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pg_createsubscriber: Add '--all' option.

Browse Source 
The '--all' option indicates that the tool queries the source server
(publisher) for all databases and creates subscriptions on the target
server (subscriber) for databases with matching names. Without this user
needs to explicitly specify all databases by using -d option for each
database.

This simplifies converting a physical standby to a logical subscriber,
particularly during upgrades.

The options '--database', '--publication', '--subscription', and
'--replication-slot' cannot be used when '--all' is specified.

Author: Shubham Khanna <khannashubham1197@gmail.com>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Euler Taveira <euler@eulerto.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Shlok Kyal <shlok.kyal.oss@gmail.com>
Discussion: https://postgr.es/m/CAHv8RjKhA=_h5vAbozzJ1Opnv=KXYQHQ-fJyaMfqfRqPpnC2bA@mail.gmail.com
This commit is contained in:
Amit Kapila 2025-03-28 12:26:39 +05:30
parent 890fc826c9
commit fb2ea12f42
3 changed files with 187 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
doc/src/sgml/ref/pg_createsubscriber.sgml
View File

@ -87,6 +87,24 @@ PostgreSQL documentation
command-line arguments:
<variablelist>
<varlistentry>
<term><option>-a</option></term>
<term><option>--all</option></term>
<listitem>
<para>
Create one subscription per database on the target server. Exceptions
are template databases and databases that don't allow connections.
If the database name is not specified in publisher-server, the postgres
database will be used, or if that does not exist, template1 will be used.
Automatically generated names for subscriptions, publications, and
replication slots are used when this option is specified.
This option cannot be used along with <option>--database</option>,
<option>--publication</option>, <option>--replication-slot</option>, or
<option>--subscription</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-d <replaceable class="parameter">dbname</replaceable></option></term>
<term><option>--database=<replaceable class="parameter">dbname</replaceable></option></term>
@ -94,10 +112,12 @@ PostgreSQL documentation
<para>
The name of the database in which to create a subscription. Multiple
databases can be selected by writing multiple <option>-d</option>
switches. If <option>-d</option> option is not provided, the database
name will be obtained from <option>-P</option> option. If the database
name is not specified in either the <option>-d</option> option or
<option>-P</option> option, an error will be reported.
switches. This option cannot be used together with <option>-a</option>.
If <option>-d</option> option is not provided, the database name will be
obtained from <option>-P</option> option. If the database name is not
specified in either the <option>-d</option> option, or the
<option>-P</option> option, and <option>-a</option> option is not
specified, an error will be reported.
</para>
</listitem>
</varlistentry>
@ -253,7 +273,8 @@ PostgreSQL documentation
names must match the number of specified databases, otherwise an error
is reported. The order of the multiple publication name switches must
match the order of database switches. If this option is not specified,
a generated name is assigned to the publication name.
a generated name is assigned to the publication name. This option cannot
be used together with <option>--all</option>.
</para>
</listitem>
</varlistentry>
@ -269,7 +290,8 @@ PostgreSQL documentation
otherwise an error is reported. The order of the multiple replication
slot name switches must match the order of database switches. If this
option is not specified, the subscription name is assigned to the
replication slot name.
replication slot name. This option cannot be used together with
<option>--all</option>.
</para>
</listitem>
</varlistentry>
@ -284,7 +306,8 @@ PostgreSQL documentation
names must match the number of specified databases, otherwise an error
is reported. The order of the multiple subscription name switches must
match the order of database switches. If this option is not specified,
a generated name is assigned to the subscription name.
a generated name is assigned to the subscription name. This option cannot
be used together with <option>--all</option>.
</para>
</listitem>
</varlistentry>

104
src/bin/pg_basebackup/pg_createsubscriber.c
View File

@ -45,6 +45,7 @@ struct CreateSubscriberOptions
SimpleStringList sub_names; /* list of subscription names */
SimpleStringList replslot_names; /* list of replication slot names */
int recovery_timeout; /* stop recovery after this time */
bool all_dbs; /* all option */
SimpleStringList objecttypes_to_remove; /* list of object types to remove */
};
@ -124,6 +125,8 @@ static void check_and_drop_existing_subscriptions(PGconn *conn,
const struct LogicalRepInfo *dbinfo);
static void drop_existing_subscriptions(PGconn *conn, const char *subname,
const char *dbname);
static void get_publisher_databases(struct CreateSubscriberOptions *opt,
bool dbnamespecified);
#define USEC_PER_SEC 1000000
#define WAIT_INTERVAL 1 /* 1 second */
@ -243,6 +246,8 @@ usage(void)
printf(_("Usage:\n"));
printf(_(" %s [OPTION]...\n"), progname);
printf(_("\nOptions:\n"));
printf(_(" -a, --all create subscriptions for all databases except template\n"
" databases or databases that don't allow connections\n"));
printf(_(" -d, --database=DBNAME database in which to create a subscription\n"));
printf(_(" -D, --pgdata=DATADIR location for the subscriber data directory\n"));
printf(_(" -n, --dry-run dry run, just show what would be done\n"));
@ -1959,11 +1964,65 @@ enable_subscription(PGconn *conn, const struct LogicalRepInfo *dbinfo)
destroyPQExpBuffer(str);
}
/*
* Fetch a list of all not-template databases from the source server and form
* a list such that they appear as if the user has specified multiple
* --database options, one for each source database.
*/
static void
get_publisher_databases(struct CreateSubscriberOptions *opt,
bool dbnamespecified)
{
PGconn *conn;
PGresult *res;
/* If a database name was specified, just connect to it. */
if (dbnamespecified)
conn = connect_database(opt->pub_conninfo_str, true);
else
{
/* Otherwise, try postgres first and then template1. */
char *conninfo;
conninfo = concat_conninfo_dbname(opt->pub_conninfo_str, "postgres");
conn = connect_database(conninfo, false);
pg_free(conninfo);
if (!conn)
{
conninfo = concat_conninfo_dbname(opt->pub_conninfo_str, "template1");
conn = connect_database(conninfo, true);
pg_free(conninfo);
}
}
res = PQexec(conn, "SELECT datname FROM pg_database WHERE datistemplate = false AND datallowconn AND datconnlimit <> -2 ORDER BY 1");
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
pg_log_error("could not obtain a list of databases: %s", PQresultErrorMessage(res));
PQclear(res);
disconnect_database(conn, true);
}
for (int i = 0; i < PQntuples(res); i++)
{
const char *dbname = PQgetvalue(res, i, 0);
simple_string_list_append(&opt->database_names, dbname);
/* Increment num_dbs to reflect multiple --database options */
num_dbs++;
}
PQclear(res);
disconnect_database(conn, false);
}
int
main(int argc, char **argv)
{
static struct option long_options[] =
{
{"all", no_argument, NULL, 'a'},
{"database", required_argument, NULL, 'd'},
{"pgdata", required_argument, NULL, 'D'},
{"dry-run", no_argument, NULL, 'n'},
@ -2034,6 +2093,7 @@ main(int argc, char **argv)
0
};
opt.recovery_timeout = 0;
opt.all_dbs = false;
/*
* Don't allow it to be run as root. It uses pg_ctl which does not allow
@ -2051,11 +2111,14 @@ main(int argc, char **argv)
get_restricted_token();
while ((c = getopt_long(argc, argv, "d:D:np:P:R:s:t:TU:v",
while ((c = getopt_long(argc, argv, "ad:D:np:P:R:s:t:TU:v",
long_options, &option_index)) != -1)
{
switch (c)
{
case 'a':
opt.all_dbs = true;
break;
case 'd':
if (!simple_string_list_member(&opt.database_names, optarg))
{
@ -2149,6 +2212,28 @@ main(int argc, char **argv)
}
}
/* Validate that --all is not used with incompatible options */
if (opt.all_dbs)
{
char *bad_switch = NULL;
if (num_dbs > 0)
bad_switch = "--database";
else if (num_pubs > 0)
bad_switch = "--publication";
else if (num_replslots > 0)
bad_switch = "--replication-slot";
else if (num_subs > 0)
bad_switch = "--subscription";
if (bad_switch)
{
pg_log_error("%s cannot be used with --all", bad_switch);
pg_log_error_hint("Try \"%s --help\" for more information.", progname);
exit(1);
}
}
/* Any non-option arguments? */
if (optind < argc)
{
@ -2202,14 +2287,25 @@ main(int argc, char **argv)
pg_log_info("validating subscriber connection string");
sub_base_conninfo = get_sub_conninfo(&opt);
/*
* Fetch all databases from the source (publisher) and treat them as if
* the user specified has multiple --database options, one for each source
* database.
*/
if (opt.all_dbs)
{
bool dbnamespecified = (dbname_conninfo != NULL);
get_publisher_databases(&opt, dbnamespecified);
}
if (opt.database_names.head == NULL)
{
pg_log_info("no database was specified");
/*
* If --database option is not provided, try to obtain the dbname from
* the publisher conninfo. If dbname parameter is not available, error
* out.
* Try to obtain the dbname from the publisher conninfo. If dbname
* parameter is not available, error out.
*/
if (dbname_conninfo)
{

57
src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
View File

@ -386,6 +386,63 @@ command_ok(
],
'run pg_createsubscriber without --databases');
# run pg_createsubscriber with '--database' and '--all' without '--dry-run'
# and verify the failure
command_fails_like(
[
'pg_createsubscriber',
'--verbose',
'--pgdata' => $node_s->data_dir,
'--publisher-server' => $node_p->connstr($db1),
'--socketdir' => $node_s->host,
'--subscriber-port' => $node_s->port,
'--database' => $db1,
'--all',
],
qr/--database cannot be used with --all/,
'fail if --database is used with --all');
# run pg_createsubscriber with '--publication' and '--all' and verify
# the failure
command_fails_like(
[
'pg_createsubscriber',
'--verbose',
'--dry-run',
'--pgdata' => $node_s->data_dir,
'--publisher-server' => $node_p->connstr($db1),
'--socketdir' => $node_s->host,
'--subscriber-port' => $node_s->port,
'--all',
'--publication' => 'pub1',
],
qr/--publication cannot be used with --all/,
'fail if --publication is used with --all');
# run pg_createsubscriber with '--all' option
my ($stdout, $stderr) = run_command(
[
'pg_createsubscriber',
'--verbose',
'--dry-run',
'--recovery-timeout' => $PostgreSQL::Test::Utils::timeout_default,
'--pgdata' => $node_s->data_dir,
'--publisher-server' => $node_p->connstr,
'--socketdir' => $node_s->host,
'--subscriber-port' => $node_s->port,
'--all',
],
'run pg_createsubscriber with --all');
# Verify that the required logical replication objects are output.
# The expected count 3 refers to postgres, $db1 and $db2 databases.
is(scalar(() = $stderr =~ /creating publication/g),
3, "verify publications are created for all databases");
is(scalar(() = $stderr =~ /creating the replication slot/g),
3, "verify replication slots are created for all databases");
is(scalar(() = $stderr =~ /creating subscription/g),
3, "verify subscriptions are created for all databases");
# Run pg_createsubscriber on node S. --verbose is used twice
# to show more information.
# In passing, also test the --enable-two-phase option and