pglogical/pglogical_create_subscriber.c at REL2_x_STABLE · githubzilla/pglogical

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/* -------------------------------------------------------------------------

* pglogical_create_subscriber.c

* Initialize a new pglogical subscriber from a physical base backup

* IDENTIFICATION

* pglogical_create_subscriber.c

* -------------------------------------------------------------------------

/* dirent.h on port/win32_msvc expects MAX_PATH to be defined */

#if defined(_WIN32)

#define WIN32_LEAN_AND_MEAN

#include <windows.h>

#endif

#include <dirent.h>

#include <fcntl.h>

#include <locale.h>

#include <signal.h>

#include <time.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <sys/stat.h>

#include <unistd.h>

#include <stdlib.h>

/* Note the order is important for debian here. */

#if !defined(pg_attribute_printf)

/* GCC and XLC support format attributes */

#if defined(__GNUC__) || defined(__IBMC__)

#define pg_attribute_format_arg(a) __attribute__((format_arg(a)))

#define pg_attribute_printf(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE, f, a)))

#else

#define pg_attribute_format_arg(a)

#define pg_attribute_printf(f,a)

#endif

#include "libpq-fe.h"

#include "postgres_fe.h"

#include "pqexpbuffer.h"

#include "getopt_long.h"

#include "miscadmin.h"

#include "access/timeline.h"

#include "access/xlog_internal.h"

#include "catalog/pg_control.h"

#include "pglogical_fe.h"

#define MAX_APPLY_DELAY 86400

typedef struct RemoteInfo {

Oid nodeid;

char *node_name;

char *sysid;

char *dbname;

char *replication_sets;

} RemoteInfo;

typedef enum {

VERBOSITY_NORMAL,

VERBOSITY_VERBOSE,

VERBOSITY_DEBUG

} VerbosityLevelEnum;

static char *argv0 = NULL;

static const char *progname;

static char *data_dir = NULL;

static char pid_file[MAXPGPATH];

static time_t start_time;

static VerbosityLevelEnum verbosity = VERBOSITY_NORMAL;

/* defined as static so that die() can close them */

static PGconn *subscriber_conn = NULL;

static PGconn *provider_conn = NULL;

static void signal_handler(int sig);

static void usage(void);

static void die(const char *fmt,...)

pg_attribute_printf(1, 2);

static void print_msg(VerbosityLevelEnum level, const char *fmt,...)

pg_attribute_printf(2, 3);

static int run_pg_ctl(const char *arg);

static void run_basebackup(const char *provider_connstr, const char *data_dir,

const char *extra_basebackup_args);

static void wait_postmaster_connection(const char *connstr);

static void wait_primary_connection(const char *connstr);

static void wait_postmaster_shutdown(void);

static char *validate_replication_set_input(char *replication_sets);

static void remove_unwanted_data(PGconn *conn);

static void initialize_replication_origin(PGconn *conn, char *origin_name, char *remote_lsn);

static char *create_restore_point(PGconn *conn, char *restore_point_name);

static char *initialize_replication_slot(PGconn *conn, char *dbname,

char *provider_node_name, char *subscription_name,

bool drop_slot_if_exists);

static void pglogical_subscribe(PGconn *conn, char *subscriber_name,

char *subscriber_dsn,

char *provider_connstr,

char *replication_sets,

int apply_delay,

bool force_text_transfer);

static RemoteInfo *get_remote_info(PGconn* conn);

static bool extension_exists(PGconn *conn, const char *extname);

static void install_extension(PGconn *conn, const char *extname);

static void initialize_data_dir(char *data_dir, char *connstr,

char *postgresql_conf, char *pg_hba_conf,

char *extra_basebackup_args);

static bool check_data_dir(char *data_dir, RemoteInfo *remoteinfo);

static char *read_sysid(const char *data_dir);

static void WriteRecoveryConf(PQExpBuffer contents);

static void CopyConfFile(char *fromfile, char *tofile, bool append);

static char *get_connstr_dbname(char *connstr);

static char *get_connstr(char *connstr, char *dbname);

static char *PQconninfoParamsToConnstr(const char *const * keywords, const char *const * values);

static void appendPQExpBufferConnstrValue(PQExpBuffer buf, const char *str);

static bool file_exists(const char *path);

static bool is_pg_dir(const char *path);

static void copy_file(char *fromfile, char *tofile, bool append);

static char *find_other_exec_or_die(const char *argv0, const char *target);

static bool postmaster_is_alive(pid_t pid);

static long get_pgpid(void);

static char **get_database_list(char *databases, int *n_databases);

static char *generate_restore_point_name(void);

static PGconn *

connectdb(const char *connstr)

{

PGconn *conn;

conn = PQconnectdb(connstr);

if (PQstatus(conn) != CONNECTION_OK)

die(_("Connection to database failed: %s, connection string was: %s\n"), PQerrorMessage(conn), connstr);

return conn;

}

void signal_handler(int sig)

{

if (sig == SIGINT)

{

die(_("\nCanceling...\n"));

}

int

main(int argc, char **argv)

{

int i;

int c;

PQExpBuffer recoveryconfcontents = createPQExpBuffer();

RemoteInfo *remote_info;

char *remote_lsn;

bool stop = false;

bool drop_slot_if_exists = false;

int optindex;

char *subscriber_name = NULL;

char *base_sub_connstr = NULL;

char *base_prov_connstr = NULL;

char *replication_sets = NULL;

char *databases = NULL;

char *postgresql_conf = NULL,

*pg_hba_conf = NULL,

*recovery_conf = NULL;

int apply_delay = 0;

bool force_text_transfer = false;

char **slot_names;

char *sub_connstr;

char *prov_connstr;

char **database_list = { NULL };

int n_databases = 1;

int dbnum;

bool use_existing_data_dir = false;

int pg_ctl_ret,

logfd;

char *restore_point_name = NULL;

char *extra_basebackup_args = NULL;

static struct option long_options[] = {

{"subscriber-name", required_argument, NULL, 'n'},

{"pgdata", required_argument, NULL, 'D'},

{"provider-dsn", required_argument, NULL, 1},

{"subscriber-dsn", required_argument, NULL, 2},

{"replication-sets", required_argument, NULL, 3},

{"postgresql-conf", required_argument, NULL, 4},

{"hba-conf", required_argument, NULL, 5},

{"recovery-conf", required_argument, NULL, 6},

{"stop", no_argument, NULL, 's'},

{"drop-slot-if-exists", no_argument, NULL, 7},

{"apply-delay", required_argument, NULL, 8},

{"databases", required_argument, NULL, 9},

{"extra-basebackup-args", required_argument, NULL, 10},

{"text-types", no_argument, NULL, 11},

{NULL, 0, NULL, 0}

};

argv0 = argv[0];

progname = get_progname(argv[0]);

start_time = time(NULL);

signal(SIGINT, signal_handler);

/* check for --help */

if (argc > 1)

{

for (i = 1; i < argc; i++)

{

if (strcmp(argv[i], "--help") == 0 || strcmp(argv[i], "-?") == 0)

{

usage();

exit(0);

}

/* Option parsing and validation */

while ((c = getopt_long(argc, argv, "D:n:sv", long_options, &optindex)) != -1)

{

switch (c)

{

case 'D':

data_dir = pg_strdup(optarg);

break;

case 'n':

subscriber_name = pg_strdup(optarg);

break;

case 1:

base_prov_connstr = pg_strdup(optarg);

break;

case 2:

base_sub_connstr = pg_strdup(optarg);

break;

case 3:

replication_sets = validate_replication_set_input(pg_strdup(optarg));

break;

case 4:

{

postgresql_conf = pg_strdup(optarg);

if (postgresql_conf != NULL && !file_exists(postgresql_conf))

die(_("The specified postgresql.conf file does not exist."));

break;

}

case 5:

{

pg_hba_conf = pg_strdup(optarg);

if (pg_hba_conf != NULL && !file_exists(pg_hba_conf))

die(_("The specified pg_hba.conf file does not exist."));

break;

}

case 6:

{

recovery_conf = pg_strdup(optarg);

if (recovery_conf != NULL && !file_exists(recovery_conf))

die(_("The specified recovery configuration file does not exist."));

break;

}

case 'v':

verbosity++;

break;

case 's':

stop = true;

break;

case 7:

drop_slot_if_exists = true;

break;

case 8:

apply_delay = atoi(optarg);

break;

case 9:

databases = pg_strdup(optarg);

break;

case 10:

extra_basebackup_args = pg_strdup(optarg);

break;

case 11:

force_text_transfer = true;

break;

default:

fprintf(stderr, _("Unknown option\n"));

fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);

exit(1);

}

* Sanity checks

if (data_dir == NULL)

{

fprintf(stderr, _("No data directory specified\n"));

fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);

exit(1);

}

else if (subscriber_name == NULL)

{

fprintf(stderr, _("No subscriber name specified\n"));

fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);

exit(1);

}

if (!base_prov_connstr || !strlen(base_prov_connstr))

die(_("Provider connection string must be specified.\n"));

if (!base_sub_connstr || !strlen(base_sub_connstr))

die(_("Subscriber connection string must be specified.\n"));

if (apply_delay < 0)

die(_("Apply delay cannot be negative.\n"));

if (apply_delay > MAX_APPLY_DELAY)

die(_("Apply delay cannot be more than %d.\n"), MAX_APPLY_DELAY);

if (!replication_sets || !strlen(replication_sets))

replication_sets = "default,default_insert_only,ddl_sql";

/* Init random numbers used for slot suffixes, etc */

srand(time(NULL));

/* Parse database list or connection string. */

if (databases != NULL)

{

database_list = get_database_list(databases, &n_databases);

}

else

{

char *dbname = get_connstr_dbname(base_prov_connstr);

if (!dbname)

die(_("Either provider connection string must contain database "

"name or --databases option must be specified.\n"));

n_databases = 1;

database_list = palloc(n_databases * sizeof(char *));

database_list[0] = dbname;

}

slot_names = palloc(n_databases * sizeof(char *));

* Check connection strings for validity before doing anything

* expensive.

for (dbnum = 0; dbnum < n_databases; dbnum++)

{

char *db = database_list[dbnum];

prov_connstr = get_connstr(base_prov_connstr, db);

if (!prov_connstr || !strlen(prov_connstr))

die(_("Provider connection string is not valid.\n"));

sub_connstr = get_connstr(base_sub_connstr, db);

if (!sub_connstr || !strlen(sub_connstr))

die(_("Subscriber connection string is not valid.\n"));

}

* Create log file where new postgres instance will log to while being

* initialized.

logfd = open("pglogical_create_subscriber_postgres.log", O_CREAT | O_RDWR,

S_IRUSR | S_IWUSR);

if (logfd == -1)

{

die(_("Creating pglogical_create_subscriber_postgres.log failed: %s"),

strerror(errno));

}

/* Safe to close() unchecked, we didn't write */

(void) close(logfd);

/* Let's start the real work... */

print_msg(VERBOSITY_NORMAL, _("%s: starting ...\n"), progname);

for (dbnum = 0; dbnum < n_databases; dbnum++)

{

char *db = database_list[dbnum];

prov_connstr = get_connstr(base_prov_connstr, db);

if (!prov_connstr || !strlen(prov_connstr))

die(_("Provider connection string is not valid.\n"));

/* Read the remote server indetification. */

print_msg(VERBOSITY_NORMAL,

_("Getting information for database %s ...\n"), db);

provider_conn = connectdb(prov_connstr);

remote_info = get_remote_info(provider_conn);

/* only need to do this piece once */

if (dbnum == 0)

{

use_existing_data_dir = check_data_dir(data_dir, remote_info);

if (use_existing_data_dir &&

strcmp(remote_info->sysid, read_sysid(data_dir)) != 0)

die(_("Subscriber data directory is not basebackup of remote node.\n"));

}

* Create replication slots on remote node.

print_msg(VERBOSITY_NORMAL,

_("Creating replication slot in database %s ...\n"), db);

slot_names[dbnum] = initialize_replication_slot(provider_conn,

remote_info->dbname,

remote_info->node_name,

subscriber_name,

drop_slot_if_exists);

PQfinish(provider_conn);

provider_conn = NULL;

}

* Create basebackup or use existing one

prov_connstr = get_connstr(base_prov_connstr, database_list[0]);

sub_connstr = get_connstr(base_sub_connstr, database_list[0]);

initialize_data_dir(data_dir,

use_existing_data_dir ? NULL : prov_connstr,

postgresql_conf, pg_hba_conf,

extra_basebackup_args);

snprintf(pid_file, MAXPGPATH, "%s/postmaster.pid", data_dir);

restore_point_name = generate_restore_point_name();

print_msg(VERBOSITY_NORMAL, _("Creating restore point \"%s\" on remote node ...\n"),

restore_point_name);

provider_conn = connectdb(prov_connstr);

remote_lsn = create_restore_point(provider_conn, restore_point_name);

PQfinish(provider_conn);

provider_conn = NULL;

* Get subscriber db to consistent state (for lsn after slot creation).

print_msg(VERBOSITY_NORMAL,

_("Bringing subscriber node to the restore point ...\n"));

if (recovery_conf)

{

#if PG_VERSION_NUM >= 120000

CopyConfFile(recovery_conf, "postgresql.auto.conf", true);

#else

CopyConfFile(recovery_conf, "recovery.conf", false);

#endif

}

else

{

#if PG_VERSION_NUM < 120000

appendPQExpBuffer(recoveryconfcontents, "standby_mode = 'on'\n");

#endif

appendPQExpBuffer(recoveryconfcontents, "primary_conninfo = '%s'\n",

escape_single_quotes_ascii(prov_connstr));

}

appendPQExpBuffer(recoveryconfcontents, "recovery_target_name = '%s'\n", restore_point_name);

appendPQExpBuffer(recoveryconfcontents, "recovery_target_inclusive = true\n");

#if PG_VERSION_NUM >= 90500

appendPQExpBuffer(recoveryconfcontents, "recovery_target_action = promote\n");

#else

appendPQExpBuffer(recoveryconfcontents, "pause_at_recovery_target = false\n");

#endif

WriteRecoveryConf(recoveryconfcontents);

free(restore_point_name);

restore_point_name = NULL;

* Start subscriber node with pglogical disabled, and wait until it starts

* accepting connections which means it has caught up to the restore point.

pg_ctl_ret = run_pg_ctl("start -l \"pglogical_create_subscriber_postgres.log\" -o \"-c shared_preload_libraries=''\"");

if (pg_ctl_ret != 0)

die(_("Postgres startup for restore point catchup failed with %d. See pglogical_create_subscriber_postgres.log."), pg_ctl_ret);

wait_primary_connection(sub_connstr);

* Clean any per-node data that were copied by pg_basebackup.

print_msg(VERBOSITY_VERBOSE,

_("Removing old pglogical configuration ...\n"));

for (dbnum = 0; dbnum < n_databases; dbnum++)

{

char *db = database_list[dbnum];

sub_connstr = get_connstr(base_sub_connstr, db);

if (!sub_connstr || !strlen(sub_connstr))

die(_("Subscriber connection string is not valid.\n"));

subscriber_conn = connectdb(sub_connstr);

remove_unwanted_data(subscriber_conn);

PQfinish(subscriber_conn);

subscriber_conn = NULL;

}

/* Stop Postgres so we can reset system id and start it with pglogical loaded. */

pg_ctl_ret = run_pg_ctl("stop");

if (pg_ctl_ret != 0)

die(_("Postgres stop after restore point catchup failed with %d. See pglogical_create_subscriber_postgres.log."), pg_ctl_ret);

wait_postmaster_shutdown();

* Start the node again, now with pglogical active so that we can start the

* logical replication. This is final start, so don't log to to special log

* file anymore.

print_msg(VERBOSITY_NORMAL,

_("Initializing pglogical on the subscriber node:\n"));

pg_ctl_ret = run_pg_ctl("start");

if (pg_ctl_ret != 0)

die(_("Postgres restart with pglogical enabled failed with %d."), pg_ctl_ret);

wait_postmaster_connection(base_sub_connstr);

for (dbnum = 0; dbnum < n_databases; dbnum++)

{

char *db = database_list[dbnum];

sub_connstr = get_connstr(base_sub_connstr, db);

prov_connstr = get_connstr(base_prov_connstr, db);

subscriber_conn = connectdb(sub_connstr);

/* Create the extension. */

print_msg(VERBOSITY_VERBOSE,

_("Creating pglogical extension for database %s...\n"), db);

if (PQserverVersion(subscriber_conn) < 90500)

install_extension(subscriber_conn, "pglogical_origin");

install_extension(subscriber_conn, "pglogical");

* Create the identifier which is setup with the position to which we

* already caught up using physical replication.

print_msg(VERBOSITY_VERBOSE,

_("Creating replication origin for database %s...\n"), db);

initialize_replication_origin(subscriber_conn, slot_names[dbnum], remote_lsn);

* And finally add the node to the cluster.

print_msg(VERBOSITY_NORMAL, _("Creating subscriber %s for database %s...\n"),

subscriber_name, db);

print_msg(VERBOSITY_VERBOSE, _("Replication sets: %s\n"), replication_sets);

pglogical_subscribe(subscriber_conn, subscriber_name, sub_connstr,

prov_connstr, replication_sets, apply_delay,

force_text_transfer);

PQfinish(subscriber_conn);

subscriber_conn = NULL;

}

/* If user does not want the node to be running at the end, stop it. */

if (stop)

{

print_msg(VERBOSITY_NORMAL, _("Stopping the subscriber node ...\n"));

pg_ctl_ret = run_pg_ctl("stop");

if (pg_ctl_ret != 0)

die(_("Stopping postgres after successful subscribtion failed with %d."), pg_ctl_ret);

wait_postmaster_shutdown();

}

print_msg(VERBOSITY_NORMAL, _("All done\n"));

return 0;

}

* Print help.

static void

usage(void)

{

printf(_("%s create new pglogical subscriber from basebackup of provider.\n\n"), progname);

printf(_("Usage:\n"));

printf(_(" %s [OPTION]...\n"), progname);

printf(_("\nGeneral options:\n"));

printf(_(" -D, --pgdata=DIRECTORY data directory to be used for new node,\n"));

printf(_(" can be either empty/non-existing directory,\n"));

printf(_(" or directory populated using\n"));

printf(_(" pg_basebackup -X stream command\n"));

printf(_(" --databases optional list of databases to replicate\n"));

printf(_(" -n, --subscriber-name=NAME name of the newly created subscriber\n"));

printf(_(" --subscriber-dsn=CONNSTR connection string to the newly created subscriber\n"));

printf(_(" --provider-dsn=CONNSTR connection string to the provider\n"));

printf(_(" --replication-sets=SETS comma separated list of replication set names\n"));

printf(_(" --apply-delay=DELAY apply delay in seconds (by default 0)\n"));

printf(_(" --drop-slot-if-exists drop replication slot of conflicting name\n"));

printf(_(" -s, --stop stop the server once the initialization is done\n"));

printf(_(" -v increase logging verbosity\n"));

printf(_(" --extra-basebackup-args additional arguments to pass to pg_basebackup.\n"));

printf(_(" Safe options: -T, -c, --xlogdir/--waldir\n"));

printf(_("\nConfiguration files override:\n"));

printf(_(" --hba-conf path to the new pg_hba.conf\n"));

printf(_(" --postgresql-conf path to the new postgresql.conf\n"));

printf(_(" --recovery-conf path to the template recovery configuration\n"));

}

* Print error and exit.

static void

die(const char *fmt,...)

{

va_list argptr;

va_start(argptr, fmt);

vfprintf(stderr, fmt, argptr);

va_end(argptr);

if (subscriber_conn)

PQfinish(subscriber_conn);

if (provider_conn)

PQfinish(provider_conn);

if (get_pgpid())

{

if (!run_pg_ctl("stop -s"))

{

fprintf(stderr, _("WARNING: postgres seems to be running, but could not be stopped\n"));

}

exit(1);

}

* Print message to stdout and flush

static void

print_msg(VerbosityLevelEnum level, const char *fmt,...)

{

if (verbosity >= level)

{

va_list argptr;

va_start(argptr, fmt);

vfprintf(stdout, fmt, argptr);

va_end(argptr);

fflush(stdout);

}

* Start pg_ctl with given argument(s) - used to start/stop postgres

* Returns the exit code reported by pg_ctl. If pg_ctl exits due to a

* signal this call will die and not return.

static int

run_pg_ctl(const char *arg)

{

int ret;

PQExpBuffer cmd = createPQExpBuffer();

char *exec_path = find_other_exec_or_die(argv0, "pg_ctl");

appendPQExpBuffer(cmd, "%s %s -D \"%s\"", exec_path, arg, data_dir);

/* Run pg_ctl in silent mode unless we run in debug mode. */

if (verbosity < VERBOSITY_DEBUG)

appendPQExpBuffer(cmd, " -s");

print_msg(VERBOSITY_DEBUG, _("Running pg_ctl: %s.\n"), cmd->data);

ret = system(cmd->data);

destroyPQExpBuffer(cmd);

if (WIFEXITED(ret))

return WEXITSTATUS(ret);

else if (WIFSIGNALED(ret))

die(_("pg_ctl exited with signal %d"), WTERMSIG(ret));

else

die(_("pg_ctl exited for an unknown reason (system() returned %d)"), ret);

return -1;

}

* Run pg_basebackup to create the copy of the origin node.

static void

run_basebackup(const char *provider_connstr, const char *data_dir,

const char *extra_basebackup_args)

{

int ret;

PQExpBuffer cmd = createPQExpBuffer();

char *exec_path = find_other_exec_or_die(argv0, "pg_basebackup");

appendPQExpBuffer(cmd, "%s -D \"%s\" -d \"%s\" -X s -P", exec_path, data_dir, provider_connstr);

/* Run pg_basebackup in verbose mode if we are running in verbose mode. */

if (verbosity >= VERBOSITY_VERBOSE)

appendPQExpBuffer(cmd, " -v");

if (extra_basebackup_args != NULL)

appendPQExpBuffer(cmd, "%s", extra_basebackup_args);

print_msg(VERBOSITY_DEBUG, _("Running pg_basebackup: %s.\n"), cmd->data);

ret = system(cmd->data);

destroyPQExpBuffer(cmd);

if (WIFEXITED(ret) && WEXITSTATUS(ret) == 0)

return;

if (WIFEXITED(ret))

die(_("pg_basebackup failed with exit status %d, cannot continue.\n"), WEXITSTATUS(ret));

else if (WIFSIGNALED(ret))

die(_("pg_basebackup exited with signal %d, cannot continue"), WTERMSIG(ret));

else

die(_("pg_basebackup exited for an unknown reason (system() returned %d)"), ret);

}

* Init the datadir

* This function can either ensure provided datadir is a postgres datadir,

* or create it using pg_basebackup.

* In any case, new postresql.conf and pg_hba.conf will be copied to the

* datadir if they are provided.

static void

initialize_data_dir(char *data_dir, char *connstr,

char *postgresql_conf, char *pg_hba_conf,

char *extra_basebackup_args)

{

if (connstr)

{

print_msg(VERBOSITY_NORMAL,

_("Creating base backup of the remote node...\n"));

run_basebackup(connstr, data_dir, extra_basebackup_args);

}

if (postgresql_conf)

CopyConfFile(postgresql_conf, "postgresql.conf", false);

if (pg_hba_conf)

CopyConfFile(pg_hba_conf, "pg_hba.conf", false);

}

* This function checks if provided datadir is clone of the remote node

* described by the remote info, or if it's emtpy directory that can be used

* as new datadir.

static bool

check_data_dir(char *data_dir, RemoteInfo *remoteinfo)

{

/* Run basebackup as needed. */

switch (pg_check_dir(data_dir))

{

case 0: /* Does not exist */

case 1: /* Exists, empty */

return false;

case 2:

case 3: /* Exists, not empty */

case 4:

{

if (!is_pg_dir(data_dir))

die(_("Directory \"%s\" exists but is not valid postgres data directory.\n"),

data_dir);

return true;

}

case -1: /* Access problem */

die(_("Could not access directory \"%s\": %s.\n"),

data_dir, strerror(errno));

}

/* Unreachable */

die(_("Unexpected result from pg_check_dir() call"));

return false;

}

* Initialize replication slots

static char *

initialize_replication_slot(PGconn *conn, char *dbname,

char *provider_node_name, char *subscription_name,

bool drop_slot_if_exists)

{

PQExpBufferData query;

char *slot_name;

PGresult *res;

/* Generate the slot name. */

initPQExpBuffer(&query);

printfPQExpBuffer(&query,

"SELECT pglogical.pglogical_gen_slot_name(%s, %s, %s)",

PQescapeLiteral(conn, dbname, strlen(dbname)),

PQescapeLiteral(conn, provider_node_name,

strlen(provider_node_name)),

PQescapeLiteral(conn, subscription_name,

strlen(subscription_name)));

res = PQexec(conn, query.data);

if (PQresultStatus(res) != PGRES_TUPLES_OK)

die(_("Could generate slot name: %s"), PQerrorMessage(conn));

slot_name = pstrdup(PQgetvalue(res, 0, 0));

PQclear(res);

resetPQExpBuffer(&query);

/* Check if the current slot exists. */

printfPQExpBuffer(&query,

"SELECT 1 FROM pg_catalog.pg_replication_slots WHERE slot_name = %s",

PQescapeLiteral(conn, slot_name, strlen(slot_name)));

res = PQexec(conn, query.data);

if (PQresultStatus(res) != PGRES_TUPLES_OK)

die(_("Could not fetch existing slot information: %s"), PQerrorMessage(conn));

/* Drop the existing slot when asked for it or error if it already exists. */

if (PQntuples(res) > 0)

{

PQclear(res);

resetPQExpBuffer(&query);

if (!drop_slot_if_exists)

die(_("Slot %s already exists, drop it or use --drop-slot-if-exists to drop it automatically.\n"),

slot_name);

print_msg(VERBOSITY_VERBOSE,

_("Droping existing slot %s ...\n"), slot_name);

printfPQExpBuffer(&query,

"SELECT pg_catalog.pg_drop_replication_slot(%s)",

PQescapeLiteral(conn, slot_name, strlen(slot_name)));

res = PQexec(conn, query.data);

if (PQresultStatus(res) != PGRES_TUPLES_OK)

die(_("Could not drop existing slot %s: %s"), slot_name,

PQerrorMessage(conn));

}

PQclear(res);

resetPQExpBuffer(&query);

/* And finally, create the slot. */

appendPQExpBuffer(&query, "SELECT pg_create_logical_replication_slot(%s, '%s');",

PQescapeLiteral(conn, slot_name, strlen(slot_name)),

"pglogical_output");

res = PQexec(conn, query.data);

if (PQresultStatus(res) != PGRES_TUPLES_OK)

{

die(_("Could not create replication slot, status %s: %s\n"),

PQresStatus(PQresultStatus(res)), PQresultErrorMessage(res));

}

PQclear(res);

termPQExpBuffer(&query);

return slot_name;

}

* Read replication info about remote connection

* TODO: unify with pglogical_remote_node_info in pglogical_rpc

static RemoteInfo *

get_remote_info(PGconn* conn)

{

RemoteInfo *ri = (RemoteInfo *)pg_malloc0(sizeof(RemoteInfo));

PGresult *res;

if (!extension_exists(conn, "pglogical"))

die(_("The remote node is not configured as a pglogical provider.\n"));

res = PQexec(conn, "SELECT node_id, node_name, sysid, dbname, replication_sets FROM pglogical.pglogical_node_info()");

if (PQresultStatus(res) != PGRES_TUPLES_OK)

die(_("could not fetch remote node info: %s\n"), PQerrorMessage(conn));

/* No nodes found? */

if (PQntuples(res) == 0)

die(_("The remote database is not configured as a pglogical node.\n"));

if (PQntuples(res) > 1)

die(_("The remote database has multiple nodes configured. That is not supported with current version of pglogical.\n"));

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

ri->nodeid = atooid(PQgetvalue(res, 0, 0));

ri->node_name = pstrdup(PQgetvalue(res, 0, 1));

ri->sysid = pstrdup(PQgetvalue(res, 0, 2));

ri->dbname = pstrdup(PQgetvalue(res, 0, 3));

ri->replication_sets = pstrdup(PQgetvalue(res, 0, 4));

PQclear(res);

return ri;

}

* Check if extension exists.

static bool

extension_exists(PGconn *conn, const char *extname)

{

PQExpBuffer query = createPQExpBuffer();

PGresult *res;

bool ret;

printfPQExpBuffer(query, "SELECT 1 FROM pg_catalog.pg_extension WHERE extname = %s;",

PQescapeLiteral(conn, extname, strlen(extname)));

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

if (PQresultStatus(res) != PGRES_TUPLES_OK)

{

PQclear(res);

die(_("Could not read extension info: %s\n"), PQerrorMessage(conn));

}

ret = PQntuples(res) == 1;

PQclear(res);

destroyPQExpBuffer(query);

return ret;

}

* Create extension.

static void

install_extension(PGconn *conn, const char *extname)

{

PQExpBuffer query = createPQExpBuffer();

PGresult *res;

printfPQExpBuffer(query, "CREATE EXTENSION IF NOT EXISTS %s;",

PQescapeIdentifier(conn, extname, strlen(extname)));

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

if (PQresultStatus(res) != PGRES_COMMAND_OK)

{

PQclear(res);

die(_("Could not install %s extension: %s\n"), extname, PQerrorMessage(conn));

}

PQclear(res);

destroyPQExpBuffer(query);

}

* Clean all the data that was copied from remote node but we don't

* want it here (currently shared security labels and replication identifiers).

static void

remove_unwanted_data(PGconn *conn)

{

PGresult *res;

* Remove replication identifiers (9.4 will get them removed by dropping

* the extension later as we emulate them there).

if (PQserverVersion(conn) >= 90500)

{

res = PQexec(conn, "SELECT pg_replication_origin_drop(external_id) FROM pg_replication_origin_status;");

if (PQresultStatus(res) != PGRES_TUPLES_OK)

{

PQclear(res);

die(_("Could not remove existing replication origins: %s\n"), PQerrorMessage(conn));

}

PQclear(res);

}

res = PQexec(conn, "DROP EXTENSION pglogical CASCADE;");

if (PQresultStatus(res) != PGRES_COMMAND_OK)

{

die(_("Could not clean the pglogical extension, status %s: %s\n"),

PQresStatus(PQresultStatus(res)), PQresultErrorMessage(res));

}

PQclear(res);

}

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