pg_repack/bin/pg_reorg.c

/*
 * pg_reorg.c: bin/pg_reorg.c
 *
 * Copyright (c) 2008, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
 */

/**
 * @brief Client Modules
 */

#include "postgres_fe.h"
#include "common.h"
#include "libpq/pqsignal.h"
#include <unistd.h>
#include <signal.h>


#define REORG_VERSION	"1.0.2"
#define REORG_URL		"http://reorg.projects.postgresql.org/"
#define REORG_EMAIL		"reorg-general@lists.pgfoundry.org"

#define APPLY_COUNT		1000


#if PG_VERSION_NUM >= 80300
#define SQL_XID_SNAPSHOT \
	"SELECT reorg.array_accum(virtualtransaction) FROM pg_locks"\
	" WHERE locktype = 'virtualxid' AND pid <> pg_backend_pid()"
#define SQL_XID_ALIVE \
	"SELECT 1 FROM pg_locks WHERE locktype = 'virtualxid'"\
	" AND pid <> pg_backend_pid() AND virtualtransaction = ANY($1) LIMIT 1"
#else
#define SQL_XID_SNAPSHOT \
	"SELECT reorg.array_accum(transactionid) FROM pg_locks"\
	" WHERE locktype = 'transactionid' AND pid <> pg_backend_pid()"
#define SQL_XID_ALIVE \
	"SELECT 1 FROM pg_locks WHERE locktype = 'transactionid'"\
	" AND pid <> pg_backend_pid() AND transactionid = ANY($1) LIMIT 1"
#endif


/*
 * per-table information
 */
typedef struct reorg_table
{
	const char	   *target_name;	/* target: relname */
	Oid				target_oid;		/* target: OID */
	Oid				target_toast;	/* target: toast OID */
	Oid				target_tidx;	/* target: toast index OID */
	Oid				pkid;			/* target: PK OID */
	Oid				ckid;			/* target: CK OID */
	const char	   *create_pktype;	/* CREATE TYPE pk */
	const char	   *create_log;		/* CREATE TABLE log */
	const char	   *create_trigger;	/* CREATE TRIGGER z_reorg_trigger */
	const char	   *create_table;	/* CREATE TABLE table AS SELECT */
	const char	   *delete_log;		/* DELETE FROM log */
	const char	   *lock_table;		/* LOCK TABLE table */
	const char	   *sql_peek;		/* SQL used in flush */
	const char	   *sql_insert;		/* SQL used in flush */
	const char	   *sql_delete;		/* SQL used in flush */
	const char	   *sql_update;		/* SQL used in flush */
	const char	   *sql_pop;		/* SQL used in flush */
} reorg_table;

/*
 * per-index information
 */
typedef struct reorg_index
{
	Oid				target_oid;		/* target: OID */
	const char	   *create_index;	/* CREATE INDEX */
} reorg_index;

static void reorg_all_databases(const char *orderby);
static bool reorg_one_database(const char *orderby, const char *table);
static void reorg_one_table(const reorg_table *table, const char* orderby);

static void reconnect(void);
static void disconnect(void);
static PGresult *execute_nothrow(const char *query, int nParams, const char **params);
static PGresult *execute(const char *query, int nParams, const char **params);
static void command(const char *query, int nParams, const char **params);
static void cleanup(void);
static void exit_with_cleanup(int exitcode);

static void reorg_setup_cancel_handler(void);
static void reorg_command_begin(PGconn *conn);
static void reorg_command_end(void);

static void PrintHelp(const char *progname);
static void PrintVersion(void);
static char *getstr(PGresult *res, int row, int col);
static Oid getoid(PGresult *res, int row, int col);


static const char  *progname = NULL;
static bool			echo = false;
static bool			verbose = false;
static bool			quiet = false;

/* connectin parameters */
static const char  *dbname = NULL;
static char		   *host = NULL;
static char		   *port = NULL;
static char		   *username = NULL;
static bool			password = false;

/*
 * The table begin re-organized. If not null, we need to cleanup temp
 * objects before the program exits.
 */
static const reorg_table *current_table = NULL;

/* Current connection initizlied with coneection parameters. */
static PGconn	   *current_conn = NULL;

/* Interrupted by SIGINT (Ctrl+C) ? */
static bool			interrupted = false;

/* Not null during executing some SQL commands. */
static PGcancel *volatile cancelConn = NULL;


#ifdef WIN32
static CRITICAL_SECTION cancelConnLock;

static unsigned int sleep(unsigned int seconds)
{
	Sleep(seconds * 1000);
	return 0;
}
#endif

/* buffer should have at least 11 bytes */
static char *
utoa(unsigned int value, char *buffer)
{
	sprintf(buffer, "%u", value);
	return buffer;
}

/* called by atexit */
static void
warn_if_unclean(void)
{
	if (current_table)
		fprintf(stderr, _("!!!FATAL ERROR!!! Please refer to a manual.\n\n"));
}

int
main(int argc, char *argv[])
{
	static struct option long_options[] = {
		{"host", required_argument, NULL, 'h'},
		{"port", required_argument, NULL, 'p'},
		{"username", required_argument, NULL, 'U'},
		{"password", no_argument, NULL, 'W'},
		{"echo", no_argument, NULL, 'e'},
		{"quiet", no_argument, NULL, 'q'},
		{"verbose", no_argument, NULL, 'v'},
		{"dbname", required_argument, NULL, 'd'},
		{"all", no_argument, NULL, 'a'},
		{"table", required_argument, NULL, 't'},
		{"no-order", no_argument, NULL, 'n'},
		{"order-by", required_argument, NULL, 'o'},
		{NULL, 0, NULL, 0}
	};

	int			optindex;
	int			c;

	bool		alldb = false;
	const char *table = NULL;
	const char *orderby = NULL;

	progname = get_progname(argv[0]);
	set_pglocale_pgservice(argv[0], "pgscripts");

	/*
	 * Help message and version are handled at first.
	 */
	if (argc > 1)
	{
		if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
		{
			PrintHelp(progname);
			return 0;
		}
		if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
		{
			PrintVersion();
			return 0;
		}
	}

	while ((c = getopt_long(argc, argv, "h:p:U:Weqvd:at:no:", long_options, &optindex)) != -1)
	{
		switch (c)
		{
			case 'h':
				host = optarg;
				break;
			case 'p':
				port = optarg;
				break;
			case 'U':
				username = optarg;
				break;
			case 'W':
				password = true;
				break;
			case 'e':
				echo = true;
				break;
			case 'q':
				quiet = true;
				break;
			case 'v':
				verbose = true;
				break;
			case 'd':
				dbname = optarg;
				break;
			case 'a':
				alldb = true;
				break;
			case 't':
				table = optarg;
				break;
			case 'n':
				orderby = "";
				break;
			case 'o':
				orderby = optarg;
				break;
			default:
				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
				exit(1);
		}
	}

	switch (argc - optind)
	{
		case 0:
			break;
		case 1:
			dbname = argv[optind];
			break;
		default:
			fprintf(stderr, _("%s: too many command-line arguments (first is \"%s\")\n"),
					progname, argv[optind + 1]);
			fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
			exit(1);
	}

	reorg_setup_cancel_handler();
	atexit(warn_if_unclean);

	if (alldb)
	{
		if (dbname)
		{
			fprintf(stderr, _("%s: cannot reorg all databases and a specific one at the same time\n"),
					progname);
			exit(1);
		}
		if (table)
		{
			fprintf(stderr, _("%s: cannot reorg a specific table in all databases\n"),
					progname);
			exit(1);
		}

		reorg_all_databases(orderby);
	}
	else
	{
		(void) (dbname ||
		(dbname = getenv("PGDATABASE")) ||
		(dbname = getenv("PGUSER")) ||
		(dbname = get_user_name(progname)));

		if (!reorg_one_database(orderby, table))
		{
			fprintf(stderr, _("ERROR:  %s is not installed\n"), progname);
			return 1;
		}
	}

	return 0;
}

/*
 * Call reorg_one_database for each database.
 */
static void
reorg_all_databases(const char *orderby)
{
	PGresult   *result;
	int			i;

	dbname = "postgres";
	reconnect();
	result = execute("SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", 0, NULL);
	disconnect();

	for (i = 0; i < PQntuples(result); i++)
	{
		bool	ret;

		dbname = PQgetvalue(result, i, 0);

		if (!quiet)
		{
			printf(_("%s: reorg database \"%s\""), progname, dbname);
			fflush(stdout);
		}

		ret = reorg_one_database(orderby, NULL);

		if (!quiet)
		{
			if (ret)
				printf("\n");
			else
				printf(_(" ... skipped\n"));
			fflush(stdout);
		}
	}

	PQclear(result);
}

/* result is not copied */
static char *
getstr(PGresult *res, int row, int col)
{
	if (PQgetisnull(res, row, col))
		return NULL;
	else
		return PQgetvalue(res, row, col);
}

static Oid
getoid(PGresult *res, int row, int col)
{
	if (PQgetisnull(res, row, col))
		return InvalidOid;
	else
		return (Oid)strtoul(PQgetvalue(res, row, col), NULL, 10);
}

/*
 * Call reorg_one_table for the target table or each table in a database.
 */
static bool
reorg_one_database(const char *orderby, const char *table)
{
	bool			ret = true;
	PGresult	   *res;
	int				i;
	int				num;
	PQExpBufferData sql;

	initPQExpBuffer(&sql);

	reconnect();

	/* Restrict search_path to system catalog. */
	command("SET search_path = pg_catalog, pg_temp", 0, NULL);

	/* To avoid annoying "create implicit ..." messages. */
	command("SET client_min_messages = warning", 0, NULL);

	/* acquire target tables */
	appendPQExpBufferStr(&sql, "SELECT * FROM reorg.tables WHERE ");
	if (table)
	{
		appendPQExpBufferStr(&sql, "relid = $1::regclass");
		res = execute_nothrow(sql.data, 1, &table);
	}
	else
	{
		appendPQExpBufferStr(&sql, "pkid IS NOT NULL");
		if (!orderby)
			appendPQExpBufferStr(&sql, " AND ckid IS NOT NULL");
		res = execute_nothrow(sql.data, 0, NULL);
	}

	if (PQresultStatus(res) != PGRES_TUPLES_OK)
	{
		const char *state = PQresultErrorField(res, PG_DIAG_SQLSTATE);
		if (state && strcmp(state, "3F000") == 0)
		{
			/* Schema reorg does not exist. Skip the database. */
			ret = false;
			goto cleanup;
		}
		else
		{
			/* exit otherwise */
			printf("%s", PQerrorMessage(current_conn));
			PQclear(res);
			exit_with_cleanup(1);
		}
	}

	num = PQntuples(res);

	for (i = 0; i < num; i++)
	{
		reorg_table	table;
		const char *create_table;
		const char *ckey;
		int			c = 0;

		table.target_name = getstr(res, i, c++);
		table.target_oid = getoid(res, i, c++);
		table.target_toast = getoid(res, i, c++);
		table.target_tidx = getoid(res, i, c++);
		table.pkid = getoid(res, i, c++);
		table.ckid = getoid(res, i, c++);

		if (table.pkid == 0)
		{
			fprintf(stderr, _("ERROR:  relation \"%s\" has no primary key\n"), table.target_name);
			exit_with_cleanup(1);
		}

		table.create_pktype = getstr(res, i, c++);
		table.create_log = getstr(res, i, c++);
		table.create_trigger = getstr(res, i, c++);

		create_table = getstr(res, i, c++);
		table.delete_log = getstr(res, i, c++);
		table.lock_table = getstr(res, i, c++);
		ckey = getstr(res, i, c++);

		resetPQExpBuffer(&sql);
		if (!orderby)
		{
			/* CLUSTER mode */
			if (ckey == NULL)
			{
				fprintf(stderr, _("ERROR:  relation \"%s\" has no cluster key\n"), table.target_name);
				exit_with_cleanup(1);
			}
			appendPQExpBuffer(&sql, "%s ORDER BY %s", create_table, ckey);
            table.create_table = sql.data;
		}
		else if (!orderby[0])
		{
			/* VACUUM FULL mode */
            table.create_table = create_table;
		}
		else
		{
			/* User specified ORDER BY */
			appendPQExpBuffer(&sql, "%s ORDER BY %s", create_table, orderby);
            table.create_table = sql.data;
		}

		table.sql_peek = getstr(res, i, c++);
		table.sql_insert = getstr(res, i, c++);
		table.sql_delete = getstr(res, i, c++);
		table.sql_update = getstr(res, i, c++);
		table.sql_pop = getstr(res, i, c++);

		reorg_one_table(&table, orderby);
	}

cleanup:
	PQclear(res);
	disconnect();
	termPQExpBuffer(&sql);
	return ret;
}

static int
apply_log(const reorg_table *table, int count)
{
	int			result;
	PGresult   *res;
	const char *params[6];
	char		buffer[12];

	params[0] = table->sql_peek;
	params[1] = table->sql_insert;
	params[2] = table->sql_delete;
	params[3] = table->sql_update;
	params[4] = table->sql_pop;
	params[5] = utoa(count, buffer);

	res = execute("SELECT reorg.reorg_apply($1, $2, $3, $4, $5, $6)",
		6, params);
	result = atoi(PQgetvalue(res, 0, 0));
	PQclear(res);

	return result;
}

/*
 * Re-organize one table.
 */
static void
reorg_one_table(const reorg_table *table, const char *orderby)
{
	PGresult   *res;
	const char *params[1];
	int			num;
	int			i;
	char	   *vxid;
	char		buffer[12];

	if (verbose)
	{
		fprintf(stderr, "---- reorg_one_table ----\n");
		fprintf(stderr, "target_name    : %s\n", table->target_name);
		fprintf(stderr, "target_oid     : %u\n", table->target_oid);
		fprintf(stderr, "target_toast   : %u\n", table->target_toast);
		fprintf(stderr, "target_tidx    : %u\n", table->target_tidx);
		fprintf(stderr, "pkid           : %u\n", table->pkid);
		fprintf(stderr, "ckid           : %u\n", table->ckid);
		fprintf(stderr, "create_pktype  : %s\n", table->create_pktype);
		fprintf(stderr, "create_log     : %s\n", table->create_log);
		fprintf(stderr, "create_trigger : %s\n", table->create_trigger);
		fprintf(stderr, "create_table   : %s\n", table->create_table);
		fprintf(stderr, "delete_log     : %s\n", table->delete_log);
		fprintf(stderr, "lock_table     : %s\n", table->lock_table);
		fprintf(stderr, "sql_peek       : %s\n", table->sql_peek);
		fprintf(stderr, "sql_insert     : %s\n", table->sql_insert);
		fprintf(stderr, "sql_delete     : %s\n", table->sql_delete);
		fprintf(stderr, "sql_update     : %s\n", table->sql_update);
		fprintf(stderr, "sql_pop        : %s\n", table->sql_pop);
	}

	/*
	 * 1. Setup workspaces and a trigger.
	 */
	if (verbose)
		fprintf(stderr, "---- setup ----\n");

	command("BEGIN ISOLATION LEVEL READ COMMITTED", 0, NULL);

	/*
	 * Check z_reorg_trigger is the trigger executed at last so that
	 * other before triggers cannot modify triggered tuples.
	 */
	params[0] = utoa(table->target_oid, buffer);

	res = execute(
		"SELECT 1 FROM pg_trigger"
		" WHERE tgrelid = $1 AND tgname >= 'z_reorg_trigger' LIMIT 1",
		1, params);
	if (PQntuples(res) > 0)
	{
		fprintf(stderr, _("%s: trigger conflicted for %s\n"),
			progname, table->target_name);
		exit_with_cleanup(1);
	}

	command(table->create_pktype, 0, NULL);
	command(table->create_log, 0, NULL);
	command(table->create_trigger, 0, NULL);
	command("COMMIT", 0, NULL);

	/*
	 * Register the table to be dropped on error. We use pktype as
	 * an advisory lock. The registration should be done after
	 * the first command is succeeded.
	 */
	current_table = table;

	/*
	 * 2. Copy tuples into temp table.
	 */
	if (verbose)
		fprintf(stderr, "---- copy tuples ----\n");

	command("BEGIN ISOLATION LEVEL SERIALIZABLE", 0, NULL);
	if (orderby && !orderby[0])
		command("SET LOCAL synchronize_seqscans = off", 0, NULL);
	res = execute(SQL_XID_SNAPSHOT, 0, NULL);
	vxid = strdup(PQgetvalue(res, 0, 0));
	PQclear(res);
	command(table->delete_log, 0, NULL);
	command(table->create_table, 0, NULL);
	command("COMMIT", 0, NULL);

	/*
	 * 3. Create indexes on temp table.
	 */
	if (verbose)
		fprintf(stderr, "---- create indexes ----\n");

	params[0] = utoa(table->target_oid, buffer);
	res = execute("SELECT indexrelid,"
		" reorg.reorg_indexdef(indexrelid, indrelid)"
		" FROM pg_index WHERE indrelid = $1", 1, params);

	num = PQntuples(res);
	for (i = 0; i < num; i++)
	{
		reorg_index	index;
		int			c = 0;

		index.target_oid = getoid(res, i, c++);
		index.create_index = getstr(res, i, c++);

		if (verbose)
		{
			fprintf(stderr, "[%d]\n", i);
			fprintf(stderr, "target_oid   : %u\n", index.target_oid);
			fprintf(stderr, "create_index : %s\n", index.create_index);
		}

		/*
		 * NOTE: If we want to create multiple indexes in parallel,
		 * we need to call create_index in multiple connections.
		 */
		command(index.create_index, 0, NULL);
	}
	PQclear(res);

	/*
	 * 4. Apply log to temp table until no tuples left in the log
	 * and all of old transactions are finished.
	 */
	for (;;)
	{
		num = apply_log(table, APPLY_COUNT);
		if (num > 0)
			continue;	/* there might be still some tuples, repeat. */

		/* old transactions still alive ? */
		params[0] = vxid;
		res = execute(SQL_XID_ALIVE, 1, params);
		num = PQntuples(res);
		PQclear(res);

		if (num > 0)
		{
			sleep(1);
			continue;	/* wait for old transactions */
		}

		/* ok, go next step. */
		break;
	}

	/*
	 * 5. Cleanup.
	 */
	if (verbose)
		fprintf(stderr, "---- cleanup ----\n");

	command("BEGIN ISOLATION LEVEL READ COMMITTED", 0, NULL);
	command(table->lock_table, 0, NULL);
	apply_log(table, 0);
	params[0] = utoa(table->target_oid, buffer);
	command("SELECT reorg.reorg_swap($1)", 1, params);
	command("SELECT reorg.reorg_drop($1)", 1, params);
	command("COMMIT", 0, NULL);
	current_table = NULL;

	free(vxid);
}

static void
cleanup(void)
{
	char		buffer[12];
	const char *params[1];

	if (!current_table)
		return;

	params[0] = utoa(current_table->target_oid, buffer);
	execute("SELECT reorg.reorg_drop($1)", 1, params);
	current_table = NULL;
}

static void
reconnect(void)
{
	disconnect();
	current_conn = connectDatabase(dbname, host, port, username, password, progname);
}

static void
disconnect(void)
{
	if (current_conn)
	{
		PQfinish(current_conn);
		current_conn = NULL;
	}
}

static void
exit_with_cleanup(int exitcode)
{
	if (current_table)
	{
		/* Rollback current transaction */
		if (current_conn)
		{
			PGresult *res;
			res = PQexec(current_conn, "ROLLBACK");
			if (PQresultStatus(res) != PGRES_COMMAND_OK)
				exit(1);	// fatal error
			PQclear(res);
		}

		/* Try reconnection if not available. */
		if (PQstatus(current_conn) != CONNECTION_OK)
			reconnect();

		cleanup();
	}

	disconnect();
	exit(exitcode);
}

static PGresult *
execute_nothrow(const char *query, int nParams, const char **params)
{
	PGresult   *res;

	if (echo)
		fprintf(stderr, _("%s: executing %s\n"), progname, query);

#ifdef DEBUG_REORG
	fprintf(stderr, "debug: suspend in execute. (sql='%s')\npush enter key: ", query);
	fgetc(stdin);
#endif

	reorg_command_begin(current_conn);
	if (nParams == 0)
		res = PQexec(current_conn, query);
	else
		res = PQexecParams(current_conn, query, nParams, NULL, params, NULL, NULL, 0);
	reorg_command_end();

	return res;
}

/*
 * execute - Execute a SQL and discard the result, or exit() if failed.
 */
static PGresult *
execute(const char *query, int nParams, const char **params)
{
	if (interrupted)
	{
		interrupted = false;
		fprintf(stderr, _("%s: interrupted\n"), progname);
	}
	else
	{
		PGresult   *res = execute_nothrow(query, nParams, params);

		if (PQresultStatus(res) == PGRES_TUPLES_OK ||
			PQresultStatus(res) == PGRES_COMMAND_OK)
			return res;

		fprintf(stderr, _("%s: query failed: %s"),
				progname, PQerrorMessage(current_conn));
		fprintf(stderr, _("%s: query was: %s\n"),
				progname, query);
		PQclear(res);
	}

	exit_with_cleanup(1);
	return NULL;	/* keep compiler quiet */
}

/*
 * command - Execute a SQL and discard the result, or exit() if failed.
 */
static void
command(const char *query, int nParams, const char **params)
{
	PGresult *res = execute(query, nParams, params);
	PQclear(res);
}

static void
PrintHelp(const char *progname)
{
	printf(_("%s re-organizes a PostgreSQL database.\n\n"), progname);
	printf(_("Usage:\n"));
	printf(_("  %s [OPTION]... [DBNAME]\n"), progname);
	printf(_("\nOptions:\n"));
	printf(_("  -a, --all                 reorg all databases\n"));
	printf(_("  -d, --dbname=DBNAME       database to reorg\n"));
	printf(_("  -t, --table=TABLE         reorg specific table only\n"));
	printf(_("  -n, --no-order            do vacuum full instead of cluster\n"));
	printf(_("  -o, --order-by=columns    order by columns instead of cluster keys\n"));
	printf(_("  -e, --echo                show the commands being sent to the server\n"));
	printf(_("  -q, --quiet               don't write any messages\n"));
	printf(_("  -v, --verbose             display detailed information during processing\n"));
	printf(_("  --help                    show this help, then exit\n"));
	printf(_("  --version                 output version information, then exit\n"));
	printf(_("\nConnection options:\n"));
	printf(_("  -h, --host=HOSTNAME       database server host or socket directory\n"));
	printf(_("  -p, --port=PORT           database server port\n"));
	printf(_("  -U, --username=USERNAME   user name to connect as\n"));
	printf(_("  -W, --password            force password prompt\n"));
#ifdef REORG_URL
	printf(_("\nRead the website for details. <" REORG_URL ">\n"));
#endif
#ifdef REORG_EMAIL
	printf(_("\nReport bugs to <" REORG_EMAIL ">.\n"));
#endif
}

static void
PrintVersion(void)
{
	fprintf(stderr, "pg_reorg " REORG_VERSION "\n");
	return;
}

/*
 * reorg_command_begin
 *
 * Set cancelConn to point to the current database connection.
 */
static void
reorg_command_begin(PGconn *conn)
{
	PGcancel   *oldCancelConn;

#ifdef WIN32
	EnterCriticalSection(&cancelConnLock);
#endif

	/* Free the old one if we have one */
	oldCancelConn = cancelConn;

	/* be sure handle_sigint doesn't use pointer while freeing */
	cancelConn = NULL;

	if (oldCancelConn != NULL)
		PQfreeCancel(oldCancelConn);

	cancelConn = PQgetCancel(conn);

#ifdef WIN32
	LeaveCriticalSection(&cancelConnLock);
#endif
}

/*
 * reorg_command_end
 *
 * Free the current cancel connection, if any, and set to NULL.
 */
static void
reorg_command_end(void)
{
	PGcancel   *oldCancelConn;

#ifdef WIN32
	EnterCriticalSection(&cancelConnLock);
#endif

	oldCancelConn = cancelConn;

	/* be sure handle_sigint doesn't use pointer while freeing */
	cancelConn = NULL;

	if (oldCancelConn != NULL)
		PQfreeCancel(oldCancelConn);

#ifdef WIN32
	LeaveCriticalSection(&cancelConnLock);
#endif
}

/*
 * Handle interrupt signals by cancelling the current command.
 */
static void
reorg_cancel(void)
{
	int			save_errno = errno;
	char		errbuf[256];

	/* Set interruped flag */
	interrupted = true;

	/* Send QueryCancel if we are processing a database query */
	if (cancelConn != NULL && PQcancel(cancelConn, errbuf, sizeof(errbuf)))
		fprintf(stderr, _("Cancel request sent\n"));

	errno = save_errno;			/* just in case the write changed it */
}

#ifndef WIN32
static void
handle_sigint(SIGNAL_ARGS)
{
	reorg_cancel();
}

static void
reorg_setup_cancel_handler(void)
{
	pqsignal(SIGINT, handle_sigint);
}
#else							/* WIN32 */

/*
 * Console control handler for Win32. Note that the control handler will
 * execute on a *different thread* than the main one, so we need to do
 * proper locking around those structures.
 */
static BOOL WINAPI
consoleHandler(DWORD dwCtrlType)
{
	if (dwCtrlType == CTRL_C_EVENT ||
		dwCtrlType == CTRL_BREAK_EVENT)
	{
		EnterCriticalSection(&cancelConnLock);
		reorg_cancel();
		LeaveCriticalSection(&cancelConnLock);
		return TRUE;
	}
	else
		/* Return FALSE for any signals not being handled */
		return FALSE;
}

static void
reorg_setup_cancel_handler(void)
{
	InitializeCriticalSection(&cancelConnLock);

	SetConsoleCtrlHandler(consoleHandler, TRUE);
}

#endif   /* WIN32 */