Check numDeletes to see if we need
									 * to vacuum, if so: Run vacuum
									 * analyze (adding analyze is small so
									 * we might as well) Update table
									 * thresholds and related information
									 * if numDeletes is not big enough for
									 * vacuum then check numInserts for
									 * analyze
									 */
									if (tbl->curr_vacuum_count - tbl->CountAtLastVacuum >= tbl->vacuum_threshold)
										perform_maintenance_command(dbs, tbl, VACUUM_ANALYZE);
									else if (tbl->curr_analyze_count - tbl->CountAtLastAnalyze >= tbl->analyze_threshold)
										perform_maintenance_command(dbs, tbl, ANALYZE_ONLY);

									break;		/* We found a match, no need to keep looping. */
								}

								/*
								 * Advance the table pointers for the next
								 * loop
								 */
								tbl_elem = DLGetSucc(tbl_elem);

							}	/* end for table while loop */
						}		/* end for j loop (tuples in PGresult) */
					}			/* end if (res != NULL) */
				}				/* close of if (xid_wraparound_check()) */
				/* Done working on this db, Clean up, then advance cur_db */
				PQclear(res);
				res = NULL;
				db_disconnect(dbs);
			}
			db_elem = DLGetSucc(db_elem);		/* move on to next DB
												 * regardless */
		}						/* end of db_list while loop */

		/* Figure out how long to sleep etc ... */
		gettimeofday(&now, 0);
		diff = (int) (now.tv_sec - then.tv_sec) * 1000000.0 + (int) (now.tv_usec - then.tv_usec);

		sleep_secs = args->sleep_base_value + args->sleep_scaling_factor * diff / 1000000.0;
		loops++;
		if (args->debug >= 2)
		{
			sprintf(logbuffer,
			 "%d All DBs checked in: %.0f usec, will sleep for %d secs.",
					loops, diff, sleep_secs);
			log_entry(logbuffer, LVL_DEBUG);
			fflush(LOGOUTPUT);
		}

		/* Larger Pause between outer loops */
		/*
		 *	pg_usleep() is wrong here because its maximum is ~2000 seconds,
		 *	and we don't need signal interruptability on Win32 here.
		 */
#ifndef WIN32
		sleep(sleep_secs);			/* Unix sleep is seconds */
#else
		sleep(sleep_secs * 1000);	/* Win32 sleep() is milliseconds */
#endif

		gettimeofday(&then, 0); /* Reset time counter */

	}							/* end of while loop */

	/*
	 * program is exiting, this should never run, but is here to make
	 * compiler / valgrind happy
	 */
	free_db_list(db_list);
	free_cmd_args();
	return 0;
}

/* Beginning of AutoVacuum Main Program */
int
main(int argc, char *argv[])
{

#ifdef WIN32
	LPVOID		lpMsgBuf;
	SERVICE_TABLE_ENTRY ServiceTable[2];
#endif

	args = get_cmd_args(argc, argv);	/* Get Command Line Args and put
										 * them in the args struct */
#ifndef WIN32
	/* Dameonize if requested */
	if (args->daemonize == 1)
		daemonize();
#endif

	if (args->logfile)
	{
		LOGOUTPUT = fopen(args->logfile, "a");
		if (!LOGOUTPUT)
		{
			fprintf(stderr, "Could not open log file - [%s]\n", args->logfile);
			exit(-1);
		}
	}
	else
		LOGOUTPUT = stderr;
	if (args->debug >= 2)
		print_cmd_args();

#ifdef WIN32
	/* Install as a Windows service if required */
	if (args->install_as_service)
	{
		if (InstallService() != 0)
		{
			FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) & lpMsgBuf, 0, NULL);
            fprintf(stderr, "Error: %s\n", (char *) lpMsgBuf);
			exit(-1);
		}
		else
		{
			fprintf(stderr, "Successfully installed pg_autovacuum as a service.\n");
			exit(0);
		}
	}

	/* Remove as a Windows service if required */
	if (args->remove_as_service)
	{
		if (RemoveService() != 0)
		{
			FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) & lpMsgBuf, 0, NULL);
            fprintf(stderr, "Error: %s\n", (char *) lpMsgBuf);
			exit(-1);
		}
		else
		{
			fprintf(stderr, "Successfully removed pg_autovacuum as a service.\n");
			exit(0);
		}
	}

	/* Normal service startup */
	ServiceTable[0].lpServiceName = "pg_autovacuum";
	ServiceTable[0].lpServiceProc = (LPSERVICE_MAIN_FUNCTION) VacuumLoop;

	ServiceTable[1].lpServiceName = NULL;
	ServiceTable[1].lpServiceProc = NULL;

	/* Start the control dispatcher thread for our service */
	if (!StartServiceCtrlDispatcher(ServiceTable))
	{
		appMode = 1;
		VacuumLoop(0, NULL);
	}

#else							/* Unix */

	/* Call the main program loop. */
	VacuumLoop(0, NULL);
#endif   /* WIN32 */

	return EXIT_SUCCESS;
}
