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pg_createsubscriber: Remove failover replication slots on subscriber

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After running pg_createsubscriber, these replication slots have no use
on subscriber, so drop them.

Author: Euler Taveira <euler.taveira@enterprisedb.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Discussion: https://www.postgresql.org/message-id/776c5cac-5ef5-4001-b1bc-5b698bc0c62a%40app.fastmail.com
This commit is contained in:
Peter Eisentraut
2024-06-17 12:12:49 +02:00
parent b963913826
commit 81d20fbf7a
3 changed files with 76 additions and 2 deletions
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49
src/bin/pg_basebackup/pg_createsubscriber.c
View File

@@ -85,6 +85,7 @@ static void setup_recovery(const struct LogicalRepInfo *dbinfo, const char *data
const char *lsn);
static void drop_primary_replication_slot(struct LogicalRepInfo *dbinfo,
const char *slotname);
static void drop_failover_replication_slots(struct LogicalRepInfo *dbinfo);
static char *create_logical_replication_slot(PGconn *conn,
struct LogicalRepInfo *dbinfo);
static void drop_replication_slot(PGconn *conn, struct LogicalRepInfo *dbinfo,
@@ -1137,6 +1138,49 @@ drop_primary_replication_slot(struct LogicalRepInfo *dbinfo, const char *slotnam
}
}
/*
* Drop failover replication slots on subscriber. After the transformation,
* they have no use.
*
* XXX We do not fail here. Instead, we provide a warning so the user can drop
* them later.
*/
static void
drop_failover_replication_slots(struct LogicalRepInfo *dbinfo)
{
PGconn *conn;
PGresult *res;
conn = connect_database(dbinfo[0].subconninfo, false);
if (conn != NULL)
{
/* Get failover replication slot names */
res = PQexec(conn,
"SELECT slot_name FROM pg_catalog.pg_replication_slots WHERE failover");
if (PQresultStatus(res) == PGRES_TUPLES_OK)
{
/* Remove failover replication slots from subscriber */
for (int i = 0; i < PQntuples(res); i++)
drop_replication_slot(conn, &dbinfo[0], PQgetvalue(res, i, 0));
}
else
{
pg_log_warning("could not obtain failover replication slot information: %s",
PQresultErrorMessage(res));
pg_log_warning_hint("Drop the failover replication slots on subscriber soon to avoid retention of WAL files.");
}
PQclear(res);
disconnect_database(conn, false);
}
else
{
pg_log_warning("could not drop failover replication slot");
pg_log_warning_hint("Drop the failover replication slots on subscriber soon to avoid retention of WAL files.");
}
}
/*
* Create a logical replication slot and returns a LSN.
*
@@ -1268,7 +1312,7 @@ start_standby_server(const struct CreateSubscriberOptions *opt, bool restricted_
PQExpBuffer pg_ctl_cmd = createPQExpBuffer();
int rc;
appendPQExpBuffer(pg_ctl_cmd, "\"%s\" start -D \"%s\" -s",
appendPQExpBuffer(pg_ctl_cmd, "\"%s\" start -D \"%s\" -s -o \"-c sync_replication_slots=off\"",
pg_ctl_path, subscriber_dir);
if (restricted_access)
{
@@ -2065,6 +2109,9 @@ main(int argc, char **argv)
/* Remove primary_slot_name if it exists on primary */
drop_primary_replication_slot(dbinfo, primary_slot_name);
/* Remove failover replication slots if they exist on subscriber */
drop_failover_replication_slots(dbinfo);
/* Stop the subscriber */
pg_log_info("stopping the subscriber");
stop_standby_server(subscriber_dir);