From 4e8ea4e327c32aa442a2113d91e6a2ef23bd7ca9 Mon Sep 17 00:00:00 2001
From: Takamichi Osumi <osumi.takamichi@fujitsu.com>
Date: Thu, 24 Nov 2022 14:35:36 +0000
Subject: [PATCH v9] Time-delayed logical replication subscriber

Similar to physical replication, a time-delayed copy of the data for
logical replication is useful for some scenarios (particularly to fix
errors that might cause data loss).

If the subscription sets min_apply_delay parameter, the logical
replication worker will delay the transaction commit for min_apply_delay
milliseconds.

The delay is calculated between the WAL time stamp and the current time
on the subscriber.

The delay occurs only on WAL records for transaction begins. The main
reason is to avoid keeping a transaction open for a long time. Regular
and prepared transactions are covered. Streamed transactions are also
covered.

Author: Euler Taveira
Discussion: https://postgr.es/m/CAB-JLwYOYwL=XTyAXKiH5CtM_Vm8KjKh7aaitCKvmCh4rzr5pQ@mail.gmail.com
---
 doc/src/sgml/catalogs.sgml                 |   9 ++
 doc/src/sgml/logical-replication.sgml      |   6 +
 doc/src/sgml/ref/alter_subscription.sgml   |   5 +-
 doc/src/sgml/ref/create_subscription.sgml  |  55 ++++++-
 src/backend/catalog/pg_subscription.c      |   1 +
 src/backend/catalog/system_views.sql       |   7 +-
 src/backend/commands/subscriptioncmds.c    |  55 ++++++-
 src/backend/replication/logical/worker.c   | 108 +++++++++++++
 src/backend/utils/adt/timestamp.c          |  32 ++++
 src/bin/pg_dump/pg_dump.c                  |  16 +-
 src/bin/pg_dump/pg_dump.h                  |   1 +
 src/bin/psql/describe.c                    |   9 +-
 src/bin/psql/tab-complete.c                |   4 +-
 src/include/catalog/pg_subscription.h      |   3 +
 src/include/datatype/timestamp.h           |   2 +
 src/include/utils/timestamp.h              |   2 +
 src/test/regress/expected/subscription.out | 176 +++++++++++++--------
 src/test/regress/sql/subscription.sql      |  25 +++
 src/test/subscription/meson.build          |   1 +
 src/test/subscription/t/032_apply_delay.pl | 129 +++++++++++++++
 20 files changed, 563 insertions(+), 83 deletions(-)
 create mode 100644 src/test/subscription/t/032_apply_delay.pl

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 9ed2b020b7..708e3520c0 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -7863,6 +7863,15 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>subapplydelay</structfield> <type>int8</type>
+      </para>
+      <para>
+       The length of time (ms) to delay the application of changes.
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>subname</structfield> <type>name</type>
diff --git a/doc/src/sgml/logical-replication.sgml b/doc/src/sgml/logical-replication.sgml
index f8756389a3..8a6ed1bc5c 100644
--- a/doc/src/sgml/logical-replication.sgml
+++ b/doc/src/sgml/logical-replication.sgml
@@ -247,6 +247,12 @@
    target table.
   </para>
 
+  <para>
+   Time delayed replica of subscription is available by indicating
+   <literal>min_apply_delay</literal>. See
+   <xref linkend="sql-createsubscription"/> for details.
+  </para>
+
   <sect2 id="logical-replication-subscription-slot">
    <title>Replication Slot Management</title>
 
diff --git a/doc/src/sgml/ref/alter_subscription.sgml b/doc/src/sgml/ref/alter_subscription.sgml
index 1e8d72062b..d63aff1b90 100644
--- a/doc/src/sgml/ref/alter_subscription.sgml
+++ b/doc/src/sgml/ref/alter_subscription.sgml
@@ -213,8 +213,9 @@ ALTER SUBSCRIPTION <replaceable class="parameter">name</replaceable> RENAME TO <
       are <literal>slot_name</literal>,
       <literal>synchronous_commit</literal>,
       <literal>binary</literal>, <literal>streaming</literal>,
-      <literal>disable_on_error</literal>, and
-      <literal>origin</literal>.
+      <literal>disable_on_error</literal>,
+      <literal>origin</literal>, and
+      <literal>min_apply_delay</literal>.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_subscription.sgml b/doc/src/sgml/ref/create_subscription.sgml
index f9a1776380..b472655ccb 100644
--- a/doc/src/sgml/ref/create_subscription.sgml
+++ b/doc/src/sgml/ref/create_subscription.sgml
@@ -333,7 +333,48 @@ CREATE SUBSCRIPTION <replaceable class="parameter">subscription_name</replaceabl
          </para>
         </listitem>
        </varlistentry>
-      </variablelist></para>
+
+       <varlistentry>
+        <term><literal>min_apply_delay</literal> (<type>integer</type>)</term>
+        <listitem>
+         <para>
+          By default, subscriber applies changes as soon as possible. As with
+          the physical replication feature
+          (<xref linkend="guc-recovery-min-apply-delay"/>), it can be useful to
+          have a time-delayed logical replica. This parameter allows you to
+          delay the application of changes by a specified amount of time. If
+          this value is specified without units, it is taken as milliseconds.
+          The default is zero, adding no delay.
+         </para>
+         <para>
+          The delay occurs only on WAL records for transaction begins and after
+          the initial table synchronization. It is possible that the
+          replication delay between publisher and subscriber exceeds the value
+          of this parameter, in which case no delay is added. Note that the
+          delay is calculated between the WAL time stamp as written on
+          publisher and the current time on the subscriber. Time spent in logical
+          decoding and in transfering the transaction may reduce the actual wait
+          time. If the system clocks on publisher and subscriber are not
+          synchronized, this may lead to apply changes earlier than expected,
+          but this is not a major issue because this parameter is typically much
+          larger than the time deviations between servers. Note that
+          in the case when this parameter is set to a long value, the
+          replication may not continue if the replication slot falls behind the
+          current LSN by more than <literal>max_slot_wal_keep_size</literal>.
+          See more details in <xref linkend="guc-max-slot-wal-keep-size"/>.
+         </para>
+         <warning>
+           <para>
+            Synchronous replication is affected by this setting when
+            <varname>synchronous_commit</varname> is set to
+            <literal>remote_write</literal>; every <literal>COMMIT</literal>
+            will need to wait to be applied.
+           </para>
+         </warning>
+        </listitem>
+       </varlistentry>
+      </variablelist>
+     </para>
 
     </listitem>
    </varlistentry>
@@ -456,6 +497,18 @@ CREATE SUBSCRIPTION mysub
         PUBLICATION insert_only
                WITH (enabled = false);
 </programlisting></para>
+
+  <para>
+   Create a subscription to a remote server that replicates tables in
+   the <literal>mypub</literal> publication and starts replicating immediately
+   on commit. Pre-existing data is not copied. The application of changes is
+   delayed by 4 hours.
+<programlisting>
+CREATE SUBSCRIPTION mysub
+         CONNECTION 'host=192.168.1.50 port=5432 user=foo dbname=foodb'
+        PUBLICATION mypub
+               WITH (copy_data = false, min_apply_delay = '4h');
+</programlisting></para>
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index a506fc3ec8..d93e374ef4 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -64,6 +64,7 @@ GetSubscription(Oid subid, bool missing_ok)
 	sub->oid = subid;
 	sub->dbid = subform->subdbid;
 	sub->skiplsn = subform->subskiplsn;
+	sub->applydelay = subform->subapplydelay;
 	sub->name = pstrdup(NameStr(subform->subname));
 	sub->owner = subform->subowner;
 	sub->enabled = subform->subenabled;
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 2d8104b090..a84019bf2a 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1299,9 +1299,10 @@ REVOKE ALL ON pg_replication_origin_status FROM public;
 
 -- All columns of pg_subscription except subconninfo are publicly readable.
 REVOKE ALL ON pg_subscription FROM public;
-GRANT SELECT (oid, subdbid, subskiplsn, subname, subowner, subenabled,
-              subbinary, substream, subtwophasestate, subdisableonerr,
-              subslotname, subsynccommit, subpublications, suborigin)
+GRANT SELECT (oid, subdbid, subskiplsn, subapplydelay, subname, subowner,
+              subenabled, subbinary, substream, subtwophasestate,
+              subdisableonerr, subslotname, subsynccommit, subpublications,
+              suborigin)
     ON pg_subscription TO public;
 
 CREATE VIEW pg_stat_subscription_stats AS
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index d673557ea4..5ca7a05dae 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -47,6 +47,7 @@
 #include "utils/memutils.h"
 #include "utils/pg_lsn.h"
 #include "utils/syscache.h"
+#include "utils/timestamp.h"
 
 /*
  * Options that can be specified by the user in CREATE/ALTER SUBSCRIPTION
@@ -65,6 +66,7 @@
 #define SUBOPT_DISABLE_ON_ERR		0x00000400
 #define SUBOPT_LSN					0x00000800
 #define SUBOPT_ORIGIN				0x00001000
+#define SUBOPT_MIN_APPLY_DELAY		0x00002000
 
 /* check if the 'val' has 'bits' set */
 #define IsSet(val, bits)  (((val) & (bits)) == (bits))
@@ -89,6 +91,7 @@ typedef struct SubOpts
 	bool		disableonerr;
 	char	   *origin;
 	XLogRecPtr	lsn;
+	int64		min_apply_delay;
 } SubOpts;
 
 static List *fetch_table_list(WalReceiverConn *wrconn, List *publications);
@@ -145,6 +148,8 @@ parse_subscription_options(ParseState *pstate, List *stmt_options,
 		opts->disableonerr = false;
 	if (IsSet(supported_opts, SUBOPT_ORIGIN))
 		opts->origin = pstrdup(LOGICALREP_ORIGIN_ANY);
+	if (IsSet(supported_opts, SUBOPT_MIN_APPLY_DELAY))
+		opts->min_apply_delay = 0;
 
 	/* Parse options */
 	foreach(lc, stmt_options)
@@ -323,6 +328,43 @@ parse_subscription_options(ParseState *pstate, List *stmt_options,
 			opts->specified_opts |= SUBOPT_LSN;
 			opts->lsn = lsn;
 		}
+		else if (IsSet(supported_opts, SUBOPT_MIN_APPLY_DELAY) &&
+				 strcmp(defel->defname, "min_apply_delay") == 0)
+		{
+			char	   *val,
+					   *tmp;
+			Interval   *interval;
+			int64		ms;
+
+			if (IsSet(opts->specified_opts, SUBOPT_MIN_APPLY_DELAY))
+				errorConflictingDefElem(defel, pstate);
+
+			opts->specified_opts |= SUBOPT_MIN_APPLY_DELAY;
+			tmp = defGetString(defel);
+
+			/*
+			 * If no unit was specified, then explicitly add 'ms' otherwise
+			 * the interval_in function would assume 'seconds'.
+			 */
+			if (strspn(tmp, "0123456789") == strlen(tmp))
+				val = psprintf("%sms", tmp);
+			else
+				val = tmp;
+
+			interval = DatumGetIntervalP(DirectFunctionCall3(interval_in,
+															 CStringGetDatum(val),
+															 ObjectIdGetDatum(InvalidOid),
+															 Int32GetDatum(-1)));
+
+			ms = interval_to_ms(interval);
+			if (ms < 0 || ms > INT_MAX)
+				ereport(ERROR,
+						errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+						errmsg("%lld ms is outside the valid range for option \"%s\"",
+							   (long long) ms, "min_apply_delay"));
+
+			opts->min_apply_delay = ms;
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
@@ -559,7 +601,8 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
 					  SUBOPT_SLOT_NAME | SUBOPT_COPY_DATA |
 					  SUBOPT_SYNCHRONOUS_COMMIT | SUBOPT_BINARY |
 					  SUBOPT_STREAMING | SUBOPT_TWOPHASE_COMMIT |
-					  SUBOPT_DISABLE_ON_ERR | SUBOPT_ORIGIN);
+					  SUBOPT_DISABLE_ON_ERR | SUBOPT_ORIGIN |
+					  SUBOPT_MIN_APPLY_DELAY);
 	parse_subscription_options(pstate, stmt->options, supported_opts, &opts);
 
 	/*
@@ -624,6 +667,7 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
 	values[Anum_pg_subscription_oid - 1] = ObjectIdGetDatum(subid);
 	values[Anum_pg_subscription_subdbid - 1] = ObjectIdGetDatum(MyDatabaseId);
 	values[Anum_pg_subscription_subskiplsn - 1] = LSNGetDatum(InvalidXLogRecPtr);
+	values[Anum_pg_subscription_subapplydelay - 1] = Int64GetDatum(opts.min_apply_delay);
 	values[Anum_pg_subscription_subname - 1] =
 		DirectFunctionCall1(namein, CStringGetDatum(stmt->subname));
 	values[Anum_pg_subscription_subowner - 1] = ObjectIdGetDatum(owner);
@@ -1053,7 +1097,7 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 				supported_opts = (SUBOPT_SLOT_NAME |
 								  SUBOPT_SYNCHRONOUS_COMMIT | SUBOPT_BINARY |
 								  SUBOPT_STREAMING | SUBOPT_DISABLE_ON_ERR |
-								  SUBOPT_ORIGIN);
+								  SUBOPT_ORIGIN | SUBOPT_MIN_APPLY_DELAY);
 
 				parse_subscription_options(pstate, stmt->options,
 										   supported_opts, &opts);
@@ -1110,6 +1154,13 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 						= true;
 				}
 
+				if (IsSet(opts.specified_opts, SUBOPT_MIN_APPLY_DELAY))
+				{
+					values[Anum_pg_subscription_subapplydelay - 1] =
+						Int64GetDatum(opts.min_apply_delay);
+					replaces[Anum_pg_subscription_subapplydelay - 1] = true;
+				}
+
 				if (IsSet(opts.specified_opts, SUBOPT_ORIGIN))
 				{
 					values[Anum_pg_subscription_suborigin - 1] =
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index e48a3f589a..aff7bf7127 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -325,6 +325,8 @@ static void maybe_reread_subscription(void);
 
 static void DisableSubscriptionAndExit(void);
 
+static void apply_delay(TimestampTz ts);
+
 /* prototype needed because of stream_commit */
 static void apply_dispatch(StringInfo s);
 
@@ -828,6 +830,80 @@ slot_modify_data(TupleTableSlot *slot, TupleTableSlot *srcslot,
 	ExecStoreVirtualTuple(slot);
 }
 
+/*
+ * When min_apply_delay parameter is set on the subscriber, we wait long enough
+ * to make sure a transaction is applied at least that interval behind the
+ * publisher.
+ *
+ * It applies the delay for the next transaction but before starting the
+ * transaction. The main reason for this design is to avoid a long-running
+ * transaction (which can cause some operational challenges) if the user sets a
+ * high value for the delay. This design is different from the physical
+ * replication (that applies the delay at commit time) mainly because write
+ * operations may allow some issues (such as bloat and locks) that can be
+ * minimized if it does not keep the transaction open for such a long time.
+ *
+ * The min_apply_delay parameter will take effect only after all tables are in
+ * READY state.
+ */
+static void
+apply_delay(TimestampTz ts)
+{
+	TimestampTz delay_until = 0;
+
+	/* Nothing to do if no delay set */
+	if (MySubscription->applydelay <= 0)
+		return;
+
+	/*
+	 * Delay apply until all tablesync workers have reached READY state. If we
+	 * allow the delay during the catchup phase, once we reach the limit of
+	 * tablesync workers, it will impose a delay for each subsequent worker.
+	 * It means it will take a long time to finish the initial table
+	 * synchronization.
+	 */
+	if (!AllTablesyncsReady())
+		return;
+
+	/* Set apply delay */
+	delay_until = TimestampTzPlusMilliseconds(TimestampTzGetDatum(ts),
+											  MySubscription->applydelay);
+
+	while (true)
+	{
+		long		diffms;
+
+		diffms = TimestampDifferenceMilliseconds(GetCurrentTimestamp(), delay_until);
+
+		/*
+		 * Exit without arming the latch if it's already past time to apply
+		 * this transaction.
+		 */
+		if (diffms <= 0)
+			break;
+
+		elog(DEBUG2, "logical replication apply delay: %ld ms", diffms);
+
+		WaitLatch(MyLatch,
+				  WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
+				  diffms,
+				  WAIT_EVENT_RECOVERY_APPLY_DELAY);
+		ResetLatch(MyLatch);
+
+		CHECK_FOR_INTERRUPTS();
+
+		/*
+		 * The worker may be waken because of the ALTER SUBSCRIPTION ...
+		 * DISABLE, so the catalog pg_subscription should be read again.
+		 */
+		if (!in_remote_transaction && !in_streamed_transaction)
+		{
+			AcceptInvalidationMessages();
+			maybe_reread_subscription();
+		}
+	}
+}
+
 /*
  * Handle BEGIN message.
  */
@@ -839,6 +915,9 @@ apply_handle_begin(StringInfo s)
 	logicalrep_read_begin(s, &begin_data);
 	set_apply_error_context_xact(begin_data.xid, begin_data.final_lsn);
 
+	/* Should we delay the current transaction? */
+	apply_delay(begin_data.committime);
+
 	remote_final_lsn = begin_data.final_lsn;
 
 	maybe_start_skipping_changes(begin_data.final_lsn);
@@ -893,6 +972,9 @@ apply_handle_begin_prepare(StringInfo s)
 	logicalrep_read_begin_prepare(s, &begin_data);
 	set_apply_error_context_xact(begin_data.xid, begin_data.prepare_lsn);
 
+	/* Should we delay the current prepared transaction? */
+	apply_delay(begin_data.prepare_time);
+
 	remote_final_lsn = begin_data.prepare_lsn;
 
 	maybe_start_skipping_changes(begin_data.prepare_lsn);
@@ -1115,6 +1197,19 @@ apply_handle_stream_prepare(StringInfo s)
 
 	elog(DEBUG1, "received prepare for streamed transaction %u", prepare_data.xid);
 
+	/*
+	 * Should we delay the current prepared transaction?
+	 *
+	 * Although the delay is applied in BEGIN PREPARE messages, streamed
+	 * prepared transactions apply the delay in a STREAM PREPARE message.
+	 * That's ok because no changes have been applied yet
+	 * (apply_spooled_messages() will do it).
+	 * The STREAM START message does not contain a prepare time (it will be
+	 * available when the in-progress prepared transaction finishes), hence, it
+	 * was not possible to apply a delay at that time.
+	 */
+	apply_delay(prepare_data.prepare_time);
+
 	/* Replay all the spooled operations. */
 	apply_spooled_messages(prepare_data.xid, prepare_data.prepare_lsn);
 
@@ -1506,6 +1601,19 @@ apply_handle_stream_commit(StringInfo s)
 
 	elog(DEBUG1, "received commit for streamed transaction %u", xid);
 
+	/*
+	 * Should we delay the current transaction?
+	 *
+	 * Although the delay is applied in BEGIN messages, streamed transactions
+	 * apply the delay in a STREAM COMMIT message. That's ok because no changes
+	 * have been applied yet (apply_spooled_messages() will do it).
+	 * The STREAM START message would be a natural choice for this delay but
+	 * there is no commit time yet (it will be available when the in-progress
+	 * transaction finishes), hence, it was not possible to apply a delay at
+	 * that time.
+	 */
+	apply_delay(commit_data.committime);
+
 	apply_spooled_messages(xid, commit_data.commit_lsn);
 
 	apply_handle_commit_internal(&commit_data);
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index ef92323fd0..f25556b0f1 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -2425,6 +2425,38 @@ interval_cmp_internal(const Interval *interval1, const Interval *interval2)
 	return int128_compare(span1, span2);
 }
 
+/*
+ * Returns the number of milliseconds in the specified Interval.
+ */
+int64
+interval_to_ms(const Interval *interval)
+{
+	int64		days;
+	int64		ms;
+	int64		result;
+
+	days = interval->month * INT64CONST(30);
+	days += interval->day;
+
+	/*
+	 * The following operations use these special functions to detect
+	 * overflow. Number of ms per informed days.
+	 */
+	if (pg_mul_s64_overflow(days, MSECS_PER_DAY, &result))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+
+	/* Adds portion time (in ms) to the previous result. */
+	ms = interval->time / INT64CONST(1000);
+	if (pg_add_s64_overflow(result, ms, &result))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+
+	return result;
+}
+
 Datum
 interval_eq(PG_FUNCTION_ARGS)
 {
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index da427f4d4a..a8e493526b 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -4442,6 +4442,7 @@ getSubscriptions(Archive *fout)
 	int			i_subsynccommit;
 	int			i_subpublications;
 	int			i_subbinary;
+	int			i_subapplydelay;
 	int			i,
 				ntups;
 
@@ -4494,9 +4495,14 @@ getSubscriptions(Archive *fout)
 						  LOGICALREP_TWOPHASE_STATE_DISABLED);
 
 	if (fout->remoteVersion >= 160000)
-		appendPQExpBufferStr(query, " s.suborigin\n");
+		appendPQExpBufferStr(query,
+							 " s.suborigin,\n"
+							 " s.subapplydelay\n");
 	else
-		appendPQExpBuffer(query, " '%s' AS suborigin\n", LOGICALREP_ORIGIN_ANY);
+	{
+		appendPQExpBuffer(query, " '%s' AS suborigin,\n", LOGICALREP_ORIGIN_ANY);
+		appendPQExpBufferStr(query, " 0 AS subapplydelay\n");
+	}
 
 	appendPQExpBufferStr(query,
 						 "FROM pg_subscription s\n"
@@ -4524,6 +4530,7 @@ getSubscriptions(Archive *fout)
 	i_subtwophasestate = PQfnumber(res, "subtwophasestate");
 	i_subdisableonerr = PQfnumber(res, "subdisableonerr");
 	i_suborigin = PQfnumber(res, "suborigin");
+	i_subapplydelay = PQfnumber(res, "subapplydelay");
 
 	subinfo = pg_malloc(ntups * sizeof(SubscriptionInfo));
 
@@ -4554,6 +4561,8 @@ getSubscriptions(Archive *fout)
 		subinfo[i].subdisableonerr =
 			pg_strdup(PQgetvalue(res, i, i_subdisableonerr));
 		subinfo[i].suborigin = pg_strdup(PQgetvalue(res, i, i_suborigin));
+		subinfo[i].subapplydelay =
+			strtoi64(PQgetvalue(res, i, i_subapplydelay), NULL, 10);
 
 		/* Decide whether we want to dump it */
 		selectDumpableObject(&(subinfo[i].dobj), fout);
@@ -4633,6 +4642,9 @@ dumpSubscription(Archive *fout, const SubscriptionInfo *subinfo)
 	if (strcmp(subinfo->subsynccommit, "off") != 0)
 		appendPQExpBuffer(query, ", synchronous_commit = %s", fmtId(subinfo->subsynccommit));
 
+	if (subinfo->subapplydelay > 0)
+		appendPQExpBuffer(query, ", min_apply_delay = '" INT64_FORMAT " ms'", subinfo->subapplydelay);
+
 	appendPQExpBufferStr(query, ");\n");
 
 	if (subinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 427f5d45f6..26d03141d8 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -661,6 +661,7 @@ typedef struct _SubscriptionInfo
 	char	   *subdisableonerr;
 	char	   *suborigin;
 	char	   *subsynccommit;
+	int64		subapplydelay;
 	char	   *subpublications;
 } SubscriptionInfo;
 
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 2eae519b1d..de7a052697 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -6471,7 +6471,7 @@ describeSubscriptions(const char *pattern, bool verbose)
 	PGresult   *res;
 	printQueryOpt myopt = pset.popt;
 	static const bool translate_columns[] = {false, false, false, false,
-	false, false, false, false, false, false, false, false};
+	false, false, false, false, false, false, false, false, false};
 
 	if (pset.sversion < 100000)
 	{
@@ -6513,10 +6513,13 @@ describeSubscriptions(const char *pattern, bool verbose)
 							  gettext_noop("Two-phase commit"),
 							  gettext_noop("Disable on error"));
 
+		/* Origin and min_apply_delay are only supported in v16 and higher */
 		if (pset.sversion >= 160000)
 			appendPQExpBuffer(&buf,
-							  ", suborigin AS \"%s\"\n",
-							  gettext_noop("Origin"));
+							  ", suborigin AS \"%s\"\n"
+							  ", subapplydelay AS \"%s\"\n",
+							  gettext_noop("Origin"),
+							  gettext_noop("Apply delay"));
 
 		appendPQExpBuffer(&buf,
 						  ",  subsynccommit AS \"%s\"\n"
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 13014f074f..6f606a1ebd 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1880,7 +1880,7 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH("(", "PUBLICATION");
 	/* ALTER SUBSCRIPTION <name> SET ( */
 	else if (HeadMatches("ALTER", "SUBSCRIPTION", MatchAny) && TailMatches("SET", "("))
-		COMPLETE_WITH("binary", "disable_on_error", "origin", "slot_name",
+		COMPLETE_WITH("binary", "disable_on_error", "min_apply_delay", "origin", "slot_name",
 					  "streaming", "synchronous_commit");
 	/* ALTER SUBSCRIPTION <name> SKIP ( */
 	else if (HeadMatches("ALTER", "SUBSCRIPTION", MatchAny) && TailMatches("SKIP", "("))
@@ -3202,7 +3202,7 @@ psql_completion(const char *text, int start, int end)
 	/* Complete "CREATE SUBSCRIPTION <name> ...  WITH ( <opt>" */
 	else if (HeadMatches("CREATE", "SUBSCRIPTION") && TailMatches("WITH", "("))
 		COMPLETE_WITH("binary", "connect", "copy_data", "create_slot",
-					  "disable_on_error", "enabled", "origin", "slot_name",
+					  "disable_on_error", "enabled", "min_apply_delay", "origin", "slot_name",
 					  "streaming", "synchronous_commit", "two_phase");
 
 /* CREATE TRIGGER --- is allowed inside CREATE SCHEMA, so use TailMatches */
diff --git a/src/include/catalog/pg_subscription.h b/src/include/catalog/pg_subscription.h
index 7b98714f30..3894b97aca 100644
--- a/src/include/catalog/pg_subscription.h
+++ b/src/include/catalog/pg_subscription.h
@@ -70,6 +70,8 @@ CATALOG(pg_subscription,6100,SubscriptionRelationId) BKI_SHARED_RELATION BKI_ROW
 	XLogRecPtr	subskiplsn;		/* All changes finished at this LSN are
 								 * skipped */
 
+	int64		subapplydelay;	/* Replication apply delay */
+
 	NameData	subname;		/* Name of the subscription */
 
 	Oid			subowner BKI_LOOKUP(pg_authid); /* Owner of the subscription */
@@ -119,6 +121,7 @@ typedef struct Subscription
 								 * in */
 	XLogRecPtr	skiplsn;		/* All changes finished at this LSN are
 								 * skipped */
+	int64		applydelay;		/* Replication apply delay */
 	char	   *name;			/* Name of the subscription */
 	Oid			owner;			/* Oid of the subscription owner */
 	bool		enabled;		/* Indicates if the subscription is enabled */
diff --git a/src/include/datatype/timestamp.h b/src/include/datatype/timestamp.h
index d155f1b03b..d5bbfad1c4 100644
--- a/src/include/datatype/timestamp.h
+++ b/src/include/datatype/timestamp.h
@@ -127,6 +127,8 @@ struct pg_itm_in
 #define SECS_PER_MINUTE 60
 #define MINS_PER_HOUR	60
 
+#define MSECS_PER_DAY	INT64CONST(86400000)
+
 #define USECS_PER_DAY	INT64CONST(86400000000)
 #define USECS_PER_HOUR	INT64CONST(3600000000)
 #define USECS_PER_MINUTE INT64CONST(60000000)
diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index 7fd0b58825..b94efaf530 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -102,6 +102,8 @@ extern bool TimestampDifferenceExceeds(TimestampTz start_time,
 									   TimestampTz stop_time,
 									   int msec);
 
+extern int64 interval_to_ms(const Interval *interval);
+
 extern TimestampTz time_t_to_timestamptz(pg_time_t tm);
 extern pg_time_t timestamptz_to_time_t(TimestampTz t);
 
diff --git a/src/test/regress/expected/subscription.out b/src/test/regress/expected/subscription.out
index c13d218dcf..1cb2fe3fb3 100644
--- a/src/test/regress/expected/subscription.out
+++ b/src/test/regress/expected/subscription.out
@@ -114,18 +114,18 @@ CREATE SUBSCRIPTION regress_testsub4 CONNECTION 'dbname=regress_doesnotexist' PU
 WARNING:  subscription was created, but is not connected
 HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+ regress_testsub4
-                                                                                         List of subscriptions
-       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
-------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub4 | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | none   | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub4 | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | none   |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub4 SET (origin = any);
 \dRs+ regress_testsub4
-                                                                                         List of subscriptions
-       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
-------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub4 | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub4 | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 DROP SUBSCRIPTION regress_testsub3;
@@ -135,10 +135,10 @@ ALTER SUBSCRIPTION regress_testsub CONNECTION 'foobar';
 ERROR:  invalid connection string syntax: missing "=" after "foobar" in connection info string
 
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub SET PUBLICATION testpub2, testpub3 WITH (refresh = false);
@@ -155,10 +155,10 @@ ERROR:  unrecognized subscription parameter: "create_slot"
 -- ok
 ALTER SUBSCRIPTION regress_testsub SKIP (lsn = '0/12345');
 \dRs+
-                                                                                             List of subscriptions
-      Name       |           Owner           | Enabled |     Publication     | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |           Conninfo           | Skip LSN 
------------------+---------------------------+---------+---------------------+--------+-----------+------------------+------------------+--------+--------------------+------------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub2,testpub3} | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist2 | 0/12345
+                                                                                                    List of subscriptions
+      Name       |           Owner           | Enabled |     Publication     | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |           Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+---------------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+------------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub2,testpub3} | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist2 | 0/12345
 (1 row)
 
 -- ok - with lsn = NONE
@@ -167,10 +167,10 @@ ALTER SUBSCRIPTION regress_testsub SKIP (lsn = NONE);
 ALTER SUBSCRIPTION regress_testsub SKIP (lsn = '0/0');
 ERROR:  invalid WAL location (LSN): 0/0
 \dRs+
-                                                                                             List of subscriptions
-      Name       |           Owner           | Enabled |     Publication     | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |           Conninfo           | Skip LSN 
------------------+---------------------------+---------+---------------------+--------+-----------+------------------+------------------+--------+--------------------+------------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub2,testpub3} | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist2 | 0/0
+                                                                                                    List of subscriptions
+      Name       |           Owner           | Enabled |     Publication     | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |           Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+---------------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+------------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub2,testpub3} | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist2 | 0/0
 (1 row)
 
 BEGIN;
@@ -202,10 +202,10 @@ ALTER SUBSCRIPTION regress_testsub_foo SET (synchronous_commit = foobar);
 ERROR:  invalid value for parameter "synchronous_commit": "foobar"
 HINT:  Available values: local, remote_write, remote_apply, on, off.
 \dRs+
-                                                                                               List of subscriptions
-        Name         |           Owner           | Enabled |     Publication     | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |           Conninfo           | Skip LSN 
----------------------+---------------------------+---------+---------------------+--------+-----------+------------------+------------------+--------+--------------------+------------------------------+----------
- regress_testsub_foo | regress_subscription_user | f       | {testpub2,testpub3} | f      | f         | d                | f                | any    | local              | dbname=regress_doesnotexist2 | 0/0
+                                                                                                      List of subscriptions
+        Name         |           Owner           | Enabled |     Publication     | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |           Conninfo           | Skip LSN 
+---------------------+---------------------------+---------+---------------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+------------------------------+----------
+ regress_testsub_foo | regress_subscription_user | f       | {testpub2,testpub3} | f      | f         | d                | f                | any    |           0 | local              | dbname=regress_doesnotexist2 | 0/0
 (1 row)
 
 -- rename back to keep the rest simple
@@ -239,19 +239,19 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 WARNING:  subscription was created, but is not connected
 HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | t      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | t      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub SET (binary = false);
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 DROP SUBSCRIPTION regress_testsub;
@@ -263,19 +263,19 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 WARNING:  subscription was created, but is not connected
 HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub SET (streaming = false);
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 -- fail - publication already exists
@@ -290,10 +290,10 @@ ALTER SUBSCRIPTION regress_testsub ADD PUBLICATION testpub1, testpub2 WITH (refr
 ALTER SUBSCRIPTION regress_testsub ADD PUBLICATION testpub1, testpub2 WITH (refresh = false);
 ERROR:  publication "testpub1" is already in subscription "regress_testsub"
 \dRs+
-                                                                                                 List of subscriptions
-      Name       |           Owner           | Enabled |         Publication         | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-----------------------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub,testpub1,testpub2} | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                        List of subscriptions
+      Name       |           Owner           | Enabled |         Publication         | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-----------------------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub,testpub1,testpub2} | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 -- fail - publication used more then once
@@ -308,10 +308,10 @@ ERROR:  publication "testpub3" is not in subscription "regress_testsub"
 -- ok - delete publications
 ALTER SUBSCRIPTION regress_testsub DROP PUBLICATION testpub1, testpub2 WITH (refresh = false);
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 DROP SUBSCRIPTION regress_testsub;
@@ -347,10 +347,10 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 WARNING:  subscription was created, but is not connected
 HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | p                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | p                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 --fail - alter of two_phase option not supported.
@@ -359,10 +359,10 @@ ERROR:  unrecognized subscription parameter: "two_phase"
 -- but can alter streaming when two_phase enabled
 ALTER SUBSCRIPTION regress_testsub SET (streaming = true);
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | p                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | p                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
@@ -372,10 +372,10 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 WARNING:  subscription was created, but is not connected
 HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | p                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | t         | p                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
@@ -388,18 +388,58 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 WARNING:  subscription was created, but is not connected
 HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub SET (disable_on_error = true);
 \dRs+
-                                                                                         List of subscriptions
-      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
------------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+--------------------+-----------------------------+----------
- regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | t                | any    | off                | dbname=regress_doesnotexist | 0/0
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | t                | any    |           0 | off                | dbname=regress_doesnotexist | 0/0
+(1 row)
+
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
+DROP SUBSCRIPTION regress_testsub;
+-- fail -- min_apply_delay must be a non-negative integer
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = foo);
+ERROR:  invalid input syntax for type interval: "foo"
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = -1);
+ERROR:  -1000 ms is outside the valid range for option "min_apply_delay"
+-- success -- 123 ms
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = 123);
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
+\dRs+
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |         123 | off                | dbname=regress_doesnotexist | 0/0
+(1 row)
+
+-- success -- 86400000 ms
+ALTER SUBSCRIPTION regress_testsub SET (min_apply_delay = '1d');
+\dRs+
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |    86400000 | off                | dbname=regress_doesnotexist | 0/0
+(1 row)
+
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
+DROP SUBSCRIPTION regress_testsub;
+-- success -- interval is converted into ms and stored as integer
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = '4h 27min 35s');
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
+\dRs+
+                                                                                                List of subscriptions
+      Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Apply delay | Synchronous commit |          Conninfo           | Skip LSN 
+-----------------+---------------------------+---------+-------------+--------+-----------+------------------+------------------+--------+-------------+--------------------+-----------------------------+----------
+ regress_testsub | regress_subscription_user | f       | {testpub}   | f      | f         | d                | f                | any    |    16055000 | off                | dbname=regress_doesnotexist | 0/0
 (1 row)
 
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
diff --git a/src/test/regress/sql/subscription.sql b/src/test/regress/sql/subscription.sql
index eaeade8cce..7a4e818857 100644
--- a/src/test/regress/sql/subscription.sql
+++ b/src/test/regress/sql/subscription.sql
@@ -275,6 +275,31 @@ ALTER SUBSCRIPTION regress_testsub SET (disable_on_error = true);
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
 DROP SUBSCRIPTION regress_testsub;
 
+-- fail -- min_apply_delay must be a non-negative integer
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = foo);
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = -1);
+
+-- success -- 123 ms
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = 123);
+
+\dRs+
+
+-- success -- 86400000 ms
+ALTER SUBSCRIPTION regress_testsub SET (min_apply_delay = '1d');
+
+\dRs+
+
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
+DROP SUBSCRIPTION regress_testsub;
+
+-- success -- interval is converted into ms and stored as integer
+CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, min_apply_delay = '4h 27min 35s');
+
+\dRs+
+
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
+DROP SUBSCRIPTION regress_testsub;
+
 RESET SESSION AUTHORIZATION;
 DROP ROLE regress_subscription_user;
 DROP ROLE regress_subscription_user2;
diff --git a/src/test/subscription/meson.build b/src/test/subscription/meson.build
index 85d1dd9295..bb15d062b8 100644
--- a/src/test/subscription/meson.build
+++ b/src/test/subscription/meson.build
@@ -36,6 +36,7 @@ tests += {
       't/029_on_error.pl',
       't/030_origin.pl',
       't/031_column_list.pl',
+      't/032_apply_delay.pl',
       't/100_bugs.pl',
     ],
   },
diff --git a/src/test/subscription/t/032_apply_delay.pl b/src/test/subscription/t/032_apply_delay.pl
new file mode 100644
index 0000000000..ad8e4e200d
--- /dev/null
+++ b/src/test/subscription/t/032_apply_delay.pl
@@ -0,0 +1,129 @@
+
+# Copyright (c) 2022, PostgreSQL Global Development Group
+
+# Test replication apply delay
+use strict;
+use warnings;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Create publisher node.
+my $node_publisher = PostgreSQL::Test::Cluster->new('publisher');
+$node_publisher->init(allows_streaming => 'logical');
+$node_publisher->append_conf('postgresql.conf',
+	'logical_decoding_work_mem = 64kB');
+$node_publisher->start;
+
+# Create subscriber node.
+my $node_subscriber = PostgreSQL::Test::Cluster->new('subscriber');
+$node_subscriber->init;
+$node_subscriber->append_conf('postgresql.conf',
+	"log_min_messages = debug2");
+$node_subscriber->start;
+
+# Create some preexisting content on publisher.
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE test_tab (a int primary key, b varchar)");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO test_tab VALUES (1, 'foo'), (2, 'bar')");
+
+# Setup structure on subscriber.
+$node_subscriber->safe_psql('postgres',
+	"CREATE TABLE test_tab (a int primary key, b text, c timestamptz DEFAULT now(), d bigint DEFAULT 999)"
+);
+
+# Setup logical replication.
+my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub FOR TABLE test_tab");
+
+my $appname = 'tap_sub';
+$node_subscriber->safe_psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub WITH (streaming = on, min_apply_delay = '3s')"
+);
+
+# Wait for initial table sync to finish.
+$node_subscriber->wait_for_subscription_sync($node_publisher, $appname);
+
+# Check log starting now for logical replication apply delay.
+my $log_location = -s $node_subscriber->logfile;
+
+my $result =
+  $node_subscriber->safe_psql('postgres',
+	"SELECT count(*), min(a), max(a) FROM test_tab");
+is($result, qq(2|1|2), 'check initial data was copied to subscriber');
+
+# New row to trigger apply delay.
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO test_tab VALUES (3, 'baz')");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO test_tab VALUES (4, 'abc')");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO test_tab VALUES (5, 'def')");
+
+$node_publisher->wait_for_catchup($appname);
+
+$result =
+  $node_subscriber->safe_psql('postgres',
+	"SELECT count(*), min(a), max(a) FROM test_tab");
+is($result, qq(5|1|5), 'check if the new rows were applied to subscriber');
+
+check_apply_delay_log("logical replication apply delay");
+
+# Test streamed transaction.
+# Insert, update and delete enough rows to exceed 64kB limit.
+$node_publisher->safe_psql(
+	'postgres', q{
+BEGIN;
+INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(6, 5000) s(i);
+UPDATE test_tab SET b = md5(b) WHERE mod(a, 2) = 0;
+DELETE FROM test_tab WHERE mod(a, 3) = 0;
+COMMIT;
+});
+
+$node_publisher->wait_for_catchup($appname);
+
+$result =
+  $node_subscriber->safe_psql('postgres',
+	"SELECT count(*), min(a), max(a) FROM test_tab");
+is($result, qq(3334|1|5000), 'check if the new rows were applied to subscriber');
+
+check_apply_delay_log("logical replication apply delay");
+
+# Test ALTER SUBSCRIPTION. Delay 86460 seconds (1 day 1 minute).
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub SET (min_apply_delay = 86460000)"
+);
+
+# New row to trigger apply delay.
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO test_tab VALUES (0, 'foobar')");
+
+# Disable subscription. worker should die immediately.
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION tap_sub DISABLE;"
+);
+
+# Wait until worker dies.
+my $sub_query =
+  "SELECT count(1) = 0 FROM pg_stat_subscription WHERE subname = 'tap_sub' AND pid IS NOT NULL;";
+$node_subscriber->poll_query_until('postgres', $sub_query)
+  or die "Timed out while waiting for subscriber to die";
+
+$node_subscriber->stop;
+$node_publisher->stop;
+
+done_testing();
+
+sub check_apply_delay_log
+{
+	my $message          = shift;
+	my $old_log_location = $log_location;
+
+	$log_location = $node_subscriber->wait_for_log(qr/$message/, $log_location);
+
+	cmp_ok($log_location, '>', $old_log_location,
+		"logfile contains triggered logical replication apply delay"
+	);
+}
-- 
2.30.0

