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[Proposal] Add foreign-server health checks infrastructure
129+ messages / 15 participants
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Commits from this thread:
  2024-07-26 857df3cef7  postgres_fdw: Add connection status check to postgres_fdw_get_connections().

* [Proposal] Add foreign-server health checks infrastructure
@ 2021-10-30 03:50 kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2021-10-30 03:50 UTC (permalink / raw)
  To: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

Dear Hackers,

I want to propose the feature that checks the health of foreign servers. 
As a first step I want to add an infrastructure for periodical checking to PostgreSQL core.
Currently this is the WIP, it does not contain docs.

## Background 

Currently there is no way to check the status of an foreign server in PostgreSQL.
If an foreign server's postmaster goes down, or if the network between servers is lost,
the backend process will only detect these when it uses the connection corresponding to that foreign server.

Consider a workload that updates data on an foreign server only at the beginning of a transaction,
and runs a lot of local SQLs. Even if the network is disconnected immediately after accessing the foreign server,
the backend process will continue to execute local SQLs without realizing it.

The process will eventually finish to execute SQLs and try to commit.
Only then will it realize that the foreign server cannot be connect and will abort the transaction.
This situation should be detected as soon as possible
because it is impossible to commit a transaction when the foreign server goes down.
This can be more of a problem if you have system-wide downtime requirements.
That's why I want to implement the health-check feature to postgres.

## Design

In general, PostgreSQL can have a variety of RDBMSs as foreign servers,
so the core cannot support all of them.
Therefore, I propose a method to leave the monitoring of the foreign server to each FDW extensions
and register it as a callback function on the body side.
The attached patch adds this monitoring infrastructure to core.
Within the callback functions, it is expected
that each FDWs will check the state of the connection they hold and call ereport (ERROR)
if it cannot connect to someone.
Of course, you can also have the callback function return false.
There is no particular reason to choose the current method.
Callback functions will be called periodically.

## Implementation

This patch introduces a new timeout and a new GUC parameter. GUC controls the timeout interval.
The timeout takes effect when the callback function is first registered,
before each SQL command is executed, and at the end of the timeout.
This implementation is based on the client_connection_check_interval and other timeouts.

## Further work

As the next step I have a plan to implement the callback function to postgres_fdw.
I already made a PoC, but it deeply depends on the following thread:
https://commitfest.postgresql.org/35/3098/

I also want you to review the postgres_fdw part,
but I think it should not be attached because cfbot cannot understand such a dependency
and will throw build error. Do you know how to deal with them in this case?

Your comments and suggestions are very welcome.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments:

v01_add_checking_infrastracture.patch (application/octet-stream, 11.9K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index aac10165ec..0c4d61a34c 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index e07cc57431..eb9c4f3f05 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,11 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +840,51 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	/* should we start checking timeout? */
+	bool first_exec = HaveCheckingRemoteServersCallbacks();
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext, sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+
+	if (first_exec && remote_servers_connection_check_interval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, remote_servers_connection_check_interval);
+}
+
+
+/*
+ * Call callbacks for checking remote servers.
+ *
+ * Note that this function will not return anything.
+ * Callback functions must throw ereport(ERROR) if disconnection has been detected.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * Check whether any callbacks has been registered.
+ */
+bool
+HaveCheckingRemoteServersCallbacks(void)
+{
+	return fdw_callbacks != NULL;
+}
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 89a5f901aa..31e39b6cbf 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -1159,7 +1159,6 @@ pq_startmsgread(void)
 		ereport(FATAL,
 				(errcode(ERRCODE_PROTOCOL_VIOLATION),
 				 errmsg("terminating connection because protocol synchronization was lost")));
-
 	PqCommReadingMsg = true;
 }
 
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 0775abe35d..d7890b5307 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -43,6 +43,7 @@
 #include "commands/async.h"
 #include "commands/prepare.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -349,6 +350,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -455,6 +457,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -2708,6 +2711,13 @@ start_xact_command(void)
 		!get_timeout_active(CLIENT_CONNECTION_CHECK_TIMEOUT))
 		enable_timeout_after(CLIENT_CONNECTION_CHECK_TIMEOUT,
 							 client_connection_check_interval);
+	if (remote_servers_connection_check_interval > 0 &&
+		IsUnderPostmaster &&
+		MyProcPort &&
+		HaveCheckingRemoteServersCallbacks() &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
 }
 
 static void
@@ -3213,6 +3223,24 @@ ProcessInterrupts(void)
 		}
 	}
 
+	if (CheckingRemoteServersTimeoutPending && CheckingRemoteServersHoldoffCount != 0)
+	{
+		/*
+		 * Skip checking foreign servers while reading messages.
+		 */
+		InterruptPending = true;
+	}
+	else if (CheckingRemoteServersTimeoutPending)
+	{
+		CheckingRemoteServersTimeoutPending = false;
+
+		CallCheckingRemoteServersCallbacks();
+
+		if (remote_servers_connection_check_interval > 0)
+			enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									remote_servers_connection_check_interval);
+	}
+
 	if (ClientConnectionLost)
 	{
 		QueryCancelPending = false; /* lost connection trumps QueryCancel */
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 381d9e548d..15b0c2727b 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 78bc64671e..fcf5d24248 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -73,6 +73,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -615,6 +616,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1245,6 +1247,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e91d5a3cfd..24172de7a9 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -51,6 +51,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -105,6 +106,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3583,6 +3585,17 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1cbc9feeb6..9b70761d9c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 8169eb76b1..98f59c1153 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,20 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+extern bool HaveCheckingRemoteServersCallbacks(void);
+
+extern int remote_servers_connection_check_interval;
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 90a3016065..377fc68aaa 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 2cbc5de4d9..ceb6b1c12c 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2021-11-16 05:26 ` Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Shinya Kato @ 2021-11-16 05:26 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com; +Cc: pgsql-hackers@lists.postgresql.org

Hi,
Thank you for the patch!

On 2021-10-30 12:50, kuroda.hayato@fujitsu.com wrote:

> ## Background
> 
> Currently there is no way to check the status of an foreign server in
> PostgreSQL.
> If an foreign server's postmaster goes down, or if the network between
> servers is lost,
> the backend process will only detect these when it uses the connection
> corresponding to that foreign server.
> 
> Consider a workload that updates data on an foreign server only at the
> beginning of a transaction,
> and runs a lot of local SQLs. Even if the network is disconnected
> immediately after accessing the foreign server,
> the backend process will continue to execute local SQLs without 
> realizing it.
> 
> The process will eventually finish to execute SQLs and try to commit.
> Only then will it realize that the foreign server cannot be connect
> and will abort the transaction.
> This situation should be detected as soon as possible
> because it is impossible to commit a transaction when the foreign
> server goes down.
> This can be more of a problem if you have system-wide downtime 
> requirements.
> That's why I want to implement the health-check feature to postgres.

It's a good idea. I also think such a situation should be avoided.

> ## Further work
> 
> As the next step I have a plan to implement the callback function to
> postgres_fdw.
> I already made a PoC, but it deeply depends on the following thread:
> https://commitfest.postgresql.org/35/3098/
> 
> I also want you to review the postgres_fdw part,
> but I think it should not be attached because cfbot cannot understand
> such a dependency
> and will throw build error. Do you know how to deal with them in this 
> case?

I don't know how to deal with them, but I hope you will attach the PoC, 
as it may be easier to review.

-- 
Regards,

--
Shinya Kato
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
@ 2021-11-18 12:43   ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2021-11-18 12:43 UTC (permalink / raw)
  To: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

Dear Kato-san,

Thank you for your interest!

> > I also want you to review the postgres_fdw part,
> > but I think it should not be attached because cfbot cannot understand
> > such a dependency
> > and will throw build error. Do you know how to deal with them in this
> > case?
> 
> I don't know how to deal with them, but I hope you will attach the PoC,
> as it may be easier to review.

OK, I attached the PoC along with the dependent patches. Please see the zip file.
add_helth_check_... patch is written by me, and other two patches are
just copied from [1].
In the new callback function ConnectionHash is searched sequentially and
WaitEventSetWait() is performed for WL_SOCKET_CLOSED socket event.
This event is added by the dependent ones.

===
How to use
===

I'll explain how to use it briefly.

1. boot two postmaster processes. One is coordinator, and another is worker
2. set remote_servers_connection_check_interval to non-zero value at the coordinator
3. create tables to worker DB-cluster.
4. create foreign server, user mapping, and foreign table to coordinator.
5. connect to coordinator via psql.
6. open a transaction and access to foreing tables.
7. do "pg_ctl stop" command to woker DB-cluser.
8. execute some commands that does not access an foreign table.
9. Finally the following output will be get:

ERROR:  Postgres foreign server XXX might be down.

===
Example in some steps
===

3. at worker

```
postgres=# \d
        List of relations
 Schema |  Name  | Type  | Owner  
--------+--------+-------+--------
 public | remote | table | hayato
(1 row)
```

4. at coordinator 

```
postgres=# select * from pg_foreign_server ;
  oid  | srvname | srvowner | srvfdw | srvtype | srvversion | srvacl |         srvoptions          
-------+---------+----------+--------+---------+------------+--------+-----------------------------
 16406 | remote  |       10 |  16402 |         |            |        | {port=5433,dbname=postgres}
(1 row)

postgres=# select * from pg_user_mapping ;
  oid  | umuser | umserver |   umoptions   
-------+--------+----------+---------------
 16407 |     10 |    16406 | {user=hayato}
(1 row)

postgres=# \d
            List of relations
 Schema |  Name  |     Type      | Owner  
--------+--------+---------------+--------
 public | local  | table         | hayato
 public | remote | foreign table | hayato
(2 rows)
```

6-9. at coordinator

```
postgres=# begin;
BEGIN
postgres=*# select * from remote ;
 id 
----
  1
(1 row)

postgres=*# select * from local ;
ERROR:  Postgres foreign server remote might be down.
postgres=!#
```

Note that some keepalive settings are needed
if you want to detect cable breakdown events.
In my understanding following parameters are needed as server options:

* keepalives_idle
* keepalives_count
* keepalives_interval

[1]: https://commitfest.postgresql.org/35/3098/

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments:

  patches.zip (application/x-zip-compressed, 6.1K) download

v01_add_checking_infrastracture.patch (application/octet-stream, 11.9K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index aac10165ec..0c4d61a34c 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index e07cc57431..eb9c4f3f05 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,11 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +840,51 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	/* should we start checking timeout? */
+	bool first_exec = HaveCheckingRemoteServersCallbacks();
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext, sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+
+	if (first_exec && remote_servers_connection_check_interval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, remote_servers_connection_check_interval);
+}
+
+
+/*
+ * Call callbacks for checking remote servers.
+ *
+ * Note that this function will not return anything.
+ * Callback functions must throw ereport(ERROR) if disconnection has been detected.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * Check whether any callbacks has been registered.
+ */
+bool
+HaveCheckingRemoteServersCallbacks(void)
+{
+	return fdw_callbacks != NULL;
+}
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 89a5f901aa..31e39b6cbf 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -1159,7 +1159,6 @@ pq_startmsgread(void)
 		ereport(FATAL,
 				(errcode(ERRCODE_PROTOCOL_VIOLATION),
 				 errmsg("terminating connection because protocol synchronization was lost")));
-
 	PqCommReadingMsg = true;
 }
 
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 0775abe35d..d7890b5307 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -43,6 +43,7 @@
 #include "commands/async.h"
 #include "commands/prepare.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -349,6 +350,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -455,6 +457,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -2708,6 +2711,13 @@ start_xact_command(void)
 		!get_timeout_active(CLIENT_CONNECTION_CHECK_TIMEOUT))
 		enable_timeout_after(CLIENT_CONNECTION_CHECK_TIMEOUT,
 							 client_connection_check_interval);
+	if (remote_servers_connection_check_interval > 0 &&
+		IsUnderPostmaster &&
+		MyProcPort &&
+		HaveCheckingRemoteServersCallbacks() &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
 }
 
 static void
@@ -3213,6 +3223,24 @@ ProcessInterrupts(void)
 		}
 	}
 
+	if (CheckingRemoteServersTimeoutPending && CheckingRemoteServersHoldoffCount != 0)
+	{
+		/*
+		 * Skip checking foreign servers while reading messages.
+		 */
+		InterruptPending = true;
+	}
+	else if (CheckingRemoteServersTimeoutPending)
+	{
+		CheckingRemoteServersTimeoutPending = false;
+
+		CallCheckingRemoteServersCallbacks();
+
+		if (remote_servers_connection_check_interval > 0)
+			enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									remote_servers_connection_check_interval);
+	}
+
 	if (ClientConnectionLost)
 	{
 		QueryCancelPending = false; /* lost connection trumps QueryCancel */
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 381d9e548d..15b0c2727b 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 78bc64671e..fcf5d24248 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -73,6 +73,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -615,6 +616,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1245,6 +1247,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e91d5a3cfd..24172de7a9 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -51,6 +51,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -105,6 +106,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3583,6 +3585,17 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1cbc9feeb6..9b70761d9c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 8169eb76b1..98f59c1153 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,20 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+extern bool HaveCheckingRemoteServersCallbacks(void);
+
+extern int remote_servers_connection_check_interval;
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 90a3016065..377fc68aaa 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 2cbc5de4d9..ceb6b1c12c 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2021-11-19 08:30     ` Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Shinya Kato @ 2021-11-19 08:30 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com; +Cc: pgsql-hackers@lists.postgresql.org

On 2021-11-18 21:43, kuroda.hayato@fujitsu.com wrote:
> Dear Kato-san,
> 
> Thank you for your interest!
> 
>> > I also want you to review the postgres_fdw part,
>> > but I think it should not be attached because cfbot cannot understand
>> > such a dependency
>> > and will throw build error. Do you know how to deal with them in this
>> > case?
>> 
>> I don't know how to deal with them, but I hope you will attach the 
>> PoC,
>> as it may be easier to review.
> 
> OK, I attached the PoC along with the dependent patches. Please see
> the zip file.
> add_helth_check_... patch is written by me, and other two patches are
> just copied from [1].
> In the new callback function ConnectionHash is searched sequentially 
> and
> WaitEventSetWait() is performed for WL_SOCKET_CLOSED socket event.
> This event is added by the dependent ones.

Thank you for sending the patches!
I confirmed that they can be compiled and tested successfully on CentOS 
8.

I haven't looked at the core of the code yet, but I took a quick look at 
it.

+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, 
CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for 
disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+	},

If you don't use check_hook, assign_hook and show_hook, you should 
explicitly write "NULL, NULL, NULL", as show below.
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, 
CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for 
disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, NULL, NULL
+	},


+			ereport(ERROR,
+					errcode(ERRCODE_CONNECTION_FAILURE),
+					errmsg("Postgres foreign server %s might be down.",
+							server->servername));

According to [1], error messages should start with a lowercase letter 
and not use a period.
Also, along with the rest of the code, it is a good idea to enclose the 
server name in double quotes.

I'll get back to you once I've read all the code.

[1] https://www.postgresql.org/docs/devel/error-style-guide.html

-- 
Regards,

--
Shinya Kato
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
@ 2021-11-24 04:57       ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-24 07:50         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  0 siblings, 2 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2021-11-24 04:57 UTC (permalink / raw)
  To: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

Dear Kato-san,

Thank you for reviewing!

> Thank you for sending the patches!
> I confirmed that they can be compiled and tested successfully on CentOS
> 8.

Thanks!

> +	{
> +		{"remote_servers_connection_check_interval", PGC_USERSET,
> CONN_AUTH_SETTINGS,
> +			gettext_noop("Sets the time interval between checks
> for
> disconnection of remote servers."),
> +			NULL,
> +			GUC_UNIT_MS
> +		},
> +		&remote_servers_connection_check_interval,
> +		0, 0, INT_MAX,
> +	},
> 
> If you don't use check_hook, assign_hook and show_hook, you should
> explicitly write "NULL, NULL, NULL", as show below.

Yeah I forgot the line. Fixed.

> +			ereport(ERROR,
> +
> 	errcode(ERRCODE_CONNECTION_FAILURE),
> +					errmsg("Postgres foreign server %s
> might be down.",
> +
> 	server->servername));
> 
> According to [1], error messages should start with a lowercase letter
> and not use a period.
> Also, along with the rest of the code, it is a good idea to enclose the
> server name in double quotes.

I confirmed the postgres error-reporting policy and fixed to follow that.
How do you think?

Attached are the latest version.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments: download all (3 files, .tar.gz)

  20211124.zip (application/x-zip-compressed, 6.2K) download

v02_add_checking_infrastracture.patch (application/octet-stream, 11.9K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index aac10165ec..0c4d61a34c 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index e07cc57431..eb9c4f3f05 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,11 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +840,51 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	/* should we start checking timeout? */
+	bool first_exec = HaveCheckingRemoteServersCallbacks();
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext, sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+
+	if (first_exec && remote_servers_connection_check_interval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, remote_servers_connection_check_interval);
+}
+
+
+/*
+ * Call callbacks for checking remote servers.
+ *
+ * Note that this function will not return anything.
+ * Callback functions must throw ereport(ERROR) if disconnection has been detected.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * Check whether any callbacks has been registered.
+ */
+bool
+HaveCheckingRemoteServersCallbacks(void)
+{
+	return fdw_callbacks != NULL;
+}
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 9ebba025cc..5130a8340b 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -1171,7 +1171,6 @@ pq_startmsgread(void)
 		ereport(FATAL,
 				(errcode(ERRCODE_PROTOCOL_VIOLATION),
 				 errmsg("terminating connection because protocol synchronization was lost")));
-
 	PqCommReadingMsg = true;
 }
 
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 0775abe35d..d7890b5307 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -43,6 +43,7 @@
 #include "commands/async.h"
 #include "commands/prepare.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -349,6 +350,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -455,6 +457,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -2708,6 +2711,13 @@ start_xact_command(void)
 		!get_timeout_active(CLIENT_CONNECTION_CHECK_TIMEOUT))
 		enable_timeout_after(CLIENT_CONNECTION_CHECK_TIMEOUT,
 							 client_connection_check_interval);
+	if (remote_servers_connection_check_interval > 0 &&
+		IsUnderPostmaster &&
+		MyProcPort &&
+		HaveCheckingRemoteServersCallbacks() &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
 }
 
 static void
@@ -3213,6 +3223,24 @@ ProcessInterrupts(void)
 		}
 	}
 
+	if (CheckingRemoteServersTimeoutPending && CheckingRemoteServersHoldoffCount != 0)
+	{
+		/*
+		 * Skip checking foreign servers while reading messages.
+		 */
+		InterruptPending = true;
+	}
+	else if (CheckingRemoteServersTimeoutPending)
+	{
+		CheckingRemoteServersTimeoutPending = false;
+
+		CallCheckingRemoteServersCallbacks();
+
+		if (remote_servers_connection_check_interval > 0)
+			enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									remote_servers_connection_check_interval);
+	}
+
 	if (ClientConnectionLost)
 	{
 		QueryCancelPending = false; /* lost connection trumps QueryCancel */
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 381d9e548d..15b0c2727b 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 646126edee..5962b1e395 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -73,6 +73,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -621,6 +622,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1250,6 +1252,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e91d5a3cfd..1faeb59b87 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -51,6 +51,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -105,6 +106,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3583,6 +3585,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, NULL, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1cbc9feeb6..9b70761d9c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 8169eb76b1..98f59c1153 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,20 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+extern bool HaveCheckingRemoteServersCallbacks(void);
+
+extern int remote_servers_connection_check_interval;
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 90a3016065..377fc68aaa 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 2cbc5de4d9..ceb6b1c12c 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


v02_add_helth_check_for_postgres_fdw.patch (application/octet-stream, 3.1K) download
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 4aff315b7c..30becdeddb 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -109,6 +109,7 @@ static void pgfdw_abort_cleanup(ConnCacheEntry *entry, const char *sql,
 								bool toplevel);
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
+static bool pgfdw_connection_check_internal(PGconn *conn);
 
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
@@ -153,6 +154,7 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+		RegisterCheckingRemoteServersCallback(pgfdw_connection_check, NULL);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -1638,3 +1640,66 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+
+/*
+ * Callback function for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Note that this might be expensive because create and wait
+ * eventset many times.
+ */
+void
+pgfdw_connection_check(void *args)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+
+	/* Exit immediately if hash is not initialized. */
+	if (!ConnectionHash)
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			ForeignServer *server = GetForeignServer(entry->serverid);
+			disconnect_pg_server(entry);
+			ereport(ERROR,
+					errcode(ERRCODE_CONNECTION_FAILURE),
+					errmsg("foreign server \"%s\"disconnected due to the health-check failure",
+							server->servername),
+					errdetail("Foreign server might be down."),
+					errhint("Please check the server and network health."));
+		}
+	}
+}
+
+/*
+ * helper fucntion for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 90b72e9ec5..4630ca05d7 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -151,6 +151,7 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern void pgfdw_connection_check(void *args);
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2021-11-24 07:50         ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 09:57           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  1 sibling, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2021-11-24 07:50 UTC (permalink / raw)
  To: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

Dear Kato-san,

I found the missing space, and I added a test.
I'm very happy if you review this.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments:

v03_0001_add_checking_infrastracture.patch (application/octet-stream, 11.9K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index aac10165ec..0c4d61a34c 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index e07cc57431..eb9c4f3f05 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,11 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +840,51 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	/* should we start checking timeout? */
+	bool first_exec = HaveCheckingRemoteServersCallbacks();
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext, sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+
+	if (first_exec && remote_servers_connection_check_interval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, remote_servers_connection_check_interval);
+}
+
+
+/*
+ * Call callbacks for checking remote servers.
+ *
+ * Note that this function will not return anything.
+ * Callback functions must throw ereport(ERROR) if disconnection has been detected.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * Check whether any callbacks has been registered.
+ */
+bool
+HaveCheckingRemoteServersCallbacks(void)
+{
+	return fdw_callbacks != NULL;
+}
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 9ebba025cc..5130a8340b 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -1171,7 +1171,6 @@ pq_startmsgread(void)
 		ereport(FATAL,
 				(errcode(ERRCODE_PROTOCOL_VIOLATION),
 				 errmsg("terminating connection because protocol synchronization was lost")));
-
 	PqCommReadingMsg = true;
 }
 
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 0775abe35d..d7890b5307 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -43,6 +43,7 @@
 #include "commands/async.h"
 #include "commands/prepare.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -349,6 +350,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -455,6 +457,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -2708,6 +2711,13 @@ start_xact_command(void)
 		!get_timeout_active(CLIENT_CONNECTION_CHECK_TIMEOUT))
 		enable_timeout_after(CLIENT_CONNECTION_CHECK_TIMEOUT,
 							 client_connection_check_interval);
+	if (remote_servers_connection_check_interval > 0 &&
+		IsUnderPostmaster &&
+		MyProcPort &&
+		HaveCheckingRemoteServersCallbacks() &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
 }
 
 static void
@@ -3213,6 +3223,24 @@ ProcessInterrupts(void)
 		}
 	}
 
+	if (CheckingRemoteServersTimeoutPending && CheckingRemoteServersHoldoffCount != 0)
+	{
+		/*
+		 * Skip checking foreign servers while reading messages.
+		 */
+		InterruptPending = true;
+	}
+	else if (CheckingRemoteServersTimeoutPending)
+	{
+		CheckingRemoteServersTimeoutPending = false;
+
+		CallCheckingRemoteServersCallbacks();
+
+		if (remote_servers_connection_check_interval > 0)
+			enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									remote_servers_connection_check_interval);
+	}
+
 	if (ClientConnectionLost)
 	{
 		QueryCancelPending = false; /* lost connection trumps QueryCancel */
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 381d9e548d..15b0c2727b 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 646126edee..5962b1e395 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -73,6 +73,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -621,6 +622,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1250,6 +1252,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e91d5a3cfd..1faeb59b87 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -51,6 +51,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -105,6 +106,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3583,6 +3585,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, NULL, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1cbc9feeb6..9b70761d9c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 8169eb76b1..98f59c1153 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,20 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+extern bool HaveCheckingRemoteServersCallbacks(void);
+
+extern int remote_servers_connection_check_interval;
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 90a3016065..377fc68aaa 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 2cbc5de4d9..ceb6b1c12c 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


  20211124_2.zip (application/x-zip-compressed, 7.2K) download

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-24 07:50         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2021-11-29 09:57           ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 0 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2021-11-29 09:57 UTC (permalink / raw)
  To: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; Zhihong Yu <zyu@yugabyte.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

Dear Hackers,

I attached new version that is based from Zhihong's comments.
And I newly attached a doc patch. I think the infrastructure part is no longer WIP. 

Could you review them?

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments: download all (3 files, .tar.gz)

  2021129.zip (application/x-zip-compressed, 7.2K) download

v04_0001_add_checking_infrastracture.patch (application/octet-stream, 11.9K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index aac10165ec..0c4d61a34c 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index e07cc57431..eb9c4f3f05 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,11 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +840,51 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	/* should we start checking timeout? */
+	bool first_exec = HaveCheckingRemoteServersCallbacks();
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext, sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+
+	if (first_exec && remote_servers_connection_check_interval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, remote_servers_connection_check_interval);
+}
+
+
+/*
+ * Call callbacks for checking remote servers.
+ *
+ * Note that this function will not return anything.
+ * Callback functions must throw ereport(ERROR) if disconnection has been detected.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * Check whether any callbacks has been registered.
+ */
+bool
+HaveCheckingRemoteServersCallbacks(void)
+{
+	return fdw_callbacks != NULL;
+}
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 9ebba025cc..5130a8340b 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -1171,7 +1171,6 @@ pq_startmsgread(void)
 		ereport(FATAL,
 				(errcode(ERRCODE_PROTOCOL_VIOLATION),
 				 errmsg("terminating connection because protocol synchronization was lost")));
-
 	PqCommReadingMsg = true;
 }
 
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 0775abe35d..ca5d50236b 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -43,6 +43,7 @@
 #include "commands/async.h"
 #include "commands/prepare.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -349,6 +350,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -455,6 +457,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -2708,6 +2711,13 @@ start_xact_command(void)
 		!get_timeout_active(CLIENT_CONNECTION_CHECK_TIMEOUT))
 		enable_timeout_after(CLIENT_CONNECTION_CHECK_TIMEOUT,
 							 client_connection_check_interval);
+	if (remote_servers_connection_check_interval > 0 &&
+		IsUnderPostmaster &&
+		MyProcPort &&
+		HaveCheckingRemoteServersCallbacks() &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
 }
 
 static void
@@ -3213,6 +3223,27 @@ ProcessInterrupts(void)
 		}
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		if (CheckingRemoteServersHoldoffCount != 0)
+		{
+			/*
+			* Skip checking foreign servers while reading messages.
+			*/
+			InterruptPending = true;
+		}
+		else
+		{
+			CheckingRemoteServersTimeoutPending = false;
+
+			CallCheckingRemoteServersCallbacks();
+
+			if (remote_servers_connection_check_interval > 0)
+				enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+										remote_servers_connection_check_interval);
+		}
+	}
+
 	if (ClientConnectionLost)
 	{
 		QueryCancelPending = false; /* lost connection trumps QueryCancel */
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 381d9e548d..15b0c2727b 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 646126edee..5962b1e395 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -73,6 +73,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -621,6 +622,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1250,6 +1252,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e91d5a3cfd..1faeb59b87 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -51,6 +51,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -105,6 +106,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3583,6 +3585,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, NULL, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1cbc9feeb6..9b70761d9c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 8169eb76b1..98f59c1153 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,20 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+extern bool HaveCheckingRemoteServersCallbacks(void);
+
+extern int remote_servers_connection_check_interval;
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 90a3016065..377fc68aaa 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 2cbc5de4d9..ceb6b1c12c 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


v04_0002_add_doc.patch (application/octet-stream, 2.4K) download
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index ab617c7b86..a93c73da2f 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1035,6 +1035,25 @@ include_dir 'conf.d'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-remote-servers-connection-check-interval" xreflabel="remote_servers_connection_check_interval">
+      <term><varname>remote_servers_connection_check_interval</varname> (<type>integer</type>)
+      <indexterm>
+       <primary><varname>remote_servers_connection_check_interval</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Sets the time interval between optional checks that the remote servers
+        are still alive. If this parameter is set to a valid value, registered
+        callback functions are executed at the specified time interval.
+        If your FDW extension does not implement a callback function, nothing
+        happens after the specified amount of time. If the value is specified
+        without units, it is taken as milliseconds. The default value is
+        <literal>0</literal>, this means the feature is disabled.
+       </para>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
      </sect2>
 
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index dbf5dd3d15..df52c53ae6 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -2136,4 +2136,26 @@ GetForeignServerByName(const char *name, bool missing_ok);
 
   </sect1>
 
+   <sect1 id="fdw-checking-remote-servers">
+    <title>Checking the Health of Remote Servers via Foreign Data Wrapper</title>
+
+    <para>
+     For verifying the health of remote servers, callback functions can be
+     registered that runs periodically. The time interval is controlled by
+     <xref linkend="guc-remote-servers-connection-check-interval"/>.
+     The API for registering functions is:
+    <programlisting>
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+    </programlisting>
+    Only functions that return void can be registered as callback functions.
+    Please set to void* arg a pointer if you want to pass an argument.
+    If you have problems with the health check results and want to
+    abort the transaction, please execute <function>ereport(ERROR)</function>
+    in the callback function.
+    </para>
+
+   </sect1>
+
+
  </chapter>


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2021-11-28 18:02         ` Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  1 sibling, 1 reply; 129+ messages in thread

From: Zhihong Yu @ 2021-11-28 18:02 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; +Cc: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

On Tue, Nov 23, 2021 at 8:57 PM kuroda.hayato@fujitsu.com <
kuroda.hayato@fujitsu.com> wrote:

> Dear Kato-san,
>
> Thank you for reviewing!
>
> > Thank you for sending the patches!
> > I confirmed that they can be compiled and tested successfully on CentOS
> > 8.
>
> Thanks!
>
> > +     {
> > +             {"remote_servers_connection_check_interval", PGC_USERSET,
> > CONN_AUTH_SETTINGS,
> > +                     gettext_noop("Sets the time interval between checks
> > for
> > disconnection of remote servers."),
> > +                     NULL,
> > +                     GUC_UNIT_MS
> > +             },
> > +             &remote_servers_connection_check_interval,
> > +             0, 0, INT_MAX,
> > +     },
> >
> > If you don't use check_hook, assign_hook and show_hook, you should
> > explicitly write "NULL, NULL, NULL", as show below.
>
> Yeah I forgot the line. Fixed.
>
> > +                     ereport(ERROR,
> > +
> >       errcode(ERRCODE_CONNECTION_FAILURE),
> > +                                     errmsg("Postgres foreign server %s
> > might be down.",
> > +
> >       server->servername));
> >
> > According to [1], error messages should start with a lowercase letter
> > and not use a period.
> > Also, along with the rest of the code, it is a good idea to enclose the
> > server name in double quotes.
>
> I confirmed the postgres error-reporting policy and fixed to follow that.
> How do you think?
>
> Attached are the latest version.
>
> Best Regards,
> Hayato Kuroda
> FUJITSU LIMITED
>
> Hi,

+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()
 (CheckingRemoteServersHoldoffCount++)

The macro contains only one operation. Can the macro be removed (with
`CheckingRemoteServersHoldoffCount++` inlined) ?

+   if (CheckingRemoteServersTimeoutPending &&
CheckingRemoteServersHoldoffCount != 0)
+   {
+       /*
+        * Skip checking foreign servers while reading messages.
+        */
+       InterruptPending = true;
+   }
+   else if (CheckingRemoteServersTimeoutPending)

Would the code be more readable if the above two if blocks be moved inside
one enclosing if block (factoring the common condition)?

+   if (CheckingRemoteServersTimeoutPending)

Cheers

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
@ 2021-11-29 08:51           ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2021-11-29 08:51 UTC (permalink / raw)
  To: Zhihong Yu <zyu@yugabyte.com>; +Cc: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

Dear Zhihong,

Thank you for giving comments! I'll post new patches later.

> +#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
> 
> The macro contains only one operation. Can the macro be removed (with `CheckingRemoteServersHoldoffCount++` inlined) ?

Hmm, these HOLD/RESUME macros are followed HOLD_INTERRUPUST() and HOLD_CANCEL_INTERRUPTS():

```
#define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)

#define RESUME_INTERRUPTS() \
do { \
        Assert(InterruptHoldoffCount > 0); \
        InterruptHoldoffCount--; \
} while(0)

#define HOLD_CANCEL_INTERRUPTS()  (QueryCancelHoldoffCount++)

#define RESUME_CANCEL_INTERRUPTS() \
do { \
        Assert(QueryCancelHoldoffCount > 0); \
        QueryCancelHoldoffCount--; \
} while(0)

#define START_CRIT_SECTION()  (CritSectionCount++)

#define END_CRIT_SECTION() \
do { \
        Assert(CritSectionCount > 0); \
        CritSectionCount--; \
} while(0)
```

So I want to keep the current style. Could you tell me if you have any other reasons?

> +   if (CheckingRemoteServersTimeoutPending && CheckingRemoteServersHoldoffCount != 0)
> +   {
> +       /*
> +        * Skip checking foreign servers while reading messages.
> +        */
> +       InterruptPending = true;
> +   }
> +   else if (CheckingRemoteServersTimeoutPending)
> 
> Would the code be more readable if the above two if blocks be moved inside one enclosing if block (factoring the common condition)?
> 
> +   if (CheckingRemoteServersTimeoutPending)

+1. Will fix.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2021-11-29 12:36             ` Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Zhihong Yu @ 2021-11-29 12:36 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; +Cc: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>

On Mon, Nov 29, 2021 at 12:51 AM kuroda.hayato@fujitsu.com <
kuroda.hayato@fujitsu.com> wrote:

> Dear Zhihong,
>
> Thank you for giving comments! I'll post new patches later.
>
> > +#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()
> (CheckingRemoteServersHoldoffCount++)
> >
> > The macro contains only one operation. Can the macro be removed (with
> `CheckingRemoteServersHoldoffCount++` inlined) ?
>
> Hmm, these HOLD/RESUME macros are followed HOLD_INTERRUPUST() and
> HOLD_CANCEL_INTERRUPTS():
>
> ```
> #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
>
> #define RESUME_INTERRUPTS() \
> do { \
>         Assert(InterruptHoldoffCount > 0); \
>         InterruptHoldoffCount--; \
> } while(0)
>
> #define HOLD_CANCEL_INTERRUPTS()  (QueryCancelHoldoffCount++)
>
> #define RESUME_CANCEL_INTERRUPTS() \
> do { \
>         Assert(QueryCancelHoldoffCount > 0); \
>         QueryCancelHoldoffCount--; \
> } while(0)
>
> #define START_CRIT_SECTION()  (CritSectionCount++)
>
> #define END_CRIT_SECTION() \
> do { \
>         Assert(CritSectionCount > 0); \
>         CritSectionCount--; \
> } while(0)
> ```
>
> So I want to keep the current style. Could you tell me if you have any
> other reasons?
>
> > +   if (CheckingRemoteServersTimeoutPending &&
> CheckingRemoteServersHoldoffCount != 0)
> > +   {
> > +       /*
> > +        * Skip checking foreign servers while reading messages.
> > +        */
> > +       InterruptPending = true;
> > +   }
> > +   else if (CheckingRemoteServersTimeoutPending)
> >
> > Would the code be more readable if the above two if blocks be moved
> inside one enclosing if block (factoring the common condition)?
> >
> > +   if (CheckingRemoteServersTimeoutPending)
>
> +1. Will fix.
>
> Best Regards,
> Hayato Kuroda
> FUJITSU LIMITED
>

Hi,

It is Okay to keep the macros.

Thanks

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
@ 2021-12-06 11:06               ` Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Shinya Kato @ 2021-12-06 11:06 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com; +Cc: pgsql-hackers@lists.postgresql.org; zyu@yugabyte.com

On 2021-11-29 21:36, Zhihong Yu wrote:
> On Mon, Nov 29, 2021 at 12:51 AM kuroda.hayato@fujitsu.com
> <kuroda.hayato@fujitsu.com> wrote:
> 
>> Dear Zhihong,
>> 
>> Thank you for giving comments! I'll post new patches later.
>> 
>>> +#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()
>> (CheckingRemoteServersHoldoffCount++)
>>> 
>>> The macro contains only one operation. Can the macro be removed
>> (with `CheckingRemoteServersHoldoffCount++` inlined) ?
>> 
>> Hmm, these HOLD/RESUME macros are followed HOLD_INTERRUPUST() and
>> HOLD_CANCEL_INTERRUPTS():
>> 
>> ```
>> #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
>> 
>> #define RESUME_INTERRUPTS() \
>> do { \
>> Assert(InterruptHoldoffCount > 0); \
>> InterruptHoldoffCount--; \
>> } while(0)
>> 
>> #define HOLD_CANCEL_INTERRUPTS()  (QueryCancelHoldoffCount++)
>> 
>> #define RESUME_CANCEL_INTERRUPTS() \
>> do { \
>> Assert(QueryCancelHoldoffCount > 0); \
>> QueryCancelHoldoffCount--; \
>> } while(0)
>> 
>> #define START_CRIT_SECTION()  (CritSectionCount++)
>> 
>> #define END_CRIT_SECTION() \
>> do { \
>> Assert(CritSectionCount > 0); \
>> CritSectionCount--; \
>> } while(0)
>> ```
>> 
>> So I want to keep the current style. Could you tell me if you have
>> any other reasons?
>> 
>>> +   if (CheckingRemoteServersTimeoutPending &&
>> CheckingRemoteServersHoldoffCount != 0)
>>> +   {
>>> +       /*
>>> +        * Skip checking foreign servers while reading messages.
>>> +        */
>>> +       InterruptPending = true;
>>> +   }
>>> +   else if (CheckingRemoteServersTimeoutPending)
>>> 
>>> Would the code be more readable if the above two if blocks be
>> moved inside one enclosing if block (factoring the common
>> condition)?
>>> 
>>> +   if (CheckingRemoteServersTimeoutPending)
>> 
>> +1. Will fix.
>> 
>> Best Regards,
>> Hayato Kuroda
>> FUJITSU LIMITED
> 
> Hi,
> 
> It is Okay to keep the macros.
> 
> Thanks

Hi, Kuroda-san. Sorry for late reply.

Even for local-only transaction, I thought it useless to execute 
CallCheckingRemoteServersCallbacks() and enable_timeout_after(). Can I 
make it so that it determines outside whether it contains SQL to the 
remote or not?

The following points are minor.
1. In foreign.c, some of the lines are too long and should be broken.
2. In pqcomm.c, the newline have been removed, what is the intention of 
this?
3. In postgres.c,
3-1. how about inserting a comment between lines 2713 and 2714, similar 
to line 2707?
3-2. the line breaks in line 3242 and line 3243 should be aligned.
3-3. you should change
			/*
			* Skip checking foreign servers while reading messages.
			*/
to
			/*
			 * Skip checking foreign servers while reading messages.
			 */
4. In connection.c, There is a typo in line 1684, so "fucntion" should 
be changed to "function".


-- 
Regards,

--
Shinya Kato
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
@ 2021-12-15 06:40                 ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-05 06:21                   ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  0 siblings, 2 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2021-12-15 06:40 UTC (permalink / raw)
  To: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; zyu@yugabyte.com <zyu@yugabyte.com>

Dear Kato-san,

Thank you for giving comments! And sorry for late reply.
I rebased my patches.

> Even for local-only transaction, I thought it useless to execute
> CallCheckingRemoteServersCallbacks() and enable_timeout_after(). Can I
> make it so that it determines outside whether it contains SQL to the
> remote or not?

Yeah, remote-checking timeout will be enable even ifa local transaction is opened. 
In my understanding, postgres cannot distinguish whether opening transactions
are using only local object or not. 
My first idea was that turning on the timeout when GetFdwRoutineXXX functions
were called, but in some cases FDWs may not use remote connection even if
they call such a handler function. e.g. postgresExplainForeignScan().
Hence I tried another approach that unregister all checking callback
the end of each transactions. Only FDWs can notice that transactions are remote or local,
so they must register callback when they really connect to other database.
This implementation will avoid calling remote checking in the case of local transaction,
but multiple registering and unregistering may lead another overhead.
I attached which implements that.

> The following points are minor.
> 1. In foreign.c, some of the lines are too long and should be broken.
> 2. In pqcomm.c, the newline have been removed, what is the intention of
> this?
> 3. In postgres.c,
> 3-1. how about inserting a comment between lines 2713 and 2714, similar
> to line 2707?
> 3-2. the line breaks in line 3242 and line 3243 should be aligned.
> 3-3. you should change
> 			/*
> 			* Skip checking foreign servers while reading
> messages.
> 			*/
> to
> 			/*
> 			 * Skip checking foreign servers while reading
> messages.
> 			 */
> 4. In connection.c, There is a typo in line 1684, so "fucntion" should
> be changed to "function".

Maybe all of them were fixed. Thanks!

How do you think?


Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments: download all (3 files, .tar.gz)

  patchset.zip (application/x-zip-compressed, 10.2K) download

v05_0001_add_checking_infrastracture.patch (application/octet-stream, 14.3K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index aac10165ec..0c4d61a34c 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index e07cc57431..d6a6d3d215 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -14,6 +14,7 @@
 
 #include "access/htup_details.h"
 #include "access/reloptions.h"
+#include "access/xact.h"
 #include "catalog/pg_foreign_data_wrapper.h"
 #include "catalog/pg_foreign_server.h"
 #include "catalog/pg_foreign_table.h"
@@ -26,7 +27,13 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
+static bool isRegistered = false;
+static void UnregisterCheckingCallbacks(XactEvent event, void *arg);
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +843,144 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	/* should we start checking timeout? */
+	bool shouldStart = !HaveCheckingRemoteServersCallbacks();
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext,
+							   sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+
+	if (shouldStart && remote_servers_connection_check_interval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
+
+	if (!isRegistered)
+	{
+		RegisterXactCallback(UnregisterCheckingCallbacks, NULL);
+		isRegistered = true;
+	}
+}
+
+static void
+UnregisterCheckingCallbacks(XactEvent event, void *arg)
+{
+	if (event != XACT_EVENT_PRE_COMMIT &&
+		event != XACT_EVENT_PRE_PREPARE)
+		UnregisterAllCheckingRemoteServersCallback();
+}
+
+/*
+ * Unregister the specified callback.
+ */
+void
+UnregisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+										void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	CheckingRemoteServersCallbackItem *prev;
+
+	prev = NULL;
+	for (item = fdw_callbacks; item; prev = item, item = item->next)
+	{
+		if (item->callback == callback && item->arg == arg)
+		{
+			if (prev)
+				prev->next = item->next;
+			else
+				fdw_callbacks = item->next;
+			pfree(item);
+			break;
+		}
+	}
+	if (!HaveCheckingRemoteServersCallbacks() &&
+		get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+}
+
+/*
+ * Unregister all callbacks.
+ *
+ * This function is called when commit/abort any transactions.
+ */
+void
+UnregisterAllCheckingRemoteServersCallback(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	item = fdw_callbacks;
+	while (item)
+	{
+		CheckingRemoteServersCallbackItem *next;
+		next = item->next;
+		pfree(item);
+		item = next;
+	}
+	fdw_callbacks = NULL;
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+}
+
+/*
+ * Call callbacks for checking remote servers.
+ *
+ * Note that this function will not return anything.
+ * Callback functions must throw ereport(ERROR)
+ * if disconnection has been detected.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * Check whether any callbacks has been registered.
+ */
+bool
+HaveCheckingRemoteServersCallbacks(void)
+{
+	return fdw_callbacks != NULL;
+}
+
+void
+assign_remote_servers_connection_check_interval(int newval,
+												void *extra)
+{
+	/* Quick return if we don't have any callbacks */
+	if (!HaveCheckingRemoteServersCallbacks())
+		return;
+
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+	{
+		/* disable timeout if zero */
+		if (newval == 0)
+			disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in ProcessInterrupts().
+		 */
+		return;
+	}
+
+	if (newval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 newval);
+}
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 82de01cdc6..de0ed3f7b6 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -44,6 +44,7 @@
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -350,6 +351,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -456,6 +458,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -2709,6 +2712,13 @@ start_xact_command(void)
 		!get_timeout_active(CLIENT_CONNECTION_CHECK_TIMEOUT))
 		enable_timeout_after(CLIENT_CONNECTION_CHECK_TIMEOUT,
 							 client_connection_check_interval);
+	if (remote_servers_connection_check_interval > 0 &&
+		IsUnderPostmaster &&
+		MyProcPort &&
+		HaveCheckingRemoteServersCallbacks() &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
 }
 
 static void
@@ -3214,6 +3224,27 @@ ProcessInterrupts(void)
 		}
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		if (CheckingRemoteServersHoldoffCount != 0)
+		{
+			/*
+			 * Skip checking foreign servers while reading messages.
+			 */
+			InterruptPending = true;
+		}
+		else
+		{
+			CheckingRemoteServersTimeoutPending = false;
+
+			CallCheckingRemoteServersCallbacks();
+
+			if (remote_servers_connection_check_interval > 0)
+				enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									 remote_servers_connection_check_interval);
+		}
+	}
+
 	if (ClientConnectionLost)
 	{
 		QueryCancelPending = false; /* lost connection trumps QueryCancel */
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 381d9e548d..15b0c2727b 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 7292e51f7d..3f936be326 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -73,6 +73,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -621,6 +622,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1239,6 +1241,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f736e8d872..763f8198e5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -51,6 +51,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -105,6 +106,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3590,6 +3592,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, assign_remote_servers_connection_check_interval, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index a1acd46b61..cad3c72336 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 8169eb76b1..a1e01d91e4 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,26 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+												  void *arg);
+extern void UnregisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+													void *arg);
+extern void UnregisterAllCheckingRemoteServersCallback(void);
+extern void CallCheckingRemoteServersCallbacks(void);
+extern bool HaveCheckingRemoteServersCallbacks(void);
+
+extern int remote_servers_connection_check_interval;
+extern void assign_remote_servers_connection_check_interval(int newval,
+															void *extra);
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 90a3016065..377fc68aaa 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 2cbc5de4d9..ceb6b1c12c 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


v05_0002_add_doc.patch (application/octet-stream, 3.2K) download
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index afbb6c35e3..08c372db63 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1012,9 +1012,9 @@ include_dir 'conf.d'
         the kernel reports that the connection is closed.
        </para>
        <para>
-        This option is currently available only on systems that support the
-        non-standard <symbol>POLLRDHUP</symbol> extension to the
-        <symbol>poll</symbol> system call, including Linux.
+        This option relies on kernel events exposed by Linux, macOS, illumos
+        and the BSD family of operating systems, and is not currently available
+        on other systems.
        </para>
        <para>
         If the value is specified without units, it is taken as milliseconds.
@@ -1035,6 +1035,25 @@ include_dir 'conf.d'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-remote-servers-connection-check-interval" xreflabel="remote_servers_connection_check_interval">
+      <term><varname>remote_servers_connection_check_interval</varname> (<type>integer</type>)
+      <indexterm>
+       <primary><varname>remote_servers_connection_check_interval</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Sets the time interval between optional checks that the remote servers
+        are still alive. If this parameter is set to a valid value, registered
+        callback functions are executed at the specified time interval.
+        If your FDW extension does not implement a callback function, nothing
+        happens after the specified amount of time. If the value is specified
+        without units, it is taken as milliseconds. The default value is
+        <literal>0</literal>, this means the feature is disabled.
+       </para>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
      </sect2>
 
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index dbf5dd3d15..38e67730bf 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -2136,4 +2136,28 @@ GetForeignServerByName(const char *name, bool missing_ok);
 
   </sect1>
 
+   <sect1 id="fdw-checking-remote-servers">
+    <title>Checking the Health of Remote Servers via Foreign Data Wrapper</title>
+
+    <para>
+     For verifying the health of remote servers, callback functions can be
+     registered that runs periodically. The time interval is controlled by
+     <xref linkend="guc-remote-servers-connection-check-interval"/>.
+     The API for registering functions is:
+    <programlisting>
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+    </programlisting>
+     Only functions that return void can be registered as callback functions.
+     Please set to void* arg a pointer if you want to pass an argument.
+     If you have problems with the health check results and want to
+     abort the transaction, please execute <function>ereport(ERROR)</function>
+     in the callback function.
+     Note that callback functions will be released at end of each transaction.
+     Please register callback functions every time you connect to remote servers.
+    </para>
+
+   </sect1>
+
+
  </chapter>


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-01-05 06:21                   ` Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2022-01-05 18:16                     ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  1 sibling, 1 reply; 129+ messages in thread

From: Shinya Kato @ 2022-01-05 06:21 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com; +Cc: pgsql-hackers@lists.postgresql.org; zyu@yugabyte.com

Thank you for the new patch!

On 2021-12-15 15:40, kuroda.hayato@fujitsu.com wrote:
> Dear Kato-san,
> 
> Thank you for giving comments! And sorry for late reply.
> I rebased my patches.
> 
>> Even for local-only transaction, I thought it useless to execute
>> CallCheckingRemoteServersCallbacks() and enable_timeout_after(). Can I
>> make it so that it determines outside whether it contains SQL to the
>> remote or not?
> 
> Yeah, remote-checking timeout will be enable even ifa local
> transaction is opened.
> In my understanding, postgres cannot distinguish whether opening 
> transactions
> are using only local object or not.
> My first idea was that turning on the timeout when GetFdwRoutineXXX 
> functions
> were called, but in some cases FDWs may not use remote connection even 
> if
> they call such a handler function. e.g. postgresExplainForeignScan().
> Hence I tried another approach that unregister all checking callback
> the end of each transactions. Only FDWs can notice that transactions
> are remote or local,
> so they must register callback when they really connect to other 
> database.
> This implementation will avoid calling remote checking in the case of
> local transaction,
> but multiple registering and unregistering may lead another overhead.
> I attached which implements that.
> 
It certainly incurs another overhead, but I think it's better than the 
previous one.
So far, I haven't encountered any problems, but I'd like other people's 
opinions.

>> The following points are minor.
>> 1. In foreign.c, some of the lines are too long and should be broken.
>> 2. In pqcomm.c, the newline have been removed, what is the intention 
>> of
>> this?
>> 3. In postgres.c,
>> 3-1. how about inserting a comment between lines 2713 and 2714, 
>> similar
>> to line 2707?
>> 3-2. the line breaks in line 3242 and line 3243 should be aligned.
>> 3-3. you should change
>> 			/*
>> 			* Skip checking foreign servers while reading
>> messages.
>> 			*/
>> to
>> 			/*
>> 			 * Skip checking foreign servers while reading
>> messages.
>> 			 */
>> 4. In connection.c, There is a typo in line 1684, so "fucntion" should
>> be changed to "function".
> 
> Maybe all of them were fixed. Thanks!
Thank you, and it looks good to me.


-- 
Regards,

--
Shinya Kato
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-05 06:21                   ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
@ 2022-01-05 18:16                     ` Zhihong Yu <zyu@yugabyte.com>
  2022-01-20 06:58                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Zhihong Yu @ 2022-01-05 18:16 UTC (permalink / raw)
  To: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; +Cc: kuroda.hayato@fujitsu.com, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>

On Tue, Jan 4, 2022 at 10:21 PM Shinya Kato <Shinya11.Kato@oss.nttdata.com>
wrote:

> Thank you for the new patch!
>
> On 2021-12-15 15:40, kuroda.hayato@fujitsu.com wrote:
> > Dear Kato-san,
> >
> > Thank you for giving comments! And sorry for late reply.
> > I rebased my patches.
> >
> >> Even for local-only transaction, I thought it useless to execute
> >> CallCheckingRemoteServersCallbacks() and enable_timeout_after(). Can I
> >> make it so that it determines outside whether it contains SQL to the
> >> remote or not?
> >
> > Yeah, remote-checking timeout will be enable even ifa local
> > transaction is opened.
> > In my understanding, postgres cannot distinguish whether opening
> > transactions
> > are using only local object or not.
> > My first idea was that turning on the timeout when GetFdwRoutineXXX
> > functions
> > were called, but in some cases FDWs may not use remote connection even
> > if
> > they call such a handler function. e.g. postgresExplainForeignScan().
> > Hence I tried another approach that unregister all checking callback
> > the end of each transactions. Only FDWs can notice that transactions
> > are remote or local,
> > so they must register callback when they really connect to other
> > database.
> > This implementation will avoid calling remote checking in the case of
> > local transaction,
> > but multiple registering and unregistering may lead another overhead.
> > I attached which implements that.
> >
> It certainly incurs another overhead, but I think it's better than the
> previous one.
> So far, I haven't encountered any problems, but I'd like other people's
> opinions.
>
> >> The following points are minor.
> >> 1. In foreign.c, some of the lines are too long and should be broken.
> >> 2. In pqcomm.c, the newline have been removed, what is the intention
> >> of
> >> this?
> >> 3. In postgres.c,
> >> 3-1. how about inserting a comment between lines 2713 and 2714,
> >> similar
> >> to line 2707?
> >> 3-2. the line breaks in line 3242 and line 3243 should be aligned.
> >> 3-3. you should change
> >>                      /*
> >>                      * Skip checking foreign servers while reading
> >> messages.
> >>                      */
> >> to
> >>                      /*
> >>                       * Skip checking foreign servers while reading
> >> messages.
> >>                       */
> >> 4. In connection.c, There is a typo in line 1684, so "fucntion" should
> >> be changed to "function".
> >
> > Maybe all of them were fixed. Thanks!
> Thank you, and it looks good to me.
>
>
> Hi,
+       UnregisterAllCheckingRemoteServersCallback();

UnregisterAllCheckingRemoteServersCallback
-> UnregisterAllCheckingRemoteServersCallbacks

+   CheckingRemoteServersCallbackItem *item;
+   item = fdw_callbacks;

The above two lines can be combined.

+UnregisterCheckingRemoteServersCallback(CheckingRemoteServersCallback
callback,
+                                       void *arg)

Is the above func called anywhere ?

+       if (item->callback == callback && item->arg == arg)

Is comparing argument pointers stable ? What if the same argument is cloned
?

+           CallCheckingRemoteServersCallbacks();
+
+           if (remote_servers_connection_check_interval > 0)
+               enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+
 remote_servers_connection_check_interval);

Should the call to CallCheckingRemoteServersCallbacks() be placed under the
if block checking remote_servers_connection_check_interval ?
If remote_servers_connection_check_interval is 0, it seems the callbacks
shouldn't be called.

Cheers

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-05 06:21                   ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2022-01-05 18:16                     ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
@ 2022-01-20 06:58                       ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 0 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-01-20 06:58 UTC (permalink / raw)
  To: Zhihong Yu <zyu@yugabyte.com>; +Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>

Dear Zhihong,

Thank you for reviewing! And I have to apologize for the late.
I'll post new patchset later.

> +       UnregisterAllCheckingRemoteServersCallback();
> 
> UnregisterAllCheckingRemoteServersCallback
> -> UnregisterAllCheckingRemoteServersCallbacks

Will fix.

> +   CheckingRemoteServersCallbackItem *item;
> +   item = fdw_callbacks;
> 
> The above two lines can be combined.

Will fix.

> +UnregisterCheckingRemoteServersCallback(CheckingRemoteServersCallback
> callback,
> +                                       void *arg)
> 
> Is the above func called anywhere ?

Currently not, I just kept the API because of any other FDW extensions.
But I cannot find any use cases, so will remove.

> +       if (item->callback == callback && item->arg == arg)
> 
> Is comparing argument pointers stable ? What if the same argument is cloned
> ?

This part is no longer needed. Will remove.

> +           CallCheckingRemoteServersCallbacks();
> +
> +           if (remote_servers_connection_check_interval > 0)
> +               enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
> +
>  remote_servers_connection_check_interval);
>
> Should the call to CallCheckingRemoteServersCallbacks() be placed under the
> if block checking remote_servers_connection_check_interval ?
> If remote_servers_connection_check_interval is 0, it seems the callbacks
> shouldn't be called.

Agreed. We force stopping timeout when the GUC sets to 0 in assign_hook,
so your saying is consistent. Will move.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-01-18 15:42                   ` Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  1 sibling, 1 reply; 129+ messages in thread

From: Fujii Masao @ 2022-01-18 15:42 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; zyu@yugabyte.com <zyu@yugabyte.com>



On 2021/12/15 15:40, kuroda.hayato@fujitsu.com wrote:
> Yeah, remote-checking timeout will be enable even ifa local transaction is opened.
> In my understanding, postgres cannot distinguish whether opening transactions
> are using only local object or not.
> My first idea was that turning on the timeout when GetFdwRoutineXXX functions
> were called,

What about starting the timeout in GetConnection(), instead?

> I attached which implements that.

v05_0004_add_tests.patch failed to be applied to the master. Could you rebase it?


-        This option is currently available only on systems that support the
-        non-standard <symbol>POLLRDHUP</symbol> extension to the
-        <symbol>poll</symbol> system call, including Linux.
+        This option relies on kernel events exposed by Linux, macOS, illumos
+        and the BSD family of operating systems, and is not currently available
+        on other systems.

The above change is included in both v5-0003-Use-WL_SOCKET_CLOSED-for-client_connection_check_.patch and v05_0002_add_doc.patch. If it should be in the former patch, it should be removed from your patch v05_0002_add_doc.patch.


There seems no user of UnregisterCheckingRemoteServersCallback(). So how about removing it?


Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-01-20 08:21                     ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-01-20 08:21 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; zyu@yugabyte.com <zyu@yugabyte.com>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>

Dear Fujii-san,

Thank you for your interest! I'll post new version within several days.

> > Yeah, remote-checking timeout will be enable even ifa local transaction is
> opened.
> > In my understanding, postgres cannot distinguish whether opening transactions
> > are using only local object or not.
> > My first idea was that turning on the timeout when GetFdwRoutineXXX
> functions
> > were called,
> 
> What about starting the timeout in GetConnection(), instead?

Did you said about a function in postgres_fdw/connection.c?
In my understanding that means that the timeout should be enabled or disabled
by each FDW extensions.
I did not find bad cases for that, so I'll change like that and make new APIs.

> v05_0004_add_tests.patch failed to be applied to the master. Could you rebase it?

It's caused because a testcase was added in postgres_fdw. Will rebase.

> The above change is included in both
> v5-0003-Use-WL_SOCKET_CLOSED-for-client_connection_check_.patch and
> v05_0002_add_doc.patch. If it should be in the former patch, it should be removed
> from your patch v05_0002_add_doc.patch.

I confused about doc-patch. Sorry for inconvenience.

> There seems no user of UnregisterCheckingRemoteServersCallback(). So how
> about removing it?

Previously I kept the API for any other extensions, but I cannot find use cases.
Will remove.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-01-21 06:08                       ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-01-21 06:08 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>

Dear Fujii-san, Zhihong,

I attached the latest version.
The biggest change is that callbacks are no longer un-registered at the end of transactions.
FDW developer must enable or disable timeout instead, via new APIs.

The timer will be turned on when:
* new GUC is >= 0, and
* anyone calls TryEnableRemoteServerCheckingTimeout().

I think this version is reduced overhead, but it might not be developer friendly...

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (3 files, .tar.gz)

  patches.zip (application/x-zip-compressed, 7.7K) download

v06_0002_add_doc.patch (application/octet-stream, 2.9K) download
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 4cd9818acf..870221fab4 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1035,6 +1035,25 @@ include_dir 'conf.d'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-remote-servers-connection-check-interval" xreflabel="remote_servers_connection_check_interval">
+      <term><varname>remote_servers_connection_check_interval</varname> (<type>integer</type>)
+      <indexterm>
+       <primary><varname>remote_servers_connection_check_interval</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Sets the time interval between optional checks that the remote servers
+        are still alive. If this parameter is set to a valid value, registered
+        callback functions are executed at the specified time interval.
+        If your FDW extension does not implement a callback function, nothing
+        happens after the specified amount of time. If the value is specified
+        without units, it is taken as milliseconds. The default value is
+        <literal>0</literal>, this means the feature is disabled.
+       </para>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
      </sect2>
 
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index dbf5dd3d15..f7482ab79f 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -2136,4 +2136,40 @@ GetForeignServerByName(const char *name, bool missing_ok);
 
   </sect1>
 
+   <sect1 id="fdw-checking-remote-servers">
+    <title>Checking the Health of Remote Servers via Foreign Data Wrapper</title>
+
+    <para>
+     For verifying the health of remote servers, callback functions can be
+     registered that runs periodically. The time interval is controlled by
+     <xref linkend="guc-remote-servers-connection-check-interval"/>.
+     The API for registering functions is:
+    <programlisting>
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+    </programlisting>
+     Only functions that return void can be registered as callback functions.
+     Please set to void* arg a pointer if you want to pass an argument.
+     If you have problems with the health check results and want to
+     abort the transaction, please execute <function>ereport(ERROR)</function>
+     in the callback function.
+    </para>
+    <para>
+     Note that starting or stopping the periodic execution is FDW's responsibility.
+     If you want to start verification, the following function must be performed
+     after registering callback functions:
+     <programlisting>
+int
+TryEnableRemoteServerCheckingTimeout(void)
+    </programlisting>
+     If you want to stop, the following function must be performed:
+     <programlisting>
+int
+TryDisableRemoteServerCheckingTimeout(void)
+    </programlisting>
+    </para>
+
+   </sect1>
+
+
  </chapter>


v06_0001_add_checking_infrastracture.patch (application/octet-stream, 12.4K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index baf328b620..996386fdd4 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 294e22c78c..9622058aaa 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,13 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
+/* counter for keeping re-entrancy */
+static int timeout_counter = 0;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +842,98 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext,
+							   sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+}
+
+/*
+ * Call callbacks for checking remote servers.
+ *
+ * Note that this function will not return anything.
+ * Callback functions must throw ereport(ERROR)
+ * if disconnection has been detected.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * Increment counter, and enable timeout if it has been not started yet.
+ */
+int
+TryEnableRemoteServerCheckingTimeout(void)
+{
+	timeout_counter++;
+
+	if (remote_servers_connection_check_interval > 0 &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
+
+	return timeout_counter;
+}
+
+/*
+ * Decrement counter, and disable timeout if it is no more needed.
+ *
+ * This functions must be called after TryEnableRemoteServerCheckingTimeout().
+ */
+int
+TryDisableRemoteServerCheckingTimeout(void)
+{
+	Assert(timeout_counter > 0);
+	timeout_counter--;
+
+	if (timeout_counter == 0 &&
+		get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+
+	return timeout_counter;
+}
+
+void
+assign_remote_servers_connection_check_interval(int newval,
+												void *extra)
+{
+	/* Quick return if we don't have any callbacks */
+	if (fdw_callbacks == NULL)
+		return;
+
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+	{
+		if (newval == 0)
+			disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in ProcessInterrupts().
+		 */
+		return;
+	}
+
+	/* Start timeout if anyone wants to */
+	if (newval > 0 && timeout_counter > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, newval);
+}
\ No newline at end of file
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index fda2e9360e..60a7e91889 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -44,6 +44,7 @@
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -350,6 +351,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -456,6 +458,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -3214,6 +3217,28 @@ ProcessInterrupts(void)
 		}
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		if (CheckingRemoteServersHoldoffCount != 0)
+		{
+			/*
+			 * Skip checking foreign servers while reading messages.
+			 */
+			InterruptPending = true;
+		}
+		else
+		{
+			CheckingRemoteServersTimeoutPending = false;
+
+			if (remote_servers_connection_check_interval > 0)
+			{
+				CallCheckingRemoteServersCallbacks();
+				enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									 remote_servers_connection_check_interval);
+			}
+		}
+	}
+
 	if (ClientConnectionLost)
 	{
 		QueryCancelPending = false; /* lost connection trumps QueryCancel */
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index c26a1a73df..7efa9cff84 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 0236165f60..d828097076 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -73,6 +73,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -621,6 +622,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1239,6 +1241,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 4c94f09c64..fc64c2e63a 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -52,6 +52,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -106,6 +107,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3600,6 +3602,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, assign_remote_servers_connection_check_interval, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 817d5f5324..b97dc30514 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 75538110fc..76364ce8a3 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,24 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+												  void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+
+extern int TryEnableRemoteServerCheckingTimeout(void);
+extern int TryDisableRemoteServerCheckingTimeout(void);
+
+extern int remote_servers_connection_check_interval;
+extern void assign_remote_servers_connection_check_interval(int newval,
+															void *extra);
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 02276d3edd..0319fe1605 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 099f91c61d..7f02a8b491 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-01-23 05:36                         ` Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Fujii Masao @ 2022-01-23 05:36 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; zyu@yugabyte.com <zyu@yugabyte.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>



On 2022/01/21 15:08, kuroda.hayato@fujitsu.com wrote:
> Dear Fujii-san, Zhihong,
> 
> I attached the latest version.

Thanks for updating the patch!

+int
+TryDisableRemoteServerCheckingTimeout(void)

When more than one FDWs are used, even if one FDW calls this function to disable the timeout, its remote-server-check-callback can still be called. Is this OK?
Please imagine the case where two FDWs are used and they registered their callbacks. Even when one FDW calls TryDisableRemoteServerCheckingTimeout(), if another FDW has not called that yet, the timeout is still being enabled. If the timeout is triggered during that period, even the callback registered by the FDW that has already called TryDisableRemoteServerCheckingTimeout() would be called.


+			if (remote_servers_connection_check_interval > 0)
+			{
+				CallCheckingRemoteServersCallbacks();
+				enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									 remote_servers_connection_check_interval);

LockErrorCleanup() needs to be called before reporting the error, doesn't it?


This can cause an error even while DoingCommandRead == true. Is that safe?


> The biggest change is that callbacks are no longer un-registered at the end of transactions.
> FDW developer must enable or disable timeout instead, via new APIs.
> 
> The timer will be turned on when:
> * new GUC is >= 0, and

This can cause the timeout to be enabled even when no remote transaction is started?

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-02-01 04:37                           ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-01 04:37 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>

Dear Fujii-san,

Thank you for reviewing! I attached the latest version.

> When more than one FDWs are used, even if one FDW calls this function to
> disable the timeout, its remote-server-check-callback can still be called. Is this
> OK?
> Please imagine the case where two FDWs are used and they registered their
> callbacks. Even when one FDW calls TryDisableRemoteServerCheckingTimeout(),
> if another FDW has not called that yet, the timeout is still being enabled. If the
> timeout is triggered during that period, even the callback registered by the FDW
> that has already called TryDisableRemoteServerCheckingTimeout() would be
> called.

Indeed and it should be avoided. I added a counter to CheckingRemoteServersCallbackItem.
The register function returns the registered item, and it must be set as the argument for
enable and disable functions.
Callback functions will be called when item->counter is larger than zero.

> +			if (remote_servers_connection_check_interval > 0)
> +			{
> +				CallCheckingRemoteServersCallbacks();
> +
> 	enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
> +
> remote_servers_connection_check_interval);
> 
> LockErrorCleanup() needs to be called before reporting the error, doesn't it?

You are right. I think this suggests that error-reporting should be done in the core layer.
For meaningful error reporting, I changed a callback specification
that it should return ForeignServer* which points to downed remote server.

> This can cause an error even while DoingCommandRead == true. Is that safe?

I read codes again and I think it is not safe. It is OK when whereToSendOutput is DestRemote,
but not good in InteractiveBackend().

I changed that if-statement for CheckingRemoteServersTimeoutPending is moved just after
ClientConnectionLost, because the that may throw a FATAL error and disconnect from client.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (3 files, .tar.gz)

  pachset.zip (application/x-zip-compressed, 7.7K) download

v07_0001_add_checking_infrastracture.patch (application/octet-stream, 13.4K) download
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index baf328b620..996386fdd4 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 294e22c78c..9779eadf01 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,13 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
+/* counter for keeping re-entrancy */
+static int timeout_counter = 0;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +842,111 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+CheckingRemoteServersCallbackItem *
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext,
+							   sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->counter = 0;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+
+	return item;
+}
+
+/*
+ * Call callbacks for checking remote servers if needed.
+ * This retruns the downed server, or NULL if all servers are good.
+ */
+ForeignServer *
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+	ForeignServer *server = NULL;
+
+	for (item = fdw_callbacks; item; item = item->next)
+	{
+		if (item->counter > 0)
+		{
+			server = item->callback(item->arg);
+			if (server != NULL)
+				break;
+		}
+	}
+
+	return server;
+}
+
+/*
+ * Increment counters, and enable timeout if it has been not started yet.
+ */
+int
+TryEnableRemoteServerCheckingTimeout(CheckingRemoteServersCallbackItem *item)
+{
+	timeout_counter++;
+	item->counter++;
+
+	if (remote_servers_connection_check_interval > 0 &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
+
+	return timeout_counter;
+}
+
+/*
+ * Decrement counters, and disable timeout if it is no more needed.
+ *
+ * This functions must be called after TryEnableRemoteServerCheckingTimeout().
+ */
+int
+TryDisableRemoteServerCheckingTimeout(CheckingRemoteServersCallbackItem *item)
+{
+	Assert(timeout_counter > 0 && item->counter > 0);
+	timeout_counter--;
+	item->counter--;
+
+	if (timeout_counter == 0 &&
+		get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+
+	return timeout_counter;
+}
+
+void
+assign_remote_servers_connection_check_interval(int newval,
+												void *extra)
+{
+	/* Quick return if we don't have any callbacks */
+	if (fdw_callbacks == NULL)
+		return;
+
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+	{
+		if (newval == 0)
+			disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in ProcessInterrupts().
+		 */
+		return;
+	}
+
+	/* Start timeout if anyone wants to */
+	if (newval > 0 && timeout_counter > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, newval);
+}
\ No newline at end of file
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index fda2e9360e..b99fcf7b48 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -44,6 +44,7 @@
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -350,6 +351,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -456,6 +458,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -3225,6 +3228,39 @@ ProcessInterrupts(void)
 				 errmsg("connection to client lost")));
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		if (CheckingRemoteServersHoldoffCount != 0 || DoingCommandRead)
+		{
+			/*
+			 * Skip checking foreign servers while reading messages or commands.
+			 */
+			InterruptPending = true;
+		}
+		else
+		{
+			CheckingRemoteServersTimeoutPending = false;
+
+			/* Check remote servers and re-arm, if still configured. */
+			if (remote_servers_connection_check_interval > 0)
+			{
+				ForeignServer *downedServer = CallCheckingRemoteServersCallbacks();
+				if (downedServer != NULL)
+				{
+					LockErrorCleanup();
+					ereport(ERROR,
+							errcode(ERRCODE_CONNECTION_FAILURE),
+							errmsg("foreign server \"%s\" disconnected due to the health-check failure",
+								   downedServer->servername),
+							errdetail("Foreign server might be down."),
+							errhint("Please check the server and network health."));
+				}
+				enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									 remote_servers_connection_check_interval);
+			}
+		}
+	}
+
 	/*
 	 * If a recovery conflict happens while we are waiting for input from the
 	 * client, the client is presumably just sitting idle in a transaction,
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index c26a1a73df..7efa9cff84 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 5b9ed2f6f5..9b0b4ddd58 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -75,6 +75,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -628,6 +629,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1246,6 +1248,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index b3fd42e0f1..6dfc171448 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -52,6 +52,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -106,6 +107,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3600,6 +3602,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, assign_remote_servers_connection_check_interval, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 817d5f5324..b97dc30514 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 75538110fc..922e63922b 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,26 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef ForeignServer* (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	int			counter;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern CheckingRemoteServersCallbackItem *
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg);
+extern ForeignServer *CallCheckingRemoteServersCallbacks(void);
+
+extern int TryEnableRemoteServerCheckingTimeout(CheckingRemoteServersCallbackItem *item);
+extern int TryDisableRemoteServerCheckingTimeout(CheckingRemoteServersCallbackItem *item);
+
+extern int remote_servers_connection_check_interval;
+extern void assign_remote_servers_connection_check_interval(int newval,
+															void *extra);
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 02276d3edd..0319fe1605 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 099f91c61d..7f02a8b491 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


v07_0002_add_doc.patch (application/octet-stream, 3.2K) download
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 692d8a2a17..fb400a3a91 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1035,6 +1035,25 @@ include_dir 'conf.d'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-remote-servers-connection-check-interval" xreflabel="remote_servers_connection_check_interval">
+      <term><varname>remote_servers_connection_check_interval</varname> (<type>integer</type>)
+      <indexterm>
+       <primary><varname>remote_servers_connection_check_interval</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Sets the time interval between optional checks that the remote servers
+        are still alive. If this parameter is set to a valid value, registered
+        callback functions are executed at the specified time interval.
+        If your FDW extension does not implement a callback function, nothing
+        happens after the specified amount of time. If the value is specified
+        without units, it is taken as milliseconds. The default value is
+        <literal>0</literal>, this means the feature is disabled.
+       </para>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
      </sect2>
 
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index dbf5dd3d15..3b75a77067 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -2136,4 +2136,40 @@ GetForeignServerByName(const char *name, bool missing_ok);
 
   </sect1>
 
+   <sect1 id="fdw-checking-remote-servers">
+    <title>Checking the Health of Remote Servers via Foreign Data Wrapper</title>
+
+    <para>
+     For verifying the health of remote servers, callback functions can be
+     registered that runs periodically. The time interval is controlled by
+     <xref linkend="guc-remote-servers-connection-check-interval"/>.
+     The API for registering functions is:
+    <programlisting>
+CheckingRemoteServersCallbackItem *
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+    </programlisting>
+     Only functions that return <type>ForeignServer*</type> can be
+     registered as callback functions. Please set to <literal>void* arg</literal>
+     if you want to pass an argument. The returning value must be set as the argument
+     of following enable and disable fucntions.
+     If you have problems with the health check results and want to abort the transaction,
+     please return the pointer of downed server as <type>ForeignServer*</type>.
+    </para>
+    <para>
+     Note that starting or stopping the periodic execution is FDW's responsibility.
+     If you want to start verification, the following function must be performed
+     after registering callback functions:
+     <programlisting>
+int
+TryEnableRemoteServerCheckingTimeout(CheckingRemoteServersCallbackItem *item)
+     </programlisting>
+     If you want to stop, the following function must be performed:
+     <programlisting>
+int
+TryDisableRemoteServerCheckingTimeout(CheckingRemoteServersCallbackItem *item)
+     </programlisting>
+    </para>
+   </sect1>
+
+
  </chapter>


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-01 14:51                             ` Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-02 12:37                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  0 siblings, 2 replies; 129+ messages in thread

From: Fujii Masao @ 2022-02-01 14:51 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>



On 2022/02/01 13:37, kuroda.hayato@fujitsu.com wrote:
> Dear Fujii-san,
> 
> Thank you for reviewing! I attached the latest version.

Thanks!

> Indeed and it should be avoided. I added a counter to CheckingRemoteServersCallbackItem.
> The register function returns the registered item, and it must be set as the argument for
> enable and disable functions.
> Callback functions will be called when item->counter is larger than zero.

This logic sounds complicated to me. I'm afraid that FDW developers may a bit easily misunderstand the logic and make the bug in their FDW.

Isn't it simpler to just disable the timeout in core whenever the transaction ends whether committed or aborted, like statement_timeout is disabled after each command? For example, call something like DisableForeignCheckTimeout() in CommitTransaction() etc.

> You are right. I think this suggests that error-reporting should be done in the core layer.
> For meaningful error reporting, I changed a callback specification
> that it should return ForeignServer* which points to downed remote server.

This approach seems to assume that FDW must manage all the ForeignServer information so that the callback can return it. Is this assumption valid for all the FDW?

How about making FDW trigger a query cancel interrupt by signaling SIGINT to the backend, instead?

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-02-02 12:37                               ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-15 12:05                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  1 sibling, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-02 12:37 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya Kato <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>

Dear Fujii-san,

Thank you for good suggestions.

> This logic sounds complicated to me. I'm afraid that FDW developers may a bit
> easily misunderstand the logic and make the bug in their FDW.
> Isn't it simpler to just disable the timeout in core whenever the transaction ends
> whether committed or aborted, like statement_timeout is disabled after each
> command? For example, call something like DisableForeignCheckTimeout() in
> CommitTransaction() etc.

Your idea is that stop the timer at the end of each transactions, right?
I had not adopted that because I thought some developers might want not to stop the timer
even if transactions ends. It caused complexed situation and not have good usecase, however,
so your logic was implemented.

> > You are right. I think this suggests that error-reporting should be done in the
> core layer.
> > For meaningful error reporting, I changed a callback specification
> > that it should return ForeignServer* which points to downed remote server.
> 
> This approach seems to assume that FDW must manage all the ForeignServer
> information so that the callback can return it. Is this assumption valid for all the
> FDW?

Not sure, the assumption might be too optimistic. 
mysql_fdw can easily return ForeignServer* because it caches serverid,
but dblink and maybe oracle_fdw cannot.

> How about making FDW trigger a query cancel interrupt by signaling SIGINT to
> the backend, instead?

I understood that the error should be caught by QueryCancelPending.
Could you check 0003? Does it follow that?

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments: download all (3 files, .tar.gz)

  patchset.zip (application/x-zip-compressed, 7.4K) download

v08_0001_add_checking_infrastracture.patch (application/octet-stream, 13.0K) download
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index c9516e03fa..1e321e18c4 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -39,6 +39,7 @@
 #include "commands/trigger.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "libpq/be-fsstubs.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
@@ -2365,6 +2366,9 @@ CommitTransaction(void)
 	XactTopFullTransactionId = InvalidFullTransactionId;
 	nParallelCurrentXids = 0;
 
+	/* stop checking remote servers */
+	DisableForeignCheckTimeout();
+
 	/*
 	 * done with commit processing, set current transaction state back to
 	 * default
@@ -2652,6 +2656,9 @@ PrepareTransaction(void)
 	XactTopFullTransactionId = InvalidFullTransactionId;
 	nParallelCurrentXids = 0;
 
+	/* stop checking remote servers */
+	DisableForeignCheckTimeout();
+
 	/*
 	 * done with 1st phase commit processing, set current transaction state
 	 * back to default
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index baf328b620..996386fdd4 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 294e22c78c..6084a77336 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,11 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +840,83 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext,
+							   sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+}
+
+/*
+ * Call callbacks for checking remote servers.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * enable timeout if it has been not started yet.
+ */
+void
+EnableForeignCheckTimeout(void)
+{
+	if (remote_servers_connection_check_interval > 0 &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
+}
+
+/*
+ * disable timeout if enabled.
+ */
+void
+DisableForeignCheckTimeout(void)
+{
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+}
+
+void
+assign_remote_servers_connection_check_interval(int newval,
+												void *extra)
+{
+	/* Quick return if we don't have any callbacks */
+	if (fdw_callbacks == NULL)
+		return;
+
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+	{
+		if (newval == 0)
+			disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in ProcessInterrupts().
+		 */
+		return;
+	}
+
+	/* Start timeout if anyone wants to */
+	if (newval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, newval);
+}
\ No newline at end of file
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index fda2e9360e..d5de5557e7 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -44,6 +44,7 @@
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -350,6 +351,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -456,6 +458,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -3225,6 +3228,29 @@ ProcessInterrupts(void)
 				 errmsg("connection to client lost")));
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		if (CheckingRemoteServersHoldoffCount != 0 || DoingCommandRead)
+		{
+			/*
+			 * Skip checking foreign servers while reading messages or commands.
+			 */
+			InterruptPending = true;
+		}
+		else
+		{
+			CheckingRemoteServersTimeoutPending = false;
+
+			/* Check remote servers and re-arm, if still configured. */
+			if (remote_servers_connection_check_interval > 0)
+			{
+				CallCheckingRemoteServersCallbacks();
+				enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									 remote_servers_connection_check_interval);
+			}
+		}
+	}
+
 	/*
 	 * If a recovery conflict happens while we are waiting for input from the
 	 * client, the client is presumably just sitting idle in a transaction,
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index c26a1a73df..7efa9cff84 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 5b9ed2f6f5..9b0b4ddd58 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -75,6 +75,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -628,6 +629,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1246,6 +1248,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index b3fd42e0f1..6dfc171448 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -52,6 +52,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -106,6 +107,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3600,6 +3602,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, assign_remote_servers_connection_check_interval, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 817d5f5324..b97dc30514 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 75538110fc..900cc4e3aa 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,24 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+												  void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+
+extern void EnableForeignCheckTimeout(void);
+extern void DisableForeignCheckTimeout(void);
+
+extern int remote_servers_connection_check_interval;
+extern void assign_remote_servers_connection_check_interval(int newval,
+															void *extra);
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 02276d3edd..0319fe1605 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 099f91c61d..7f02a8b491 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


v08_0002_add_doc.patch (application/octet-stream, 2.8K) download
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 692d8a2a17..fb400a3a91 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1035,6 +1035,25 @@ include_dir 'conf.d'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-remote-servers-connection-check-interval" xreflabel="remote_servers_connection_check_interval">
+      <term><varname>remote_servers_connection_check_interval</varname> (<type>integer</type>)
+      <indexterm>
+       <primary><varname>remote_servers_connection_check_interval</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Sets the time interval between optional checks that the remote servers
+        are still alive. If this parameter is set to a valid value, registered
+        callback functions are executed at the specified time interval.
+        If your FDW extension does not implement a callback function, nothing
+        happens after the specified amount of time. If the value is specified
+        without units, it is taken as milliseconds. The default value is
+        <literal>0</literal>, this means the feature is disabled.
+       </para>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
      </sect2>
 
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index dbf5dd3d15..8e245f87dc 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -2136,4 +2136,34 @@ GetForeignServerByName(const char *name, bool missing_ok);
 
   </sect1>
 
+   <sect1 id="fdw-checking-remote-servers">
+    <title>Checking the Health of Remote Servers via Foreign Data Wrapper</title>
+
+    <para>
+     For verifying the health of remote servers, callback functions can be
+     registered that runs periodically. The time interval is controlled by
+     <xref linkend="guc-remote-servers-connection-check-interval"/>.
+     The API for registering functions is:
+    <programlisting>
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+    </programlisting>
+     Only functions that return nothing can be registered as callback functions.
+     Please set to <literal>void* arg</literal> if you want to pass an argument.
+     If problems are found by the health check and want to abort the transaction,
+     please send a signal <systemitem>SIGINT</systemitem> to the backend process.
+    </para>
+    <para>
+     Note that starting the periodic run is FDW's responsibility.
+     If you want to start verification, the following function must be performed
+     after registering callback functions:
+     <programlisting>
+int
+EnableForeignCheckTimeout(void)
+     </programlisting>
+      The periodic run will stop at end of each transaction.
+    </para>
+   </sect1>
+
+
  </chapter>


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-02 12:37                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-15 12:05                                 ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 0 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-15 12:05 UTC (permalink / raw)
  To: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; +Cc: Shinya Kato <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Fujii Masao <masao.fujii@oss.nttdata.com>

Dear Hackers,

I found patches we depend have been committed, so rebased.
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=50e570a59e7f86bb41f029a66b781fc79b8d5...

In this version there is a little bit change in part of postgres_fdw.
A system checking by WaitEventSetCanReportClosed() is added
because some OSes cannot wait WL_SOCKET_CLOSED event.
Note that test cannot be added in the regression test
because cfbot may be not happy.
In my environment a test that contained in previous patches works well.

0001, 0002 is not changed from previous version. 

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments: download all (3 files, .tar.gz)

v09_0003_helth_check_for_postgres_fdw.patch (application/octet-stream, 4.2K) download
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 29fcb6a76e..10316d2f10 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -109,6 +109,7 @@ static void pgfdw_abort_cleanup(ConnCacheEntry *entry, const char *sql,
 								bool toplevel);
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
+static bool pgfdw_connection_check_internal(PGconn *conn);
 
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
@@ -153,11 +154,17 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a callback fore checking remote servers */
+		RegisterCheckingRemoteServersCallback(pgfdw_connection_check, NULL);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
 	xact_got_connection = true;
 
+	/* Start checking timer */
+	EnableForeignCheckTimeout();
+
 	/* Create hash key for the entry.  Assume no pad bytes in key struct */
 	key = user->umid;
 
@@ -1709,3 +1716,71 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Callback function for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+void
+pgfdw_connection_check(void *args)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+
+	/* Exit immediately if hash is not initialized. */
+	if (!ConnectionHash)
+		return;
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			ForeignServer *server = GetForeignServer(entry->serverid);
+			elog(LOG, "Foreign Server %s might be down.", server->servername);
+			disconnect_pg_server(entry);
+			raise(SIGINT);
+		}
+	}
+
+	return;
+}
+
+/*
+ * helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 8ae79e97e4..0f4f4641c6 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -151,6 +151,7 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern void pgfdw_connection_check(void *args);
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index 2bb31f1125..228f4629a5 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -774,6 +774,16 @@ postgres=# SELECT postgres_fdw_disconnect_all();
    connections that are no longer necessary, thereby releasing
    connections on the foreign server.
   </para>
+
+  <para>
+   During a remote transaction, postgres_fdw checks the health of used connections
+   if <xref linkend="guc-remote-servers-connection-check-interval"/> sets to
+   greater than zero. When losing a remote connection is detected,
+   the running transaction is aborted. Note that this feature is performed
+   by polling the socket, and available platforms are the
+   same as <xref linkend="guc-client-connection-check-interval"/>.
+  </para>
+
  </sect2>
 
  <sect2>


v09_0002_add_doc_about_infrastructure.patch (application/octet-stream, 2.8K) download
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 53b361e7a9..6e4f67aed9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1035,6 +1035,25 @@ include_dir 'conf.d'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-remote-servers-connection-check-interval" xreflabel="remote_servers_connection_check_interval">
+      <term><varname>remote_servers_connection_check_interval</varname> (<type>integer</type>)
+      <indexterm>
+       <primary><varname>remote_servers_connection_check_interval</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Sets the time interval between optional checks that the remote servers
+        are still alive. If this parameter is set to a valid value, registered
+        callback functions are executed at the specified time interval.
+        If your FDW extension does not implement a callback function, nothing
+        happens after the specified amount of time. If the value is specified
+        without units, it is taken as milliseconds. The default value is
+        <literal>0</literal>, this means the feature is disabled.
+       </para>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
      </sect2>
 
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index dbf5dd3d15..8e245f87dc 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -2136,4 +2136,34 @@ GetForeignServerByName(const char *name, bool missing_ok);
 
   </sect1>
 
+   <sect1 id="fdw-checking-remote-servers">
+    <title>Checking the Health of Remote Servers via Foreign Data Wrapper</title>
+
+    <para>
+     For verifying the health of remote servers, callback functions can be
+     registered that runs periodically. The time interval is controlled by
+     <xref linkend="guc-remote-servers-connection-check-interval"/>.
+     The API for registering functions is:
+    <programlisting>
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback, void *arg);
+    </programlisting>
+     Only functions that return nothing can be registered as callback functions.
+     Please set to <literal>void* arg</literal> if you want to pass an argument.
+     If problems are found by the health check and want to abort the transaction,
+     please send a signal <systemitem>SIGINT</systemitem> to the backend process.
+    </para>
+    <para>
+     Note that starting the periodic run is FDW's responsibility.
+     If you want to start verification, the following function must be performed
+     after registering callback functions:
+     <programlisting>
+int
+EnableForeignCheckTimeout(void)
+     </programlisting>
+      The periodic run will stop at end of each transaction.
+    </para>
+   </sect1>
+
+
  </chapter>


v09_0001_add_checking_infrastracture.patch (application/octet-stream, 13.0K) download
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index c9516e03fa..1e321e18c4 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -39,6 +39,7 @@
 #include "commands/trigger.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "libpq/be-fsstubs.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
@@ -2365,6 +2366,9 @@ CommitTransaction(void)
 	XactTopFullTransactionId = InvalidFullTransactionId;
 	nParallelCurrentXids = 0;
 
+	/* stop checking remote servers */
+	DisableForeignCheckTimeout();
+
 	/*
 	 * done with commit processing, set current transaction state back to
 	 * default
@@ -2652,6 +2656,9 @@ PrepareTransaction(void)
 	XactTopFullTransactionId = InvalidFullTransactionId;
 	nParallelCurrentXids = 0;
 
+	/* stop checking remote servers */
+	DisableForeignCheckTimeout();
+
 	/*
 	 * done with 1st phase commit processing, set current transaction state
 	 * back to default
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index baf328b620..996386fdd4 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -269,6 +269,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 
 			readmessage:
 					HOLD_CANCEL_INTERRUPTS();
+					HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					pq_startmsgread();
 					mtype = pq_getbyte();
 					if (mtype == EOF)
@@ -300,6 +301,7 @@ CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
 						ereport(ERROR,
 								(errcode(ERRCODE_CONNECTION_FAILURE),
 								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 					RESUME_CANCEL_INTERRUPTS();
 					/* ... and process it */
 					switch (mtype)
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 294e22c78c..6084a77336 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -26,7 +26,11 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
+/* for checking remote servers */
+int remote_servers_connection_check_interval = 0;
+static CheckingRemoteServersCallbackItem *fdw_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -836,3 +840,83 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ * The checking timeout will be fired after registering the first callback.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext,
+							   sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = fdw_callbacks;
+	fdw_callbacks = item;
+}
+
+/*
+ * Call callbacks for checking remote servers.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	for (item = fdw_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
+
+/*
+ * enable timeout if it has been not started yet.
+ */
+void
+EnableForeignCheckTimeout(void)
+{
+	if (remote_servers_connection_check_interval > 0 &&
+		!get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+							 remote_servers_connection_check_interval);
+}
+
+/*
+ * disable timeout if enabled.
+ */
+void
+DisableForeignCheckTimeout(void)
+{
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+		disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+}
+
+void
+assign_remote_servers_connection_check_interval(int newval,
+												void *extra)
+{
+	/* Quick return if we don't have any callbacks */
+	if (fdw_callbacks == NULL)
+		return;
+
+	if (get_timeout_active(CHECKING_REMOTE_SERVERS_TIMEOUT))
+	{
+		if (newval == 0)
+			disable_timeout(CHECKING_REMOTE_SERVERS_TIMEOUT, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in ProcessInterrupts().
+		 */
+		return;
+	}
+
+	/* Start timeout if anyone wants to */
+	if (newval > 0)
+		enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT, newval);
+}
\ No newline at end of file
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index fda2e9360e..d5de5557e7 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -44,6 +44,7 @@
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -350,6 +351,7 @@ SocketBackend(StringInfo inBuf)
 	 * Get message type code from the frontend.
 	 */
 	HOLD_CANCEL_INTERRUPTS();
+	HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	pq_startmsgread();
 	qtype = pq_getbyte();
 
@@ -456,6 +458,7 @@ SocketBackend(StringInfo inBuf)
 	 */
 	if (pq_getmessage(inBuf, maxmsglen))
 		return EOF;				/* suitable message already logged */
+	RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS();
 	RESUME_CANCEL_INTERRUPTS();
 
 	return qtype;
@@ -3225,6 +3228,29 @@ ProcessInterrupts(void)
 				 errmsg("connection to client lost")));
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		if (CheckingRemoteServersHoldoffCount != 0 || DoingCommandRead)
+		{
+			/*
+			 * Skip checking foreign servers while reading messages or commands.
+			 */
+			InterruptPending = true;
+		}
+		else
+		{
+			CheckingRemoteServersTimeoutPending = false;
+
+			/* Check remote servers and re-arm, if still configured. */
+			if (remote_servers_connection_check_interval > 0)
+			{
+				CallCheckingRemoteServersCallbacks();
+				enable_timeout_after(CHECKING_REMOTE_SERVERS_TIMEOUT,
+									 remote_servers_connection_check_interval);
+			}
+		}
+	}
+
 	/*
 	 * If a recovery conflict happens while we are waiting for input from the
 	 * client, the client is presumably just sitting idle in a transaction,
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index c26a1a73df..7efa9cff84 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -36,9 +36,11 @@ volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
 volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
+volatile uint32 CheckingRemoteServersHoldoffCount = 0;
 
 int			MyProcPid;
 pg_time_t	MyStartTime;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 02207a5b6f..9ce99df962 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -80,6 +80,7 @@ static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
 static void IdleSessionTimeoutHandler(void);
 static void ClientCheckTimeoutHandler(void);
+static void CheckingRemoteServersTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -700,6 +701,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 						IdleInTransactionSessionTimeoutHandler);
 		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 		RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
+		RegisterTimeout(CHECKING_REMOTE_SERVERS_TIMEOUT, CheckingRemoteServersTimeoutHandler);
 	}
 
 	/*
@@ -1318,6 +1320,14 @@ ClientCheckTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+CheckingRemoteServersTimeoutHandler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
 /*
  * Returns true if at least one role is defined in this database cluster.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e2fe219aa8..d558117e64 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -52,6 +52,7 @@
 #include "commands/vacuum.h"
 #include "commands/variable.h"
 #include "common/string.h"
+#include "foreign/foreign.h"
 #include "funcapi.h"
 #include "jit/jit.h"
 #include "libpq/auth.h"
@@ -106,6 +107,7 @@
 #include "utils/queryjumble.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/timeout.h"
 #include "utils/tzparser.h"
 #include "utils/inval.h"
 #include "utils/varlena.h"
@@ -3600,6 +3602,18 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+
+	{
+		{"remote_servers_connection_check_interval", PGC_USERSET, CONN_AUTH_SETTINGS,
+			gettext_noop("Sets the time interval between checks for disconnection of remote servers."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&remote_servers_connection_check_interval,
+		0, 0, INT_MAX,
+		NULL, assign_remote_servers_connection_check_interval, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 56d0bee6d9..04fa73967b 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -90,6 +90,10 @@
 					# disconnection while running queries;
 					# 0 for never
 
+#remote_servers_connection_check_interval = 0	# time between time between checks for
+					# foreign server disconnection;
+					# 0 for never
+
 # - Authentication -
 
 #authentication_timeout = 1min		# 1s-600s
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 75538110fc..900cc4e3aa 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -81,4 +81,24 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* functions and variables for fdw checking. */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+typedef struct CheckingRemoteServersCallbackItem
+{
+	struct CheckingRemoteServersCallbackItem *next;
+	CheckingRemoteServersCallback callback;
+	void		*arg;
+} CheckingRemoteServersCallbackItem;
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+												  void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+
+extern void EnableForeignCheckTimeout(void);
+extern void DisableForeignCheckTimeout(void);
+
+extern int remote_servers_connection_check_interval;
+extern void assign_remote_servers_connection_check_interval(int newval,
+															void *extra);
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 0abc3ad540..b14152e66b 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -98,10 +98,13 @@ extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
 extern PGDLLIMPORT volatile uint32 CritSectionCount;
+extern PGDLLIMPORT volatile uint32 CheckingRemoteServersHoldoffCount;
 
 /* in tcop/postgres.c */
 extern void ProcessInterrupts(void);
@@ -126,7 +129,7 @@ do { \
 /* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
 #define INTERRUPTS_CAN_BE_PROCESSED() \
 	(InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
-	 QueryCancelHoldoffCount == 0)
+	 QueryCancelHoldoffCount == 0 && CheckingRemoteServersHoldoffCount == 0)
 
 #define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
@@ -152,6 +155,13 @@ do { \
 	CritSectionCount--; \
 } while(0)
 
+#define HOLD_CHECKING_REMOTE_SERVERS_INTERRUPTS()  (CheckingRemoteServersHoldoffCount++)
+
+#define RESUME_CHECKING_REMOTE_SERVERS_INTERRUPTS() \
+do { \
+	Assert(CheckingRemoteServersHoldoffCount > 0); \
+	CheckingRemoteServersHoldoffCount--; \
+} while(0)
 
 /*****************************************************************************
  *	  globals.h --															 *
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 099f91c61d..7f02a8b491 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -34,6 +34,7 @@ typedef enum TimeoutId
 	IDLE_SESSION_TIMEOUT,
 	CLIENT_CONNECTION_CHECK_TIMEOUT,
 	STARTUP_PROGRESS_TIMEOUT,
+	CHECKING_REMOTE_SERVERS_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */


^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-02-16 02:50                               ` Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  1 sibling, 1 reply; 129+ messages in thread

From: Kyotaro Horiguchi @ 2022-02-16 02:50 UTC (permalink / raw)
  To: masao.fujii@oss.nttdata.com; +Cc: kuroda.hayato@fujitsu.com; pgsql-hackers@lists.postgresql.org; Shinya11.Kato@oss.nttdata.com; zyu@yugabyte.com

At Tue, 1 Feb 2022 23:51:54 +0900, Fujii Masao <masao.fujii@oss.nttdata.com> wrote in 
> This logic sounds complicated to me. I'm afraid that FDW developers
> may a bit easily misunderstand the logic and make the bug in their
> FDW.

> Isn't it simpler to just disable the timeout in core whenever the
> transaction ends whether committed or aborted, like statement_timeout
> is disabled after each command? For example, call something like
> DisableForeignCheckTimeout() in CommitTransaction() etc.

> This approach seems to assume that FDW must manage all the
> ForeignServer information so that the callback can return it. Is this
> assumption valid for all the FDW?

FWIW, I'm not sure this feature necessarily requires core support
dedicated to FDWs.  The core have USER_TIMEOUT feature already and
FDWs are not necessarily connection based.  It seems better if FDWs
can implement health check feature without core support and it seems
possible.  Or at least the core feature should be more generic and
simpler. Why don't we just expose InTransactionHealthCheckCallbacks or
something and operating functions on it?


> How about making FDW trigger a query cancel interrupt by signaling
> SIGINT to the backend, instead?

Mmm. AFAICS the running command will stop with "canceling statement
due to user request", which is a hoax.  We need a more decent message
there.

I understand that the motive of this patch is "to avoid wasted long
local work when fdw-connection dies".  In regard to the workload in
your first mail, it is easily avoided by ending the transaction as soon
as remote access ends. This feature doesn't work for the case "begin;
<long local query>; <fdw access>". But the same measure also works in
that case.  So the only case where this feature is useful is "begin;
<fdw-access>; <some long work>; <fdw-access>; end;".  But in the first
place how frequently do you expecting remote-connection close happens?
If that happens so frequently, you might need to recheck the system
health before implementing this feature.  Since it is correctly
detected when something really went wrong, I feel that it is a bit too
complex for the usefulness especially for the core part.


In conclusion, as my humble opinion I would like to propose to reduce
this feature to:

- Just periodically check health (in any aspect) of all live
  connections regardless of the session state.

- If an existing connection is found to be dead, just try canceling
  the query (or sending query cancel).

One issue with it is how to show the decent message for the query
cancel, but maybe we can have a global variable that suggests the
reason for the cancel.


regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
@ 2022-02-17 04:11                                 ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 04:32                                   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  0 siblings, 2 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-17 04:11 UTC (permalink / raw)
  To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; masao.fujii@oss.nttdata.com <masao.fujii@oss.nttdata.com>

Dear Horiguchi-san,

Thank you for giving your suggestions. I want to confirm your saying.

> FWIW, I'm not sure this feature necessarily requires core support
> dedicated to FDWs.  The core have USER_TIMEOUT feature already and
> FDWs are not necessarily connection based.  It seems better if FDWs
> can implement health check feature without core support and it seems
> possible.  Or at least the core feature should be more generic and
> simpler. Why don't we just expose InTransactionHealthCheckCallbacks or
> something and operating functions on it?

I understood that core is too complicated and FDW side is too stupid, right?

> Mmm. AFAICS the running command will stop with "canceling statement
> due to user request", which is a hoax.  We need a more decent message
> there.

+1 about better messages.

> I understand that the motive of this patch is "to avoid wasted long
> local work when fdw-connection dies".

Yeah your understanding is right.

> In regard to the workload in
> your first mail, it is easily avoided by ending the transaction as soon
> as remote access ends. This feature doesn't work for the case "begin;
> <long local query>; <fdw access>". But the same measure also works in
> that case.  So the only case where this feature is useful is "begin;
> <fdw-access>; <some long work>; <fdw-access>; end;".  But in the first
> place how frequently do you expecting remote-connection close happens?
> If that happens so frequently, you might need to recheck the system
> health before implementing this feature.  Since it is correctly
> detected when something really went wrong, I feel that it is a bit too
> complex for the usefulness especially for the core part.

Thanks for analyzing motivation.
Indeed, some cases may be resolved by separating tx and this event rarely happens.

> In conclusion, as my humble opinion I would like to propose to reduce
> this feature to:
> 
> - Just periodically check health (in any aspect) of all live
>   connections regardless of the session state.

I understood here as removing following mechanism from core:

* disable timeout at end of tx.
* skip if held off or read commands

> - If an existing connection is found to be dead, just try canceling
>   the query (or sending query cancel).
> One issue with it is how to show the decent message for the query
> cancel, but maybe we can have a global variable that suggests the
> reason for the cancel.

Currently I have no good idea for that but I'll try.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED






^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-17 04:32                                   ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:14                                     ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  1 sibling, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-17 04:32 UTC (permalink / raw)
  To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; masao.fujii@oss.nttdata.com <masao.fujii@oss.nttdata.com>

> I understood here as removing following mechanism from core:
> 
> * disable timeout at end of tx.

While reading again and this part might be wrong.
Sorry for inconvenience.
But anyway some codes should be (re)moved from core, right?

Best Regards,
Hayato Kuroda
FUJITSU LIMITED





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 04:32                                   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-17 08:14                                     ` Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 10:35                                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Kyotaro Horiguchi @ 2022-02-17 08:14 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com; +Cc: pgsql-hackers@lists.postgresql.org; Shinya11.Kato@oss.nttdata.com; zyu@yugabyte.com; masao.fujii@oss.nttdata.com

At Thu, 17 Feb 2022 04:32:26 +0000, "kuroda.hayato@fujitsu.com" <kuroda.hayato@fujitsu.com> wrote in 
> > I understood here as removing following mechanism from core:
> > 
> > * disable timeout at end of tx.
> 
> While reading again and this part might be wrong.
> Sorry for inconvenience.
> But anyway some codes should be (re)moved from core, right?

I think we just don't need to add the special timeout kind to the
core.  postgres_fdw can use USER_TIMEOUT and it would be suffiction to
keep running health checking regardless of transaction state then fire
query cancel if disconnection happens. As I said in the previous main,
possible extra query cancel woud be safe.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 04:32                                   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:14                                     ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
@ 2022-02-17 10:35                                       ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-18 08:59                                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-17 10:35 UTC (permalink / raw)
  To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; masao.fujii@oss.nttdata.com <masao.fujii@oss.nttdata.com>

Dear Horiguchi-san,

> I think we just don't need to add the special timeout kind to the
> core.  postgres_fdw can use USER_TIMEOUT and it would be suffiction to
> keep running health checking regardless of transaction state then fire
> query cancel if disconnection happens. As I said in the previous main,
> possible extra query cancel woud be safe.

I finally figured out that you mentioned about user-defined timeout system.
Firstly - before posting to hackers - I designed like that,
but I was afraid of an overhead that many FDW registers timeout
and call setitimer() many times. Is it too overcautious?

Best Regards,
Hayato Kuroda
FUJITSU LIMITED
 






^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 04:32                                   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:14                                     ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 10:35                                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-18 08:59                                         ` Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 02:51                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Fujii Masao @ 2022-02-18 08:59 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>



On 2022/02/17 19:35, kuroda.hayato@fujitsu.com wrote:
> Dear Horiguchi-san,
> 
>> I think we just don't need to add the special timeout kind to the
>> core.  postgres_fdw can use USER_TIMEOUT and it would be suffiction to
>> keep running health checking regardless of transaction state then fire
>> query cancel if disconnection happens. As I said in the previous main,
>> possible extra query cancel woud be safe.

Sounds reasonable to me.


> I finally figured out that you mentioned about user-defined timeout system.
> Firstly - before posting to hackers - I designed like that,
> but I was afraid of an overhead that many FDW registers timeout
> and call setitimer() many times. Is it too overcautious?

Isn't it a very special case where many FDWs use their own user timeouts? Could you tell me the assumption that you're thinking, especially how many FDWs are working?

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 04:32                                   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:14                                     ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 10:35                                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-18 08:59                                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-02-22 02:51                                           ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 0 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-22 02:51 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>

Dear Fujii-san,

> Isn't it a very special case where many FDWs use their own user timeouts? Could
> you tell me the assumption that you're thinking, especially how many FDWs are
> working?

I came up with the case like star schema, which postgres database connects data store.
If each dbms are different and FDWs have each timeout, many timeout will be registered.
But it may be a corner case and should not be confused with OLTP case. 
So I'll post new patch based on his post.


Best Regards,
Hayato Kuroda
FUJITSU LIMITED



^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-17 08:08                                   ` Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  1 sibling, 1 reply; 129+ messages in thread

From: Kyotaro Horiguchi @ 2022-02-17 08:08 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com; +Cc: pgsql-hackers@lists.postgresql.org; Shinya11.Kato@oss.nttdata.com; zyu@yugabyte.com; masao.fujii@oss.nttdata.com

Hi, Kuroda-san.

At Thu, 17 Feb 2022 04:11:09 +0000, "kuroda.hayato@fujitsu.com" <kuroda.hayato@fujitsu.com> wrote in 
> Dear Horiguchi-san,
> 
> Thank you for giving your suggestions. I want to confirm your saying.
> 
> > FWIW, I'm not sure this feature necessarily requires core support
> > dedicated to FDWs.  The core have USER_TIMEOUT feature already and
> > FDWs are not necessarily connection based.  It seems better if FDWs
> > can implement health check feature without core support and it seems
> > possible.  Or at least the core feature should be more generic and
> > simpler. Why don't we just expose InTransactionHealthCheckCallbacks or
> > something and operating functions on it?
> 
> I understood that core is too complicated and FDW side is too stupid, right?

I don't think the FDW side is stupid but seem too complex for the
benefit.  And just think that maybe we don't need the core part.

> > Mmm. AFAICS the running command will stop with "canceling statement
> > due to user request", which is a hoax.  We need a more decent message
> > there.
> 
> +1 about better messages.
> 
> > I understand that the motive of this patch is "to avoid wasted long
> > local work when fdw-connection dies".
> 
> Yeah your understanding is right.
> 
> > In regard to the workload in
> > your first mail, it is easily avoided by ending the transaction as soon
> > as remote access ends. This feature doesn't work for the case "begin;
> > <long local query>; <fdw access>". But the same measure also works in
> > that case.  So the only case where this feature is useful is "begin;
> > <fdw-access>; <some long work>; <fdw-access>; end;".  But in the first
> > place how frequently do you expecting remote-connection close happens?
> > If that happens so frequently, you might need to recheck the system
> > health before implementing this feature.  Since it is correctly
> > detected when something really went wrong, I feel that it is a bit too
> > complex for the usefulness especially for the core part.
> 
> Thanks for analyzing motivation.
> Indeed, some cases may be resolved by separating tx and this event rarely happens.
> 
> > In conclusion, as my humble opinion I would like to propose to reduce
> > this feature to:
> > 
> > - Just periodically check health (in any aspect) of all live
> >   connections regardless of the session state.
> 
> I understood here as removing following mechanism from core:
> 
> * disable timeout at end of tx.
> * skip if held off or read commands

I think we're on the same page. Anyway query cancel interrupt is
ignored while rading input.

> > - If an existing connection is found to be dead, just try canceling
> >   the query (or sending query cancel).
> > One issue with it is how to show the decent message for the query
> > cancel, but maybe we can have a global variable that suggests the
> > reason for the cancel.
> 
> Currently I have no good idea for that but I'll try.

However, I would like to hear others' opnions about the direction, of
course.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
@ 2022-02-22 02:53                                     ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-22 02:53 UTC (permalink / raw)
  To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; masao.fujii@oss.nttdata.com <masao.fujii@oss.nttdata.com>

Dear Horiguchi-san, Fujii-san,

> > I understood here as removing following mechanism from core:
> >
> > * disable timeout at end of tx.
> > * skip if held off or read commands
> 
> I think we're on the same page. Anyway query cancel interrupt is
> ignored while rading input.
> 
> > > - If an existing connection is found to be dead, just try canceling
> > >   the query (or sending query cancel).
> > > One issue with it is how to show the decent message for the query
> > > cancel, but maybe we can have a global variable that suggests the
> > > reason for the cancel.
> >
> > Currently I have no good idea for that but I'll try.
> 
> However, I would like to hear others' opnions about the direction, of
> course.
>

Based on the idea, I re-implemented the feature. Almost all feature is
moved to postgres_fdw. The abstract of my patch is as follows:

# core

* Exposes QueryCancelMessage for error reporting
* Uses above if it was not NULL

# postgres_fdw

* Defines new GUC postgres_fdw.health_check_interval.
  It is renamed simpler.
* Registers a timeout when initializing connection hash.
* Raises SIGINT and sets QueryCancelMessage to message.
  if detects a connection lost.

I also attached a test as zipped file for keep cfbot quiet.
When connection lost is detected, the following message will show:

```
ERROR:  Foreign Server (servername) might be down.
```

How do you think?

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Attachments: download all (4 files, .tar.gz)

v10_0001_expose_cancel_message.patch (application/octet-stream, 1.4K) download
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 38d8b97894..891d6ac204 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -106,6 +106,8 @@ int			PostAuthDelay = 0;
 /* Time between checks that the client is still connected. */
 int			client_connection_check_interval = 0;
 
+char 		*QeuryCancelMessage = NULL;
+
 /* ----------------
  *		private typedefs etc
  * ----------------
@@ -3329,6 +3331,8 @@ ProcessInterrupts(void)
 			LockErrorCleanup();
 			ereport(ERROR,
 					(errcode(ERRCODE_QUERY_CANCELED),
+					 QeuryCancelMessage ?
+					 errmsg("%s", QeuryCancelMessage) :
 					 errmsg("canceling statement due to user request")));
 		}
 	}
@@ -4240,6 +4244,9 @@ PostgresMain(const char *dbname, const char *username)
 		/* Report the error to the client and/or server log */
 		EmitErrorReport();
 
+		/* Make sure QeuryCancelMessage is reset. */
+		QeuryCancelMessage = NULL;
+
 		/*
 		 * Make sure debug_query_string gets reset before we possibly clobber
 		 * the storage it points at.
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 15a11bc3ff..54ea1de9de 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -30,6 +30,7 @@ extern PGDLLIMPORT const char *debug_query_string;
 extern int	max_stack_depth;
 extern int	PostAuthDelay;
 extern int	client_connection_check_interval;
+extern char* QeuryCancelMessage;
 
 /* GUC-configurable parameters */
 


v10_0002_add_health_check.patch (application/octet-stream, 6.7K) download
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index f753c6e232..d55243fb7e 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -23,12 +23,14 @@
 #include "postgres_fdw.h"
 #include "storage/fd.h"
 #include "storage/latch.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/datetime.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
 /*
  * Connection cache hash table entry
@@ -109,6 +111,10 @@ static void pgfdw_abort_cleanup(ConnCacheEntry *entry, const char *sql,
 								bool toplevel);
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
+static void pgfdw_connection_check(void);
+static bool pgfdw_connection_check_internal(PGconn *conn);
+static TimeoutId pgfdw_health_check_timeout = MAX_TIMEOUTS;
+int pgfdw_health_check_interval;
 
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
@@ -153,6 +159,9 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a timeout for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT, pgfdw_connection_check);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -276,6 +285,12 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (state)
 		*state = &entry->state;
 
+	/* Fire timeout if needed */
+	if (pgfdw_health_check_interval > 0 &&
+		!get_timeout_active(pgfdw_health_check_timeout))
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
 	return entry->conn;
 }
 
@@ -1702,3 +1717,133 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Signal handler for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+void
+pgfdw_connection_check(void)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+	bool raised = false;
+
+	Assert(ConnectionHash);
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	/* Is there any cancel messages? */
+	if (QeuryCancelMessage != NULL)
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)) && !raised)
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			/*
+			 * Foreign server might be down, so raise SIGINT.
+			 * Note that error message is passed to QeuryCancelMessage
+			 * for reporting error in ProcessInterrupts().
+			 */
+			char msg[31 + MAXDATELEN];
+			MemoryContext old;
+			ForeignServer *server;
+
+			/*
+			 * Switch to CurTransactionContext in order to
+			 * make sure that the lifetime of palloc'd is transaction.
+			 */
+			old = MemoryContextSwitchTo(CurTransactionContext);
+			server = GetForeignServer(entry->serverid);
+			snprintf(msg, sizeof(msg), "Foreign Server %s might be down.", server->servername);
+			QeuryCancelMessage = pstrdup(msg);
+			MemoryContextSwitchTo(old);
+
+			disconnect_pg_server(entry);
+			raise(SIGINT);
+			raised = true;
+			break;
+		}
+	}
+
+	/* re-schedule timer if needed. */
+	if (!raised && pgfdw_health_check_interval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
+	return;
+}
+
+/*
+ * helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
+
+bool
+check_pgfdw_health_check_interval(int *newval, void **extra, GucSource source)
+{
+	if (!WaitEventSetCanReportClosed() && *newval != 0)
+	{
+		GUC_check_errdetail("pgfdw_health_check_interval must be set to 0 on this platform");
+		return false;
+	}
+	return true;
+}
+
+void
+assign_pgfdw_health_check_interval(int newval, void *extra)
+{
+	/* Quick return if timeout is not registered yet. */
+	if (pgfdw_health_check_timeout == MAX_TIMEOUTS)
+		return;
+
+	if (get_timeout_active(pgfdw_health_check_timeout))
+	{
+		if (newval == 0)
+			disable_timeout(pgfdw_health_check_timeout, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in pgfdw_connection_check().
+		 */
+		return;
+	}
+
+	/* Start timeout if wants to */
+	if (newval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout, newval);
+}
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index fc3ce6a53a..4dd18b565a 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -532,5 +532,18 @@ _PG_init(void)
 							   NULL,
 							   NULL);
 
+	DefineCustomIntVariable("postgres_fdw.health_check_interval",
+							"Sets the time interval between checks of remote servers.",
+							NULL,
+							&pgfdw_health_check_interval,
+							0,
+							0,
+							INT_MAX,
+							PGC_USERSET,
+							GUC_UNIT_MS,
+							check_pgfdw_health_check_interval,
+							assign_pgfdw_health_check_interval,
+							NULL);
+
 	EmitWarningsOnPlaceholders("postgres_fdw");
 }
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 8ae79e97e4..c129af5082 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -18,6 +18,7 @@
 #include "libpq-fe.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
+#include "utils/guc.h"
 #include "utils/relcache.h"
 
 /*
@@ -151,6 +152,10 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern bool check_pgfdw_health_check_interval(int *newval, void **extra,
+											  GucSource source);
+extern void assign_pgfdw_health_check_interval(int newval, void *extra);
+extern int pgfdw_health_check_interval;
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,


v10_0003_add_doc.patch (application/octet-stream, 1.4K) download
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index 7bb6e525a4..dcc821df17 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1014,6 +1014,32 @@ postgres=# SELECT postgres_fdw_disconnect_all();
 
     </listitem>
    </varlistentry>
+   <varlistentry id="guc-pgfdw-health-check-interval" xreflabel="postgres_fdw.health_check_interval">
+    <term>
+     <varname>postgres_fdw.health_check_interval</varname> (<type>integer</type>)
+     <indexterm>
+      <primary><varname>postgres_fdw.health_check_interval</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the time interval between optional checks that remote servers
+      are still alive. When losing a remote connection is detected,
+      the running transaction is aborted. This feature is performed
+      by polling the socket.
+     </para>
+     <para>
+      this option relies on kernel events exposed by Linux, macOS,
+      illumos and the BSD family of operating systems, and is not currently available 
+      on other systems.
+     </para>
+     <para>
+      If the value is specified without units, it is taken as milliseconds.
+      The default value is <literal>0</literal>, which disables connection
+      checks.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </sect2>
 


  v10_0004_add_test.zip (application/x-zip-compressed, 854B) download

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-22 03:57                                       ` Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Fujii Masao @ 2022-02-22 03:57 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>



On 2022/02/22 11:53, kuroda.hayato@fujitsu.com wrote:
> How do you think?

Thanks for updating the patches! I will read them.

cfbot is reporting that the 0002 patch fails to be applied cleanly. Could you update the patch?
http://cfbot.cputube.org/patch_37_3388.log

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-02-22 05:25                                         ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-22 05:25 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>

Dear Fujii-san,

> cfbot is reporting that the 0002 patch fails to be applied cleanly. Could you update
> the patch?
> http://cfbot.cputube.org/patch_37_3388.log

Thanks for reporting and sorry for inconvenience.
I repo was not latest version. Attached can be applied to 52e4f0c

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (4 files, .tar.gz)

v11_0001_add_checking_infrastracture.patch (application/octet-stream, 1.4K) download
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 3c7d08209f..206f7e1d59 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -106,6 +106,8 @@ int			PostAuthDelay = 0;
 /* Time between checks that the client is still connected. */
 int			client_connection_check_interval = 0;
 
+char 		*QeuryCancelMessage = NULL;
+
 /* ----------------
  *		private typedefs etc
  * ----------------
@@ -3327,6 +3329,8 @@ ProcessInterrupts(void)
 			LockErrorCleanup();
 			ereport(ERROR,
 					(errcode(ERRCODE_QUERY_CANCELED),
+					 QeuryCancelMessage ?
+					 errmsg("%s", QeuryCancelMessage) :
 					 errmsg("canceling statement due to user request")));
 		}
 	}
@@ -4248,6 +4252,9 @@ PostgresMain(const char *dbname, const char *username)
 		/* Report the error to the client and/or server log */
 		EmitErrorReport();
 
+		/* Make sure QeuryCancelMessage is reset. */
+		QeuryCancelMessage = NULL;
+
 		/*
 		 * Make sure debug_query_string gets reset before we possibly clobber
 		 * the storage it points at.
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 15a11bc3ff..54ea1de9de 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -30,6 +30,7 @@ extern PGDLLIMPORT const char *debug_query_string;
 extern int	max_stack_depth;
 extern int	PostAuthDelay;
 extern int	client_connection_check_interval;
+extern char* QeuryCancelMessage;
 
 /* GUC-configurable parameters */
 


v11_0002_add_health_check.patch (application/octet-stream, 6.7K) download
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index f753c6e232..d55243fb7e 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -23,12 +23,14 @@
 #include "postgres_fdw.h"
 #include "storage/fd.h"
 #include "storage/latch.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/datetime.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
 /*
  * Connection cache hash table entry
@@ -109,6 +111,10 @@ static void pgfdw_abort_cleanup(ConnCacheEntry *entry, const char *sql,
 								bool toplevel);
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
+static void pgfdw_connection_check(void);
+static bool pgfdw_connection_check_internal(PGconn *conn);
+static TimeoutId pgfdw_health_check_timeout = MAX_TIMEOUTS;
+int pgfdw_health_check_interval;
 
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
@@ -153,6 +159,9 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a timeout for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT, pgfdw_connection_check);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -276,6 +285,12 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (state)
 		*state = &entry->state;
 
+	/* Fire timeout if needed */
+	if (pgfdw_health_check_interval > 0 &&
+		!get_timeout_active(pgfdw_health_check_timeout))
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
 	return entry->conn;
 }
 
@@ -1702,3 +1717,133 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Signal handler for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+void
+pgfdw_connection_check(void)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+	bool raised = false;
+
+	Assert(ConnectionHash);
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	/* Is there any cancel messages? */
+	if (QeuryCancelMessage != NULL)
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)) && !raised)
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			/*
+			 * Foreign server might be down, so raise SIGINT.
+			 * Note that error message is passed to QeuryCancelMessage
+			 * for reporting error in ProcessInterrupts().
+			 */
+			char msg[31 + MAXDATELEN];
+			MemoryContext old;
+			ForeignServer *server;
+
+			/*
+			 * Switch to CurTransactionContext in order to
+			 * make sure that the lifetime of palloc'd is transaction.
+			 */
+			old = MemoryContextSwitchTo(CurTransactionContext);
+			server = GetForeignServer(entry->serverid);
+			snprintf(msg, sizeof(msg), "Foreign Server %s might be down.", server->servername);
+			QeuryCancelMessage = pstrdup(msg);
+			MemoryContextSwitchTo(old);
+
+			disconnect_pg_server(entry);
+			raise(SIGINT);
+			raised = true;
+			break;
+		}
+	}
+
+	/* re-schedule timer if needed. */
+	if (!raised && pgfdw_health_check_interval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
+	return;
+}
+
+/*
+ * helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
+
+bool
+check_pgfdw_health_check_interval(int *newval, void **extra, GucSource source)
+{
+	if (!WaitEventSetCanReportClosed() && *newval != 0)
+	{
+		GUC_check_errdetail("pgfdw_health_check_interval must be set to 0 on this platform");
+		return false;
+	}
+	return true;
+}
+
+void
+assign_pgfdw_health_check_interval(int newval, void *extra)
+{
+	/* Quick return if timeout is not registered yet. */
+	if (pgfdw_health_check_timeout == MAX_TIMEOUTS)
+		return;
+
+	if (get_timeout_active(pgfdw_health_check_timeout))
+	{
+		if (newval == 0)
+			disable_timeout(pgfdw_health_check_timeout, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in pgfdw_connection_check().
+		 */
+		return;
+	}
+
+	/* Start timeout if wants to */
+	if (newval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout, newval);
+}
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index 2c6b2894b9..75a910b0ff 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -538,5 +538,18 @@ _PG_init(void)
 							   NULL,
 							   NULL);
 
+	DefineCustomIntVariable("postgres_fdw.health_check_interval",
+							"Sets the time interval between checks of remote servers.",
+							NULL,
+							&pgfdw_health_check_interval,
+							0,
+							0,
+							INT_MAX,
+							PGC_USERSET,
+							GUC_UNIT_MS,
+							check_pgfdw_health_check_interval,
+							assign_pgfdw_health_check_interval,
+							NULL);
+
 	MarkGUCPrefixReserved("postgres_fdw");
 }
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 8ae79e97e4..c129af5082 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -18,6 +18,7 @@
 #include "libpq-fe.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
+#include "utils/guc.h"
 #include "utils/relcache.h"
 
 /*
@@ -151,6 +152,10 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern bool check_pgfdw_health_check_interval(int *newval, void **extra,
+											  GucSource source);
+extern void assign_pgfdw_health_check_interval(int newval, void *extra);
+extern int pgfdw_health_check_interval;
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,


v11_0003_add_doc.patch (application/octet-stream, 1.4K) download
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index dc57fe4b0d..21532e19d9 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1028,6 +1028,32 @@ postgres=# SELECT postgres_fdw_disconnect_all();
 
     </listitem>
    </varlistentry>
+   <varlistentry id="guc-pgfdw-health-check-interval" xreflabel="postgres_fdw.health_check_interval">
+    <term>
+     <varname>postgres_fdw.health_check_interval</varname> (<type>integer</type>)
+     <indexterm>
+      <primary><varname>postgres_fdw.health_check_interval</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the time interval between optional checks that remote servers
+      are still alive. When losing a remote connection is detected,
+      the running transaction is aborted. This feature is performed
+      by polling the socket.
+     </para>
+     <para>
+      this option relies on kernel events exposed by Linux, macOS,
+      illumos and the BSD family of operating systems, and is not currently available 
+      on other systems.
+     </para>
+     <para>
+      If the value is specified without units, it is taken as milliseconds.
+      The default value is <literal>0</literal>, which disables connection
+      checks.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </sect2>
 


  v11_0004_add_test.zip (application/x-zip-compressed, 855B) download

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-22 06:41                                           ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-22 06:41 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>

Cfbot is still angry because of missing PGDLLIMPORT, so attached.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (4 files, .tar.gz)

v12_0001_add_checking_infrastracture.patch (application/octet-stream, 1.5K) download
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 3c7d08209f..206f7e1d59 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -106,6 +106,8 @@ int			PostAuthDelay = 0;
 /* Time between checks that the client is still connected. */
 int			client_connection_check_interval = 0;
 
+char 		*QeuryCancelMessage = NULL;
+
 /* ----------------
  *		private typedefs etc
  * ----------------
@@ -3327,6 +3329,8 @@ ProcessInterrupts(void)
 			LockErrorCleanup();
 			ereport(ERROR,
 					(errcode(ERRCODE_QUERY_CANCELED),
+					 QeuryCancelMessage ?
+					 errmsg("%s", QeuryCancelMessage) :
 					 errmsg("canceling statement due to user request")));
 		}
 	}
@@ -4248,6 +4252,9 @@ PostgresMain(const char *dbname, const char *username)
 		/* Report the error to the client and/or server log */
 		EmitErrorReport();
 
+		/* Make sure QeuryCancelMessage is reset. */
+		QeuryCancelMessage = NULL;
+
 		/*
 		 * Make sure debug_query_string gets reset before we possibly clobber
 		 * the storage it points at.
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 15a11bc3ff..83f894cbd0 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -30,6 +30,7 @@ extern PGDLLIMPORT const char *debug_query_string;
 extern int	max_stack_depth;
 extern int	PostAuthDelay;
 extern int	client_connection_check_interval;
+extern PGDLLIMPORT char* QeuryCancelMessage;
 
 /* GUC-configurable parameters */
 


v12_0002_add_health_check.patch (application/octet-stream, 6.7K) download
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index f753c6e232..d55243fb7e 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -23,12 +23,14 @@
 #include "postgres_fdw.h"
 #include "storage/fd.h"
 #include "storage/latch.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/datetime.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
 /*
  * Connection cache hash table entry
@@ -109,6 +111,10 @@ static void pgfdw_abort_cleanup(ConnCacheEntry *entry, const char *sql,
 								bool toplevel);
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
+static void pgfdw_connection_check(void);
+static bool pgfdw_connection_check_internal(PGconn *conn);
+static TimeoutId pgfdw_health_check_timeout = MAX_TIMEOUTS;
+int pgfdw_health_check_interval;
 
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
@@ -153,6 +159,9 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a timeout for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT, pgfdw_connection_check);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -276,6 +285,12 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (state)
 		*state = &entry->state;
 
+	/* Fire timeout if needed */
+	if (pgfdw_health_check_interval > 0 &&
+		!get_timeout_active(pgfdw_health_check_timeout))
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
 	return entry->conn;
 }
 
@@ -1702,3 +1717,133 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Signal handler for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+void
+pgfdw_connection_check(void)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+	bool raised = false;
+
+	Assert(ConnectionHash);
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	/* Is there any cancel messages? */
+	if (QeuryCancelMessage != NULL)
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)) && !raised)
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			/*
+			 * Foreign server might be down, so raise SIGINT.
+			 * Note that error message is passed to QeuryCancelMessage
+			 * for reporting error in ProcessInterrupts().
+			 */
+			char msg[31 + MAXDATELEN];
+			MemoryContext old;
+			ForeignServer *server;
+
+			/*
+			 * Switch to CurTransactionContext in order to
+			 * make sure that the lifetime of palloc'd is transaction.
+			 */
+			old = MemoryContextSwitchTo(CurTransactionContext);
+			server = GetForeignServer(entry->serverid);
+			snprintf(msg, sizeof(msg), "Foreign Server %s might be down.", server->servername);
+			QeuryCancelMessage = pstrdup(msg);
+			MemoryContextSwitchTo(old);
+
+			disconnect_pg_server(entry);
+			raise(SIGINT);
+			raised = true;
+			break;
+		}
+	}
+
+	/* re-schedule timer if needed. */
+	if (!raised && pgfdw_health_check_interval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
+	return;
+}
+
+/*
+ * helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
+
+bool
+check_pgfdw_health_check_interval(int *newval, void **extra, GucSource source)
+{
+	if (!WaitEventSetCanReportClosed() && *newval != 0)
+	{
+		GUC_check_errdetail("pgfdw_health_check_interval must be set to 0 on this platform");
+		return false;
+	}
+	return true;
+}
+
+void
+assign_pgfdw_health_check_interval(int newval, void *extra)
+{
+	/* Quick return if timeout is not registered yet. */
+	if (pgfdw_health_check_timeout == MAX_TIMEOUTS)
+		return;
+
+	if (get_timeout_active(pgfdw_health_check_timeout))
+	{
+		if (newval == 0)
+			disable_timeout(pgfdw_health_check_timeout, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in pgfdw_connection_check().
+		 */
+		return;
+	}
+
+	/* Start timeout if wants to */
+	if (newval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout, newval);
+}
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index 2c6b2894b9..75a910b0ff 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -538,5 +538,18 @@ _PG_init(void)
 							   NULL,
 							   NULL);
 
+	DefineCustomIntVariable("postgres_fdw.health_check_interval",
+							"Sets the time interval between checks of remote servers.",
+							NULL,
+							&pgfdw_health_check_interval,
+							0,
+							0,
+							INT_MAX,
+							PGC_USERSET,
+							GUC_UNIT_MS,
+							check_pgfdw_health_check_interval,
+							assign_pgfdw_health_check_interval,
+							NULL);
+
 	MarkGUCPrefixReserved("postgres_fdw");
 }
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 8ae79e97e4..c129af5082 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -18,6 +18,7 @@
 #include "libpq-fe.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
+#include "utils/guc.h"
 #include "utils/relcache.h"
 
 /*
@@ -151,6 +152,10 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern bool check_pgfdw_health_check_interval(int *newval, void **extra,
+											  GucSource source);
+extern void assign_pgfdw_health_check_interval(int newval, void *extra);
+extern int pgfdw_health_check_interval;
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,


v12_0003_add_doc.patch (application/octet-stream, 1.4K) download
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index dc57fe4b0d..21532e19d9 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1028,6 +1028,32 @@ postgres=# SELECT postgres_fdw_disconnect_all();
 
     </listitem>
    </varlistentry>
+   <varlistentry id="guc-pgfdw-health-check-interval" xreflabel="postgres_fdw.health_check_interval">
+    <term>
+     <varname>postgres_fdw.health_check_interval</varname> (<type>integer</type>)
+     <indexterm>
+      <primary><varname>postgres_fdw.health_check_interval</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the time interval between optional checks that remote servers
+      are still alive. When losing a remote connection is detected,
+      the running transaction is aborted. This feature is performed
+      by polling the socket.
+     </para>
+     <para>
+      this option relies on kernel events exposed by Linux, macOS,
+      illumos and the BSD family of operating systems, and is not currently available 
+      on other systems.
+     </para>
+     <para>
+      If the value is specified without units, it is taken as milliseconds.
+      The default value is <literal>0</literal>, which disables connection
+      checks.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </sect2>
 


  v12_0004_add_test.zip (application/x-zip-compressed, 855B) download

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-02-22 07:52                                             ` Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Fujii Masao @ 2022-02-22 07:52 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>



On 2022/02/22 15:41, kuroda.hayato@fujitsu.com wrote:
> Cfbot is still angry because of missing PGDLLIMPORT, so attached.

Thanks for updating the patches!

The connection check timer is re-scheduled repeatedly even while the backend is in idle state or is running a local transaction that doesn't access to any foreign servers. I'm not sure if it's really worth checking the connections even in those states. Even without the periodic connection checks, if the connections are closed in those states, subsequent GetConnection() will detect that closed connection and re-establish the connection when starting remote transaction. Thought?


When a closed connection is detected in idle-in-transaction state and SIGINT is raised, nothing happens because there is no query running to be canceled by SIGINT. Also in this case the connection check timer gets disabled. So we can still execute queries that don't access to foreign servers, in the same transaction, and then the transaction commit fails. Is this expected behavior?


When I shutdowned the foreign server while the local backend is in idle-in-transaction state, the connection check timer was triggered and detected the closed connection. Then when I executed COMMIT command, I got the following WARNING message. Is this a bug?

     WARNING:  leaked hash_seq_search scan for hash table 0x7fd2ca878f20

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-02-24 02:34                                               ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-02-24 02:34 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>

Dear Fujii-san,

Thank you for your quick reviewing! I attached new version.
I found previous patches have wrong name. Sorry.

> The connection check timer is re-scheduled repeatedly even while the backend is
> in idle state or is running a local transaction that doesn't access to any foreign
> servers. I'm not sure if it's really worth checking the connections even in those
> states. Even without the periodic connection checks, if the connections are closed
> in those states, subsequent GetConnection() will detect that closed connection
> and re-establish the connection when starting remote transaction. Thought?

Indeed. We can now control the timer in fdw layer, so disable_timeout() was added
at the bottom of pgfdw_xact_callback(). 

> When a closed connection is detected in idle-in-transaction state and SIGINT is
> raised, nothing happens because there is no query running to be canceled by
> SIGINT. Also in this case the connection check timer gets disabled. So we can still
> execute queries that don't access to foreign servers, in the same transaction, and
> then the transaction commit fails. Is this expected behavior?

It's not happy, but I'm not sure about a good solution. I made a timer reschedule
if connection lost had detected. But if queries in the transaction are quite short,
catching SIGINT may be fail.

> When I shutdowned the foreign server while the local backend is in
> idle-in-transaction state, the connection check timer was triggered and detected
> the closed connection. Then when I executed COMMIT command, I got the
> following WARNING message. Is this a bug?
> 
>      WARNING:  leaked hash_seq_search scan for hash table 0x7fd2ca878f20

Fixed. It is caused because hash_seq_term() was not called when checker detects
a connection lost.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (4 files, .tar.gz)

v13_0001_expose_cancel_message.patch (application/octet-stream, 1.5K) download
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 3c7d08209f..206f7e1d59 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -106,6 +106,8 @@ int			PostAuthDelay = 0;
 /* Time between checks that the client is still connected. */
 int			client_connection_check_interval = 0;
 
+char 		*QeuryCancelMessage = NULL;
+
 /* ----------------
  *		private typedefs etc
  * ----------------
@@ -3327,6 +3329,8 @@ ProcessInterrupts(void)
 			LockErrorCleanup();
 			ereport(ERROR,
 					(errcode(ERRCODE_QUERY_CANCELED),
+					 QeuryCancelMessage ?
+					 errmsg("%s", QeuryCancelMessage) :
 					 errmsg("canceling statement due to user request")));
 		}
 	}
@@ -4248,6 +4252,9 @@ PostgresMain(const char *dbname, const char *username)
 		/* Report the error to the client and/or server log */
 		EmitErrorReport();
 
+		/* Make sure QeuryCancelMessage is reset. */
+		QeuryCancelMessage = NULL;
+
 		/*
 		 * Make sure debug_query_string gets reset before we possibly clobber
 		 * the storage it points at.
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 15a11bc3ff..83f894cbd0 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -30,6 +30,7 @@ extern PGDLLIMPORT const char *debug_query_string;
 extern int	max_stack_depth;
 extern int	PostAuthDelay;
 extern int	client_connection_check_interval;
+extern PGDLLIMPORT char* QeuryCancelMessage;
 
 /* GUC-configurable parameters */
 


v13_0002_add_health_check.patch (application/octet-stream, 7.1K) download
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index f753c6e232..f691b482a1 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -23,12 +23,14 @@
 #include "postgres_fdw.h"
 #include "storage/fd.h"
 #include "storage/latch.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/datetime.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
 /*
  * Connection cache hash table entry
@@ -109,6 +111,10 @@ static void pgfdw_abort_cleanup(ConnCacheEntry *entry, const char *sql,
 								bool toplevel);
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
+static void pgfdw_connection_check(void);
+static bool pgfdw_connection_check_internal(PGconn *conn);
+static TimeoutId pgfdw_health_check_timeout = MAX_TIMEOUTS;
+int pgfdw_health_check_interval;
 
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
@@ -153,6 +159,9 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a timeout for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT, pgfdw_connection_check);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -276,6 +285,12 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (state)
 		*state = &entry->state;
 
+	/* Fire timeout if needed */
+	if (pgfdw_health_check_interval > 0 &&
+		!get_timeout_active(pgfdw_health_check_timeout))
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
 	return entry->conn;
 }
 
@@ -1007,6 +1022,9 @@ pgfdw_xact_callback(XactEvent event, void *arg)
 	 */
 	xact_got_connection = false;
 
+	/* stop timer because checking is no more needed. */
+	disable_timeout(pgfdw_health_check_timeout, false);
+
 	/* Also reset cursor numbering for next transaction */
 	cursor_number = 0;
 }
@@ -1702,3 +1720,139 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Signal handler for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+void
+pgfdw_connection_check(void)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+
+	Assert(ConnectionHash);
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	/* Is there any cancel messages? If so, raise again and re-schedule */
+	if (QeuryCancelMessage != NULL)
+	{
+		raise(SIGINT);
+		if (pgfdw_health_check_interval > 0)
+			enable_timeout_after(pgfdw_health_check_timeout,
+								 pgfdw_health_check_interval);
+		return;
+	}
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			/*
+			 * Foreign server might be down, so raise SIGINT.
+			 * Note that error message is passed to QeuryCancelMessage
+			 * for reporting error in ProcessInterrupts().
+			 */
+			char msg[31 + MAXDATELEN];
+			MemoryContext old;
+			ForeignServer *server;
+
+			/*
+			 * Switch to CurTransactionContext in order to
+			 * make sure that the lifetime of palloc'd is transaction.
+			 */
+			old = MemoryContextSwitchTo(CurTransactionContext);
+			server = GetForeignServer(entry->serverid);
+			snprintf(msg, sizeof(msg), "Foreign Server %s might be down.", server->servername);
+			QeuryCancelMessage = pstrdup(msg);
+			MemoryContextSwitchTo(old);
+
+			disconnect_pg_server(entry);
+			hash_seq_term(&scan);
+
+			raise(SIGINT);
+			break;
+		}
+	}
+
+	/* re-schedule timer if needed. */
+	if (pgfdw_health_check_interval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
+	return;
+}
+
+/*
+ * helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
+
+bool
+check_pgfdw_health_check_interval(int *newval, void **extra, GucSource source)
+{
+	if (!WaitEventSetCanReportClosed() && *newval != 0)
+	{
+		GUC_check_errdetail("pgfdw_health_check_interval must be set to 0 on this platform");
+		return false;
+	}
+	return true;
+}
+
+void
+assign_pgfdw_health_check_interval(int newval, void *extra)
+{
+	/* Quick return if timeout is not registered yet. */
+	if (pgfdw_health_check_timeout == MAX_TIMEOUTS)
+		return;
+
+	if (get_timeout_active(pgfdw_health_check_timeout))
+	{
+		if (newval == 0)
+			disable_timeout(pgfdw_health_check_timeout, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in pgfdw_connection_check().
+		 */
+		return;
+	}
+
+	/* Start timeout if wants to */
+	if (newval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout, newval);
+}
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index 2c6b2894b9..75a910b0ff 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -538,5 +538,18 @@ _PG_init(void)
 							   NULL,
 							   NULL);
 
+	DefineCustomIntVariable("postgres_fdw.health_check_interval",
+							"Sets the time interval between checks of remote servers.",
+							NULL,
+							&pgfdw_health_check_interval,
+							0,
+							0,
+							INT_MAX,
+							PGC_USERSET,
+							GUC_UNIT_MS,
+							check_pgfdw_health_check_interval,
+							assign_pgfdw_health_check_interval,
+							NULL);
+
 	MarkGUCPrefixReserved("postgres_fdw");
 }
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 8ae79e97e4..c129af5082 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -18,6 +18,7 @@
 #include "libpq-fe.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
+#include "utils/guc.h"
 #include "utils/relcache.h"
 
 /*
@@ -151,6 +152,10 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern bool check_pgfdw_health_check_interval(int *newval, void **extra,
+											  GucSource source);
+extern void assign_pgfdw_health_check_interval(int newval, void *extra);
+extern int pgfdw_health_check_interval;
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,


v13_0003_add_doc.patch (application/octet-stream, 1.4K) download
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index dc57fe4b0d..21532e19d9 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1028,6 +1028,32 @@ postgres=# SELECT postgres_fdw_disconnect_all();
 
     </listitem>
    </varlistentry>
+   <varlistentry id="guc-pgfdw-health-check-interval" xreflabel="postgres_fdw.health_check_interval">
+    <term>
+     <varname>postgres_fdw.health_check_interval</varname> (<type>integer</type>)
+     <indexterm>
+      <primary><varname>postgres_fdw.health_check_interval</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the time interval between optional checks that remote servers
+      are still alive. When losing a remote connection is detected,
+      the running transaction is aborted. This feature is performed
+      by polling the socket.
+     </para>
+     <para>
+      this option relies on kernel events exposed by Linux, macOS,
+      illumos and the BSD family of operating systems, and is not currently available 
+      on other systems.
+     </para>
+     <para>
+      If the value is specified without units, it is taken as milliseconds.
+      The default value is <literal>0</literal>, which disables connection
+      checks.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </sect2>
 


  v13_0004_add_test.zip (application/x-zip-compressed, 855B) download

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-03-04 06:17                                                 ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-03-04 06:17 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>

Hi Hackers,

> It's not happy, but I'm not sure about a good solution. I made a timer reschedule
> if connection lost had detected. But if queries in the transaction are quite short,
> catching SIGINT may be fail.

Attached uses another way: sets pending flags again if DoingCommandRead is true.
If a remote server goes down while it is in idle_in_transaction,
next query will fail because of ereport(ERROR).

How do you think?

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (4 files, .tar.gz)

v14_0001_expose_cancel_message.patch (application/octet-stream, 1.8K) download
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 34c13a1113..47c72def5b 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -105,6 +105,8 @@ int			PostAuthDelay = 0;
 /* Time between checks that the client is still connected. */
 int			client_connection_check_interval = 0;
 
+char 		*QueryCancelMessage = NULL;
+
 /* ----------------
  *		private typedefs etc
  * ----------------
@@ -3326,8 +3328,20 @@ ProcessInterrupts(void)
 			LockErrorCleanup();
 			ereport(ERROR,
 					(errcode(ERRCODE_QUERY_CANCELED),
+					 QueryCancelMessage ?
+					 errmsg("%s", QueryCancelMessage) :
 					 errmsg("canceling statement due to user request")));
 		}
+		else if (QueryCancelMessage != NULL)
+		{
+			/*
+			 * If we reach here someone wanted to cancel query but it was skepped
+			 * because connection status was idle. So re-arm Pending flags
+			 * for next iteration.
+			 */
+			InterruptPending = true;
+			QueryCancelPending = true;
+		}
 	}
 
 	if (IdleInTransactionSessionTimeoutPending)
@@ -4247,6 +4261,9 @@ PostgresMain(const char *dbname, const char *username)
 		/* Report the error to the client and/or server log */
 		EmitErrorReport();
 
+		/* Make sure QueryCancelMessage is reset. */
+		QueryCancelMessage = NULL;
+
 		/*
 		 * Make sure debug_query_string gets reset before we possibly clobber
 		 * the storage it points at.
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 15a11bc3ff..51f91be14b 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -30,6 +30,7 @@ extern PGDLLIMPORT const char *debug_query_string;
 extern int	max_stack_depth;
 extern int	PostAuthDelay;
 extern int	client_connection_check_interval;
+extern PGDLLIMPORT char* QueryCancelMessage;
 
 /* GUC-configurable parameters */
 


v14_0002_add_health_check.patch (application/octet-stream, 7.0K) download
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8c64d42dda..cc9aeab799 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -23,12 +23,14 @@
 #include "postgres_fdw.h"
 #include "storage/fd.h"
 #include "storage/latch.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/datetime.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
 /*
  * Connection cache hash table entry
@@ -117,6 +119,10 @@ static void pgfdw_finish_pre_subcommit_cleanup(List *pending_entries,
 											   int curlevel);
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
+static void pgfdw_connection_check(void);
+static bool pgfdw_connection_check_internal(PGconn *conn);
+static TimeoutId pgfdw_health_check_timeout = MAX_TIMEOUTS;
+int pgfdw_health_check_interval;
 
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
@@ -161,6 +167,9 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a timeout for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT, pgfdw_connection_check);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -284,6 +293,12 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (state)
 		*state = &entry->state;
 
+	/* Fire timeout if needed */
+	if (pgfdw_health_check_interval > 0 &&
+		!get_timeout_active(pgfdw_health_check_timeout))
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
 	return entry->conn;
 }
 
@@ -1040,6 +1055,9 @@ pgfdw_xact_callback(XactEvent event, void *arg)
 	 */
 	xact_got_connection = false;
 
+	/* stop timer because checking is no more needed. */
+	disable_timeout(pgfdw_health_check_timeout, false);
+
 	/* Also reset cursor numbering for next transaction */
 	cursor_number = 0;
 }
@@ -1889,3 +1907,133 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Signal handler for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+void
+pgfdw_connection_check(void)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+
+	Assert(ConnectionHash);
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	/* Quick exit if QueryCancelMessage has already set. */
+	if (QueryCancelMessage != NULL)
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			/*
+			 * Foreign server might be down, so raise SIGINT.
+			 * Note that error message is passed to QueryCancelMessage
+			 * for reporting error in ProcessInterrupts().
+			 */
+			char msg[31 + MAXDATELEN];
+			MemoryContext old;
+			ForeignServer *server;
+
+			/*
+			 * Switch to CurTransactionContext in order to
+			 * make sure that the lifetime of palloc'd is transaction.
+			 */
+			old = MemoryContextSwitchTo(CurTransactionContext);
+			server = GetForeignServer(entry->serverid);
+			snprintf(msg, sizeof(msg), "Foreign Server %s might be down.", server->servername);
+			QueryCancelMessage = pstrdup(msg);
+			MemoryContextSwitchTo(old);
+
+			disconnect_pg_server(entry);
+			hash_seq_term(&scan);
+
+			raise(SIGINT);
+			break;
+		}
+	}
+
+	/* re-schedule timer if needed. */
+	if (pgfdw_health_check_interval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
+	return;
+}
+
+/*
+ * helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
+
+bool
+check_pgfdw_health_check_interval(int *newval, void **extra, GucSource source)
+{
+	if (!WaitEventSetCanReportClosed() && *newval != 0)
+	{
+		GUC_check_errdetail("pgfdw_health_check_interval must be set to 0 on this platform");
+		return false;
+	}
+	return true;
+}
+
+void
+assign_pgfdw_health_check_interval(int newval, void *extra)
+{
+	/* Quick return if timeout is not registered yet. */
+	if (pgfdw_health_check_timeout == MAX_TIMEOUTS)
+		return;
+
+	if (get_timeout_active(pgfdw_health_check_timeout))
+	{
+		if (newval == 0)
+			disable_timeout(pgfdw_health_check_timeout, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in pgfdw_connection_check().
+		 */
+		return;
+	}
+
+	/* Start timeout if wants to */
+	if (newval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout, newval);
+}
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index 572591a558..496a27960c 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -540,5 +540,18 @@ _PG_init(void)
 							   NULL,
 							   NULL);
 
+	DefineCustomIntVariable("postgres_fdw.health_check_interval",
+							"Sets the time interval between checks of remote servers.",
+							NULL,
+							&pgfdw_health_check_interval,
+							0,
+							0,
+							INT_MAX,
+							PGC_USERSET,
+							GUC_UNIT_MS,
+							check_pgfdw_health_check_interval,
+							assign_pgfdw_health_check_interval,
+							NULL);
+
 	MarkGUCPrefixReserved("postgres_fdw");
 }
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 8ae79e97e4..c129af5082 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -18,6 +18,7 @@
 #include "libpq-fe.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
+#include "utils/guc.h"
 #include "utils/relcache.h"
 
 /*
@@ -151,6 +152,10 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern bool check_pgfdw_health_check_interval(int *newval, void **extra,
+											  GucSource source);
+extern void assign_pgfdw_health_check_interval(int newval, void *extra);
+extern int pgfdw_health_check_interval;
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,


v14_0003_add_doc.patch (application/octet-stream, 1.4K) download
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index 8ebf0dc3a0..992f093992 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1074,6 +1074,32 @@ postgres=# SELECT postgres_fdw_disconnect_all();
 
     </listitem>
    </varlistentry>
+   <varlistentry id="guc-pgfdw-health-check-interval" xreflabel="postgres_fdw.health_check_interval">
+    <term>
+     <varname>postgres_fdw.health_check_interval</varname> (<type>integer</type>)
+     <indexterm>
+      <primary><varname>postgres_fdw.health_check_interval</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the time interval between optional checks that remote servers
+      are still alive. When losing a remote connection is detected,
+      the running transaction is aborted. This feature is performed
+      by polling the socket.
+     </para>
+     <para>
+      this option relies on kernel events exposed by Linux, macOS,
+      illumos and the BSD family of operating systems, and is not currently available 
+      on other systems.
+     </para>
+     <para>
+      If the value is specified without units, it is taken as milliseconds.
+      The default value is <literal>0</literal>, which disables connection
+      checks.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </sect2>
 


  v14_0004_add_test.zip (application/x-zip-compressed, 843B) download

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-09-18 03:39                                                   ` Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Fujii Masao @ 2022-09-18 03:39 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>



On 2022/03/04 15:17, kuroda.hayato@fujitsu.com wrote:
> Hi Hackers,
> 
>> It's not happy, but I'm not sure about a good solution. I made a timer reschedule
>> if connection lost had detected. But if queries in the transaction are quite short,
>> catching SIGINT may be fail.
> 
> Attached uses another way: sets pending flags again if DoingCommandRead is true.
> If a remote server goes down while it is in idle_in_transaction,
> next query will fail because of ereport(ERROR).
> 
> How do you think?

Sounds ok to me.

Thanks for updating the patches!

These failed to be applied to the master branch cleanly. Could you update them?

+      this option relies on kernel events exposed by Linux, macOS,

s/this/This

+		GUC_check_errdetail("pgfdw_health_check_interval must be set to 0 on this platform");

The actual parameter name "postgres_fdw.health_check_interval"
should be used for the message instead of internal variable name.

+		/* Register a timeout for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT, pgfdw_connection_check);

This registered signal handler does lots of things. But that's not acceptable
and they should be performed outside signal handler. No?

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2022-09-21 11:56                                                     ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-02 15:39                                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Andres Freund <andres@anarazel.de>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-09-21 11:56 UTC (permalink / raw)
  To: Fujii Masao <masao.fujii@oss.nttdata.com>; +Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Dear Fujii-san,

Thanks for checking!

> These failed to be applied to the master branch cleanly. Could you update them?

PSA rebased patches. I reviewed my myself and they contain changes.
E.g., move GUC-related code to option.c.


> +      this option relies on kernel events exposed by Linux, macOS,
> 
> s/this/This

Fixed.

> 
> +		GUC_check_errdetail("pgfdw_health_check_interval must be set
> to 0 on this platform");
> 
> The actual parameter name "postgres_fdw.health_check_interval"
> should be used for the message instead of internal variable name.

Fixed.

> This registered signal handler does lots of things. But that's not acceptable
> and they should be performed outside signal handler. No?


I modified like v09 or earlier versions, which has a mechanism for registering CheckingRemoteServersCallback.
It had been removed because we want to keep core simpler, but IIUC it is needed
if the signal handler just sets some flags.
The core-side does not consider the current status of transaction and running query for simpleness.


Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (4 files, .tar.gz)

v15-0001-Add-an-infrastracture-for-checking-remote-server.patch (application/octet-stream, 7.9K) download
From adca9c34d807d37b3226ea83800f0d6187586b73 Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:02:45 +0000
Subject: [PATCH v15 1/4] Add an infrastracture for checking remote servers

This patch adds a mechanism for registering callback functions.
They should be used for checking health of remote servers.

These functions will be called when an added flag is set to true.
The flag is expected that it is set from signal handlers, which is registered by FDWs.
Inside the function a signal SIGINT should be raised and a message should be set to QueryCancelMessage
if one of remote servers is disconnected.

When a query is canceled and a string is set to QueryCancelMessage,
the server will output the given message to the log instead of the normal message.

Note that QueryCancelMessage will be never pfree()'d.
Developers must use appropriate memory context.
---
 src/backend/foreign/foreign.c    | 57 ++++++++++++++++++++++++++++++++
 src/backend/tcop/postgres.c      | 26 +++++++++++++++
 src/backend/utils/init/globals.c |  1 +
 src/include/foreign/foreign.h    | 19 +++++++++++
 src/include/miscadmin.h          |  2 ++
 src/include/tcop/tcopprot.h      |  1 +
 6 files changed, 106 insertions(+)

diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 353e20a0cf..fbc943bea9 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -28,7 +28,9 @@
 #include "utils/rel.h"
 #include "utils/syscache.h"
 #include "utils/varlena.h"
+#include "utils/timeout.h"
 
+static CheckingRemoteServersCallbackItem *remote_check_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -810,3 +812,58 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext,
+			sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = remote_check_callbacks;
+	remote_check_callbacks = item;
+}
+
+void
+UnRegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+										void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	CheckingRemoteServersCallbackItem *prev;
+
+	prev = NULL;
+	for (item = remote_check_callbacks; item; prev = item, item = item->next)
+	{
+			if (item->callback == callback && item->arg == arg)
+			{
+					if (prev)
+							prev->next = item->next;
+					else
+							remote_check_callbacks = item->next;
+					pfree(item);
+					break;
+			}
+	}
+}
+
+/*
+ * Call callbacks for checking remote servers.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	for (item = remote_check_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 35eff28bd3..772a388a87 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -35,6 +35,7 @@
 #include "commands/async.h"
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -98,6 +99,9 @@ int			PostAuthDelay = 0;
 /* Time between checks that the client is still connected. */
 int			client_connection_check_interval = 0;
 
+/* Message string for canceling qurery caused by extensions */
+char		*QueryCancelMessage = NULL;
+
 /* ----------------
  *		private typedefs etc
  * ----------------
@@ -3224,6 +3228,13 @@ ProcessInterrupts(void)
 				 errmsg("connection to client lost")));
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		CheckingRemoteServersTimeoutPending = false;
+
+		CallCheckingRemoteServersCallbacks();
+	}
+
 	/*
 	 * If a recovery conflict happens while we are waiting for input from the
 	 * client, the client is presumably just sitting idle in a transaction,
@@ -3328,8 +3339,20 @@ ProcessInterrupts(void)
 			LockErrorCleanup();
 			ereport(ERROR,
 					(errcode(ERRCODE_QUERY_CANCELED),
+					 QueryCancelMessage ?
+					 errmsg("%s", QueryCancelMessage) :
 					 errmsg("canceling statement due to user request")));
 		}
+		else if (QueryCancelMessage != NULL)
+		{
+			/*
+			 * If we reach here someone wanted to cancel query but it was skepped
+			 * because connection status was idle. So re-arm Pending flags
+			 * for next iteration.
+			 */
+			InterruptPending = true;
+			QueryCancelPending = true;
+		}
 	}
 
 	if (IdleInTransactionSessionTimeoutPending)
@@ -4264,6 +4287,9 @@ PostgresMain(const char *dbname, const char *username)
 		/* Report the error to the client and/or server log */
 		EmitErrorReport();
 
+		/* Make sure QueryCancelMessage is reset. */
+		QueryCancelMessage = NULL;
+
 		/*
 		 * Make sure debug_query_string gets reset before we possibly clobber
 		 * the storage it points at.
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 1a5d29ac9b..bb94adfea8 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -37,6 +37,7 @@ volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
 volatile sig_atomic_t IdleStatsUpdateTimeoutPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index ac82125530..9859513ac6 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -82,4 +82,23 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* Functions and variables for fdw checking */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+
+typedef struct CheckingRemoteServersCallbackItem CheckingRemoteServersCallbackItem;
+
+struct CheckingRemoteServersCallbackItem
+{
+	CheckingRemoteServersCallbackItem	*next;
+	CheckingRemoteServersCallback		callback;
+	void								*arg;
+};
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+												  void *arg);
+extern void UnRegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+													void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index ee48e392ed..95b7d66ce3 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -99,6 +99,8 @@ extern PGDLLIMPORT volatile sig_atomic_t IdleStatsUpdateTimeoutPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 5d34978f32..3a8e8c5a19 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -30,6 +30,7 @@ extern PGDLLIMPORT const char *debug_query_string;
 extern PGDLLIMPORT int max_stack_depth;
 extern PGDLLIMPORT int PostAuthDelay;
 extern PGDLLIMPORT int client_connection_check_interval;
+extern PGDLLIMPORT char* QueryCancelMessage;
 
 /* GUC-configurable parameters */
 
-- 
2.27.0



v15-0002-postgres_fdw-Implement-health-check-feature.patch (application/octet-stream, 9.5K) download
From 87a482835635070347cc1c3fdf6847a4a54e5b55 Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:30:56 +0000
Subject: [PATCH v15 2/4] postgres_fdw: Implement health check feature

This patch adds a new GUC parameter postgres_fdw.health_check_interval.
This defines a time interval between checking remote servers.

In the checking function we use a socket event WL_SOCKET_CLOSED.
---
 contrib/postgres_fdw/connection.c   | 130 ++++++++++++++++++++++++++++
 contrib/postgres_fdw/option.c       |  63 ++++++++++++++
 contrib/postgres_fdw/postgres_fdw.h |   3 +
 3 files changed, 196 insertions(+)

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 939d114f02..64ec57b54e 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -23,12 +23,14 @@
 #include "postgres_fdw.h"
 #include "storage/fd.h"
 #include "storage/latch.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/datetime.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
 /*
  * Connection cache hash table entry
@@ -80,6 +82,9 @@ static unsigned int prep_stmt_number = 0;
 /* tracks whether any work is needed in callback functions */
 static bool xact_got_connection = false;
 
+/* Timeout identifier for health check  */
+TimeoutId pgfdw_health_check_timeout = MAX_TIMEOUTS;
+
 /*
  * SQL functions
  */
@@ -117,6 +122,11 @@ static void pgfdw_finish_pre_subcommit_cleanup(List *pending_entries,
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
 
+/* Functions for checking remote servers */
+static void pgfdw_connection_check(void *arg);
+static bool pgfdw_connection_check_internal(PGconn *conn);
+static void pgfdw_checking_remote_servers_timeout_handler(void);
+
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
  * server with the user's authorization.  A new connection is established
@@ -160,6 +170,11 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a timeout and a callback for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT,
+													 pgfdw_checking_remote_servers_timeout_handler);
+		RegisterCheckingRemoteServersCallback(pgfdw_connection_check, NULL);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -283,6 +298,12 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (state)
 		*state = &entry->state;
 
+	/* Start health-check timer if needed */
+	if (pgfdw_health_check_interval > 0 &&
+		!get_timeout_active(pgfdw_health_check_timeout))
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
 	return entry->conn;
 }
 
@@ -1040,6 +1061,9 @@ pgfdw_xact_callback(XactEvent event, void *arg)
 	 */
 	xact_got_connection = false;
 
+	/* Stop timer because checking is no more needed. */
+	disable_timeout(pgfdw_health_check_timeout, false);
+
 	/* Also reset cursor numbering for next transaction */
 	cursor_number = 0;
 }
@@ -1862,3 +1886,109 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Signal handler for calling callbacks
+ */
+static void
+pgfdw_checking_remote_servers_timeout_handler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
+/*
+ * Function for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+static void
+pgfdw_connection_check(void *arg)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+
+	Assert(ConnectionHash);
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	/* Quick exit if QueryCancelMessage has already set. */
+	if (QueryCancelMessage != NULL)
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			/*
+			 * Foreign server might be down, so raise SIGINT.
+			 * Note that error message is passed to QueryCancelMessage
+			 * for reporting error in ProcessInterrupts().
+			 */
+			char msg[31 + MAXDATELEN];
+			MemoryContext old;
+			ForeignServer *server;
+
+			/*
+			 * Switch to CurTransactionContext in order to
+			 * make sure that the lifetime of palloc'd is transaction.
+			 */
+			old = MemoryContextSwitchTo(CurTransactionContext);
+			server = GetForeignServer(entry->serverid);
+			snprintf(msg, sizeof(msg), "Foreign Server %s might be down.", server->servername);
+			QueryCancelMessage = pstrdup(msg);
+			MemoryContextSwitchTo(old);
+
+			disconnect_pg_server(entry);
+			hash_seq_term(&scan);
+
+			raise(SIGINT);
+			break;
+		}
+	}
+
+	/* re-schedule timer if needed. */
+	if (pgfdw_health_check_interval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
+	return;
+}
+
+/*
+ * Helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
+	AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+	FreeWaitEventSet(eventset);
+
+	return true;
+}
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index fa80ee2a55..9cd5a32e77 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -20,6 +20,7 @@
 #include "commands/extension.h"
 #include "libpq/libpq-be.h"
 #include "postgres_fdw.h"
+#include "storage/latch.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
 #include "utils/varlena.h"
@@ -50,6 +51,7 @@ static PQconninfoOption *libpq_options;
  * GUC parameters
  */
 char	   *pgfdw_application_name = NULL;
+int			pgfdw_health_check_interval;
 
 /*
  * Helper functions
@@ -58,6 +60,13 @@ static void InitPgFdwOptions(void);
 static bool is_valid_option(const char *keyword, Oid context);
 static bool is_libpq_option(const char *keyword);
 
+/*
+ * GUC hooks
+ */
+static bool check_pgfdw_health_check_interval(int *newval, void **extra,
+											  GucSource source);
+static void assign_pgfdw_health_check_interval(int newval, void *extra);
+
 #include "miscadmin.h"
 
 /*
@@ -518,6 +527,47 @@ process_pgfdw_appname(const char *appname)
 	return buf.data;
 }
 
+/*
+ * Check hook for pgfdw_health_check_interval
+ */
+static bool
+check_pgfdw_health_check_interval(int *newval, void **extra, GucSource source)
+{
+	if (!WaitEventSetCanReportClosed() && *newval != 0)
+	{
+		GUC_check_errdetail("postgres_fdw.health_check_interval must be set to 0 on this platform");
+		return false;
+	}
+	return true;
+}
+
+/*
+ * Assign hook for pgfdw_health_check_interval
+ */
+static void
+assign_pgfdw_health_check_interval(int newval, void *extra)
+{
+	/* Quick return if timeout is not registered yet. */
+	if (pgfdw_health_check_timeout == MAX_TIMEOUTS)
+		return;
+
+	if (get_timeout_active(pgfdw_health_check_timeout))
+	{
+		if (newval == 0)
+			disable_timeout(pgfdw_health_check_timeout, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in pgfdw_connection_check().
+		 */
+		return;
+	}
+
+	/* Start timeout if wants to */
+	if (newval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout, newval);
+}
+
 /*
  * Module load callback
  */
@@ -543,5 +593,18 @@ _PG_init(void)
 							   NULL,
 							   NULL);
 
+	DefineCustomIntVariable("postgres_fdw.health_check_interval",
+							"Sets the time interval between checks of remote servers.",
+							NULL,
+							&pgfdw_health_check_interval,
+							0,
+							0,
+							INT_MAX,
+							PGC_USERSET,
+							GUC_UNIT_MS,
+							check_pgfdw_health_check_interval,
+							assign_pgfdw_health_check_interval,
+							NULL);
+
 	MarkGUCPrefixReserved("postgres_fdw");
 }
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index 21f2b20ce8..6b13544903 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -18,6 +18,7 @@
 #include "libpq-fe.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
+#include "utils/timeout.h"
 #include "utils/relcache.h"
 
 /*
@@ -151,6 +152,7 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern TimeoutId pgfdw_health_check_timeout;
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,
@@ -160,6 +162,7 @@ extern List *ExtractExtensionList(const char *extensionsString,
 								  bool warnOnMissing);
 extern char *process_pgfdw_appname(const char *appname);
 extern char *pgfdw_application_name;
+extern int	pgfdw_health_check_interval;
 
 /* in deparse.c */
 extern void classifyConditions(PlannerInfo *root,
-- 
2.27.0



v15-0003-add-doc.patch (application/octet-stream, 1.8K) download
From 4ffb4293db58cdc30af7962db22d95df40331d42 Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:47:55 +0000
Subject: [PATCH v15 3/4] add doc

This patch adds descriptions about postgres_fdw.health_check_interval
---
 doc/src/sgml/postgres-fdw.sgml | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index bfd344cdc0..44e4f07dd9 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1078,6 +1078,32 @@ postgres=# SELECT postgres_fdw_disconnect_all();
 
     </listitem>
    </varlistentry>
+   <varlistentry id="guc-pgfdw-health-check-interval" xreflabel="postgres_fdw.health_check_interval">
+    <term>
+     <varname>postgres_fdw.health_check_interval</varname> (<type>integer</type>)
+     <indexterm>
+      <primary><varname>postgres_fdw.health_check_interval</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the time interval between optional checks that remote servers
+      are still alive. When losing a remote connection is detected,
+      the running transaction is aborted. This feature is performed
+      by polling the socket.
+     </para>
+     <para>
+      This option relies on kernel events exposed by Linux, macOS,
+      illumos and the BSD family of operating systems, and is not currently available
+      on other systems.
+     </para>
+     <para>
+      If the value is specified without units, it is taken as milliseconds.
+      The default value is <literal>0</literal>, which disables connection
+      checks.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </sect2>
 
-- 
2.27.0



v15-0004-add-test.patch (application/octet-stream, 3.1K) download
From 5572c8468059a10dac58e74f7961528ab68f1013 Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:52:23 +0000
Subject: [PATCH v15 4/4] add test

---
 .../postgres_fdw/expected/postgres_fdw.out    | 36 +++++++++++++++++++
 contrib/postgres_fdw/sql/postgres_fdw.sql     | 26 ++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 2e4e82a94f..476e4966cc 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -11463,3 +11463,39 @@ SELECT * FROM prem2;
 
 ALTER SERVER loopback OPTIONS (DROP parallel_commit);
 ALTER SERVER loopback2 OPTIONS (DROP parallel_commit);
+-- ===================================================================
+-- test for health-check feature
+-- ===================================================================
+-- Disable debug_discard_caches in order to manage remote connections
+SET debug_discard_caches TO '0';
+-- Disconnect once and set application_name to an arbitrary value
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ ?column? 
+----------
+        1
+(1 row)
+
+ALTER SERVER loopback OPTIONS (SET application_name 'healthcheck');
+-- Set GUC for checking the health of remote servers
+SET postgres_fdw.health_check_interval TO '1s';
+BEGIN;
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- Terminate the remote backend process
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+       WHERE application_name = 'healthcheck';
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+-- While sleeping the process down will be detected.
+SELECT pg_sleep(3);
+ERROR:  Foreign Server loopback might be down.
+COMMIT;
+-- Clean up
+RESET debug_discard_caches;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index e48ccd286b..1e1f30fc6c 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -3682,3 +3682,29 @@ SELECT * FROM prem2;
 
 ALTER SERVER loopback OPTIONS (DROP parallel_commit);
 ALTER SERVER loopback2 OPTIONS (DROP parallel_commit);
+
+-- ===================================================================
+-- test for health-check feature
+-- ===================================================================
+
+-- Disable debug_discard_caches in order to manage remote connections
+SET debug_discard_caches TO '0';
+
+-- Disconnect once and set application_name to an arbitrary value
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ALTER SERVER loopback OPTIONS (SET application_name 'healthcheck');
+
+-- Set GUC for checking the health of remote servers
+SET postgres_fdw.health_check_interval TO '1s';
+
+BEGIN;
+SELECT 1 FROM ft1 LIMIT 1;
+-- Terminate the remote backend process
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+       WHERE application_name = 'healthcheck';
+-- While sleeping the process down will be detected.
+SELECT pg_sleep(3);
+COMMIT;
+
+-- Clean up
+RESET debug_discard_caches;
-- 
2.27.0



^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-10-02 15:39                                                       ` Andres Freund <andres@anarazel.de>
  2022-10-03 07:50                                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Andres Freund @ 2022-10-02 15:39 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; +Cc: Fujii Masao <masao.fujii@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Hi,

On 2022-09-21 11:56:56 +0000, kuroda.hayato@fujitsu.com wrote:
> PSA rebased patches. I reviewed my myself and they contain changes.
> E.g., move GUC-related code to option.c.

This seems to reliably fail on windows. See
https://cirrus-ci.com/task/6454408568373248
https://cirrus-ci.com/github/postgresql-cfbot/postgresql/commitfest/39/3388

https://api.cirrus-ci.com/v1/artifact/task/6454408568373248/testrun/build/testrun/postgres_fdw/regre...

inline patch 1: C:/cirrus/build/testrun/postgres_fdw/regress/results/postgres_fdw.out (+11/-1 lines) download inline-1.patch
diff -w -U3 C:/cirrus/contrib/postgres_fdw/expected/postgres_fdw.out C:/cirrus/build/testrun/postgres_fdw/regress/results/postgres_fdw.out
--- C:/cirrus/contrib/postgres_fdw/expected/postgres_fdw.out	2022-10-02 14:47:24.486355800 +0000
+++ C:/cirrus/build/testrun/postgres_fdw/regress/results/postgres_fdw.out	2022-10-02 15:02:03.039752800 +0000
@@ -11478,6 +11478,8 @@
 ALTER SERVER loopback OPTIONS (SET application_name 'healthcheck');
 -- Set GUC for checking the health of remote servers
 SET postgres_fdw.health_check_interval TO '1s';
+ERROR:  invalid value for parameter "postgres_fdw.health_check_interval": 1000
+DETAIL:  postgres_fdw.health_check_interval must be set to 0 on this platform
 BEGIN;
 SELECT 1 FROM ft1 LIMIT 1;
  ?column?
@@ -11495,7 +11497,15 @@

 -- While sleeping the process down will be detected.
 SELECT pg_sleep(3);
-ERROR:  Foreign Server loopback might be down.
+ pg_sleep
+----------
+
+(1 row)
+
 COMMIT;
+ERROR:  server closed the connection unexpectedly
+	This probably means the server terminated abnormally
+	before or while processing the request.
+CONTEXT:  remote SQL command: COMMIT TRANSACTION
 -- Clean up
 RESET debug_discard_caches;


Greetings,

Andres Freund





^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-02 15:39                                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Andres Freund <andres@anarazel.de>
@ 2022-10-03 07:50                                                         ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 08:59                                                           ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-10-03 07:50 UTC (permalink / raw)
  To: Andres Freund <andres@anarazel.de>; +Cc: Fujii Masao <masao.fujii@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Dear Andres,

> This seems to reliably fail on windows. See

Thanks for reporting. Actually this feature cannot be used on Windows machine.
To check the status of each socket that connects to the foreign server,
the socket event WL_SOCKET_CLOSED is used.
The event is only enabled on some OSes, and Windows machine cannot.  

The part must be skipped if the system cannot be used the event, but I was not sure how to do that...

Best Regards,
Hayato Kuroda
FUJITSU LIMITED






^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-02 15:39                                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Andres Freund <andres@anarazel.de>
  2022-10-03 07:50                                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-10-03 08:59                                                           ` Önder Kalacı <onderkalaci@gmail.com>
  2022-10-03 09:58                                                             ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Önder Kalacı @ 2022-10-03 08:59 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; +Cc: Andres Freund <andres@anarazel.de>; Fujii Masao <masao.fujii@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Hi Hayato Kuroda,

Thanks for the patch. I think there are some non-fdw extensions out there
which could benefit from this logic. That's why I want to first learn some
more about high-level design/goals of the patch a little more.

+/*
> + * Call callbacks for checking remote servers.
> + */
> +void
> +CallCheckingRemoteServersCallbacks(void)


Why do we run this periodically, but not when a specific connection is
going to be used? Wouldn't running it periodically prevent detecting some
already-closed sockets at the time of the connection used (e.g., we checked
10 seconds ago, the server died 5 seconds ago)?

In other words, what is the trade-off for calling
pgfdw_connection_check_internal() inside GetConnection() when we are about
to use a "cached" connection? I think that might simplify the patch as well.

+/*
> + * Helper function for pgfdw_connection_check
> + */
> +static bool
> +pgfdw_connection_check_internal(PGconn *conn)
> +{


Can we have this function/logic on Postgres core, so that other extensions
can also use?

 + AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL,
> NULL);


What if PQsocket(conn) returns -1? Maybe we move certain connection state
checks into pgfdw_connection_check_internal() such that it is more generic?
I can think of checks like: conn!=NULL, PQsocket(conn) != PGINVALID_SOCKET,
PQstatus == CONNECTION_OK


+ eventset = CreateWaitEventSet(CurrentMemoryContext, 1);
> + AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL,
> NULL);
> +
> + WaitEventSetWait(eventset, 0, &events, 1, 0);
> +
> + if (events.events & WL_SOCKET_CLOSED)
> + {
> + FreeWaitEventSet(eventset);
> + return false;
> + }
> + FreeWaitEventSet(eventset);


Do you see any performance implications of creating/freeing waitEventSets
per check? I wonder if we can somehow re-use the same waitEventSet by
modifyWaitEvent? I guess no, but still, if this check causes a performance
implication, can we somehow cache 1 waitEventSet per connection?


Thanks,
Onder KALACI
Developing the Citus extension @Microsoft

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-02 15:39                                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Andres Freund <andres@anarazel.de>
  2022-10-03 07:50                                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 08:59                                                           ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
@ 2022-10-03 09:58                                                             ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 14:19                                                               ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
  0 siblings, 1 reply; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-10-03 09:58 UTC (permalink / raw)
  To: 'Önder Kalacı' <onderkalaci@gmail.com>; +Cc: Andres Freund <andres@anarazel.de>; Fujii Masao <masao.fujii@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Dear Önder,

Thank you for being interest to my patch! Your suggestions will be included to newer version.

> In other words, what is the trade-off for calling
> pgfdw_connection_check_internal() inside GetConnection() when we are about
> to use a "cached" connection? I think that might simplify the patch as well

If the checking function is called not periodically but GetConnection(),
it means that the health of foreign servers will be check only when remote connections are used.
So following workload described in [1] cannot handle the issue.

BEGIN --- remote operations--- local operations --- COMMIT

But, yes, I perfectly agreed that it could simplify the code
because we can reduce the timer part. This is second plan of this patch,
I may move on this approach if it is still useful.

> Can we have this function/logic on Postgres core, so that other extensions
> can also use?

I was not sure about any use-case, but I think it can because it does quite general things.
Is there any good motivation to do that?

> What if PQsocket(conn) returns -1? Maybe we move certain connection state
> checks into pgfdw_connection_check_internal() such that it is more generic?
> I can think of checks like: conn!=NULL, PQsocket(conn) != PGINVALID_SOCKET,
> PQstatus == CONNECTION_OK

ereport(ERROR) will be thrown if PQsocket(conn) returns -1.
All of you said should be handled here. I will modify it.

> Do you see any performance implications of creating/freeing waitEventSets
> per check? I wonder if we can somehow re-use the same waitEventSet by
> modifyWaitEvent? I guess no, but still, if this check causes a performance
> implication, can we somehow cache 1 waitEventSet per connection?

I have not tested yet, but I agreed this will be caused performance decrease.
In next version first I will re-use the event set anyway, and it must be considered later.
Actually I'm not sure your suggestion,
but you mean to say that we can add a hash table that associates  PGconn and WaitEventSet,  right?

[1]: https://www.postgresql.org/message-id/TYAPR01MB58662809E678253B90E82CE5F5889%40TYAPR01MB5866.jpnprd0...

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* Re: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-02 15:39                                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Andres Freund <andres@anarazel.de>
  2022-10-03 07:50                                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 08:59                                                           ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
  2022-10-03 09:58                                                             ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-10-03 14:19                                                               ` Önder Kalacı <onderkalaci@gmail.com>
  2022-10-04 02:26                                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  0 siblings, 1 reply; 129+ messages in thread

From: Önder Kalacı @ 2022-10-03 14:19 UTC (permalink / raw)
  To: kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>; +Cc: Andres Freund <andres@anarazel.de>; Fujii Masao <masao.fujii@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Hi Hayato Kuroda,



> If the checking function is called not periodically but GetConnection(),
> it means that the health of foreign servers will be check only when remote
> connections are used.
> So following workload described in [1] cannot handle the issue.
>
> BEGIN --- remote operations--- local operations --- COMMIT
>
>
As far as I can see this patch is mostly useful for detecting the failures
on the initial remote command. This is especially common when the remote
server does a failover/switchover and postgres_fdw uses a cached connection
to access to the remote server.

The remote server failures within a transaction block sounds like a much
less common problem. Still, you can give a good error message before COMMIT
is sent to the remote server.

I agree that this doesn't solve the issue you described, but I'm not sure
if it is worthwhile to fix such a problem.


> > Can we have this function/logic on Postgres core, so that other
> extensions
> > can also use?
>
> I was not sure about any use-case, but I think it can because it does
> quite general things.
> Is there any good motivation to do that?
>

I think any extension that deals with multiple Postgres nodes can benefit
from such logic. In fact, the reason I realized this patch is that on the
Citus extension, we are trying to solve a similar problem [1], [2].

Thinking even more, I think any extension that uses libpq and WaitEventSets
can benefit from such a function.


> > Do you see any performance implications of creating/freeing waitEventSets
> > per check? I wonder if we can somehow re-use the same waitEventSet by
> > modifyWaitEvent? I guess no, but still, if this check causes a
> performance
> > implication, can we somehow cache 1 waitEventSet per connection?
>
> I have not tested yet, but I agreed this will be caused performance
> decrease.
> In next version first I will re-use the event set anyway, and it must be
> considered later.
> Actually I'm not sure your suggestion,
> but you mean to say that we can add a hash table that associates  PGconn
> and WaitEventSet,  right?
>
>
I think it also depends on where you decide to put
pgfdw_connection_check_internal(). If you prefer the postgres_fdw side,
could we maybe use ConnCacheEntry in contrib/postgres_fdw/connection.c?

But if you decide to put it into the Postgres side, the API
for pgfdw_connection_check_internal() -- or equivalent function -- could be
discussed. Do we pass a WaitEventSet and if it is NULL create a new one,
else use what is passed to the function? Not sure, maybe you can come up
with a better API.

Thanks,
Onder KALACI

[1]: Check WL_SOCKET_CLOSED before using any connection by onderkalaci ·
Pull Request #6259 · citusdata/citus (github.com)
<https://github.com/citusdata/citus/pull/6259;
[2]: Add a single connection retry in MULTI_CONNECTION_LOST state by
marcocitus · Pull Request #6283 · citusdata/citus (github.com)
<https://github.com/citusdata/citus/pull/6283;

^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-02 15:39                                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Andres Freund <andres@anarazel.de>
  2022-10-03 07:50                                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 08:59                                                           ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
  2022-10-03 09:58                                                             ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 14:19                                                               ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
@ 2022-10-04 02:26                                                                 ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-05 09:27                                                                   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-12 13:30                                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
  0 siblings, 2 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-10-04 02:26 UTC (permalink / raw)
  To: 'Önder Kalacı' <onderkalaci@gmail.com>; +Cc: Andres Freund <andres@anarazel.de>; Fujii Masao <masao.fujii@oss.nttdata.com>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Dear Önder,

> As far as I can see this patch is mostly useful for detecting the failures
> on the initial remote command. This is especially common when the remote
> server does a failover/switchover and postgres_fdw uses a cached connection
> to access to the remote server.

Sounds reasonable. Do you mean that we can add additional GUC like "postgres_fdw.initial_check",
wait WL_SOCKET_CLOSED if the conneciton is found in the hash table, and do reconnection if it might be closed, right?

> I think any extension that deals with multiple Postgres nodes can benefit
> from such logic. In fact, the reason I realized this patch is that on the
> Citus extension, we are trying to solve a similar problem [1], [2].

> Thinking even more, I think any extension that uses libpq and WaitEventSets
> can benefit from such a function.

OK, I agreed it may be useful, but where should this function be?
This cannot be used from application, so it should not in interface/libpq dir. So backend/libpq/pqcomm.c?

> I think it also depends on where you decide to put
> pgfdw_connection_check_internal(). If you prefer the postgres_fdw side,
> could we maybe use ConnCacheEntry in contrib/postgres_fdw/connection.c?
> But if you decide to put it into the Postgres side, the API
> for pgfdw_connection_check_internal() -- or equivalent function -- could be
> discussed. Do we pass a WaitEventSet and if it is NULL create a new one,
> else use what is passed to the function? Not sure, maybe you can come up
> with a better API.

Thank you for describing more detail. I can imagine you said.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED



^ permalink  raw  reply  [nested|flat] 129+ messages in thread

* RE: [Proposal] Add foreign-server health checks infrastructure
  2021-10-30 03:50 [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-16 05:26 ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-18 12:43   ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-19 08:30     ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-11-24 04:57       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-28 18:02         ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-11-29 08:51           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2021-11-29 12:36             ` Re: [Proposal] Add foreign-server health checks infrastructure Zhihong Yu <zyu@yugabyte.com>
  2021-12-06 11:06               ` Re: [Proposal] Add foreign-server health checks infrastructure Shinya Kato <Shinya11.Kato@oss.nttdata.com>
  2021-12-15 06:40                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-18 15:42                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-01-20 08:21                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-21 06:08                       ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-01-23 05:36                         ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-01 04:37                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-01 14:51                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-16 02:50                               ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-17 04:11                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-17 08:08                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Kyotaro Horiguchi <horikyota.ntt@gmail.com>
  2022-02-22 02:53                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 03:57                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-22 05:25                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 06:41                                           ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-02-22 07:52                                             ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-02-24 02:34                                               ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-03-04 06:17                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-09-18 03:39                                                   ` Re: [Proposal] Add foreign-server health checks infrastructure Fujii Masao <masao.fujii@oss.nttdata.com>
  2022-09-21 11:56                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-02 15:39                                                       ` Re: [Proposal] Add foreign-server health checks infrastructure Andres Freund <andres@anarazel.de>
  2022-10-03 07:50                                                         ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 08:59                                                           ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
  2022-10-03 09:58                                                             ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-03 14:19                                                               ` Re: [Proposal] Add foreign-server health checks infrastructure Önder Kalacı <onderkalaci@gmail.com>
  2022-10-04 02:26                                                                 ` RE: [Proposal] Add foreign-server health checks infrastructure kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
@ 2022-10-05 09:27                                                                   ` kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com>
  2022-10-17 01:45                                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure osumi.takamichi@fujitsu.com <osumi.takamichi@fujitsu.com>
  2022-10-17 03:02                                                                     ` RE: [Proposal] Add foreign-server health checks infrastructure osumi.takamichi@fujitsu.com <osumi.takamichi@fujitsu.com>
  1 sibling, 2 replies; 129+ messages in thread

From: kuroda.hayato@fujitsu.com @ 2022-10-05 09:27 UTC (permalink / raw)
  To: 'Önder Kalacı' <onderkalaci@gmail.com>; Fujii Masao <masao.fujii@oss.nttdata.com>; +Cc: Andres Freund <andres@anarazel.de>; pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>; Shinya11.Kato@oss.nttdata.com <Shinya11.Kato@oss.nttdata.com>; zyu@yugabyte.com <zyu@yugabyte.com>; Kyotaro Horiguchi <horikyota.ntt@gmail.com>

Dear Önder, Fujii-san,

Thanks for giving many comments! Based on off and on discussions, I modified my patch.
Note that this patch-set did not contain all of fixes you said.

[Modified]

1.
QueryCancelPending was cleaned up when the query cancel was skipped.
In the previous version the QueryCancelPending was set to true again even if the ereport(ERROR) was skipped.
It was because I thought the transaction that accessed to foreign servers but one of them crashed should be aborted immediately.
But currenlty postgres does not have such "delayed" query cancel mechanism, so I followed the manner.

Another approach is documenting like "If QueryCancelPending is already filled, the callback function must send SIGINT signal".
This seems simpler for us, but it may be troublesome for FDW authors. How do you think?

2.
The new filed servername was added to the hash entry. It was needed
because the server name must be logged in the pgfdw_connection_check(), but according to [1],
the catalog should not be read in ProcessInterrupts() to avoid the race condition.
The string is pstrdup()'d when the entry has been created, and replaced when ALTER SERER RENAME has been executed.

3.
The manner to implement the health check function was documented.

4.
raise() was replaced to kill(), because it was not used in core code. 

5.
APIs to handle QueryCancelMessage were added to avoid overriding the message.

6.
Some checks for socket was added in the checking function.

[1]: https://www.postgresql.org/message-id/CA%2BTgmoYW_rSOW4JMQ9_0Df9PKQ%3DsQDOKUGA4Gc9D8w4wui8fSA%40mail...



[Unmodified]

a.
The checking function is still in the postgres_fdw.
This is because I could not find any good file to move this function.
IIUC this function needs PGconn as an argument,
but it seems that it is declared in libpq-fe.h and it should not be included from core. 

b.
In the checking function, the eventset is still created, added, and freed.
Firstly I tried to declare eventset as inner-function static variable and reuse that, but I could not do. This is because:

* The size of eventset cannot be determined when the function is called for the first time.
  The size must be set in CreateWaitEventSet(), and it must be more than the number of remote connection.
* To reuse the eventset the added event must be removed every time, but it cannot.
  The API ModifyWaitEvent() can be only used for "modifying" the event, not "removing".
  If the function is called as events=0, we will get assertion failure in WaitEventAdjustEpoll() or something.

To avoid creating/freeing the event set, hash table must be modified but it has not done yet.

c.
Currently the status of socket is not checked in the GetConnection().
I agreed it may be useful, but I thought it might be out of scope. It could not meet the requirements.
I think it can be added separately.


Best Regards,
Hayato Kuroda
FUJITSU LIMITED



Attachments: download all (4 files, .tar.gz)

v16-0001-Add-an-infrastracture-for-checking-remote-server.patch (application/octet-stream, 8.8K) download
From df7068c18cda5dd5662e2a8c0eedaa025543a43c Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:02:45 +0000
Subject: [PATCH v16 1/4] Add an infrastracture for checking remote servers

This patch adds a mechanism for registering callback functions.
They should be used for checking health of remote servers.

These functions will be called when flags CheckingRemoteServersTimeoutPending and InterruptPending are set to true.
CheckingRemoteServersTimeoutPending is expected that it is set from signal handlers, which is registered by FDWs.
Inside the function a signal SIGINT should be raised and a message should be set to QueryCancelMessage
if one of remote servers is disconnected. To fill the message new API TrySetQueryCancelMessage can be used.

When a query is canceled and a string is set to QueryCancelMessage,
the server will output the given message to the log instead of the normal message.

Note that TrySetQueryCancelMessage does not allow to override the QueryCancelMessage.
If the function is called but the message is already filled, returns immediately
---
 src/backend/foreign/foreign.c    | 57 ++++++++++++++++++++++++++++++++
 src/backend/tcop/postgres.c      | 50 ++++++++++++++++++++++++++++
 src/backend/utils/init/globals.c |  1 +
 src/include/foreign/foreign.h    | 19 +++++++++++
 src/include/miscadmin.h          |  2 ++
 src/include/tcop/tcopprot.h      |  3 ++
 6 files changed, 132 insertions(+)

diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 353e20a0cf..fbc943bea9 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -28,7 +28,9 @@
 #include "utils/rel.h"
 #include "utils/syscache.h"
 #include "utils/varlena.h"
+#include "utils/timeout.h"
 
+static CheckingRemoteServersCallbackItem *remote_check_callbacks = NULL;
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -810,3 +812,58 @@ GetExistingLocalJoinPath(RelOptInfo *joinrel)
 	}
 	return NULL;
 }
+
+
+/*
+ * Register callbacks for checking remote servers.
+ *
+ * This function is intended for use by FDW extensions.
+ */
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+									  void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	item = (CheckingRemoteServersCallbackItem *)
+			MemoryContextAlloc(TopMemoryContext,
+			sizeof(CheckingRemoteServersCallbackItem));
+	item->callback = callback;
+	item->arg = arg;
+	item->next = remote_check_callbacks;
+	remote_check_callbacks = item;
+}
+
+void
+UnRegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+										void *arg)
+{
+	CheckingRemoteServersCallbackItem *item;
+	CheckingRemoteServersCallbackItem *prev;
+
+	prev = NULL;
+	for (item = remote_check_callbacks; item; prev = item, item = item->next)
+	{
+			if (item->callback == callback && item->arg == arg)
+			{
+					if (prev)
+							prev->next = item->next;
+					else
+							remote_check_callbacks = item->next;
+					pfree(item);
+					break;
+			}
+	}
+}
+
+/*
+ * Call callbacks for checking remote servers.
+ */
+void
+CallCheckingRemoteServersCallbacks(void)
+{
+	CheckingRemoteServersCallbackItem *item;
+
+	for (item = remote_check_callbacks; item; item = item->next)
+		item->callback(item->arg);
+}
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 5352d5f4c6..5a24e4f0a4 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -35,6 +35,7 @@
 #include "commands/async.h"
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
+#include "foreign/foreign.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
@@ -166,6 +167,9 @@ static ProcSignalReason RecoveryConflictReason;
 static MemoryContext row_description_context = NULL;
 static StringInfoData row_description_buf;
 
+/* Message string for canceling qurery caused by extensions */
+static char		*QueryCancelMessage = NULL;
+
 /* ----------------------------------------------------------------
  *		decls for routines only used in this file
  * ----------------------------------------------------------------
@@ -3226,6 +3230,13 @@ ProcessInterrupts(void)
 				 errmsg("connection to client lost")));
 	}
 
+	if (CheckingRemoteServersTimeoutPending)
+	{
+		CheckingRemoteServersTimeoutPending = false;
+
+		CallCheckingRemoteServersCallbacks();
+	}
+
 	/*
 	 * If a recovery conflict happens while we are waiting for input from the
 	 * client, the client is presumably just sitting idle in a transaction,
@@ -3330,8 +3341,21 @@ ProcessInterrupts(void)
 			LockErrorCleanup();
 			ereport(ERROR,
 					(errcode(ERRCODE_QUERY_CANCELED),
+					 QueryCancelMessage ?
+					 errmsg("%s", QueryCancelMessage) :
 					 errmsg("canceling statement due to user request")));
 		}
+
+		/*
+		 * If a cancel request from FDW is ignored, we expect that it raise SIGINT and
+		 * fill QueryCancelMessage again. But some FDWs may skip its health check if
+		 * we already have a cancel message. To avoid that we clean up it.
+		 */
+		if (QueryCancelMessage != NULL)
+		{
+			pfree(QueryCancelMessage);
+			QueryCancelMessage = NULL;
+		}
 	}
 
 	if (IdleInTransactionSessionTimeoutPending)
@@ -4266,6 +4290,9 @@ PostgresMain(const char *dbname, const char *username)
 		/* Report the error to the client and/or server log */
 		EmitErrorReport();
 
+		/* Make sure QueryCancelMessage is reset. */
+		QueryCancelMessage = NULL;
+
 		/*
 		 * Make sure debug_query_string gets reset before we possibly clobber
 		 * the storage it points at.
@@ -5024,3 +5051,26 @@ disable_statement_timeout(void)
 	if (get_timeout_active(STATEMENT_TIMEOUT))
 		disable_timeout(STATEMENT_TIMEOUT, false);
 }
+
+bool
+TrySetQueryCancelMessage(char *message)
+{
+	if (!HasQueryCancelMessage())
+	{
+		MemoryContext old;
+
+		old = MemoryContextSwitchTo(CurTransactionContext);
+		QueryCancelMessage = pstrdup(message);
+		MemoryContextSwitchTo(old);
+
+		return true;
+	}
+
+	return false;
+}
+
+bool
+HasQueryCancelMessage(void)
+{
+	return QueryCancelMessage != NULL;
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 1a5d29ac9b..bb94adfea8 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -37,6 +37,7 @@ volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile sig_atomic_t LogMemoryContextPending = false;
 volatile sig_atomic_t IdleStatsUpdateTimeoutPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index ac82125530..9859513ac6 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -82,4 +82,23 @@ extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 extern Oid	get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
 extern Oid	get_foreign_server_oid(const char *servername, bool missing_ok);
 
+
+/* Functions and variables for fdw checking */
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+
+typedef struct CheckingRemoteServersCallbackItem CheckingRemoteServersCallbackItem;
+
+struct CheckingRemoteServersCallbackItem
+{
+	CheckingRemoteServersCallbackItem	*next;
+	CheckingRemoteServersCallback		callback;
+	void								*arg;
+};
+
+extern void RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+												  void *arg);
+extern void UnRegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+													void *arg);
+extern void CallCheckingRemoteServersCallbacks(void);
+
 #endif							/* FOREIGN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index e7ebea4ff4..75697e2be0 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -99,6 +99,8 @@ extern PGDLLIMPORT volatile sig_atomic_t IdleStatsUpdateTimeoutPending;
 extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
+extern PGDLLIMPORT volatile sig_atomic_t CheckingRemoteServersTimeoutPending;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
 extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 5d34978f32..5d1216f170 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -91,4 +91,7 @@ extern bool set_plan_disabling_options(const char *arg,
 									   GucContext context, GucSource source);
 extern const char *get_stats_option_name(const char *arg);
 
+extern bool TrySetQueryCancelMessage(char *message);
+extern bool HasQueryCancelMessage(void);
+
 #endif							/* TCOPPROT_H */
-- 
2.27.0



v16-0002-postgres_fdw-Implement-health-check-feature.patch (application/octet-stream, 12.6K) download
From afdf9a6738f54672c3d2767d205e9fa79ca6f6fa Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:30:56 +0000
Subject: [PATCH v16 2/4] postgres_fdw: Implement health check feature

This patch adds a new GUC parameter postgres_fdw.health_check_interval.
This defines a time interval between checking remote servers.

In the checking function we use a socket event WL_SOCKET_CLOSED.
---
 contrib/postgres_fdw/connection.c   | 170 +++++++++++++++++++++++++++-
 contrib/postgres_fdw/option.c       |  63 +++++++++++
 contrib/postgres_fdw/postgres_fdw.h |   3 +
 3 files changed, 233 insertions(+), 3 deletions(-)

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 939d114f02..70f87e5d38 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -23,12 +23,14 @@
 #include "postgres_fdw.h"
 #include "storage/fd.h"
 #include "storage/latch.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/datetime.h"
 #include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/syscache.h"
+#include "utils/timeout.h"
 
 /*
  * Connection cache hash table entry
@@ -63,6 +65,7 @@ typedef struct ConnCacheEntry
 	bool		keep_connections;	/* setting value of keep_connections
 									 * server option */
 	Oid			serverid;		/* foreign server OID used to get server name */
+	char	   *servername;		/* foreign server name used to report ERROR */
 	uint32		server_hashvalue;	/* hash value of foreign server OID */
 	uint32		mapping_hashvalue;	/* hash value of user mapping OID */
 	PgFdwConnState state;		/* extra per-connection state */
@@ -80,6 +83,9 @@ static unsigned int prep_stmt_number = 0;
 /* tracks whether any work is needed in callback functions */
 static bool xact_got_connection = false;
 
+/* Timeout identifier for health check  */
+TimeoutId pgfdw_health_check_timeout = MAX_TIMEOUTS;
+
 /*
  * SQL functions
  */
@@ -117,6 +123,11 @@ static void pgfdw_finish_pre_subcommit_cleanup(List *pending_entries,
 static bool UserMappingPasswordRequired(UserMapping *user);
 static bool disconnect_cached_connections(Oid serverid);
 
+/* Functions for checking remote servers */
+static void pgfdw_connection_check(void *arg);
+static bool pgfdw_connection_check_internal(PGconn *conn);
+static void pgfdw_checking_remote_servers_timeout_handler(void);
+
 /*
  * Get a PGconn which can be used to execute queries on the remote PostgreSQL
  * server with the user's authorization.  A new connection is established
@@ -138,6 +149,8 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	ConnCacheEntry *entry;
 	ConnCacheKey key;
 	MemoryContext ccxt = CurrentMemoryContext;
+	MemoryContext old;
+	ForeignServer *server = GetForeignServer(user->serverid);
 
 	/* First time through, initialize connection cache hashtable */
 	if (ConnectionHash == NULL)
@@ -160,6 +173,13 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 									  pgfdw_inval_callback, (Datum) 0);
 		CacheRegisterSyscacheCallback(USERMAPPINGOID,
 									  pgfdw_inval_callback, (Datum) 0);
+		CacheRegisterSyscacheCallback(FOREIGNSERVERNAME,
+									  pgfdw_inval_callback, (Datum) 0);
+
+		/* Register a timeout and a callback for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT,
+													 pgfdw_checking_remote_servers_timeout_handler);
+		RegisterCheckingRemoteServersCallback(pgfdw_connection_check, NULL);
 	}
 
 	/* Set flag that we did GetConnection during the current transaction */
@@ -175,10 +195,11 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (!found)
 	{
 		/*
-		 * We need only clear "conn" here; remaining fields will be filled
-		 * later when "conn" is set.
+		 * We need clear "conn" and "servername" here; remaining fields will be filled
+		 * later when they are set.
 		 */
 		entry->conn = NULL;
+		entry->servername = NULL;
 	}
 
 	/* Reject further use of connections which failed abort cleanup. */
@@ -203,6 +224,16 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (entry->conn == NULL)
 		make_new_connection(entry, user);
 
+	/*
+	 * If cache entry doesn't have a name, duplicate it to the TopMemoryContext
+	 */
+	if (entry->servername == NULL)
+	{
+		old = MemoryContextSwitchTo(TopMemoryContext);
+		entry->servername = pstrdup(server->servername);
+		MemoryContextSwitchTo(old);
+	}
+
 	/*
 	 * We check the health of the cached connection here when using it.  In
 	 * cases where we're out of all transactions, if a broken connection is
@@ -283,6 +314,12 @@ GetConnection(UserMapping *user, bool will_prep_stmt, PgFdwConnState **state)
 	if (state)
 		*state = &entry->state;
 
+	/* Start health-check timer if needed */
+	if (pgfdw_health_check_interval > 0 &&
+		!get_timeout_active(pgfdw_health_check_timeout))
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
 	return entry->conn;
 }
 
@@ -532,6 +569,12 @@ disconnect_pg_server(ConnCacheEntry *entry)
 		entry->conn = NULL;
 		ReleaseExternalFD();
 	}
+
+	if (entry->servername != NULL)
+	{
+		pfree(entry->servername);
+		entry->servername = NULL;
+	}
 }
 
 /*
@@ -1040,6 +1083,9 @@ pgfdw_xact_callback(XactEvent event, void *arg)
 	 */
 	xact_got_connection = false;
 
+	/* Stop timer because checking is no more needed. */
+	disable_timeout(pgfdw_health_check_timeout, false);
+
 	/* Also reset cursor numbering for next transaction */
 	cursor_number = 0;
 }
@@ -1148,7 +1194,7 @@ pgfdw_inval_callback(Datum arg, int cacheid, uint32 hashvalue)
 	HASH_SEQ_STATUS scan;
 	ConnCacheEntry *entry;
 
-	Assert(cacheid == FOREIGNSERVEROID || cacheid == USERMAPPINGOID);
+	Assert(cacheid == FOREIGNSERVEROID || cacheid == USERMAPPINGOID || cacheid == FOREIGNSERVERNAME);
 
 	/* ConnectionHash must exist already, if we're registered */
 	hash_seq_init(&scan, ConnectionHash);
@@ -1179,6 +1225,21 @@ pgfdw_inval_callback(Datum arg, int cacheid, uint32 hashvalue)
 			else
 				entry->invalidated = true;
 		}
+
+		/* If ALTER SERVER RENAME is executed, the entry must be also modified. */
+		if (cacheid == FOREIGNSERVERNAME &&
+			entry->server_hashvalue == hashvalue)
+		{
+			ForeignServer *server = GetForeignServer(entry->serverid);
+			MemoryContext old;
+
+			if (entry->servername != NULL)
+				pfree(entry->servername);
+
+			old = MemoryContextSwitchTo(TopMemoryContext);
+			entry->servername = pstrdup(server->servername);
+			MemoryContextSwitchTo(old);
+		}
 	}
 }
 
@@ -1862,3 +1923,106 @@ disconnect_cached_connections(Oid serverid)
 
 	return result;
 }
+
+/*
+ * Signal handler for triggering health check
+ */
+static void
+pgfdw_checking_remote_servers_timeout_handler(void)
+{
+	CheckingRemoteServersTimeoutPending = true;
+	InterruptPending = true;
+	SetLatch(MyLatch);
+}
+
+/*
+ * Function for checking remote servers.
+ *
+ * This function searches the hash table from the beginning
+ * and performs a health-check on each entry.
+ *
+ * Raise SIGINT if someone might be down, otherwise do nothing.
+ */
+static void
+pgfdw_connection_check(void *arg)
+{
+	HASH_SEQ_STATUS scan;
+	ConnCacheEntry *entry;
+
+	Assert(ConnectionHash);
+
+	/*
+	 * checking will be done by waiting WL_SOCKET_CLOSED event,
+	 * so exit immediately if it cannot be used in this system.
+	 */
+	if (!WaitEventSetCanReportClosed())
+		return;
+
+	/* Quick exit if QueryCancelMessage has already set. */
+	if (HasQueryCancelMessage())
+		return;
+
+	hash_seq_init(&scan, ConnectionHash);
+	while ((entry = (ConnCacheEntry *) hash_seq_search(&scan)))
+	{
+		if (entry->conn == NULL || entry->xact_depth == 0)
+			continue;
+		if (!pgfdw_connection_check_internal(entry->conn))
+		{
+			/*
+			 * Foreign server might be down, so raise SIGINT.
+			 * Note that error message is passed to QueryCancelMessage
+			 * for reporting error in ProcessInterrupts().
+			 */
+			char msg[31 + MAXDATELEN];
+			snprintf(msg, sizeof(msg), "Foreign Server %s might be down.", entry->servername);
+			TrySetQueryCancelMessage(msg);
+
+			disconnect_pg_server(entry);
+			hash_seq_term(&scan);
+
+			kill(MyProcPid, SIGINT);
+			break;
+		}
+	}
+
+	/* re-schedule timer if needed. */
+	if (pgfdw_health_check_interval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout,
+							 pgfdw_health_check_interval);
+
+	return;
+}
+
+/*
+ * Helper function for pgfdw_connection_check
+ */
+static bool
+pgfdw_connection_check_internal(PGconn *conn)
+{
+	WaitEventSet *eventset;
+	WaitEvent events;
+
+	Assert(WaitEventSetCanReportClosed());
+
+	/* Raise an ERROR if invalid socket has come */
+	if (conn == NULL ||
+		PQsocket(conn) == PGINVALID_SOCKET)
+		elog(ERROR, "Invalid connection has been arrived");
+
+	eventset = CreateWaitEventSet(TopMemoryContext, 1);
+
+	(void) AddWaitEventToSet(eventset, WL_SOCKET_CLOSED, PQsocket(conn), NULL, NULL);
+
+	WaitEventSetWait(eventset, 0, &events, 1, 0);
+
+	/* return false is if the socket seems to be closed. */
+	if (events.events & WL_SOCKET_CLOSED)
+	{
+		FreeWaitEventSet(eventset);
+		return false;
+	}
+
+	FreeWaitEventSet(eventset);
+	return true;
+}
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index fa80ee2a55..9cd5a32e77 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -20,6 +20,7 @@
 #include "commands/extension.h"
 #include "libpq/libpq-be.h"
 #include "postgres_fdw.h"
+#include "storage/latch.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
 #include "utils/varlena.h"
@@ -50,6 +51,7 @@ static PQconninfoOption *libpq_options;
  * GUC parameters
  */
 char	   *pgfdw_application_name = NULL;
+int			pgfdw_health_check_interval;
 
 /*
  * Helper functions
@@ -58,6 +60,13 @@ static void InitPgFdwOptions(void);
 static bool is_valid_option(const char *keyword, Oid context);
 static bool is_libpq_option(const char *keyword);
 
+/*
+ * GUC hooks
+ */
+static bool check_pgfdw_health_check_interval(int *newval, void **extra,
+											  GucSource source);
+static void assign_pgfdw_health_check_interval(int newval, void *extra);
+
 #include "miscadmin.h"
 
 /*
@@ -518,6 +527,47 @@ process_pgfdw_appname(const char *appname)
 	return buf.data;
 }
 
+/*
+ * Check hook for pgfdw_health_check_interval
+ */
+static bool
+check_pgfdw_health_check_interval(int *newval, void **extra, GucSource source)
+{
+	if (!WaitEventSetCanReportClosed() && *newval != 0)
+	{
+		GUC_check_errdetail("postgres_fdw.health_check_interval must be set to 0 on this platform");
+		return false;
+	}
+	return true;
+}
+
+/*
+ * Assign hook for pgfdw_health_check_interval
+ */
+static void
+assign_pgfdw_health_check_interval(int newval, void *extra)
+{
+	/* Quick return if timeout is not registered yet. */
+	if (pgfdw_health_check_timeout == MAX_TIMEOUTS)
+		return;
+
+	if (get_timeout_active(pgfdw_health_check_timeout))
+	{
+		if (newval == 0)
+			disable_timeout(pgfdw_health_check_timeout, false);
+
+		/*
+		 * we don't have to do anything because
+		 * new value will be used in pgfdw_connection_check().
+		 */
+		return;
+	}
+
+	/* Start timeout if wants to */
+	if (newval > 0)
+		enable_timeout_after(pgfdw_health_check_timeout, newval);
+}
+
 /*
  * Module load callback
  */
@@ -543,5 +593,18 @@ _PG_init(void)
 							   NULL,
 							   NULL);
 
+	DefineCustomIntVariable("postgres_fdw.health_check_interval",
+							"Sets the time interval between checks of remote servers.",
+							NULL,
+							&pgfdw_health_check_interval,
+							0,
+							0,
+							INT_MAX,
+							PGC_USERSET,
+							GUC_UNIT_MS,
+							check_pgfdw_health_check_interval,
+							assign_pgfdw_health_check_interval,
+							NULL);
+
 	MarkGUCPrefixReserved("postgres_fdw");
 }
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index a11d45bedf..4670e8d391 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -18,6 +18,7 @@
 #include "libpq-fe.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
+#include "utils/timeout.h"
 #include "utils/relcache.h"
 
 /*
@@ -151,6 +152,7 @@ extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
 								  PgFdwConnState *state);
 extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 							   bool clear, const char *sql);
+extern TimeoutId pgfdw_health_check_timeout;
 
 /* in option.c */
 extern int	ExtractConnectionOptions(List *defelems,
@@ -160,6 +162,7 @@ extern List *ExtractExtensionList(const char *extensionsString,
 								  bool warnOnMissing);
 extern char *process_pgfdw_appname(const char *appname);
 extern char *pgfdw_application_name;
+extern int	pgfdw_health_check_interval;
 
 /* in deparse.c */
 extern void classifyConditions(PlannerInfo *root,
-- 
2.27.0



v16-0003-add-doc.patch (application/octet-stream, 4.7K) download
From c387f441289f6e2895108802d8f6bc5fe6e6ec07 Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:47:55 +0000
Subject: [PATCH v16 3/4] add doc

This patch adds descriptions about postgres_fdw.health_check_interval
---
 doc/src/sgml/fdwhandler.sgml   | 75 ++++++++++++++++++++++++++++++++++
 doc/src/sgml/postgres-fdw.sgml | 26 ++++++++++++
 2 files changed, 101 insertions(+)

diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index d0b5951019..4c1c252bc1 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -2136,4 +2136,79 @@ GetForeignServerByName(const char *name, bool missing_ok);
 
   </sect1>
 
+   <sect1 id="fdw-health-check">
+    <title>Health check of Foreign servers</title>
+
+    <para>
+     Additionally, the FDW author can implement a function to check health of
+     foreign servers. PostgreSQL has a mechanism to call callback functions
+     registered by FDW, and they will be done when flags are set. To enable the
+     feature, FDW authors must  1) implement health check function, 2) register
+     the implemented function as health check callback function, and
+     3) set flags in arbitrary ways.
+    </para>
+
+    <sect2 id="fdw-health-check-implement">
+     <title>Implement health check function</title>
+
+     <para>
+      The health check function must be defined as following datatype.
+<programlisting>
+typedef void (*CheckingRemoteServersCallback) (void *arg);
+</programlisting>
+     </para>
+
+     <para>
+      When FDW finds disconnections to foreign servers, the function must set
+      an error message and send SIGINT signal to its backend process. To fill
+      and check the message following APIs can be used, which are declared in
+      <filename>tcop/tcopprot.h</filename>.
+
+<programlisting>
+extern bool TrySetQueryCancelMessage(char *message);
+extern bool HasQueryCancelMessage(void);
+</programlisting>
+
+      Note that the message will be duplicated to the transactional memory
+      context. The message does not have to be allocated memory by FDW author.
+     </para>
+
+    </sect2>
+
+    <sect2 id="fdw-health-check-callback">
+     <title>Register a callback</title>
+
+     <para>
+      Authors needs to register the callback function via following API.
+
+<programlisting>
+void
+RegisterCheckingRemoteServersCallback(CheckingRemoteServersCallback callback,
+                                      void *arg)
+</programlisting>
+     </para>
+
+    </sect2>
+
+    <sect2 id="fdw-health-check-timeout">
+     <title>Set flags in arbitrary ways</title>
+
+     <para>
+      Finally, authors must implement a mechanism to fire the health check
+      callbacks. It can be done by setting flags <literal>CheckingRemoteServersTimeoutPending</literal>
+      and <literal>InterruptPending</literal> to true. They are declared in <filename>miscadmin.h</filename>.
+
+<programlisting>
+volatile sig_atomic_t InterruptPending = false;
+volatile sig_atomic_t CheckingRemoteServersTimeoutPending = false;
+</programlisting>
+
+      Typically, the timeout mechanism can be used to set these flags. The
+      detailed description and usage are written in <filename>src/backend/utils/misc/timeout.c</filename>.
+     </para>
+
+    </sect2>
+
+   </sect1>
+
  </chapter>
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index bfd344cdc0..44e4f07dd9 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1078,6 +1078,32 @@ postgres=# SELECT postgres_fdw_disconnect_all();
 
     </listitem>
    </varlistentry>
+   <varlistentry id="guc-pgfdw-health-check-interval" xreflabel="postgres_fdw.health_check_interval">
+    <term>
+     <varname>postgres_fdw.health_check_interval</varname> (<type>integer</type>)
+     <indexterm>
+      <primary><varname>postgres_fdw.health_check_interval</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the time interval between optional checks that remote servers
+      are still alive. When losing a remote connection is detected,
+      the running transaction is aborted. This feature is performed
+      by polling the socket.
+     </para>
+     <para>
+      This option relies on kernel events exposed by Linux, macOS,
+      illumos and the BSD family of operating systems, and is not currently available
+      on other systems.
+     </para>
+     <para>
+      If the value is specified without units, it is taken as milliseconds.
+      The default value is <literal>0</literal>, which disables connection
+      checks.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </sect2>
 
-- 
2.27.0



v16-0004-add-test.patch (application/octet-stream, 563.4K) download
From 4f8eab3117db2c03401f89e07c426041acacf6fd Mon Sep 17 00:00:00 2001
From: "kuroda.hayato%40jp.fujitsu.com" <kuroda.hayato@jp.fujitsu.com>
Date: Wed, 21 Sep 2022 06:52:23 +0000
Subject: [PATCH v16 4/4] add test

---
 .../postgres_fdw/expected/postgres_fdw.out    |    37 +
 .../postgres_fdw/expected/postgres_fdw_1.out  | 11515 ++++++++++++++++
 contrib/postgres_fdw/sql/postgres_fdw.sql     |    27 +
 3 files changed, 11579 insertions(+)
 create mode 100644 contrib/postgres_fdw/expected/postgres_fdw_1.out

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index cc9e39c4a5..88c6b9ef21 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -11466,3 +11466,40 @@ SELECT * FROM prem2;
 
 ALTER SERVER loopback OPTIONS (DROP parallel_commit);
 ALTER SERVER loopback2 OPTIONS (DROP parallel_commit);
+-- ===================================================================
+-- test for health-check feature
+-- ===================================================================
+-- Disable debug_discard_caches in order to manage remote connections
+SET debug_discard_caches TO '0';
+-- Disconnect once and set application_name to an arbitrary value
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ ?column? 
+----------
+        1
+(1 row)
+
+ALTER SERVER loopback OPTIONS (SET application_name 'healthcheck');
+-- Set GUC for checking the health of remote servers
+SET postgres_fdw.health_check_interval TO '1s';
+BEGIN;
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- Terminate the remote backend process
+-- FIXME: this should be skipped in some platforms
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+       WHERE application_name = 'healthcheck';
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+-- While sleeping the process down will be detected.
+SELECT pg_sleep(3);
+ERROR:  Foreign Server loopback might be down.
+COMMIT;
+-- Clean up
+RESET debug_discard_caches;
diff --git a/contrib/postgres_fdw/expected/postgres_fdw_1.out b/contrib/postgres_fdw/expected/postgres_fdw_1.out
new file mode 100644
index 0000000000..d1670c6702
--- /dev/null
+++ b/contrib/postgres_fdw/expected/postgres_fdw_1.out
@@ -0,0 +1,11515 @@
+-- ===================================================================
+-- create FDW objects
+-- ===================================================================
+CREATE EXTENSION postgres_fdw;
+CREATE SERVER testserver1 FOREIGN DATA WRAPPER postgres_fdw;
+DO $d$
+    BEGIN
+        EXECUTE $$CREATE SERVER loopback FOREIGN DATA WRAPPER postgres_fdw
+            OPTIONS (dbname '$$||current_database()||$$',
+                     port '$$||current_setting('port')||$$'
+            )$$;
+        EXECUTE $$CREATE SERVER loopback2 FOREIGN DATA WRAPPER postgres_fdw
+            OPTIONS (dbname '$$||current_database()||$$',
+                     port '$$||current_setting('port')||$$'
+            )$$;
+        EXECUTE $$CREATE SERVER loopback3 FOREIGN DATA WRAPPER postgres_fdw
+            OPTIONS (dbname '$$||current_database()||$$',
+                     port '$$||current_setting('port')||$$'
+            )$$;
+    END;
+$d$;
+CREATE USER MAPPING FOR public SERVER testserver1
+	OPTIONS (user 'value', password 'value');
+CREATE USER MAPPING FOR CURRENT_USER SERVER loopback;
+CREATE USER MAPPING FOR CURRENT_USER SERVER loopback2;
+CREATE USER MAPPING FOR public SERVER loopback3;
+-- ===================================================================
+-- create objects used through FDW loopback server
+-- ===================================================================
+CREATE TYPE user_enum AS ENUM ('foo', 'bar', 'buz');
+CREATE SCHEMA "S 1";
+CREATE TABLE "S 1"."T 1" (
+	"C 1" int NOT NULL,
+	c2 int NOT NULL,
+	c3 text,
+	c4 timestamptz,
+	c5 timestamp,
+	c6 varchar(10),
+	c7 char(10),
+	c8 user_enum,
+	CONSTRAINT t1_pkey PRIMARY KEY ("C 1")
+);
+CREATE TABLE "S 1"."T 2" (
+	c1 int NOT NULL,
+	c2 text,
+	CONSTRAINT t2_pkey PRIMARY KEY (c1)
+);
+CREATE TABLE "S 1"."T 3" (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text,
+	CONSTRAINT t3_pkey PRIMARY KEY (c1)
+);
+CREATE TABLE "S 1"."T 4" (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text,
+	CONSTRAINT t4_pkey PRIMARY KEY (c1)
+);
+-- Disable autovacuum for these tables to avoid unexpected effects of that
+ALTER TABLE "S 1"."T 1" SET (autovacuum_enabled = 'false');
+ALTER TABLE "S 1"."T 2" SET (autovacuum_enabled = 'false');
+ALTER TABLE "S 1"."T 3" SET (autovacuum_enabled = 'false');
+ALTER TABLE "S 1"."T 4" SET (autovacuum_enabled = 'false');
+INSERT INTO "S 1"."T 1"
+	SELECT id,
+	       id % 10,
+	       to_char(id, 'FM00000'),
+	       '1970-01-01'::timestamptz + ((id % 100) || ' days')::interval,
+	       '1970-01-01'::timestamp + ((id % 100) || ' days')::interval,
+	       id % 10,
+	       id % 10,
+	       'foo'::user_enum
+	FROM generate_series(1, 1000) id;
+INSERT INTO "S 1"."T 2"
+	SELECT id,
+	       'AAA' || to_char(id, 'FM000')
+	FROM generate_series(1, 100) id;
+INSERT INTO "S 1"."T 3"
+	SELECT id,
+	       id + 1,
+	       'AAA' || to_char(id, 'FM000')
+	FROM generate_series(1, 100) id;
+DELETE FROM "S 1"."T 3" WHERE c1 % 2 != 0;	-- delete for outer join tests
+INSERT INTO "S 1"."T 4"
+	SELECT id,
+	       id + 1,
+	       'AAA' || to_char(id, 'FM000')
+	FROM generate_series(1, 100) id;
+DELETE FROM "S 1"."T 4" WHERE c1 % 3 != 0;	-- delete for outer join tests
+ANALYZE "S 1"."T 1";
+ANALYZE "S 1"."T 2";
+ANALYZE "S 1"."T 3";
+ANALYZE "S 1"."T 4";
+-- ===================================================================
+-- create foreign tables
+-- ===================================================================
+CREATE FOREIGN TABLE ft1 (
+	c0 int,
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text,
+	c4 timestamptz,
+	c5 timestamp,
+	c6 varchar(10),
+	c7 char(10) default 'ft1',
+	c8 user_enum
+) SERVER loopback;
+ALTER FOREIGN TABLE ft1 DROP COLUMN c0;
+CREATE FOREIGN TABLE ft2 (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	cx int,
+	c3 text,
+	c4 timestamptz,
+	c5 timestamp,
+	c6 varchar(10),
+	c7 char(10) default 'ft2',
+	c8 user_enum
+) SERVER loopback;
+ALTER FOREIGN TABLE ft2 DROP COLUMN cx;
+CREATE FOREIGN TABLE ft4 (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text
+) SERVER loopback OPTIONS (schema_name 'S 1', table_name 'T 3');
+CREATE FOREIGN TABLE ft5 (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text
+) SERVER loopback OPTIONS (schema_name 'S 1', table_name 'T 4');
+CREATE FOREIGN TABLE ft6 (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text
+) SERVER loopback2 OPTIONS (schema_name 'S 1', table_name 'T 4');
+CREATE FOREIGN TABLE ft7 (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text
+) SERVER loopback3 OPTIONS (schema_name 'S 1', table_name 'T 4');
+-- ===================================================================
+-- tests for validator
+-- ===================================================================
+-- requiressl and some other parameters are omitted because
+-- valid values for them depend on configure options
+ALTER SERVER testserver1 OPTIONS (
+	use_remote_estimate 'false',
+	updatable 'true',
+	fdw_startup_cost '123.456',
+	fdw_tuple_cost '0.123',
+	service 'value',
+	connect_timeout 'value',
+	dbname 'value',
+	host 'value',
+	hostaddr 'value',
+	port 'value',
+	--client_encoding 'value',
+	application_name 'value',
+	--fallback_application_name 'value',
+	keepalives 'value',
+	keepalives_idle 'value',
+	keepalives_interval 'value',
+	tcp_user_timeout 'value',
+	-- requiressl 'value',
+	sslcompression 'value',
+	sslmode 'value',
+	sslcert 'value',
+	sslkey 'value',
+	sslrootcert 'value',
+	sslcrl 'value',
+	--requirepeer 'value',
+	krbsrvname 'value',
+	gsslib 'value'
+	--replication 'value'
+);
+-- Error, invalid list syntax
+ALTER SERVER testserver1 OPTIONS (ADD extensions 'foo; bar');
+ERROR:  parameter "extensions" must be a list of extension names
+-- OK but gets a warning
+ALTER SERVER testserver1 OPTIONS (ADD extensions 'foo, bar');
+WARNING:  extension "foo" is not installed
+WARNING:  extension "bar" is not installed
+ALTER SERVER testserver1 OPTIONS (DROP extensions);
+ALTER USER MAPPING FOR public SERVER testserver1
+	OPTIONS (DROP user, DROP password);
+-- Attempt to add a valid option that's not allowed in a user mapping
+ALTER USER MAPPING FOR public SERVER testserver1
+	OPTIONS (ADD sslmode 'require');
+ERROR:  invalid option "sslmode"
+-- But we can add valid ones fine
+ALTER USER MAPPING FOR public SERVER testserver1
+	OPTIONS (ADD sslpassword 'dummy');
+-- Ensure valid options we haven't used in a user mapping yet are
+-- permitted to check validation.
+ALTER USER MAPPING FOR public SERVER testserver1
+	OPTIONS (ADD sslkey 'value', ADD sslcert 'value');
+ALTER FOREIGN TABLE ft1 OPTIONS (schema_name 'S 1', table_name 'T 1');
+ALTER FOREIGN TABLE ft2 OPTIONS (schema_name 'S 1', table_name 'T 1');
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 OPTIONS (column_name 'C 1');
+ALTER FOREIGN TABLE ft2 ALTER COLUMN c1 OPTIONS (column_name 'C 1');
+\det+
+                              List of foreign tables
+ Schema | Table |  Server   |              FDW options              | Description 
+--------+-------+-----------+---------------------------------------+-------------
+ public | ft1   | loopback  | (schema_name 'S 1', table_name 'T 1') | 
+ public | ft2   | loopback  | (schema_name 'S 1', table_name 'T 1') | 
+ public | ft4   | loopback  | (schema_name 'S 1', table_name 'T 3') | 
+ public | ft5   | loopback  | (schema_name 'S 1', table_name 'T 4') | 
+ public | ft6   | loopback2 | (schema_name 'S 1', table_name 'T 4') | 
+ public | ft7   | loopback3 | (schema_name 'S 1', table_name 'T 4') | 
+(6 rows)
+
+-- Test that alteration of server options causes reconnection
+-- Remote's errors might be non-English, so hide them to ensure stable results
+\set VERBOSITY terse
+SELECT c3, c4 FROM ft1 ORDER BY c3, c1 LIMIT 1;  -- should work
+  c3   |              c4              
+-------+------------------------------
+ 00001 | Fri Jan 02 00:00:00 1970 PST
+(1 row)
+
+ALTER SERVER loopback OPTIONS (SET dbname 'no such database');
+SELECT c3, c4 FROM ft1 ORDER BY c3, c1 LIMIT 1;  -- should fail
+ERROR:  could not connect to server "loopback"
+DO $d$
+    BEGIN
+        EXECUTE $$ALTER SERVER loopback
+            OPTIONS (SET dbname '$$||current_database()||$$')$$;
+    END;
+$d$;
+SELECT c3, c4 FROM ft1 ORDER BY c3, c1 LIMIT 1;  -- should work again
+  c3   |              c4              
+-------+------------------------------
+ 00001 | Fri Jan 02 00:00:00 1970 PST
+(1 row)
+
+-- Test that alteration of user mapping options causes reconnection
+ALTER USER MAPPING FOR CURRENT_USER SERVER loopback
+  OPTIONS (ADD user 'no such user');
+SELECT c3, c4 FROM ft1 ORDER BY c3, c1 LIMIT 1;  -- should fail
+ERROR:  could not connect to server "loopback"
+ALTER USER MAPPING FOR CURRENT_USER SERVER loopback
+  OPTIONS (DROP user);
+SELECT c3, c4 FROM ft1 ORDER BY c3, c1 LIMIT 1;  -- should work again
+  c3   |              c4              
+-------+------------------------------
+ 00001 | Fri Jan 02 00:00:00 1970 PST
+(1 row)
+
+\set VERBOSITY default
+-- Now we should be able to run ANALYZE.
+-- To exercise multiple code paths, we use local stats on ft1
+-- and remote-estimate mode on ft2.
+ANALYZE ft1;
+ALTER FOREIGN TABLE ft2 OPTIONS (use_remote_estimate 'true');
+-- ===================================================================
+-- test error case for create publication on foreign table
+-- ===================================================================
+CREATE PUBLICATION testpub_ftbl FOR TABLE ft1;  -- should fail
+ERROR:  cannot add relation "ft1" to publication
+DETAIL:  This operation is not supported for foreign tables.
+-- ===================================================================
+-- simple queries
+-- ===================================================================
+-- single table without alias
+EXPLAIN (COSTS OFF) SELECT * FROM ft1 ORDER BY c3, c1 OFFSET 100 LIMIT 10;
+     QUERY PLAN      
+---------------------
+ Foreign Scan on ft1
+(1 row)
+
+SELECT * FROM ft1 ORDER BY c3, c1 OFFSET 100 LIMIT 10;
+ c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 101 |  1 | 00101 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+ 102 |  2 | 00102 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+ 103 |  3 | 00103 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+ 104 |  4 | 00104 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4  | 4          | foo
+ 105 |  5 | 00105 | Tue Jan 06 00:00:00 1970 PST | Tue Jan 06 00:00:00 1970 | 5  | 5          | foo
+ 106 |  6 | 00106 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 107 |  7 | 00107 | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+ 108 |  8 | 00108 | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+ 109 |  9 | 00109 | Sat Jan 10 00:00:00 1970 PST | Sat Jan 10 00:00:00 1970 | 9  | 9          | foo
+ 110 |  0 | 00110 | Sun Jan 11 00:00:00 1970 PST | Sun Jan 11 00:00:00 1970 | 0  | 0          | foo
+(10 rows)
+
+-- single table with alias - also test that tableoid sort is not pushed to remote side
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 ORDER BY t1.c3, t1.c1, t1.tableoid OFFSET 100 LIMIT 10;
+                                     QUERY PLAN                                      
+-------------------------------------------------------------------------------------
+ Limit
+   Output: c1, c2, c3, c4, c5, c6, c7, c8, tableoid
+   ->  Sort
+         Output: c1, c2, c3, c4, c5, c6, c7, c8, tableoid
+         Sort Key: t1.c3, t1.c1, t1.tableoid
+         ->  Foreign Scan on public.ft1 t1
+               Output: c1, c2, c3, c4, c5, c6, c7, c8, tableoid
+               Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(8 rows)
+
+SELECT * FROM ft1 t1 ORDER BY t1.c3, t1.c1, t1.tableoid OFFSET 100 LIMIT 10;
+ c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 101 |  1 | 00101 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+ 102 |  2 | 00102 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+ 103 |  3 | 00103 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+ 104 |  4 | 00104 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4  | 4          | foo
+ 105 |  5 | 00105 | Tue Jan 06 00:00:00 1970 PST | Tue Jan 06 00:00:00 1970 | 5  | 5          | foo
+ 106 |  6 | 00106 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 107 |  7 | 00107 | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+ 108 |  8 | 00108 | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+ 109 |  9 | 00109 | Sat Jan 10 00:00:00 1970 PST | Sat Jan 10 00:00:00 1970 | 9  | 9          | foo
+ 110 |  0 | 00110 | Sun Jan 11 00:00:00 1970 PST | Sun Jan 11 00:00:00 1970 | 0  | 0          | foo
+(10 rows)
+
+-- whole-row reference
+EXPLAIN (VERBOSE, COSTS OFF) SELECT t1 FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                                                          QUERY PLAN                                                                          
+--------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: t1.*, c3, c1
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" ORDER BY c3 ASC NULLS LAST, "C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint
+(3 rows)
+
+SELECT t1 FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                             t1                                             
+--------------------------------------------------------------------------------------------
+ (101,1,00101,"Fri Jan 02 00:00:00 1970 PST","Fri Jan 02 00:00:00 1970",1,"1         ",foo)
+ (102,2,00102,"Sat Jan 03 00:00:00 1970 PST","Sat Jan 03 00:00:00 1970",2,"2         ",foo)
+ (103,3,00103,"Sun Jan 04 00:00:00 1970 PST","Sun Jan 04 00:00:00 1970",3,"3         ",foo)
+ (104,4,00104,"Mon Jan 05 00:00:00 1970 PST","Mon Jan 05 00:00:00 1970",4,"4         ",foo)
+ (105,5,00105,"Tue Jan 06 00:00:00 1970 PST","Tue Jan 06 00:00:00 1970",5,"5         ",foo)
+ (106,6,00106,"Wed Jan 07 00:00:00 1970 PST","Wed Jan 07 00:00:00 1970",6,"6         ",foo)
+ (107,7,00107,"Thu Jan 08 00:00:00 1970 PST","Thu Jan 08 00:00:00 1970",7,"7         ",foo)
+ (108,8,00108,"Fri Jan 09 00:00:00 1970 PST","Fri Jan 09 00:00:00 1970",8,"8         ",foo)
+ (109,9,00109,"Sat Jan 10 00:00:00 1970 PST","Sat Jan 10 00:00:00 1970",9,"9         ",foo)
+ (110,0,00110,"Sun Jan 11 00:00:00 1970 PST","Sun Jan 11 00:00:00 1970",0,"0         ",foo)
+(10 rows)
+
+-- empty result
+SELECT * FROM ft1 WHERE false;
+ c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8 
+----+----+----+----+----+----+----+----
+(0 rows)
+
+-- with WHERE clause
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE t1.c1 = 101 AND t1.c6 = '1' AND t1.c7 >= '1';
+                                                            QUERY PLAN                                                            
+----------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c7 >= '1')) AND (("C 1" = 101)) AND ((c6 = '1'))
+(3 rows)
+
+SELECT * FROM ft1 t1 WHERE t1.c1 = 101 AND t1.c6 = '1' AND t1.c7 >= '1';
+ c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 101 |  1 | 00101 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+-- with FOR UPDATE/SHARE
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 = 101 FOR UPDATE;
+                                                QUERY PLAN                                                
+----------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8, t1.*
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 101)) FOR UPDATE
+(3 rows)
+
+SELECT * FROM ft1 t1 WHERE c1 = 101 FOR UPDATE;
+ c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 101 |  1 | 00101 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 = 102 FOR SHARE;
+                                               QUERY PLAN                                                
+---------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8, t1.*
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 102)) FOR SHARE
+(3 rows)
+
+SELECT * FROM ft1 t1 WHERE c1 = 102 FOR SHARE;
+ c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 102 |  2 | 00102 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+(1 row)
+
+-- aggregate
+SELECT COUNT(*) FROM ft1 t1;
+ count 
+-------
+  1000
+(1 row)
+
+-- subquery
+SELECT * FROM ft1 t1 WHERE t1.c3 IN (SELECT c3 FROM ft2 t2 WHERE c1 <= 10) ORDER BY c1;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+  3 |  3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+  4 |  4 | 00004 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4  | 4          | foo
+  5 |  5 | 00005 | Tue Jan 06 00:00:00 1970 PST | Tue Jan 06 00:00:00 1970 | 5  | 5          | foo
+  6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+  7 |  7 | 00007 | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  8 |  8 | 00008 | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  9 |  9 | 00009 | Sat Jan 10 00:00:00 1970 PST | Sat Jan 10 00:00:00 1970 | 9  | 9          | foo
+ 10 |  0 | 00010 | Sun Jan 11 00:00:00 1970 PST | Sun Jan 11 00:00:00 1970 | 0  | 0          | foo
+(10 rows)
+
+-- subquery+MAX
+SELECT * FROM ft1 t1 WHERE t1.c3 = (SELECT MAX(c3) FROM ft2 t2) ORDER BY c1;
+  c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+------+----+-------+------------------------------+--------------------------+----+------------+-----
+ 1000 |  0 | 01000 | Thu Jan 01 00:00:00 1970 PST | Thu Jan 01 00:00:00 1970 | 0  | 0          | foo
+(1 row)
+
+-- used in CTE
+WITH t1 AS (SELECT * FROM ft1 WHERE c1 <= 10) SELECT t2.c1, t2.c2, t2.c3, t2.c4 FROM t1, ft2 t2 WHERE t1.c1 = t2.c1 ORDER BY t1.c1;
+ c1 | c2 |  c3   |              c4              
+----+----+-------+------------------------------
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST
+  3 |  3 | 00003 | Sun Jan 04 00:00:00 1970 PST
+  4 |  4 | 00004 | Mon Jan 05 00:00:00 1970 PST
+  5 |  5 | 00005 | Tue Jan 06 00:00:00 1970 PST
+  6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST
+  7 |  7 | 00007 | Thu Jan 08 00:00:00 1970 PST
+  8 |  8 | 00008 | Fri Jan 09 00:00:00 1970 PST
+  9 |  9 | 00009 | Sat Jan 10 00:00:00 1970 PST
+ 10 |  0 | 00010 | Sun Jan 11 00:00:00 1970 PST
+(10 rows)
+
+-- fixed values
+SELECT 'fixed', NULL FROM ft1 t1 WHERE c1 = 1;
+ ?column? | ?column? 
+----------+----------
+ fixed    | 
+(1 row)
+
+-- Test forcing the remote server to produce sorted data for a merge join.
+SET enable_hashjoin TO false;
+SET enable_nestloop TO false;
+-- inner join; expressions in the clauses appear in the equivalence class list
+EXPLAIN (VERBOSE, COSTS OFF)
+	SELECT t1.c1, t2."C 1" FROM ft2 t1 JOIN "S 1"."T 1" t2 ON (t1.c1 = t2."C 1") OFFSET 100 LIMIT 10;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2."C 1"
+   ->  Merge Join
+         Output: t1.c1, t2."C 1"
+         Inner Unique: true
+         Merge Cond: (t1.c1 = t2."C 1")
+         ->  Foreign Scan on public.ft2 t1
+               Output: t1.c1
+               Remote SQL: SELECT "C 1" FROM "S 1"."T 1" ORDER BY "C 1" ASC NULLS LAST
+         ->  Index Only Scan using t1_pkey on "S 1"."T 1" t2
+               Output: t2."C 1"
+(11 rows)
+
+SELECT t1.c1, t2."C 1" FROM ft2 t1 JOIN "S 1"."T 1" t2 ON (t1.c1 = t2."C 1") OFFSET 100 LIMIT 10;
+ c1  | C 1 
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+-- outer join; expressions in the clauses do not appear in equivalence class
+-- list but no output change as compared to the previous query
+EXPLAIN (VERBOSE, COSTS OFF)
+	SELECT t1.c1, t2."C 1" FROM ft2 t1 LEFT JOIN "S 1"."T 1" t2 ON (t1.c1 = t2."C 1") OFFSET 100 LIMIT 10;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2."C 1"
+   ->  Merge Left Join
+         Output: t1.c1, t2."C 1"
+         Inner Unique: true
+         Merge Cond: (t1.c1 = t2."C 1")
+         ->  Foreign Scan on public.ft2 t1
+               Output: t1.c1
+               Remote SQL: SELECT "C 1" FROM "S 1"."T 1" ORDER BY "C 1" ASC NULLS LAST
+         ->  Index Only Scan using t1_pkey on "S 1"."T 1" t2
+               Output: t2."C 1"
+(11 rows)
+
+SELECT t1.c1, t2."C 1" FROM ft2 t1 LEFT JOIN "S 1"."T 1" t2 ON (t1.c1 = t2."C 1") OFFSET 100 LIMIT 10;
+ c1  | C 1 
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+-- A join between local table and foreign join. ORDER BY clause is added to the
+-- foreign join so that the local table can be joined using merge join strategy.
+EXPLAIN (VERBOSE, COSTS OFF)
+	SELECT t1."C 1" FROM "S 1"."T 1" t1 left join ft1 t2 join ft2 t3 on (t2.c1 = t3.c1) on (t3.c1 = t1."C 1") OFFSET 100 LIMIT 10;
+                                                                       QUERY PLAN                                                                        
+---------------------------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1."C 1"
+   ->  Merge Right Join
+         Output: t1."C 1"
+         Inner Unique: true
+         Merge Cond: (t3.c1 = t1."C 1")
+         ->  Foreign Scan
+               Output: t3.c1
+               Relations: (public.ft1 t2) INNER JOIN (public.ft2 t3)
+               Remote SQL: SELECT r3."C 1" FROM ("S 1"."T 1" r2 INNER JOIN "S 1"."T 1" r3 ON (((r2."C 1" = r3."C 1")))) ORDER BY r2."C 1" ASC NULLS LAST
+         ->  Index Only Scan using t1_pkey on "S 1"."T 1" t1
+               Output: t1."C 1"
+(12 rows)
+
+SELECT t1."C 1" FROM "S 1"."T 1" t1 left join ft1 t2 join ft2 t3 on (t2.c1 = t3.c1) on (t3.c1 = t1."C 1") OFFSET 100 LIMIT 10;
+ C 1 
+-----
+ 101
+ 102
+ 103
+ 104
+ 105
+ 106
+ 107
+ 108
+ 109
+ 110
+(10 rows)
+
+-- Test similar to above, except that the full join prevents any equivalence
+-- classes from being merged. This produces single relation equivalence classes
+-- included in join restrictions.
+EXPLAIN (VERBOSE, COSTS OFF)
+	SELECT t1."C 1", t2.c1, t3.c1 FROM "S 1"."T 1" t1 left join ft1 t2 full join ft2 t3 on (t2.c1 = t3.c1) on (t3.c1 = t1."C 1") OFFSET 100 LIMIT 10;
+                                                                            QUERY PLAN                                                                            
+------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1."C 1", t2.c1, t3.c1
+   ->  Merge Right Join
+         Output: t1."C 1", t2.c1, t3.c1
+         Inner Unique: true
+         Merge Cond: (t3.c1 = t1."C 1")
+         ->  Foreign Scan
+               Output: t3.c1, t2.c1
+               Relations: (public.ft2 t3) LEFT JOIN (public.ft1 t2)
+               Remote SQL: SELECT r3."C 1", r2."C 1" FROM ("S 1"."T 1" r3 LEFT JOIN "S 1"."T 1" r2 ON (((r2."C 1" = r3."C 1")))) ORDER BY r3."C 1" ASC NULLS LAST
+         ->  Index Only Scan using t1_pkey on "S 1"."T 1" t1
+               Output: t1."C 1"
+(12 rows)
+
+SELECT t1."C 1", t2.c1, t3.c1 FROM "S 1"."T 1" t1 left join ft1 t2 full join ft2 t3 on (t2.c1 = t3.c1) on (t3.c1 = t1."C 1") OFFSET 100 LIMIT 10;
+ C 1 | c1  | c1  
+-----+-----+-----
+ 101 | 101 | 101
+ 102 | 102 | 102
+ 103 | 103 | 103
+ 104 | 104 | 104
+ 105 | 105 | 105
+ 106 | 106 | 106
+ 107 | 107 | 107
+ 108 | 108 | 108
+ 109 | 109 | 109
+ 110 | 110 | 110
+(10 rows)
+
+-- Test similar to above with all full outer joins
+EXPLAIN (VERBOSE, COSTS OFF)
+	SELECT t1."C 1", t2.c1, t3.c1 FROM "S 1"."T 1" t1 full join ft1 t2 full join ft2 t3 on (t2.c1 = t3.c1) on (t3.c1 = t1."C 1") OFFSET 100 LIMIT 10;
+                                                                            QUERY PLAN                                                                            
+------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1."C 1", t2.c1, t3.c1
+   ->  Merge Full Join
+         Output: t1."C 1", t2.c1, t3.c1
+         Inner Unique: true
+         Merge Cond: (t3.c1 = t1."C 1")
+         ->  Foreign Scan
+               Output: t2.c1, t3.c1
+               Relations: (public.ft1 t2) FULL JOIN (public.ft2 t3)
+               Remote SQL: SELECT r2."C 1", r3."C 1" FROM ("S 1"."T 1" r2 FULL JOIN "S 1"."T 1" r3 ON (((r2."C 1" = r3."C 1")))) ORDER BY r3."C 1" ASC NULLS LAST
+         ->  Index Only Scan using t1_pkey on "S 1"."T 1" t1
+               Output: t1."C 1"
+(12 rows)
+
+SELECT t1."C 1", t2.c1, t3.c1 FROM "S 1"."T 1" t1 full join ft1 t2 full join ft2 t3 on (t2.c1 = t3.c1) on (t3.c1 = t1."C 1") OFFSET 100 LIMIT 10;
+ C 1 | c1  | c1  
+-----+-----+-----
+ 101 | 101 | 101
+ 102 | 102 | 102
+ 103 | 103 | 103
+ 104 | 104 | 104
+ 105 | 105 | 105
+ 106 | 106 | 106
+ 107 | 107 | 107
+ 108 | 108 | 108
+ 109 | 109 | 109
+ 110 | 110 | 110
+(10 rows)
+
+RESET enable_hashjoin;
+RESET enable_nestloop;
+-- Test executing assertion in estimate_path_cost_size() that makes sure that
+-- retrieved_rows for foreign rel re-used to cost pre-sorted foreign paths is
+-- a sensible value even when the rel has tuples=0
+CREATE TABLE loct_empty (c1 int NOT NULL, c2 text);
+CREATE FOREIGN TABLE ft_empty (c1 int NOT NULL, c2 text)
+  SERVER loopback OPTIONS (table_name 'loct_empty');
+INSERT INTO loct_empty
+  SELECT id, 'AAA' || to_char(id, 'FM000') FROM generate_series(1, 100) id;
+DELETE FROM loct_empty;
+ANALYZE ft_empty;
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft_empty ORDER BY c1;
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Foreign Scan on public.ft_empty
+   Output: c1, c2
+   Remote SQL: SELECT c1, c2 FROM public.loct_empty ORDER BY c1 ASC NULLS LAST
+(3 rows)
+
+-- ===================================================================
+-- WHERE with remotely-executable conditions
+-- ===================================================================
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE t1.c1 = 1;         -- Var, OpExpr(b), Const
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE t1.c1 = 100 AND t1.c2 = 0; -- BoolExpr
+                                                  QUERY PLAN                                                  
+--------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 100)) AND ((c2 = 0))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 IS NULL;        -- NullTest
+                                           QUERY PLAN                                            
+-------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" IS NULL))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 IS NOT NULL;    -- NullTest
+                                             QUERY PLAN                                              
+-----------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" IS NOT NULL))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE round(abs(c1), 0) = 1; -- FuncExpr
+                                                     QUERY PLAN                                                      
+---------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((round(abs("C 1"), 0) = 1::numeric))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 = -c1;          -- OpExpr(l)
+                                             QUERY PLAN                                              
+-----------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = (- "C 1")))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE (c1 IS NOT NULL) IS DISTINCT FROM (c1 IS NOT NULL); -- DistinctExpr
+                                                                 QUERY PLAN                                                                 
+--------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((("C 1" IS NOT NULL) IS DISTINCT FROM ("C 1" IS NOT NULL)))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 = ANY(ARRAY[c2, 1, c1 + 0]); -- ScalarArrayOpExpr
+                                                        QUERY PLAN                                                         
+---------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = ANY (ARRAY[c2, 1, ("C 1" + 0)])))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 = (ARRAY[c1,c2,3])[1]; -- SubscriptingRef
+                                                      QUERY PLAN                                                      
+----------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = ((ARRAY["C 1", c2, 3])[1])))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c6 = E'foo''s\\bar';  -- check special chars
+                                              QUERY PLAN                                               
+-------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c6 = E'foo''s\\bar'))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c8 = 'foo';  -- can't be sent to remote
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (t1.c8 = 'foo'::user_enum)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(4 rows)
+
+-- parameterized remote path for foreign table
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT * FROM "S 1"."T 1" a, ft2 b WHERE a."C 1" = 47 AND b.c1 = a.c2;
+                                                 QUERY PLAN                                                  
+-------------------------------------------------------------------------------------------------------------
+ Nested Loop
+   Output: a."C 1", a.c2, a.c3, a.c4, a.c5, a.c6, a.c7, a.c8, b.c1, b.c2, b.c3, b.c4, b.c5, b.c6, b.c7, b.c8
+   ->  Index Scan using t1_pkey on "S 1"."T 1" a
+         Output: a."C 1", a.c2, a.c3, a.c4, a.c5, a.c6, a.c7, a.c8
+         Index Cond: (a."C 1" = 47)
+   ->  Foreign Scan on public.ft2 b
+         Output: b.c1, b.c2, b.c3, b.c4, b.c5, b.c6, b.c7, b.c8
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (($1::integer = "C 1"))
+(8 rows)
+
+SELECT * FROM ft2 a, ft2 b WHERE a.c1 = 47 AND b.c1 = a.c2;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  | c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----+----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 47 |  7 | 00047 | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo |  7 |  7 | 00007 | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+(1 row)
+
+-- check both safe and unsafe join conditions
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT * FROM ft2 a, ft2 b
+  WHERE a.c2 = 6 AND b.c1 = a.c1 AND a.c8 = 'foo' AND b.c7 = upper(a.c7);
+                                                 QUERY PLAN                                                  
+-------------------------------------------------------------------------------------------------------------
+ Nested Loop
+   Output: a.c1, a.c2, a.c3, a.c4, a.c5, a.c6, a.c7, a.c8, b.c1, b.c2, b.c3, b.c4, b.c5, b.c6, b.c7, b.c8
+   ->  Foreign Scan on public.ft2 a
+         Output: a.c1, a.c2, a.c3, a.c4, a.c5, a.c6, a.c7, a.c8
+         Filter: (a.c8 = 'foo'::user_enum)
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c2 = 6))
+   ->  Foreign Scan on public.ft2 b
+         Output: b.c1, b.c2, b.c3, b.c4, b.c5, b.c6, b.c7, b.c8
+         Filter: (upper((a.c7)::text) = (b.c7)::text)
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (($1::integer = "C 1"))
+(10 rows)
+
+SELECT * FROM ft2 a, ft2 b
+WHERE a.c2 = 6 AND b.c1 = a.c1 AND a.c8 = 'foo' AND b.c7 = upper(a.c7);
+ c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  | c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-----+----+-------+------------------------------+--------------------------+----+------------+-----+-----+----+-------+------------------------------+--------------------------+----+------------+-----
+   6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo |   6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+  16 |  6 | 00016 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo |  16 |  6 | 00016 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+  26 |  6 | 00026 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo |  26 |  6 | 00026 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+  36 |  6 | 00036 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo |  36 |  6 | 00036 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+  46 |  6 | 00046 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo |  46 |  6 | 00046 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+  56 |  6 | 00056 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo |  56 |  6 | 00056 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+  66 |  6 | 00066 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo |  66 |  6 | 00066 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+  76 |  6 | 00076 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo |  76 |  6 | 00076 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+  86 |  6 | 00086 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo |  86 |  6 | 00086 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+  96 |  6 | 00096 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo |  96 |  6 | 00096 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 106 |  6 | 00106 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 106 |  6 | 00106 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 116 |  6 | 00116 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 116 |  6 | 00116 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 126 |  6 | 00126 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 126 |  6 | 00126 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 136 |  6 | 00136 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 136 |  6 | 00136 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 146 |  6 | 00146 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 146 |  6 | 00146 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 156 |  6 | 00156 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 156 |  6 | 00156 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 166 |  6 | 00166 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 166 |  6 | 00166 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 176 |  6 | 00176 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 176 |  6 | 00176 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 186 |  6 | 00186 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 186 |  6 | 00186 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 196 |  6 | 00196 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 196 |  6 | 00196 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 206 |  6 | 00206 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 206 |  6 | 00206 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 216 |  6 | 00216 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 216 |  6 | 00216 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 226 |  6 | 00226 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 226 |  6 | 00226 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 236 |  6 | 00236 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 236 |  6 | 00236 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 246 |  6 | 00246 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 246 |  6 | 00246 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 256 |  6 | 00256 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 256 |  6 | 00256 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 266 |  6 | 00266 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 266 |  6 | 00266 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 276 |  6 | 00276 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 276 |  6 | 00276 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 286 |  6 | 00286 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 286 |  6 | 00286 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 296 |  6 | 00296 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 296 |  6 | 00296 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 306 |  6 | 00306 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 306 |  6 | 00306 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 316 |  6 | 00316 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 316 |  6 | 00316 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 326 |  6 | 00326 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 326 |  6 | 00326 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 336 |  6 | 00336 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 336 |  6 | 00336 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 346 |  6 | 00346 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 346 |  6 | 00346 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 356 |  6 | 00356 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 356 |  6 | 00356 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 366 |  6 | 00366 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 366 |  6 | 00366 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 376 |  6 | 00376 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 376 |  6 | 00376 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 386 |  6 | 00386 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 386 |  6 | 00386 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 396 |  6 | 00396 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 396 |  6 | 00396 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 406 |  6 | 00406 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 406 |  6 | 00406 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 416 |  6 | 00416 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 416 |  6 | 00416 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 426 |  6 | 00426 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 426 |  6 | 00426 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 436 |  6 | 00436 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 436 |  6 | 00436 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 446 |  6 | 00446 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 446 |  6 | 00446 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 456 |  6 | 00456 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 456 |  6 | 00456 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 466 |  6 | 00466 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 466 |  6 | 00466 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 476 |  6 | 00476 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 476 |  6 | 00476 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 486 |  6 | 00486 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 486 |  6 | 00486 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 496 |  6 | 00496 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 496 |  6 | 00496 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 506 |  6 | 00506 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 506 |  6 | 00506 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 516 |  6 | 00516 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 516 |  6 | 00516 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 526 |  6 | 00526 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 526 |  6 | 00526 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 536 |  6 | 00536 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 536 |  6 | 00536 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 546 |  6 | 00546 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 546 |  6 | 00546 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 556 |  6 | 00556 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 556 |  6 | 00556 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 566 |  6 | 00566 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 566 |  6 | 00566 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 576 |  6 | 00576 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 576 |  6 | 00576 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 586 |  6 | 00586 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 586 |  6 | 00586 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 596 |  6 | 00596 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 596 |  6 | 00596 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 606 |  6 | 00606 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 606 |  6 | 00606 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 616 |  6 | 00616 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 616 |  6 | 00616 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 626 |  6 | 00626 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 626 |  6 | 00626 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 636 |  6 | 00636 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 636 |  6 | 00636 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 646 |  6 | 00646 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 646 |  6 | 00646 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 656 |  6 | 00656 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 656 |  6 | 00656 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 666 |  6 | 00666 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 666 |  6 | 00666 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 676 |  6 | 00676 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 676 |  6 | 00676 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 686 |  6 | 00686 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 686 |  6 | 00686 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 696 |  6 | 00696 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 696 |  6 | 00696 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 706 |  6 | 00706 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 706 |  6 | 00706 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 716 |  6 | 00716 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 716 |  6 | 00716 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 726 |  6 | 00726 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 726 |  6 | 00726 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 736 |  6 | 00736 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 736 |  6 | 00736 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 746 |  6 | 00746 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 746 |  6 | 00746 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 756 |  6 | 00756 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 756 |  6 | 00756 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 766 |  6 | 00766 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 766 |  6 | 00766 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 776 |  6 | 00776 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 776 |  6 | 00776 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 786 |  6 | 00786 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 786 |  6 | 00786 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 796 |  6 | 00796 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 796 |  6 | 00796 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 806 |  6 | 00806 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 806 |  6 | 00806 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 816 |  6 | 00816 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 816 |  6 | 00816 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 826 |  6 | 00826 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 826 |  6 | 00826 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 836 |  6 | 00836 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 836 |  6 | 00836 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 846 |  6 | 00846 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 846 |  6 | 00846 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 856 |  6 | 00856 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 856 |  6 | 00856 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 866 |  6 | 00866 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 866 |  6 | 00866 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 876 |  6 | 00876 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 876 |  6 | 00876 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 886 |  6 | 00886 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 886 |  6 | 00886 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 896 |  6 | 00896 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 896 |  6 | 00896 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+ 906 |  6 | 00906 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo | 906 |  6 | 00906 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+ 916 |  6 | 00916 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 916 |  6 | 00916 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+ 926 |  6 | 00926 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 926 |  6 | 00926 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo
+ 936 |  6 | 00936 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 936 |  6 | 00936 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo
+ 946 |  6 | 00946 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 946 |  6 | 00946 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo
+ 956 |  6 | 00956 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 956 |  6 | 00956 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo
+ 966 |  6 | 00966 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 966 |  6 | 00966 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo
+ 976 |  6 | 00976 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 976 |  6 | 00976 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo
+ 986 |  6 | 00986 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 986 |  6 | 00986 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo
+ 996 |  6 | 00996 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 996 |  6 | 00996 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo
+(100 rows)
+
+-- bug before 9.3.5 due to sloppy handling of remote-estimate parameters
+SELECT * FROM ft1 WHERE c1 = ANY (ARRAY(SELECT c1 FROM ft2 WHERE c1 < 5));
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+  3 |  3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+  4 |  4 | 00004 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4  | 4          | foo
+(4 rows)
+
+SELECT * FROM ft2 WHERE c1 = ANY (ARRAY(SELECT c1 FROM ft1 WHERE c1 < 5));
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+  3 |  3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+  4 |  4 | 00004 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4  | 4          | foo
+(4 rows)
+
+-- we should not push order by clause with volatile expressions or unsafe
+-- collations
+EXPLAIN (VERBOSE, COSTS OFF)
+	SELECT * FROM ft2 ORDER BY ft2.c1, random();
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Sort
+   Output: c1, c2, c3, c4, c5, c6, c7, c8, (random())
+   Sort Key: ft2.c1, (random())
+   ->  Foreign Scan on public.ft2
+         Output: c1, c2, c3, c4, c5, c6, c7, c8, random()
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(6 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+	SELECT * FROM ft2 ORDER BY ft2.c1, ft2.c3 collate "C";
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Sort
+   Output: c1, c2, c3, c4, c5, c6, c7, c8, ((c3)::text)
+   Sort Key: ft2.c1, ft2.c3 COLLATE "C"
+   ->  Foreign Scan on public.ft2
+         Output: c1, c2, c3, c4, c5, c6, c7, c8, c3
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(6 rows)
+
+-- user-defined operator/function
+CREATE FUNCTION postgres_fdw_abs(int) RETURNS int AS $$
+BEGIN
+RETURN abs($1);
+END
+$$ LANGUAGE plpgsql IMMUTABLE;
+CREATE OPERATOR === (
+    LEFTARG = int,
+    RIGHTARG = int,
+    PROCEDURE = int4eq,
+    COMMUTATOR = ===
+);
+-- built-in operators and functions can be shipped for remote execution
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = abs(t1.c2);
+                                QUERY PLAN                                 
+---------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c3))
+   Relations: Aggregate on (public.ft1 t1)
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" = abs(c2)))
+(4 rows)
+
+SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = abs(t1.c2);
+ count 
+-------
+     9
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = t1.c2;
+                              QUERY PLAN                              
+----------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c3))
+   Relations: Aggregate on (public.ft1 t1)
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" = c2))
+(4 rows)
+
+SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = t1.c2;
+ count 
+-------
+     9
+(1 row)
+
+-- by default, user-defined ones cannot
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = postgres_fdw_abs(t1.c2);
+                        QUERY PLAN                         
+-----------------------------------------------------------
+ Aggregate
+   Output: count(c3)
+   ->  Foreign Scan on public.ft1 t1
+         Output: c3
+         Filter: (t1.c1 = postgres_fdw_abs(t1.c2))
+         Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1"
+(6 rows)
+
+SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = postgres_fdw_abs(t1.c2);
+ count 
+-------
+     9
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
+                        QUERY PLAN                         
+-----------------------------------------------------------
+ Aggregate
+   Output: count(c3)
+   ->  Foreign Scan on public.ft1 t1
+         Output: c3
+         Filter: (t1.c1 === t1.c2)
+         Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1"
+(6 rows)
+
+SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
+ count 
+-------
+     9
+(1 row)
+
+-- ORDER BY can be shipped, though
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
+                                                QUERY PLAN                                                
+----------------------------------------------------------------------------------------------------------
+ Limit
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   ->  Foreign Scan on public.ft1 t1
+         Output: c1, c2, c3, c4, c5, c6, c7, c8
+         Filter: (t1.c1 === t1.c2)
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" ORDER BY c2 ASC NULLS LAST
+(6 rows)
+
+SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+-- but let's put them in an extension ...
+ALTER EXTENSION postgres_fdw ADD FUNCTION postgres_fdw_abs(int);
+ALTER EXTENSION postgres_fdw ADD OPERATOR === (int, int);
+ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
+-- ... now they can be shipped
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = postgres_fdw_abs(t1.c2);
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c3))
+   Relations: Aggregate on (public.ft1 t1)
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" = public.postgres_fdw_abs(c2)))
+(4 rows)
+
+SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = postgres_fdw_abs(t1.c2);
+ count 
+-------
+     9
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c3))
+   Relations: Aggregate on (public.ft1 t1)
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" OPERATOR(public.===) c2))
+(4 rows)
+
+SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
+ count 
+-------
+     9
+(1 row)
+
+-- and both ORDER BY and LIMIT can be shipped
+EXPLAIN (VERBOSE, COSTS OFF)
+  SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
+                                                                         QUERY PLAN                                                                         
+------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" OPERATOR(public.===) c2)) ORDER BY c2 ASC NULLS LAST LIMIT 1::bigint
+(3 rows)
+
+SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+-- Test CASE pushdown
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT c1,c2,c3 FROM ft2 WHERE CASE WHEN c1 > 990 THEN c1 END < 1000 ORDER BY c1;
+                                                                           QUERY PLAN                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft2
+   Output: c1, c2, c3
+   Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1" WHERE (((CASE WHEN ("C 1" > 990) THEN "C 1" ELSE NULL::integer END) < 1000)) ORDER BY "C 1" ASC NULLS LAST
+(3 rows)
+
+SELECT c1,c2,c3 FROM ft2 WHERE CASE WHEN c1 > 990 THEN c1 END < 1000 ORDER BY c1;
+ c1  | c2 |  c3   
+-----+----+-------
+ 991 |  1 | 00991
+ 992 |  2 | 00992
+ 993 |  3 | 00993
+ 994 |  4 | 00994
+ 995 |  5 | 00995
+ 996 |  6 | 00996
+ 997 |  7 | 00997
+ 998 |  8 | 00998
+ 999 |  9 | 00999
+(9 rows)
+
+-- Nested CASE
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT c1,c2,c3 FROM ft2 WHERE CASE CASE WHEN c2 > 0 THEN c2 END WHEN 100 THEN 601 WHEN c2 THEN c2 ELSE 0 END > 600 ORDER BY c1;
+                                                                                                QUERY PLAN                                                                                                 
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft2
+   Output: c1, c2, c3
+   Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1" WHERE (((CASE (CASE WHEN (c2 > 0) THEN c2 ELSE NULL::integer END) WHEN 100 THEN 601 WHEN c2 THEN c2 ELSE 0 END) > 600)) ORDER BY "C 1" ASC NULLS LAST
+(3 rows)
+
+SELECT c1,c2,c3 FROM ft2 WHERE CASE CASE WHEN c2 > 0 THEN c2 END WHEN 100 THEN 601 WHEN c2 THEN c2 ELSE 0 END > 600 ORDER BY c1;
+ c1 | c2 | c3 
+----+----+----
+(0 rows)
+
+-- CASE arg WHEN
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE c1 > (CASE mod(c1, 4) WHEN 0 THEN 1 WHEN 2 THEN 50 ELSE 100 END);
+                                                                        QUERY PLAN                                                                        
+----------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" > (CASE mod("C 1", 4) WHEN 0 THEN 1 WHEN 2 THEN 50 ELSE 100 END)))
+(3 rows)
+
+-- CASE cannot be pushed down because of unshippable arg clause
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE c1 > (CASE random()::integer WHEN 0 THEN 1 WHEN 2 THEN 50 ELSE 100 END);
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (ft1.c1 > CASE (random())::integer WHEN 0 THEN 1 WHEN 2 THEN 50 ELSE 100 END)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(4 rows)
+
+-- these are shippable
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE CASE c6 WHEN 'foo' THEN true ELSE c3 < 'bar' END;
+                                                                 QUERY PLAN                                                                 
+--------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((CASE c6 WHEN 'foo'::text THEN true ELSE (c3 < 'bar') END))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE CASE c3 WHEN c6 THEN true ELSE c3 < 'bar' END;
+                                                            QUERY PLAN                                                             
+-----------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((CASE c3 WHEN c6 THEN true ELSE (c3 < 'bar') END))
+(3 rows)
+
+-- but this is not because of collation
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE CASE c3 COLLATE "C" WHEN c6 THEN true ELSE c3 < 'bar' END;
+                                     QUERY PLAN                                      
+-------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: CASE (ft1.c3)::text WHEN ft1.c6 THEN true ELSE (ft1.c3 < 'bar'::text) END
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(4 rows)
+
+-- a regconfig constant referring to this text search configuration
+-- is initially unshippable
+CREATE TEXT SEARCH CONFIGURATION public.custom_search
+  (COPY = pg_catalog.english);
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
+WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, to_tsvector('custom_search'::regconfig, c3)
+   Filter: (length(to_tsvector('custom_search'::regconfig, ft1.c3)) > 0)
+   Remote SQL: SELECT "C 1", c3 FROM "S 1"."T 1" WHERE (("C 1" = 642))
+(4 rows)
+
+SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
+WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
+ c1  | to_tsvector 
+-----+-------------
+ 642 | '00642':1
+(1 row)
+
+-- but if it's in a shippable extension, it can be shipped
+ALTER EXTENSION postgres_fdw ADD TEXT SEARCH CONFIGURATION public.custom_search;
+-- however, that doesn't flush the shippability cache, so do a quick reconnect
+\c -
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
+WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
+                                                                  QUERY PLAN                                                                  
+----------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, to_tsvector('custom_search'::regconfig, c3)
+   Remote SQL: SELECT "C 1", c3 FROM "S 1"."T 1" WHERE (("C 1" = 642)) AND ((length(to_tsvector('public.custom_search'::regconfig, c3)) > 0))
+(3 rows)
+
+SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
+WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
+ c1  | to_tsvector 
+-----+-------------
+ 642 | '00642':1
+(1 row)
+
+-- ===================================================================
+-- JOIN queries
+-- ===================================================================
+-- Analyze ft4 and ft5 so that we have better statistics. These tables do not
+-- have use_remote_estimate set.
+ANALYZE ft4;
+ANALYZE ft5;
+-- join two tables
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                                                                                       QUERY PLAN                                                                                                       
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1, t1.c3
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3 FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+ c1  | c1  
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+-- join three tables
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) JOIN ft4 t3 ON (t3.c1 = t1.c1) ORDER BY t1.c3, t1.c1 OFFSET 10 LIMIT 10;
+                                                                                                                                   QUERY PLAN                                                                                                                                    
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3, t1.c3
+   Relations: ((public.ft1 t1) INNER JOIN (public.ft2 t2)) INNER JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3, r1.c3 FROM (("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) INNER JOIN "S 1"."T 3" r4 ON (((r1."C 1" = r4.c1)))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) JOIN ft4 t3 ON (t3.c1 = t1.c1) ORDER BY t1.c3, t1.c1 OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 22 |  2 | AAA022
+ 24 |  4 | AAA024
+ 26 |  6 | AAA026
+ 28 |  8 | AAA028
+ 30 |  0 | AAA030
+ 32 |  2 | AAA032
+ 34 |  4 | AAA034
+ 36 |  6 | AAA036
+ 38 |  8 | AAA038
+ 40 |  0 | AAA040
+(10 rows)
+
+-- left outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft4 t1 LEFT JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+                                                                                           QUERY PLAN                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1
+   Relations: (public.ft4 t1) LEFT JOIN (public.ft5 t2)
+   Remote SQL: SELECT r1.c1, r2.c1 FROM ("S 1"."T 3" r1 LEFT JOIN "S 1"."T 4" r2 ON (((r1.c1 = r2.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft4 t1 LEFT JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+ c1 | c1 
+----+----
+ 22 |   
+ 24 | 24
+ 26 |   
+ 28 |   
+ 30 | 30
+ 32 |   
+ 34 |   
+ 36 | 36
+ 38 |   
+ 40 |   
+(10 rows)
+
+-- left outer join three tables
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) LEFT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft2 t1) LEFT JOIN (public.ft2 t2)) LEFT JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 1" r1 LEFT JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) LEFT JOIN "S 1"."T 3" r4 ON (((r2."C 1" = r4.c1)))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) LEFT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 11 |  1 | 
+ 12 |  2 | AAA012
+ 13 |  3 | 
+ 14 |  4 | AAA014
+ 15 |  5 | 
+ 16 |  6 | AAA016
+ 17 |  7 | 
+ 18 |  8 | AAA018
+ 19 |  9 | 
+ 20 |  0 | AAA020
+(10 rows)
+
+-- left outer join + placement of clauses.
+-- clauses within the nullable side are not pulled up, but top level clause on
+-- non-nullable side is pushed into non-nullable side
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t1.c2, t2.c1, t2.c2 FROM ft4 t1 LEFT JOIN (SELECT * FROM ft5 WHERE c1 < 10) t2 ON (t1.c1 = t2.c1) WHERE t1.c1 < 10;
+                                                                          QUERY PLAN                                                                           
+---------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t1.c2, ft5.c1, ft5.c2
+   Relations: (public.ft4 t1) LEFT JOIN (public.ft5)
+   Remote SQL: SELECT r1.c1, r1.c2, r4.c1, r4.c2 FROM ("S 1"."T 3" r1 LEFT JOIN "S 1"."T 4" r4 ON (((r1.c1 = r4.c1)) AND ((r4.c1 < 10)))) WHERE ((r1.c1 < 10))
+(4 rows)
+
+SELECT t1.c1, t1.c2, t2.c1, t2.c2 FROM ft4 t1 LEFT JOIN (SELECT * FROM ft5 WHERE c1 < 10) t2 ON (t1.c1 = t2.c1) WHERE t1.c1 < 10;
+ c1 | c2 | c1 | c2 
+----+----+----+----
+  2 |  3 |    |   
+  4 |  5 |    |   
+  6 |  7 |  6 |  7
+  8 |  9 |    |   
+(4 rows)
+
+-- clauses within the nullable side are not pulled up, but the top level clause
+-- on nullable side is not pushed down into nullable side
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t1.c2, t2.c1, t2.c2 FROM ft4 t1 LEFT JOIN (SELECT * FROM ft5 WHERE c1 < 10) t2 ON (t1.c1 = t2.c1)
+			WHERE (t2.c1 < 10 OR t2.c1 IS NULL) AND t1.c1 < 10;
+                                                                                              QUERY PLAN                                                                                               
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t1.c2, ft5.c1, ft5.c2
+   Relations: (public.ft4 t1) LEFT JOIN (public.ft5)
+   Remote SQL: SELECT r1.c1, r1.c2, r4.c1, r4.c2 FROM ("S 1"."T 3" r1 LEFT JOIN "S 1"."T 4" r4 ON (((r1.c1 = r4.c1)) AND ((r4.c1 < 10)))) WHERE (((r4.c1 < 10) OR (r4.c1 IS NULL))) AND ((r1.c1 < 10))
+(4 rows)
+
+SELECT t1.c1, t1.c2, t2.c1, t2.c2 FROM ft4 t1 LEFT JOIN (SELECT * FROM ft5 WHERE c1 < 10) t2 ON (t1.c1 = t2.c1)
+			WHERE (t2.c1 < 10 OR t2.c1 IS NULL) AND t1.c1 < 10;
+ c1 | c2 | c1 | c2 
+----+----+----+----
+  2 |  3 |    |   
+  4 |  5 |    |   
+  6 |  7 |  6 |  7
+  8 |  9 |    |   
+(4 rows)
+
+-- right outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft5 t1 RIGHT JOIN ft4 t2 ON (t1.c1 = t2.c1) ORDER BY t2.c1, t1.c1 OFFSET 10 LIMIT 10;
+                                                                                           QUERY PLAN                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1
+   Relations: (public.ft4 t2) LEFT JOIN (public.ft5 t1)
+   Remote SQL: SELECT r1.c1, r2.c1 FROM ("S 1"."T 3" r2 LEFT JOIN "S 1"."T 4" r1 ON (((r1.c1 = r2.c1)))) ORDER BY r2.c1 ASC NULLS LAST, r1.c1 ASC NULLS LAST LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft5 t1 RIGHT JOIN ft4 t2 ON (t1.c1 = t2.c1) ORDER BY t2.c1, t1.c1 OFFSET 10 LIMIT 10;
+ c1 | c1 
+----+----
+    | 22
+ 24 | 24
+    | 26
+    | 28
+ 30 | 30
+    | 32
+    | 34
+ 36 | 36
+    | 38
+    | 40
+(10 rows)
+
+-- right outer join three tables
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 RIGHT JOIN ft2 t2 ON (t1.c1 = t2.c1) RIGHT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft4 t3) LEFT JOIN (public.ft2 t2)) LEFT JOIN (public.ft2 t1)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 3" r4 LEFT JOIN "S 1"."T 1" r2 ON (((r2."C 1" = r4.c1)))) LEFT JOIN "S 1"."T 1" r1 ON (((r1."C 1" = r2."C 1")))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 RIGHT JOIN ft2 t2 ON (t1.c1 = t2.c1) RIGHT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 22 |  2 | AAA022
+ 24 |  4 | AAA024
+ 26 |  6 | AAA026
+ 28 |  8 | AAA028
+ 30 |  0 | AAA030
+ 32 |  2 | AAA032
+ 34 |  4 | AAA034
+ 36 |  6 | AAA036
+ 38 |  8 | AAA038
+ 40 |  0 | AAA040
+(10 rows)
+
+-- full outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft4 t1 FULL JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 45 LIMIT 10;
+                                                                                           QUERY PLAN                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1
+   Relations: (public.ft4 t1) FULL JOIN (public.ft5 t2)
+   Remote SQL: SELECT r1.c1, r2.c1 FROM ("S 1"."T 3" r1 FULL JOIN "S 1"."T 4" r2 ON (((r1.c1 = r2.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST LIMIT 10::bigint OFFSET 45::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft4 t1 FULL JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 45 LIMIT 10;
+ c1  | c1 
+-----+----
+  92 |   
+  94 |   
+  96 | 96
+  98 |   
+ 100 |   
+     |  3
+     |  9
+     | 15
+     | 21
+     | 27
+(10 rows)
+
+-- full outer join with restrictions on the joining relations
+-- a. the joining relations are both base relations
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1;
+                                                                                                                                  QUERY PLAN                                                                                                                                   
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: ft4.c1, ft5.c1
+   Relations: (public.ft4) FULL JOIN (public.ft5)
+   Remote SQL: SELECT s4.c1, s5.c1 FROM ((SELECT c1 FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s4(c1) FULL JOIN (SELECT c1 FROM "S 1"."T 4" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s5(c1) ON (((s4.c1 = s5.c1)))) ORDER BY s4.c1 ASC NULLS LAST, s5.c1 ASC NULLS LAST
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1;
+ c1 | c1 
+----+----
+ 50 |   
+ 52 |   
+ 54 | 54
+ 56 |   
+ 58 |   
+ 60 | 60
+    | 51
+    | 57
+(8 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT 1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t2 ON (TRUE) OFFSET 10 LIMIT 10;
+                                                                                                             QUERY PLAN                                                                                                              
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: 1
+   Relations: (public.ft4) FULL JOIN (public.ft5)
+   Remote SQL: SELECT NULL FROM ((SELECT NULL FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s4 FULL JOIN (SELECT NULL FROM "S 1"."T 4" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s5 ON (TRUE)) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT 1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t2 ON (TRUE) OFFSET 10 LIMIT 10;
+ ?column? 
+----------
+        1
+        1
+        1
+        1
+        1
+        1
+        1
+        1
+        1
+        1
+(10 rows)
+
+-- b. one of the joining relations is a base relation and the other is a join
+-- relation
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT t2.c1, t3.c1 FROM ft4 t2 LEFT JOIN ft5 t3 ON (t2.c1 = t3.c1) WHERE (t2.c1 between 50 and 60)) ss(a, b) ON (t1.c1 = ss.a) ORDER BY t1.c1, ss.a, ss.b;
+                                                                                                                                                                                     QUERY PLAN                                                                                                                                                                                      
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: ft4.c1, t2.c1, t3.c1
+   Relations: (public.ft4) FULL JOIN ((public.ft4 t2) LEFT JOIN (public.ft5 t3))
+   Remote SQL: SELECT s4.c1, s8.c1, s8.c2 FROM ((SELECT c1 FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s4(c1) FULL JOIN (SELECT r5.c1, r6.c1 FROM ("S 1"."T 3" r5 LEFT JOIN "S 1"."T 4" r6 ON (((r5.c1 = r6.c1)))) WHERE ((r5.c1 >= 50)) AND ((r5.c1 <= 60))) s8(c1, c2) ON (((s4.c1 = s8.c1)))) ORDER BY s4.c1 ASC NULLS LAST, s8.c1 ASC NULLS LAST, s8.c2 ASC NULLS LAST
+(4 rows)
+
+SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT t2.c1, t3.c1 FROM ft4 t2 LEFT JOIN ft5 t3 ON (t2.c1 = t3.c1) WHERE (t2.c1 between 50 and 60)) ss(a, b) ON (t1.c1 = ss.a) ORDER BY t1.c1, ss.a, ss.b;
+ c1 | a  | b  
+----+----+----
+ 50 | 50 |   
+ 52 | 52 |   
+ 54 | 54 | 54
+ 56 | 56 |   
+ 58 | 58 |   
+ 60 | 60 | 60
+(6 rows)
+
+-- c. test deparsing the remote query as nested subqueries
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT t2.c1, t3.c1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t2 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t3 ON (t2.c1 = t3.c1) WHERE t2.c1 IS NULL OR t2.c1 IS NOT NULL) ss(a, b) ON (t1.c1 = ss.a) ORDER BY t1.c1, ss.a, ss.b;
+                                                                                                                                                                                                                                                     QUERY PLAN                                                                                                                                                                                                                                                     
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: ft4.c1, ft4_1.c1, ft5.c1
+   Relations: (public.ft4) FULL JOIN ((public.ft4 ft4_1) FULL JOIN (public.ft5))
+   Remote SQL: SELECT s4.c1, s10.c1, s10.c2 FROM ((SELECT c1 FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s4(c1) FULL JOIN (SELECT s8.c1, s9.c1 FROM ((SELECT c1 FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s8(c1) FULL JOIN (SELECT c1 FROM "S 1"."T 4" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s9(c1) ON (((s8.c1 = s9.c1)))) WHERE (((s8.c1 IS NULL) OR (s8.c1 IS NOT NULL)))) s10(c1, c2) ON (((s4.c1 = s10.c1)))) ORDER BY s4.c1 ASC NULLS LAST, s10.c1 ASC NULLS LAST, s10.c2 ASC NULLS LAST
+(4 rows)
+
+SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t1 FULL JOIN (SELECT t2.c1, t3.c1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t2 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t3 ON (t2.c1 = t3.c1) WHERE t2.c1 IS NULL OR t2.c1 IS NOT NULL) ss(a, b) ON (t1.c1 = ss.a) ORDER BY t1.c1, ss.a, ss.b;
+ c1 | a  | b  
+----+----+----
+ 50 | 50 |   
+ 52 | 52 |   
+ 54 | 54 | 54
+ 56 | 56 |   
+ 58 | 58 |   
+ 60 | 60 | 60
+    |    | 51
+    |    | 57
+(8 rows)
+
+-- d. test deparsing rowmarked relations as subqueries
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNER JOIN (SELECT t2.c1, t3.c1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t2 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t3 ON (t2.c1 = t3.c1) WHERE t2.c1 IS NULL OR t2.c1 IS NOT NULL) ss(a, b) ON (TRUE) ORDER BY t1.c1, ss.a, ss.b FOR UPDATE OF t1;
+                                                                                                                                                                                             QUERY PLAN                                                                                                                                                                                             
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ LockRows
+   Output: "T 3".c1, ft4.c1, ft5.c1, "T 3".ctid, ft4.*, ft5.*
+   ->  Nested Loop
+         Output: "T 3".c1, ft4.c1, ft5.c1, "T 3".ctid, ft4.*, ft5.*
+         ->  Foreign Scan
+               Output: ft4.c1, ft4.*, ft5.c1, ft5.*
+               Relations: (public.ft4) FULL JOIN (public.ft5)
+               Remote SQL: SELECT s8.c1, s8.c2, s9.c1, s9.c2 FROM ((SELECT c1, ROW(c1, c2, c3) FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s8(c1, c2) FULL JOIN (SELECT c1, ROW(c1, c2, c3) FROM "S 1"."T 4" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s9(c1, c2) ON (((s8.c1 = s9.c1)))) WHERE (((s8.c1 IS NULL) OR (s8.c1 IS NOT NULL))) ORDER BY s8.c1 ASC NULLS LAST, s9.c1 ASC NULLS LAST
+               ->  Sort
+                     Output: ft4.c1, ft4.*, ft5.c1, ft5.*
+                     Sort Key: ft4.c1, ft5.c1
+                     ->  Hash Full Join
+                           Output: ft4.c1, ft4.*, ft5.c1, ft5.*
+                           Hash Cond: (ft4.c1 = ft5.c1)
+                           Filter: ((ft4.c1 IS NULL) OR (ft4.c1 IS NOT NULL))
+                           ->  Foreign Scan on public.ft4
+                                 Output: ft4.c1, ft4.*
+                                 Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))
+                           ->  Hash
+                                 Output: ft5.c1, ft5.*
+                                 ->  Foreign Scan on public.ft5
+                                       Output: ft5.c1, ft5.*
+                                       Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 4" WHERE ((c1 >= 50)) AND ((c1 <= 60))
+         ->  Materialize
+               Output: "T 3".c1, "T 3".ctid
+               ->  Seq Scan on "S 1"."T 3"
+                     Output: "T 3".c1, "T 3".ctid
+                     Filter: ("T 3".c1 = 50)
+(28 rows)
+
+SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNER JOIN (SELECT t2.c1, t3.c1 FROM (SELECT c1 FROM ft4 WHERE c1 between 50 and 60) t2 FULL JOIN (SELECT c1 FROM ft5 WHERE c1 between 50 and 60) t3 ON (t2.c1 = t3.c1) WHERE t2.c1 IS NULL OR t2.c1 IS NOT NULL) ss(a, b) ON (TRUE) ORDER BY t1.c1, ss.a, ss.b FOR UPDATE OF t1;
+ c1 | a  | b  
+----+----+----
+ 50 | 50 |   
+ 50 | 52 |   
+ 50 | 54 | 54
+ 50 | 56 |   
+ 50 | 58 |   
+ 50 | 60 | 60
+ 50 |    | 51
+ 50 |    | 57
+(8 rows)
+
+-- full outer join + inner join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
+                                                                                                                                                 QUERY PLAN                                                                                                                                                 
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1, t3.c1
+   Relations: ((public.ft4 t1) INNER JOIN (public.ft5 t2)) FULL JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
+ c1 | c1 | c1 
+----+----+----
+ 52 | 51 |   
+ 58 | 57 |   
+    |    |  2
+    |    |  4
+    |    |  6
+    |    |  8
+    |    | 10
+    |    | 12
+    |    | 14
+    |    | 16
+(10 rows)
+
+-- full outer join three tables
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft2 t1) FULL JOIN (public.ft2 t2)) FULL JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 1" r1 FULL JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) FULL JOIN "S 1"."T 3" r4 ON (((r2."C 1" = r4.c1)))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 11 |  1 | 
+ 12 |  2 | AAA012
+ 13 |  3 | 
+ 14 |  4 | AAA014
+ 15 |  5 | 
+ 16 |  6 | AAA016
+ 17 |  7 | 
+ 18 |  8 | AAA018
+ 19 |  9 | 
+ 20 |  0 | AAA020
+(10 rows)
+
+-- full outer join + right outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) RIGHT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft4 t3) LEFT JOIN (public.ft2 t2)) LEFT JOIN (public.ft2 t1)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 3" r4 LEFT JOIN "S 1"."T 1" r2 ON (((r2."C 1" = r4.c1)))) LEFT JOIN "S 1"."T 1" r1 ON (((r1."C 1" = r2."C 1")))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) RIGHT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 22 |  2 | AAA022
+ 24 |  4 | AAA024
+ 26 |  6 | AAA026
+ 28 |  8 | AAA028
+ 30 |  0 | AAA030
+ 32 |  2 | AAA032
+ 34 |  4 | AAA034
+ 36 |  6 | AAA036
+ 38 |  8 | AAA038
+ 40 |  0 | AAA040
+(10 rows)
+
+-- right outer join + full outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 RIGHT JOIN ft2 t2 ON (t1.c1 = t2.c1) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft2 t2) LEFT JOIN (public.ft2 t1)) FULL JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 1" r2 LEFT JOIN "S 1"."T 1" r1 ON (((r1."C 1" = r2."C 1")))) FULL JOIN "S 1"."T 3" r4 ON (((r2."C 1" = r4.c1)))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 RIGHT JOIN ft2 t2 ON (t1.c1 = t2.c1) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 11 |  1 | 
+ 12 |  2 | AAA012
+ 13 |  3 | 
+ 14 |  4 | AAA014
+ 15 |  5 | 
+ 16 |  6 | AAA016
+ 17 |  7 | 
+ 18 |  8 | AAA018
+ 19 |  9 | 
+ 20 |  0 | AAA020
+(10 rows)
+
+-- full outer join + left outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) LEFT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft2 t1) FULL JOIN (public.ft2 t2)) LEFT JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 1" r1 FULL JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) LEFT JOIN "S 1"."T 3" r4 ON (((r2."C 1" = r4.c1)))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) LEFT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 11 |  1 | 
+ 12 |  2 | AAA012
+ 13 |  3 | 
+ 14 |  4 | AAA014
+ 15 |  5 | 
+ 16 |  6 | AAA016
+ 17 |  7 | 
+ 18 |  8 | AAA018
+ 19 |  9 | 
+ 20 |  0 | AAA020
+(10 rows)
+
+-- left outer join + full outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft2 t1) LEFT JOIN (public.ft2 t2)) FULL JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 1" r1 LEFT JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) FULL JOIN "S 1"."T 3" r4 ON (((r2."C 1" = r4.c1)))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 11 |  1 | 
+ 12 |  2 | AAA012
+ 13 |  3 | 
+ 14 |  4 | AAA014
+ 15 |  5 | 
+ 16 |  6 | AAA016
+ 17 |  7 | 
+ 18 |  8 | AAA018
+ 19 |  9 | 
+ 20 |  0 | AAA020
+(10 rows)
+
+SET enable_memoize TO off;
+-- right outer join + left outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 RIGHT JOIN ft2 t2 ON (t1.c1 = t2.c1) LEFT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                   QUERY PLAN                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: ((public.ft2 t2) LEFT JOIN (public.ft2 t1)) LEFT JOIN (public.ft4 t3)
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM (("S 1"."T 1" r2 LEFT JOIN "S 1"."T 1" r1 ON (((r1."C 1" = r2."C 1")))) LEFT JOIN "S 1"."T 3" r4 ON (((r2."C 1" = r4.c1)))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 RIGHT JOIN ft2 t2 ON (t1.c1 = t2.c1) LEFT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 11 |  1 | 
+ 12 |  2 | AAA012
+ 13 |  3 | 
+ 14 |  4 | AAA014
+ 15 |  5 | 
+ 16 |  6 | AAA016
+ 17 |  7 | 
+ 18 |  8 | AAA018
+ 19 |  9 | 
+ 20 |  0 | AAA020
+(10 rows)
+
+RESET enable_memoize;
+-- left outer join + right outer join
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) RIGHT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+                                                                                                    QUERY PLAN                                                                                                    
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t3.c3
+   Relations: (public.ft4 t3) LEFT JOIN ((public.ft2 t1) INNER JOIN (public.ft2 t2))
+   Remote SQL: SELECT r1."C 1", r2.c2, r4.c3 FROM ("S 1"."T 3" r4 LEFT JOIN ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ON (((r2."C 1" = r4.c1)))) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) RIGHT JOIN ft4 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
+ c1 | c2 |   c3   
+----+----+--------
+ 22 |  2 | AAA022
+ 24 |  4 | AAA024
+ 26 |  6 | AAA026
+ 28 |  8 | AAA028
+ 30 |  0 | AAA030
+ 32 |  2 | AAA032
+ 34 |  4 | AAA034
+ 36 |  6 | AAA036
+ 38 |  8 | AAA038
+ 40 |  0 | AAA040
+(10 rows)
+
+-- full outer join + WHERE clause, only matched rows
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft4 t1 FULL JOIN ft5 t2 ON (t1.c1 = t2.c1) WHERE (t1.c1 = t2.c1 OR t1.c1 IS NULL) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+                                                                            QUERY PLAN                                                                            
+------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2.c1
+   ->  Sort
+         Output: t1.c1, t2.c1
+         Sort Key: t1.c1, t2.c1
+         ->  Foreign Scan
+               Output: t1.c1, t2.c1
+               Relations: (public.ft4 t1) FULL JOIN (public.ft5 t2)
+               Remote SQL: SELECT r1.c1, r2.c1 FROM ("S 1"."T 3" r1 FULL JOIN "S 1"."T 4" r2 ON (((r1.c1 = r2.c1)))) WHERE (((r1.c1 = r2.c1) OR (r1.c1 IS NULL)))
+(9 rows)
+
+SELECT t1.c1, t2.c1 FROM ft4 t1 FULL JOIN ft5 t2 ON (t1.c1 = t2.c1) WHERE (t1.c1 = t2.c1 OR t1.c1 IS NULL) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+ c1 | c1 
+----+----
+ 66 | 66
+ 72 | 72
+ 78 | 78
+ 84 | 84
+ 90 | 90
+ 96 | 96
+    |  3
+    |  9
+    | 15
+    | 21
+(10 rows)
+
+-- full outer join + WHERE clause with shippable extensions set
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t1.c3 FROM ft1 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE postgres_fdw_abs(t1.c1) > 0 OFFSET 10 LIMIT 10;
+                                                                                                 QUERY PLAN                                                                                                 
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c2, t1.c3
+   Relations: (public.ft1 t1) FULL JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1."C 1", r2.c2, r1.c3 FROM ("S 1"."T 1" r1 FULL JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) WHERE ((public.postgres_fdw_abs(r1."C 1") > 0)) LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+ALTER SERVER loopback OPTIONS (DROP extensions);
+-- full outer join + WHERE clause with shippable extensions not set
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2, t1.c3 FROM ft1 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE postgres_fdw_abs(t1.c1) > 0 OFFSET 10 LIMIT 10;
+                                                          QUERY PLAN                                                           
+-------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2.c2, t1.c3
+   ->  Foreign Scan
+         Output: t1.c1, t2.c2, t1.c3
+         Filter: (postgres_fdw_abs(t1.c1) > 0)
+         Relations: (public.ft1 t1) FULL JOIN (public.ft2 t2)
+         Remote SQL: SELECT r1."C 1", r2.c2, r1.c3 FROM ("S 1"."T 1" r1 FULL JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1"))))
+(7 rows)
+
+ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
+-- join two tables with FOR UPDATE clause
+-- tests whole-row reference for row marks
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR UPDATE OF t1;
+                                                                                                                                                                                                                           QUERY PLAN                                                                                                                                                                                                                            
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint FOR UPDATE OF r1
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR UPDATE OF t1;
+ c1  | c1  
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR UPDATE;
+                                                                                                                                                                                                                                    QUERY PLAN                                                                                                                                                                                                                                    
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint FOR UPDATE OF r1 FOR UPDATE OF r2
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR UPDATE;
+ c1  | c1  
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+-- join two tables with FOR SHARE clause
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR SHARE OF t1;
+                                                                                                                                                                                                                           QUERY PLAN                                                                                                                                                                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint FOR SHARE OF r1
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR SHARE OF t1;
+ c1  | c1  
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR SHARE;
+                                                                                                                                                                                                                                   QUERY PLAN                                                                                                                                                                                                                                   
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1, t1.c3, t1.*, t2.*
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint FOR SHARE OF r1 FOR SHARE OF r2
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10 FOR SHARE;
+ c1  | c1  
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+-- join in CTE
+EXPLAIN (VERBOSE, COSTS OFF)
+WITH t (c1_1, c1_3, c2_1) AS MATERIALIZED (SELECT t1.c1, t1.c3, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1)) SELECT c1_1, c2_1 FROM t ORDER BY c1_3, c1_1 OFFSET 100 LIMIT 10;
+                                                             QUERY PLAN                                                              
+-------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t.c1_1, t.c2_1, t.c1_3
+   CTE t
+     ->  Foreign Scan
+           Output: t1.c1, t1.c3, t2.c1
+           Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+           Remote SQL: SELECT r1."C 1", r1.c3, r2."C 1" FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1"))))
+   ->  Sort
+         Output: t.c1_1, t.c2_1, t.c1_3
+         Sort Key: t.c1_3, t.c1_1
+         ->  CTE Scan on t
+               Output: t.c1_1, t.c2_1, t.c1_3
+(12 rows)
+
+WITH t (c1_1, c1_3, c2_1) AS MATERIALIZED (SELECT t1.c1, t1.c3, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1)) SELECT c1_1, c2_1 FROM t ORDER BY c1_3, c1_1 OFFSET 100 LIMIT 10;
+ c1_1 | c2_1 
+------+------
+  101 |  101
+  102 |  102
+  103 |  103
+  104 |  104
+  105 |  105
+  106 |  106
+  107 |  107
+  108 |  108
+  109 |  109
+  110 |  110
+(10 rows)
+
+-- ctid with whole-row reference
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.ctid, t1, t2, t1.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                                                                                                                                                                                                  QUERY PLAN                                                                                                                                                                                                                   
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.ctid, t1.*, t2.*, t1.c1, t1.c3
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r1."C 1", r1.c3 FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")))) ORDER BY r1.c3 ASC NULLS LAST, r1."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint
+(4 rows)
+
+-- SEMI JOIN, not pushed down
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1 FROM ft1 t1 WHERE EXISTS (SELECT 1 FROM ft2 t2 WHERE t1.c1 = t2.c1) ORDER BY t1.c1 OFFSET 100 LIMIT 10;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1
+   ->  Merge Semi Join
+         Output: t1.c1
+         Merge Cond: (t1.c1 = t2.c1)
+         ->  Foreign Scan on public.ft1 t1
+               Output: t1.c1
+               Remote SQL: SELECT "C 1" FROM "S 1"."T 1" ORDER BY "C 1" ASC NULLS LAST
+         ->  Foreign Scan on public.ft2 t2
+               Output: t2.c1
+               Remote SQL: SELECT "C 1" FROM "S 1"."T 1" ORDER BY "C 1" ASC NULLS LAST
+(11 rows)
+
+SELECT t1.c1 FROM ft1 t1 WHERE EXISTS (SELECT 1 FROM ft2 t2 WHERE t1.c1 = t2.c1) ORDER BY t1.c1 OFFSET 100 LIMIT 10;
+ c1  
+-----
+ 101
+ 102
+ 103
+ 104
+ 105
+ 106
+ 107
+ 108
+ 109
+ 110
+(10 rows)
+
+-- ANTI JOIN, not pushed down
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1 FROM ft1 t1 WHERE NOT EXISTS (SELECT 1 FROM ft2 t2 WHERE t1.c1 = t2.c2) ORDER BY t1.c1 OFFSET 100 LIMIT 10;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1
+   ->  Merge Anti Join
+         Output: t1.c1
+         Merge Cond: (t1.c1 = t2.c2)
+         ->  Foreign Scan on public.ft1 t1
+               Output: t1.c1
+               Remote SQL: SELECT "C 1" FROM "S 1"."T 1" ORDER BY "C 1" ASC NULLS LAST
+         ->  Foreign Scan on public.ft2 t2
+               Output: t2.c2
+               Remote SQL: SELECT c2 FROM "S 1"."T 1" ORDER BY c2 ASC NULLS LAST
+(11 rows)
+
+SELECT t1.c1 FROM ft1 t1 WHERE NOT EXISTS (SELECT 1 FROM ft2 t2 WHERE t1.c1 = t2.c2) ORDER BY t1.c1 OFFSET 100 LIMIT 10;
+ c1  
+-----
+ 110
+ 111
+ 112
+ 113
+ 114
+ 115
+ 116
+ 117
+ 118
+ 119
+(10 rows)
+
+-- CROSS JOIN can be pushed down
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 CROSS JOIN ft2 t2 ORDER BY t1.c1, t2.c1 OFFSET 100 LIMIT 10;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c1, t2.c1
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1."C 1", r2."C 1" FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (TRUE)) ORDER BY r1."C 1" ASC NULLS LAST, r2."C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 100::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 CROSS JOIN ft2 t2 ORDER BY t1.c1, t2.c1 OFFSET 100 LIMIT 10;
+ c1 | c1  
+----+-----
+  1 | 101
+  1 | 102
+  1 | 103
+  1 | 104
+  1 | 105
+  1 | 106
+  1 | 107
+  1 | 108
+  1 | 109
+  1 | 110
+(10 rows)
+
+-- different server, not pushed down. No result expected.
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft5 t1 JOIN ft6 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 100 LIMIT 10;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2.c1
+   ->  Merge Join
+         Output: t1.c1, t2.c1
+         Merge Cond: (t2.c1 = t1.c1)
+         ->  Foreign Scan on public.ft6 t2
+               Output: t2.c1, t2.c2, t2.c3
+               Remote SQL: SELECT c1 FROM "S 1"."T 4" ORDER BY c1 ASC NULLS LAST
+         ->  Materialize
+               Output: t1.c1, t1.c2, t1.c3
+               ->  Foreign Scan on public.ft5 t1
+                     Output: t1.c1, t1.c2, t1.c3
+                     Remote SQL: SELECT c1 FROM "S 1"."T 4" ORDER BY c1 ASC NULLS LAST
+(13 rows)
+
+SELECT t1.c1, t2.c1 FROM ft5 t1 JOIN ft6 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 100 LIMIT 10;
+ c1 | c1 
+----+----
+(0 rows)
+
+-- unsafe join conditions (c8 has a UDT), not pushed down. Practically a CROSS
+-- JOIN since c8 in both tables has same value.
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 LEFT JOIN ft2 t2 ON (t1.c8 = t2.c8) ORDER BY t1.c1, t2.c1 OFFSET 100 LIMIT 10;
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2.c1
+   ->  Sort
+         Output: t1.c1, t2.c1
+         Sort Key: t1.c1, t2.c1
+         ->  Merge Left Join
+               Output: t1.c1, t2.c1
+               Merge Cond: (t1.c8 = t2.c8)
+               ->  Sort
+                     Output: t1.c1, t1.c8
+                     Sort Key: t1.c8
+                     ->  Foreign Scan on public.ft1 t1
+                           Output: t1.c1, t1.c8
+                           Remote SQL: SELECT "C 1", c8 FROM "S 1"."T 1"
+               ->  Sort
+                     Output: t2.c1, t2.c8
+                     Sort Key: t2.c8
+                     ->  Foreign Scan on public.ft2 t2
+                           Output: t2.c1, t2.c8
+                           Remote SQL: SELECT "C 1", c8 FROM "S 1"."T 1"
+(20 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 LEFT JOIN ft2 t2 ON (t1.c8 = t2.c8) ORDER BY t1.c1, t2.c1 OFFSET 100 LIMIT 10;
+ c1 | c1  
+----+-----
+  1 | 101
+  1 | 102
+  1 | 103
+  1 | 104
+  1 | 105
+  1 | 106
+  1 | 107
+  1 | 108
+  1 | 109
+  1 | 110
+(10 rows)
+
+-- unsafe conditions on one side (c8 has a UDT), not pushed down.
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE t1.c8 = 'foo' ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2.c1, t1.c3
+   ->  Sort
+         Output: t1.c1, t2.c1, t1.c3
+         Sort Key: t1.c3, t1.c1
+         ->  Hash Right Join
+               Output: t1.c1, t2.c1, t1.c3
+               Hash Cond: (t2.c1 = t1.c1)
+               ->  Foreign Scan on public.ft2 t2
+                     Output: t2.c1
+                     Remote SQL: SELECT "C 1" FROM "S 1"."T 1"
+               ->  Hash
+                     Output: t1.c1, t1.c3
+                     ->  Foreign Scan on public.ft1 t1
+                           Output: t1.c1, t1.c3
+                           Filter: (t1.c8 = 'foo'::user_enum)
+                           Remote SQL: SELECT "C 1", c3, c8 FROM "S 1"."T 1"
+(17 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE t1.c8 = 'foo' ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+ c1  | c1  
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+-- join where unsafe to pushdown condition in WHERE clause has a column not
+-- in the SELECT clause. In this test unsafe clause needs to have column
+-- references from both joining sides so that the clause is not pushed down
+-- into one of the joining sides.
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE t1.c8 = t2.c8 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                                                      QUERY PLAN                                                                       
+-------------------------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, t2.c1, t1.c3
+   ->  Sort
+         Output: t1.c1, t2.c1, t1.c3
+         Sort Key: t1.c3, t1.c1
+         ->  Foreign Scan
+               Output: t1.c1, t2.c1, t1.c3
+               Filter: (t1.c8 = t2.c8)
+               Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+               Remote SQL: SELECT r1."C 1", r2."C 1", r1.c3, r1.c8, r2.c8 FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1"))))
+(10 rows)
+
+SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE t1.c8 = t2.c8 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+ c1  | c1  
+-----+-----
+ 101 | 101
+ 102 | 102
+ 103 | 103
+ 104 | 104
+ 105 | 105
+ 106 | 106
+ 107 | 107
+ 108 | 108
+ 109 | 109
+ 110 | 110
+(10 rows)
+
+-- Aggregate after UNION, for testing setrefs
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1c1, avg(t1c1 + t2c1) FROM (SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) UNION SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1)) AS t (t1c1, t2c1) GROUP BY t1c1 ORDER BY t1c1 OFFSET 100 LIMIT 10;
+                                                                     QUERY PLAN                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1.c1, (avg((t1.c1 + t2.c1)))
+   ->  Sort
+         Output: t1.c1, (avg((t1.c1 + t2.c1)))
+         Sort Key: t1.c1
+         ->  HashAggregate
+               Output: t1.c1, avg((t1.c1 + t2.c1))
+               Group Key: t1.c1
+               ->  HashAggregate
+                     Output: t1.c1, t2.c1
+                     Group Key: t1.c1, t2.c1
+                     ->  Append
+                           ->  Foreign Scan
+                                 Output: t1.c1, t2.c1
+                                 Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+                                 Remote SQL: SELECT r1."C 1", r2."C 1" FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1"))))
+                           ->  Foreign Scan
+                                 Output: t1_1.c1, t2_1.c1
+                                 Relations: (public.ft1 t1_1) INNER JOIN (public.ft2 t2_1)
+                                 Remote SQL: SELECT r1."C 1", r2."C 1" FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1"))))
+(20 rows)
+
+SELECT t1c1, avg(t1c1 + t2c1) FROM (SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1) UNION SELECT t1.c1, t2.c1 FROM ft1 t1 JOIN ft2 t2 ON (t1.c1 = t2.c1)) AS t (t1c1, t2c1) GROUP BY t1c1 ORDER BY t1c1 OFFSET 100 LIMIT 10;
+ t1c1 |         avg          
+------+----------------------
+  101 | 202.0000000000000000
+  102 | 204.0000000000000000
+  103 | 206.0000000000000000
+  104 | 208.0000000000000000
+  105 | 210.0000000000000000
+  106 | 212.0000000000000000
+  107 | 214.0000000000000000
+  108 | 216.0000000000000000
+  109 | 218.0000000000000000
+  110 | 220.0000000000000000
+(10 rows)
+
+-- join with lateral reference
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1."C 1" FROM "S 1"."T 1" t1, LATERAL (SELECT DISTINCT t2.c1, t3.c1 FROM ft1 t2, ft2 t3 WHERE t2.c1 = t3.c1 AND t2.c2 = t1.c2) q ORDER BY t1."C 1" OFFSET 10 LIMIT 10;
+                                                                                   QUERY PLAN                                                                                   
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Limit
+   Output: t1."C 1"
+   ->  Nested Loop
+         Output: t1."C 1"
+         ->  Index Scan using t1_pkey on "S 1"."T 1" t1
+               Output: t1."C 1", t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+         ->  Memoize
+               Cache Key: t1.c2
+               Cache Mode: binary
+               ->  Subquery Scan on q
+                     ->  HashAggregate
+                           Output: t2.c1, t3.c1
+                           Group Key: t2.c1, t3.c1
+                           ->  Foreign Scan
+                                 Output: t2.c1, t3.c1
+                                 Relations: (public.ft1 t2) INNER JOIN (public.ft2 t3)
+                                 Remote SQL: SELECT r1."C 1", r2."C 1" FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1.c2 = $1::integer))))
+(17 rows)
+
+SELECT t1."C 1" FROM "S 1"."T 1" t1, LATERAL (SELECT DISTINCT t2.c1, t3.c1 FROM ft1 t2, ft2 t3 WHERE t2.c1 = t3.c1 AND t2.c2 = t1.c2) q ORDER BY t1."C 1" OFFSET 10 LIMIT 10;
+ C 1 
+-----
+   1
+   1
+   1
+   1
+   1
+   1
+   1
+   1
+   1
+   1
+(10 rows)
+
+-- non-Var items in targetlist of the nullable rel of a join preventing
+-- push-down in some cases
+-- unable to push {ft1, ft2}
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT q.a, ft2.c1 FROM (SELECT 13 FROM ft1 WHERE c1 = 13) q(a) RIGHT JOIN ft2 ON (q.a = ft2.c1) WHERE ft2.c1 BETWEEN 10 AND 15;
+                                                        QUERY PLAN                                                         
+---------------------------------------------------------------------------------------------------------------------------
+ Nested Loop Left Join
+   Output: (13), ft2.c1
+   Join Filter: (13 = ft2.c1)
+   ->  Foreign Scan on public.ft2
+         Output: ft2.c1
+         Remote SQL: SELECT "C 1" FROM "S 1"."T 1" WHERE (("C 1" >= 10)) AND (("C 1" <= 15)) ORDER BY "C 1" ASC NULLS LAST
+   ->  Materialize
+         Output: (13)
+         ->  Foreign Scan on public.ft1
+               Output: 13
+               Remote SQL: SELECT NULL FROM "S 1"."T 1" WHERE (("C 1" = 13))
+(11 rows)
+
+SELECT q.a, ft2.c1 FROM (SELECT 13 FROM ft1 WHERE c1 = 13) q(a) RIGHT JOIN ft2 ON (q.a = ft2.c1) WHERE ft2.c1 BETWEEN 10 AND 15;
+ a  | c1 
+----+----
+    | 10
+    | 11
+    | 12
+ 13 | 13
+    | 14
+    | 15
+(6 rows)
+
+-- ok to push {ft1, ft2} but not {ft1, ft2, ft4}
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT JOIN ft2 ON (ft1.c1 = ft2.c1) WHERE ft1.c1 = 12) q(a, b, c) ON (ft4.c1 = q.b) WHERE ft4.c1 BETWEEN 10 AND 15;
+                                                                                    QUERY PLAN                                                                                     
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Nested Loop Left Join
+   Output: ft4.c1, (13), ft1.c1, ft2.c1
+   Join Filter: (ft4.c1 = ft1.c1)
+   ->  Foreign Scan on public.ft4
+         Output: ft4.c1, ft4.c2, ft4.c3
+         Remote SQL: SELECT c1 FROM "S 1"."T 3" WHERE ((c1 >= 10)) AND ((c1 <= 15))
+   ->  Materialize
+         Output: ft1.c1, ft2.c1, (13)
+         ->  Foreign Scan
+               Output: ft1.c1, ft2.c1, 13
+               Relations: (public.ft1) INNER JOIN (public.ft2)
+               Remote SQL: SELECT r4."C 1", r5."C 1" FROM ("S 1"."T 1" r4 INNER JOIN "S 1"."T 1" r5 ON (((r5."C 1" = 12)) AND ((r4."C 1" = 12)))) ORDER BY r4."C 1" ASC NULLS LAST
+(12 rows)
+
+SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT JOIN ft2 ON (ft1.c1 = ft2.c1) WHERE ft1.c1 = 12) q(a, b, c) ON (ft4.c1 = q.b) WHERE ft4.c1 BETWEEN 10 AND 15;
+ c1 | a  | b  | c  
+----+----+----+----
+ 10 |    |    |   
+ 12 | 13 | 12 | 12
+ 14 |    |    |   
+(3 rows)
+
+-- join with nullable side with some columns with null values
+UPDATE ft5 SET c3 = null where c1 % 9 = 0;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
+                                                                                                                                QUERY PLAN                                                                                                                                 
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
+   Relations: (public.ft5) INNER JOIN (public.ft4)
+   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
+(4 rows)
+
+SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
+      ft5       | c1 | c2 |   c3   | c1 | c2 
+----------------+----+----+--------+----+----
+ (12,13,AAA012) | 12 | 13 | AAA012 | 12 | 13
+ (18,19,)       | 18 | 19 |        | 18 | 19
+ (24,25,AAA024) | 24 | 25 | AAA024 | 24 | 25
+ (30,31,AAA030) | 30 | 31 | AAA030 | 30 | 31
+(4 rows)
+
+-- multi-way join involving multiple merge joins
+-- (this case used to have EPQ-related planning problems)
+CREATE TABLE local_tbl (c1 int NOT NULL, c2 int NOT NULL, c3 text, CONSTRAINT local_tbl_pkey PRIMARY KEY (c1));
+INSERT INTO local_tbl SELECT id, id % 10, to_char(id, 'FM0000') FROM generate_series(1, 1000) id;
+ANALYZE local_tbl;
+SET enable_nestloop TO false;
+SET enable_hashjoin TO false;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
+    AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
+                                                                                                                                                                                                                                                                                                                                                                                                                                               QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                               
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ LockRows
+   Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
+   ->  Merge Join
+         Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
+         Inner Unique: true
+         Merge Cond: (ft1.c2 = local_tbl.c1)
+         ->  Foreign Scan
+               Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
+               Relations: (((public.ft1) INNER JOIN (public.ft2)) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
+               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
+               ->  Merge Join
+                     Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
+                     Merge Cond: (ft1.c2 = ft5.c1)
+                     ->  Merge Join
+                           Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*
+                           Merge Cond: (ft1.c2 = ft4.c1)
+                           ->  Sort
+                                 Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
+                                 Sort Key: ft1.c2
+                                 ->  Merge Join
+                                       Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
+                                       Merge Cond: (ft1.c1 = ft2.c1)
+                                       ->  Sort
+                                             Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
+                                             Sort Key: ft1.c1
+                                             ->  Foreign Scan on public.ft1
+                                                   Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
+                                       ->  Materialize
+                                             Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
+                                             ->  Foreign Scan on public.ft2
+                                                   Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+                           ->  Sort
+                                 Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
+                                 Sort Key: ft4.c1
+                                 ->  Foreign Scan on public.ft4
+                                       Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
+                                       Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 3" FOR UPDATE
+                     ->  Sort
+                           Output: ft5.c1, ft5.c2, ft5.c3, ft5.*
+                           Sort Key: ft5.c1
+                           ->  Foreign Scan on public.ft5
+                                 Output: ft5.c1, ft5.c2, ft5.c3, ft5.*
+                                 Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 4" FOR UPDATE
+         ->  Index Scan using local_tbl_pkey on public.local_tbl
+               Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, local_tbl.ctid
+(47 rows)
+
+SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
+    AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  | c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  | c1 | c2 |   c3   | c1 | c2 |   c3   | c1 | c2 |  c3  
+----+----+-------+------------------------------+--------------------------+----+------------+-----+----+----+-------+------------------------------+--------------------------+----+------------+-----+----+----+--------+----+----+--------+----+----+------
+  6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo |  6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 16 |  6 | 00016 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo | 16 |  6 | 00016 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 26 |  6 | 00026 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo | 26 |  6 | 00026 | Tue Jan 27 00:00:00 1970 PST | Tue Jan 27 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 36 |  6 | 00036 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo | 36 |  6 | 00036 | Fri Feb 06 00:00:00 1970 PST | Fri Feb 06 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 46 |  6 | 00046 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo | 46 |  6 | 00046 | Mon Feb 16 00:00:00 1970 PST | Mon Feb 16 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 56 |  6 | 00056 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo | 56 |  6 | 00056 | Thu Feb 26 00:00:00 1970 PST | Thu Feb 26 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 66 |  6 | 00066 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo | 66 |  6 | 00066 | Sun Mar 08 00:00:00 1970 PST | Sun Mar 08 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 76 |  6 | 00076 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo | 76 |  6 | 00076 | Wed Mar 18 00:00:00 1970 PST | Wed Mar 18 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 86 |  6 | 00086 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo | 86 |  6 | 00086 | Sat Mar 28 00:00:00 1970 PST | Sat Mar 28 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+ 96 |  6 | 00096 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo | 96 |  6 | 00096 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6  | 6          | foo |  6 |  7 | AAA006 |  6 |  7 | AAA006 |  6 |  6 | 0006
+(10 rows)
+
+RESET enable_nestloop;
+RESET enable_hashjoin;
+-- test that add_paths_with_pathkeys_for_rel() arranges for the epq_path to
+-- return columns needed by the parent ForeignScan node
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM local_tbl LEFT JOIN (SELECT ft1.*, COALESCE(ft1.c3 || ft2.c3, 'foobar') FROM ft1 INNER JOIN ft2 ON (ft1.c1 = ft2.c1 AND ft1.c1 < 100)) ss ON (local_tbl.c1 = ss.c1) ORDER BY local_tbl.c1 FOR UPDATE OF local_tbl;
+                                                                                                                                                                                                                              QUERY PLAN                                                                                                                                                                                                                              
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ LockRows
+   Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, (COALESCE((ft1.c3 || ft2.c3), 'foobar'::text)), local_tbl.ctid, ft1.*, ft2.*
+   ->  Merge Left Join
+         Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, (COALESCE((ft1.c3 || ft2.c3), 'foobar'::text)), local_tbl.ctid, ft1.*, ft2.*
+         Merge Cond: (local_tbl.c1 = ft1.c1)
+         ->  Index Scan using local_tbl_pkey on public.local_tbl
+               Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, local_tbl.ctid
+         ->  Materialize
+               Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*, (COALESCE((ft1.c3 || ft2.c3), 'foobar'::text))
+               ->  Foreign Scan
+                     Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*, COALESCE((ft1.c3 || ft2.c3), 'foobar'::text)
+                     Relations: (public.ft1) INNER JOIN (public.ft2)
+                     Remote SQL: SELECT r4."C 1", r4.c2, r4.c3, r4.c4, r4.c5, r4.c6, r4.c7, r4.c8, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4."C 1", r4.c2, r4.c3, r4.c4, r4.c5, r4.c6, r4.c7, r4.c8) END, CASE WHEN (r5.*)::text IS NOT NULL THEN ROW(r5."C 1", r5.c2, r5.c3, r5.c4, r5.c5, r5.c6, r5.c7, r5.c8) END, r5.c3 FROM ("S 1"."T 1" r4 INNER JOIN "S 1"."T 1" r5 ON (((r4."C 1" = r5."C 1")) AND ((r4."C 1" < 100)))) ORDER BY r4."C 1" ASC NULLS LAST
+                     ->  Result
+                           Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*, ft2.c3
+                           ->  Sort
+                                 Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*, (COALESCE((ft1.c3 || ft2.c3), 'foobar'::text)), ft2.c3
+                                 Sort Key: ft1.c1
+                                 ->  Hash Join
+                                       Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*, COALESCE((ft1.c3 || ft2.c3), 'foobar'::text), ft2.c3
+                                       Hash Cond: (ft1.c1 = ft2.c1)
+                                       ->  Foreign Scan on public.ft1
+                                             Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
+                                             Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100))
+                                       ->  Hash
+                                             Output: ft2.*, ft2.c1, ft2.c3
+                                             ->  Foreign Scan on public.ft2
+                                                   Output: ft2.*, ft2.c1, ft2.c3
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(29 rows)
+
+ALTER SERVER loopback OPTIONS (DROP extensions);
+ALTER SERVER loopback OPTIONS (ADD fdw_startup_cost '10000.0');
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM local_tbl LEFT JOIN (SELECT ft1.* FROM ft1 INNER JOIN ft2 ON (ft1.c1 = ft2.c1 AND ft1.c1 < 100 AND ft1.c1 = postgres_fdw_abs(ft2.c2))) ss ON (local_tbl.c3 = ss.c3) ORDER BY local_tbl.c1 FOR UPDATE OF local_tbl;
+                                                                                                                                                                                                                            QUERY PLAN                                                                                                                                                                                                                             
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ LockRows
+   Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, local_tbl.ctid, ft1.*, ft2.*
+   ->  Nested Loop Left Join
+         Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, local_tbl.ctid, ft1.*, ft2.*
+         Join Filter: (local_tbl.c3 = ft1.c3)
+         ->  Index Scan using local_tbl_pkey on public.local_tbl
+               Output: local_tbl.c1, local_tbl.c2, local_tbl.c3, local_tbl.ctid
+         ->  Materialize
+               Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*
+               ->  Foreign Scan
+                     Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*
+                     Filter: (ft1.c1 = postgres_fdw_abs(ft2.c2))
+                     Relations: (public.ft1) INNER JOIN (public.ft2)
+                     Remote SQL: SELECT r4."C 1", r4.c2, r4.c3, r4.c4, r4.c5, r4.c6, r4.c7, r4.c8, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4."C 1", r4.c2, r4.c3, r4.c4, r4.c5, r4.c6, r4.c7, r4.c8) END, CASE WHEN (r5.*)::text IS NOT NULL THEN ROW(r5."C 1", r5.c2, r5.c3, r5.c4, r5.c5, r5.c6, r5.c7, r5.c8) END, r5.c2 FROM ("S 1"."T 1" r4 INNER JOIN "S 1"."T 1" r5 ON (((r4."C 1" = r5."C 1")) AND ((r4."C 1" < 100)))) ORDER BY r4.c3 ASC NULLS LAST
+                     ->  Sort
+                           Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*, ft2.c2
+                           Sort Key: ft1.c3
+                           ->  Merge Join
+                                 Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.*, ft2.c2
+                                 Merge Cond: ((ft1.c1 = (postgres_fdw_abs(ft2.c2))) AND (ft1.c1 = ft2.c1))
+                                 ->  Sort
+                                       Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
+                                       Sort Key: ft1.c1
+                                       ->  Foreign Scan on public.ft1
+                                             Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
+                                             Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100))
+                                 ->  Sort
+                                       Output: ft2.*, ft2.c1, ft2.c2, (postgres_fdw_abs(ft2.c2))
+                                       Sort Key: (postgres_fdw_abs(ft2.c2)), ft2.c1
+                                       ->  Foreign Scan on public.ft2
+                                             Output: ft2.*, ft2.c1, ft2.c2, postgres_fdw_abs(ft2.c2)
+                                             Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" ORDER BY "C 1" ASC NULLS LAST
+(32 rows)
+
+ALTER SERVER loopback OPTIONS (DROP fdw_startup_cost);
+ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
+DROP TABLE local_tbl;
+-- check join pushdown in situations where multiple userids are involved
+CREATE ROLE regress_view_owner SUPERUSER;
+CREATE USER MAPPING FOR regress_view_owner SERVER loopback;
+GRANT SELECT ON ft4 TO regress_view_owner;
+GRANT SELECT ON ft5 TO regress_view_owner;
+CREATE VIEW v4 AS SELECT * FROM ft4;
+CREATE VIEW v5 AS SELECT * FROM ft5;
+ALTER VIEW v5 OWNER TO regress_view_owner;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN v5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;  -- can't be pushed down, different view owners
+                              QUERY PLAN                              
+----------------------------------------------------------------------
+ Limit
+   Output: ft4.c1, ft5.c2, ft5.c1
+   ->  Sort
+         Output: ft4.c1, ft5.c2, ft5.c1
+         Sort Key: ft4.c1, ft5.c1
+         ->  Hash Left Join
+               Output: ft4.c1, ft5.c2, ft5.c1
+               Hash Cond: (ft4.c1 = ft5.c1)
+               ->  Foreign Scan on public.ft4
+                     Output: ft4.c1, ft4.c2, ft4.c3
+                     Remote SQL: SELECT c1 FROM "S 1"."T 3"
+               ->  Hash
+                     Output: ft5.c2, ft5.c1
+                     ->  Foreign Scan on public.ft5
+                           Output: ft5.c2, ft5.c1
+                           Remote SQL: SELECT c1, c2 FROM "S 1"."T 4"
+(16 rows)
+
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN v5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+ c1 | c2 
+----+----
+ 22 |   
+ 24 | 25
+ 26 |   
+ 28 |   
+ 30 | 31
+ 32 |   
+ 34 |   
+ 36 | 37
+ 38 |   
+ 40 |   
+(10 rows)
+
+ALTER VIEW v4 OWNER TO regress_view_owner;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN v5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;  -- can be pushed down
+                                                                                              QUERY PLAN                                                                                               
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: ft4.c1, ft5.c2, ft5.c1
+   Relations: (public.ft4) LEFT JOIN (public.ft5)
+   Remote SQL: SELECT r6.c1, r9.c2, r9.c1 FROM ("S 1"."T 3" r6 LEFT JOIN "S 1"."T 4" r9 ON (((r6.c1 = r9.c1)))) ORDER BY r6.c1 ASC NULLS LAST, r9.c1 ASC NULLS LAST LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN v5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+ c1 | c2 
+----+----
+ 22 |   
+ 24 | 25
+ 26 |   
+ 28 |   
+ 30 | 31
+ 32 |   
+ 34 |   
+ 36 | 37
+ 38 |   
+ 40 |   
+(10 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;  -- can't be pushed down, view owner not current user
+                              QUERY PLAN                              
+----------------------------------------------------------------------
+ Limit
+   Output: ft4.c1, t2.c2, t2.c1
+   ->  Sort
+         Output: ft4.c1, t2.c2, t2.c1
+         Sort Key: ft4.c1, t2.c1
+         ->  Hash Left Join
+               Output: ft4.c1, t2.c2, t2.c1
+               Hash Cond: (ft4.c1 = t2.c1)
+               ->  Foreign Scan on public.ft4
+                     Output: ft4.c1, ft4.c2, ft4.c3
+                     Remote SQL: SELECT c1 FROM "S 1"."T 3"
+               ->  Hash
+                     Output: t2.c2, t2.c1
+                     ->  Foreign Scan on public.ft5 t2
+                           Output: t2.c2, t2.c1
+                           Remote SQL: SELECT c1, c2 FROM "S 1"."T 4"
+(16 rows)
+
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+ c1 | c2 
+----+----
+ 22 |   
+ 24 | 25
+ 26 |   
+ 28 |   
+ 30 | 31
+ 32 |   
+ 34 |   
+ 36 | 37
+ 38 |   
+ 40 |   
+(10 rows)
+
+ALTER VIEW v4 OWNER TO CURRENT_USER;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;  -- can be pushed down
+                                                                                              QUERY PLAN                                                                                               
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: ft4.c1, t2.c2, t2.c1
+   Relations: (public.ft4) LEFT JOIN (public.ft5 t2)
+   Remote SQL: SELECT r6.c1, r2.c2, r2.c1 FROM ("S 1"."T 3" r6 LEFT JOIN "S 1"."T 4" r2 ON (((r6.c1 = r2.c1)))) ORDER BY r6.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST LIMIT 10::bigint OFFSET 10::bigint
+(4 rows)
+
+SELECT t1.c1, t2.c2 FROM v4 t1 LEFT JOIN ft5 t2 ON (t1.c1 = t2.c1) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
+ c1 | c2 
+----+----
+ 22 |   
+ 24 | 25
+ 26 |   
+ 28 |   
+ 30 | 31
+ 32 |   
+ 34 |   
+ 36 | 37
+ 38 |   
+ 40 |   
+(10 rows)
+
+ALTER VIEW v4 OWNER TO regress_view_owner;
+-- cleanup
+DROP OWNED BY regress_view_owner;
+DROP ROLE regress_view_owner;
+-- ===================================================================
+-- Aggregate and grouping queries
+-- ===================================================================
+-- Simple aggregates
+explain (verbose, costs off)
+select count(c6), sum(c1), avg(c1), min(c2), max(c1), stddev(c2), sum(c1) * (random() <= 1)::int as sum2 from ft1 where c2 < 5 group by c2 order by 1, 2;
+                                                                                              QUERY PLAN                                                                                               
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c6)), (sum(c1)), (avg(c1)), (min(c2)), (max(c1)), (stddev(c2)), ((sum(c1)) * ((random() <= '1'::double precision))::integer), c2
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT count(c6), sum("C 1"), avg("C 1"), min(c2), max("C 1"), stddev(c2), c2 FROM "S 1"."T 1" WHERE ((c2 < 5)) GROUP BY 7 ORDER BY count(c6) ASC NULLS LAST, sum("C 1") ASC NULLS LAST
+(4 rows)
+
+select count(c6), sum(c1), avg(c1), min(c2), max(c1), stddev(c2), sum(c1) * (random() <= 1)::int as sum2 from ft1 where c2 < 5 group by c2 order by 1, 2;
+ count |  sum  |         avg          | min | max  | stddev | sum2  
+-------+-------+----------------------+-----+------+--------+-------
+   100 | 49600 | 496.0000000000000000 |   1 |  991 |      0 | 49600
+   100 | 49700 | 497.0000000000000000 |   2 |  992 |      0 | 49700
+   100 | 49800 | 498.0000000000000000 |   3 |  993 |      0 | 49800
+   100 | 49900 | 499.0000000000000000 |   4 |  994 |      0 | 49900
+   100 | 50500 | 505.0000000000000000 |   0 | 1000 |      0 | 50500
+(5 rows)
+
+explain (verbose, costs off)
+select count(c6), sum(c1), avg(c1), min(c2), max(c1), stddev(c2), sum(c1) * (random() <= 1)::int as sum2 from ft1 where c2 < 5 group by c2 order by 1, 2 limit 1;
+                                                                                                      QUERY PLAN                                                                                                       
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c6)), (sum(c1)), (avg(c1)), (min(c2)), (max(c1)), (stddev(c2)), ((sum(c1)) * ((random() <= '1'::double precision))::integer), c2
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT count(c6), sum("C 1"), avg("C 1"), min(c2), max("C 1"), stddev(c2), c2 FROM "S 1"."T 1" WHERE ((c2 < 5)) GROUP BY 7 ORDER BY count(c6) ASC NULLS LAST, sum("C 1") ASC NULLS LAST LIMIT 1::bigint
+(4 rows)
+
+select count(c6), sum(c1), avg(c1), min(c2), max(c1), stddev(c2), sum(c1) * (random() <= 1)::int as sum2 from ft1 where c2 < 5 group by c2 order by 1, 2 limit 1;
+ count |  sum  |         avg          | min | max | stddev | sum2  
+-------+-------+----------------------+-----+-----+--------+-------
+   100 | 49600 | 496.0000000000000000 |   1 | 991 |      0 | 49600
+(1 row)
+
+-- Aggregate is not pushed down as aggregation contains random()
+explain (verbose, costs off)
+select sum(c1 * (random() <= 1)::int) as sum, avg(c1) from ft1;
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Aggregate
+   Output: sum((c1 * ((random() <= '1'::double precision))::integer)), avg(c1)
+   ->  Foreign Scan on public.ft1
+         Output: c1
+         Remote SQL: SELECT "C 1" FROM "S 1"."T 1"
+(5 rows)
+
+-- Aggregate over join query
+explain (verbose, costs off)
+select count(*), sum(t1.c1), avg(t2.c1) from ft1 t1 inner join ft1 t2 on (t1.c2 = t2.c2) where t1.c2 = 6;
+                                                                    QUERY PLAN                                                                    
+--------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(*)), (sum(t1.c1)), (avg(t2.c1))
+   Relations: Aggregate on ((public.ft1 t1) INNER JOIN (public.ft1 t2))
+   Remote SQL: SELECT count(*), sum(r1."C 1"), avg(r2."C 1") FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r2.c2 = 6)) AND ((r1.c2 = 6))))
+(4 rows)
+
+select count(*), sum(t1.c1), avg(t2.c1) from ft1 t1 inner join ft1 t2 on (t1.c2 = t2.c2) where t1.c2 = 6;
+ count |   sum   |         avg          
+-------+---------+----------------------
+ 10000 | 5010000 | 501.0000000000000000
+(1 row)
+
+-- Not pushed down due to local conditions present in underneath input rel
+explain (verbose, costs off)
+select sum(t1.c1), count(t2.c1) from ft1 t1 inner join ft2 t2 on (t1.c1 = t2.c1) where ((t1.c1 * t2.c1)/(t1.c1 * t2.c1)) * random() <= 1;
+                                                         QUERY PLAN                                                         
+----------------------------------------------------------------------------------------------------------------------------
+ Aggregate
+   Output: sum(t1.c1), count(t2.c1)
+   ->  Foreign Scan
+         Output: t1.c1, t2.c1
+         Filter: (((((t1.c1 * t2.c1) / (t1.c1 * t2.c1)))::double precision * random()) <= '1'::double precision)
+         Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+         Remote SQL: SELECT r1."C 1", r2."C 1" FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1"))))
+(7 rows)
+
+-- GROUP BY clause having expressions
+explain (verbose, costs off)
+select c2/2, sum(c2) * (c2/2) from ft1 group by c2/2 order by c2/2;
+                                                    QUERY PLAN                                                    
+------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: ((c2 / 2)), ((sum(c2) * (c2 / 2)))
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT (c2 / 2), (sum(c2) * (c2 / 2)) FROM "S 1"."T 1" GROUP BY 1 ORDER BY (c2 / 2) ASC NULLS LAST
+(4 rows)
+
+select c2/2, sum(c2) * (c2/2) from ft1 group by c2/2 order by c2/2;
+ ?column? | ?column? 
+----------+----------
+        0 |        0
+        1 |      500
+        2 |     1800
+        3 |     3900
+        4 |     6800
+(5 rows)
+
+-- Aggregates in subquery are pushed down.
+explain (verbose, costs off)
+select count(x.a), sum(x.a) from (select c2 a, sum(c1) b from ft1 group by c2, sqrt(c1) order by 1, 2) x;
+                                                                 QUERY PLAN                                                                  
+---------------------------------------------------------------------------------------------------------------------------------------------
+ Aggregate
+   Output: count(ft1.c2), sum(ft1.c2)
+   ->  Foreign Scan
+         Output: ft1.c2, (sum(ft1.c1)), (sqrt((ft1.c1)::double precision))
+         Relations: Aggregate on (public.ft1)
+         Remote SQL: SELECT c2, sum("C 1"), sqrt("C 1") FROM "S 1"."T 1" GROUP BY 1, 3 ORDER BY c2 ASC NULLS LAST, sum("C 1") ASC NULLS LAST
+(6 rows)
+
+select count(x.a), sum(x.a) from (select c2 a, sum(c1) b from ft1 group by c2, sqrt(c1) order by 1, 2) x;
+ count | sum  
+-------+------
+  1000 | 4500
+(1 row)
+
+-- Aggregate is still pushed down by taking unshippable expression out
+explain (verbose, costs off)
+select c2 * (random() <= 1)::int as sum1, sum(c1) * c2 as sum2 from ft1 group by c2 order by 1, 2;
+                                            QUERY PLAN                                             
+---------------------------------------------------------------------------------------------------
+ Sort
+   Output: ((c2 * ((random() <= '1'::double precision))::integer)), ((sum(c1) * c2)), c2
+   Sort Key: ((ft1.c2 * ((random() <= '1'::double precision))::integer)), ((sum(ft1.c1) * ft1.c2))
+   ->  Foreign Scan
+         Output: (c2 * ((random() <= '1'::double precision))::integer), ((sum(c1) * c2)), c2
+         Relations: Aggregate on (public.ft1)
+         Remote SQL: SELECT (sum("C 1") * c2), c2 FROM "S 1"."T 1" GROUP BY 2
+(7 rows)
+
+select c2 * (random() <= 1)::int as sum1, sum(c1) * c2 as sum2 from ft1 group by c2 order by 1, 2;
+ sum1 |  sum2  
+------+--------
+    0 |      0
+    1 |  49600
+    2 |  99400
+    3 | 149400
+    4 | 199600
+    5 | 250000
+    6 | 300600
+    7 | 351400
+    8 | 402400
+    9 | 453600
+(10 rows)
+
+-- Aggregate with unshippable GROUP BY clause are not pushed
+explain (verbose, costs off)
+select c2 * (random() <= 1)::int as c2 from ft2 group by c2 * (random() <= 1)::int order by 1;
+                                  QUERY PLAN                                  
+------------------------------------------------------------------------------
+ Sort
+   Output: ((c2 * ((random() <= '1'::double precision))::integer))
+   Sort Key: ((ft2.c2 * ((random() <= '1'::double precision))::integer))
+   ->  HashAggregate
+         Output: ((c2 * ((random() <= '1'::double precision))::integer))
+         Group Key: (ft2.c2 * ((random() <= '1'::double precision))::integer)
+         ->  Foreign Scan on public.ft2
+               Output: (c2 * ((random() <= '1'::double precision))::integer)
+               Remote SQL: SELECT c2 FROM "S 1"."T 1"
+(9 rows)
+
+-- GROUP BY clause in various forms, cardinal, alias and constant expression
+explain (verbose, costs off)
+select count(c2) w, c2 x, 5 y, 7.0 z from ft1 group by 2, y, 9.0::int order by 2;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Sort
+   Output: (count(c2)), c2, 5, 7.0, 9
+   Sort Key: ft1.c2
+   ->  Foreign Scan
+         Output: (count(c2)), c2, 5, 7.0, 9
+         Relations: Aggregate on (public.ft1)
+         Remote SQL: SELECT count(c2), c2, 5, 7.0, 9 FROM "S 1"."T 1" GROUP BY 2, 3, 5
+(7 rows)
+
+select count(c2) w, c2 x, 5 y, 7.0 z from ft1 group by 2, y, 9.0::int order by 2;
+  w  | x | y |  z  
+-----+---+---+-----
+ 100 | 0 | 5 | 7.0
+ 100 | 1 | 5 | 7.0
+ 100 | 2 | 5 | 7.0
+ 100 | 3 | 5 | 7.0
+ 100 | 4 | 5 | 7.0
+ 100 | 5 | 5 | 7.0
+ 100 | 6 | 5 | 7.0
+ 100 | 7 | 5 | 7.0
+ 100 | 8 | 5 | 7.0
+ 100 | 9 | 5 | 7.0
+(10 rows)
+
+-- GROUP BY clause referring to same column multiple times
+-- Also, ORDER BY contains an aggregate function
+explain (verbose, costs off)
+select c2, c2 from ft1 where c2 > 6 group by 1, 2 order by sum(c1);
+                                                         QUERY PLAN                                                         
+----------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: c2, c2, (sum(c1))
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT c2, c2, sum("C 1") FROM "S 1"."T 1" WHERE ((c2 > 6)) GROUP BY 1, 2 ORDER BY sum("C 1") ASC NULLS LAST
+(4 rows)
+
+select c2, c2 from ft1 where c2 > 6 group by 1, 2 order by sum(c1);
+ c2 | c2 
+----+----
+  7 |  7
+  8 |  8
+  9 |  9
+(3 rows)
+
+-- Testing HAVING clause shippability
+explain (verbose, costs off)
+select c2, sum(c1) from ft2 group by c2 having avg(c1) < 500 and sum(c1) < 49800 order by c2;
+                                                                         QUERY PLAN                                                                         
+------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: c2, (sum(c1))
+   Relations: Aggregate on (public.ft2)
+   Remote SQL: SELECT c2, sum("C 1") FROM "S 1"."T 1" GROUP BY 1 HAVING ((avg("C 1") < 500::numeric)) AND ((sum("C 1") < 49800)) ORDER BY c2 ASC NULLS LAST
+(4 rows)
+
+select c2, sum(c1) from ft2 group by c2 having avg(c1) < 500 and sum(c1) < 49800 order by c2;
+ c2 |  sum  
+----+-------
+  1 | 49600
+  2 | 49700
+(2 rows)
+
+-- Unshippable HAVING clause will be evaluated locally, and other qual in HAVING clause is pushed down
+explain (verbose, costs off)
+select count(*) from (select c5, count(c1) from ft1 group by c5, sqrt(c2) having (avg(c1) / avg(c1)) * random() <= 1 and avg(c1) < 500) x;
+                                                              QUERY PLAN                                                               
+---------------------------------------------------------------------------------------------------------------------------------------
+ Aggregate
+   Output: count(*)
+   ->  Foreign Scan
+         Output: ft1.c5, NULL::bigint, (sqrt((ft1.c2)::double precision))
+         Filter: (((((avg(ft1.c1)) / (avg(ft1.c1))))::double precision * random()) <= '1'::double precision)
+         Relations: Aggregate on (public.ft1)
+         Remote SQL: SELECT c5, NULL::bigint, sqrt(c2), avg("C 1") FROM "S 1"."T 1" GROUP BY 1, 3 HAVING ((avg("C 1") < 500::numeric))
+(7 rows)
+
+select count(*) from (select c5, count(c1) from ft1 group by c5, sqrt(c2) having (avg(c1) / avg(c1)) * random() <= 1 and avg(c1) < 500) x;
+ count 
+-------
+    49
+(1 row)
+
+-- Aggregate in HAVING clause is not pushable, and thus aggregation is not pushed down
+explain (verbose, costs off)
+select sum(c1) from ft1 group by c2 having avg(c1 * (random() <= 1)::int) > 100 order by 1;
+                                            QUERY PLAN                                             
+---------------------------------------------------------------------------------------------------
+ Sort
+   Output: (sum(c1)), c2
+   Sort Key: (sum(ft1.c1))
+   ->  HashAggregate
+         Output: sum(c1), c2
+         Group Key: ft1.c2
+         Filter: (avg((ft1.c1 * ((random() <= '1'::double precision))::integer)) > '100'::numeric)
+         ->  Foreign Scan on public.ft1
+               Output: c1, c2
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1"
+(10 rows)
+
+-- Remote aggregate in combination with a local Param (for the output
+-- of an initplan) can be trouble, per bug #15781
+explain (verbose, costs off)
+select exists(select 1 from pg_enum), sum(c1) from ft1;
+                    QUERY PLAN                    
+--------------------------------------------------
+ Foreign Scan
+   Output: $0, (sum(ft1.c1))
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT sum("C 1") FROM "S 1"."T 1"
+   InitPlan 1 (returns $0)
+     ->  Seq Scan on pg_catalog.pg_enum
+(6 rows)
+
+select exists(select 1 from pg_enum), sum(c1) from ft1;
+ exists |  sum   
+--------+--------
+ t      | 500500
+(1 row)
+
+explain (verbose, costs off)
+select exists(select 1 from pg_enum), sum(c1) from ft1 group by 1;
+                    QUERY PLAN                     
+---------------------------------------------------
+ GroupAggregate
+   Output: ($0), sum(ft1.c1)
+   Group Key: $0
+   InitPlan 1 (returns $0)
+     ->  Seq Scan on pg_catalog.pg_enum
+   ->  Foreign Scan on public.ft1
+         Output: $0, ft1.c1
+         Remote SQL: SELECT "C 1" FROM "S 1"."T 1"
+(8 rows)
+
+select exists(select 1 from pg_enum), sum(c1) from ft1 group by 1;
+ exists |  sum   
+--------+--------
+ t      | 500500
+(1 row)
+
+-- Testing ORDER BY, DISTINCT, FILTER, Ordered-sets and VARIADIC within aggregates
+-- ORDER BY within aggregate, same column used to order
+explain (verbose, costs off)
+select array_agg(c1 order by c1) from ft1 where c1 < 100 group by c2 order by 1;
+                                                                                            QUERY PLAN                                                                                            
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (array_agg(c1 ORDER BY c1)), c2
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT array_agg("C 1" ORDER BY "C 1" ASC NULLS LAST), c2 FROM "S 1"."T 1" WHERE (("C 1" < 100)) GROUP BY 2 ORDER BY array_agg("C 1" ORDER BY "C 1" ASC NULLS LAST) ASC NULLS LAST
+(4 rows)
+
+select array_agg(c1 order by c1) from ft1 where c1 < 100 group by c2 order by 1;
+           array_agg            
+--------------------------------
+ {1,11,21,31,41,51,61,71,81,91}
+ {2,12,22,32,42,52,62,72,82,92}
+ {3,13,23,33,43,53,63,73,83,93}
+ {4,14,24,34,44,54,64,74,84,94}
+ {5,15,25,35,45,55,65,75,85,95}
+ {6,16,26,36,46,56,66,76,86,96}
+ {7,17,27,37,47,57,67,77,87,97}
+ {8,18,28,38,48,58,68,78,88,98}
+ {9,19,29,39,49,59,69,79,89,99}
+ {10,20,30,40,50,60,70,80,90}
+(10 rows)
+
+-- ORDER BY within aggregate, different column used to order also using DESC
+explain (verbose, costs off)
+select array_agg(c5 order by c1 desc) from ft2 where c2 = 6 and c1 < 50;
+                                                       QUERY PLAN                                                        
+-------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (array_agg(c5 ORDER BY c1 DESC))
+   Relations: Aggregate on (public.ft2)
+   Remote SQL: SELECT array_agg(c5 ORDER BY "C 1" DESC NULLS FIRST) FROM "S 1"."T 1" WHERE (("C 1" < 50)) AND ((c2 = 6))
+(4 rows)
+
+select array_agg(c5 order by c1 desc) from ft2 where c2 = 6 and c1 < 50;
+                                                                array_agg                                                                 
+------------------------------------------------------------------------------------------------------------------------------------------
+ {"Mon Feb 16 00:00:00 1970","Fri Feb 06 00:00:00 1970","Tue Jan 27 00:00:00 1970","Sat Jan 17 00:00:00 1970","Wed Jan 07 00:00:00 1970"}
+(1 row)
+
+-- DISTINCT within aggregate
+explain (verbose, costs off)
+select array_agg(distinct (t1.c1)%5) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) where t1.c1 < 20 or (t1.c1 is null and t2.c1 < 5) group by (t2.c1)%3 order by 1;
+                                                                                                                               QUERY PLAN                                                                                                                               
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (array_agg(DISTINCT (t1.c1 % 5))), ((t2.c1 % 3))
+   Relations: Aggregate on ((public.ft4 t1) FULL JOIN (public.ft5 t2))
+   Remote SQL: SELECT array_agg(DISTINCT (r1.c1 % 5)), (r2.c1 % 3) FROM ("S 1"."T 3" r1 FULL JOIN "S 1"."T 4" r2 ON (((r1.c1 = r2.c1)))) WHERE (((r1.c1 < 20) OR ((r1.c1 IS NULL) AND (r2.c1 < 5)))) GROUP BY 2 ORDER BY array_agg(DISTINCT (r1.c1 % 5)) ASC NULLS LAST
+(4 rows)
+
+select array_agg(distinct (t1.c1)%5) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) where t1.c1 < 20 or (t1.c1 is null and t2.c1 < 5) group by (t2.c1)%3 order by 1;
+  array_agg   
+--------------
+ {0,1,2,3,4}
+ {1,2,3,NULL}
+(2 rows)
+
+-- DISTINCT combined with ORDER BY within aggregate
+explain (verbose, costs off)
+select array_agg(distinct (t1.c1)%5 order by (t1.c1)%5) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) where t1.c1 < 20 or (t1.c1 is null and t2.c1 < 5) group by (t2.c1)%3 order by 1;
+                                                                                                                                                                     QUERY PLAN                                                                                                                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (array_agg(DISTINCT (t1.c1 % 5) ORDER BY (t1.c1 % 5))), ((t2.c1 % 3))
+   Relations: Aggregate on ((public.ft4 t1) FULL JOIN (public.ft5 t2))
+   Remote SQL: SELECT array_agg(DISTINCT (r1.c1 % 5) ORDER BY ((r1.c1 % 5)) ASC NULLS LAST), (r2.c1 % 3) FROM ("S 1"."T 3" r1 FULL JOIN "S 1"."T 4" r2 ON (((r1.c1 = r2.c1)))) WHERE (((r1.c1 < 20) OR ((r1.c1 IS NULL) AND (r2.c1 < 5)))) GROUP BY 2 ORDER BY array_agg(DISTINCT (r1.c1 % 5) ORDER BY ((r1.c1 % 5)) ASC NULLS LAST) ASC NULLS LAST
+(4 rows)
+
+select array_agg(distinct (t1.c1)%5 order by (t1.c1)%5) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) where t1.c1 < 20 or (t1.c1 is null and t2.c1 < 5) group by (t2.c1)%3 order by 1;
+  array_agg   
+--------------
+ {0,1,2,3,4}
+ {1,2,3,NULL}
+(2 rows)
+
+explain (verbose, costs off)
+select array_agg(distinct (t1.c1)%5 order by (t1.c1)%5 desc nulls last) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) where t1.c1 < 20 or (t1.c1 is null and t2.c1 < 5) group by (t2.c1)%3 order by 1;
+                                                                                                                                                                      QUERY PLAN                                                                                                                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (array_agg(DISTINCT (t1.c1 % 5) ORDER BY (t1.c1 % 5) DESC NULLS LAST)), ((t2.c1 % 3))
+   Relations: Aggregate on ((public.ft4 t1) FULL JOIN (public.ft5 t2))
+   Remote SQL: SELECT array_agg(DISTINCT (r1.c1 % 5) ORDER BY ((r1.c1 % 5)) DESC NULLS LAST), (r2.c1 % 3) FROM ("S 1"."T 3" r1 FULL JOIN "S 1"."T 4" r2 ON (((r1.c1 = r2.c1)))) WHERE (((r1.c1 < 20) OR ((r1.c1 IS NULL) AND (r2.c1 < 5)))) GROUP BY 2 ORDER BY array_agg(DISTINCT (r1.c1 % 5) ORDER BY ((r1.c1 % 5)) DESC NULLS LAST) ASC NULLS LAST
+(4 rows)
+
+select array_agg(distinct (t1.c1)%5 order by (t1.c1)%5 desc nulls last) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) where t1.c1 < 20 or (t1.c1 is null and t2.c1 < 5) group by (t2.c1)%3 order by 1;
+  array_agg   
+--------------
+ {3,2,1,NULL}
+ {4,3,2,1,0}
+(2 rows)
+
+-- FILTER within aggregate
+explain (verbose, costs off)
+select sum(c1) filter (where c1 < 100 and c2 > 5) from ft1 group by c2 order by 1 nulls last;
+                                                                                         QUERY PLAN                                                                                         
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (sum(c1) FILTER (WHERE ((c1 < 100) AND (c2 > 5)))), c2
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT sum("C 1") FILTER (WHERE (("C 1" < 100) AND (c2 > 5))), c2 FROM "S 1"."T 1" GROUP BY 2 ORDER BY sum("C 1") FILTER (WHERE (("C 1" < 100) AND (c2 > 5))) ASC NULLS LAST
+(4 rows)
+
+select sum(c1) filter (where c1 < 100 and c2 > 5) from ft1 group by c2 order by 1 nulls last;
+ sum 
+-----
+ 510
+ 520
+ 530
+ 540
+    
+    
+    
+    
+    
+    
+(10 rows)
+
+-- DISTINCT, ORDER BY and FILTER within aggregate
+explain (verbose, costs off)
+select sum(c1%3), sum(distinct c1%3 order by c1%3) filter (where c1%3 < 2), c2 from ft1 where c2 = 6 group by c2;
+                                                                                        QUERY PLAN                                                                                        
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (sum((c1 % 3))), (sum(DISTINCT (c1 % 3) ORDER BY (c1 % 3)) FILTER (WHERE ((c1 % 3) < 2))), c2
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT sum(("C 1" % 3)), sum(DISTINCT ("C 1" % 3) ORDER BY (("C 1" % 3)) ASC NULLS LAST) FILTER (WHERE (("C 1" % 3) < 2)), c2 FROM "S 1"."T 1" WHERE ((c2 = 6)) GROUP BY 3
+(4 rows)
+
+select sum(c1%3), sum(distinct c1%3 order by c1%3) filter (where c1%3 < 2), c2 from ft1 where c2 = 6 group by c2;
+ sum | sum | c2 
+-----+-----+----
+  99 |   1 |  6
+(1 row)
+
+-- Outer query is aggregation query
+explain (verbose, costs off)
+select distinct (select count(*) filter (where t2.c2 = 6 and t2.c1 < 10) from ft1 t1 where t1.c1 = 6) from ft2 t2 where t2.c2 % 6 = 0 order by 1;
+                                                          QUERY PLAN                                                          
+------------------------------------------------------------------------------------------------------------------------------
+ Unique
+   Output: ((SubPlan 1))
+   ->  Sort
+         Output: ((SubPlan 1))
+         Sort Key: ((SubPlan 1))
+         ->  Foreign Scan
+               Output: (SubPlan 1)
+               Relations: Aggregate on (public.ft2 t2)
+               Remote SQL: SELECT count(*) FILTER (WHERE ((c2 = 6) AND ("C 1" < 10))) FROM "S 1"."T 1" WHERE (((c2 % 6) = 0))
+               SubPlan 1
+                 ->  Foreign Scan on public.ft1 t1
+                       Output: (count(*) FILTER (WHERE ((t2.c2 = 6) AND (t2.c1 < 10))))
+                       Remote SQL: SELECT NULL FROM "S 1"."T 1" WHERE (("C 1" = 6))
+(13 rows)
+
+select distinct (select count(*) filter (where t2.c2 = 6 and t2.c1 < 10) from ft1 t1 where t1.c1 = 6) from ft2 t2 where t2.c2 % 6 = 0 order by 1;
+ count 
+-------
+     1
+(1 row)
+
+-- Inner query is aggregation query
+explain (verbose, costs off)
+select distinct (select count(t1.c1) filter (where t2.c2 = 6 and t2.c1 < 10) from ft1 t1 where t1.c1 = 6) from ft2 t2 where t2.c2 % 6 = 0 order by 1;
+                                                                      QUERY PLAN                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------
+ Unique
+   Output: ((SubPlan 1))
+   ->  Sort
+         Output: ((SubPlan 1))
+         Sort Key: ((SubPlan 1))
+         ->  Foreign Scan on public.ft2 t2
+               Output: (SubPlan 1)
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" WHERE (((c2 % 6) = 0))
+               SubPlan 1
+                 ->  Foreign Scan
+                       Output: (count(t1.c1) FILTER (WHERE ((t2.c2 = 6) AND (t2.c1 < 10))))
+                       Relations: Aggregate on (public.ft1 t1)
+                       Remote SQL: SELECT count("C 1") FILTER (WHERE (($1::integer = 6) AND ($2::integer < 10))) FROM "S 1"."T 1" WHERE (("C 1" = 6))
+(13 rows)
+
+select distinct (select count(t1.c1) filter (where t2.c2 = 6 and t2.c1 < 10) from ft1 t1 where t1.c1 = 6) from ft2 t2 where t2.c2 % 6 = 0 order by 1;
+ count 
+-------
+     0
+     1
+(2 rows)
+
+-- Aggregate not pushed down as FILTER condition is not pushable
+explain (verbose, costs off)
+select sum(c1) filter (where (c1 / c1) * random() <= 1) from ft1 group by c2 order by 1;
+                                                       QUERY PLAN                                                       
+------------------------------------------------------------------------------------------------------------------------
+ Sort
+   Output: (sum(c1) FILTER (WHERE ((((c1 / c1))::double precision * random()) <= '1'::double precision))), c2
+   Sort Key: (sum(ft1.c1) FILTER (WHERE ((((ft1.c1 / ft1.c1))::double precision * random()) <= '1'::double precision)))
+   ->  HashAggregate
+         Output: sum(c1) FILTER (WHERE ((((c1 / c1))::double precision * random()) <= '1'::double precision)), c2
+         Group Key: ft1.c2
+         ->  Foreign Scan on public.ft1
+               Output: c1, c2
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1"
+(9 rows)
+
+explain (verbose, costs off)
+select sum(c2) filter (where c2 in (select c2 from ft1 where c2 < 5)) from ft1;
+                            QUERY PLAN                             
+-------------------------------------------------------------------
+ Aggregate
+   Output: sum(ft1.c2) FILTER (WHERE (hashed SubPlan 1))
+   ->  Foreign Scan on public.ft1
+         Output: ft1.c2
+         Remote SQL: SELECT c2 FROM "S 1"."T 1"
+   SubPlan 1
+     ->  Foreign Scan on public.ft1 ft1_1
+           Output: ft1_1.c2
+           Remote SQL: SELECT c2 FROM "S 1"."T 1" WHERE ((c2 < 5))
+(9 rows)
+
+-- Ordered-sets within aggregate
+explain (verbose, costs off)
+select c2, rank('10'::varchar) within group (order by c6), percentile_cont(c2/10::numeric) within group (order by c1) from ft1 where c2 < 10 group by c2 having percentile_cont(c2/10::numeric) within group (order by c1) < 500 order by c2;
+                                                                                                                                                                           QUERY PLAN                                                                                                                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Sort
+   Output: c2, (rank('10'::character varying) WITHIN GROUP (ORDER BY c6)), (percentile_cont((((c2)::numeric / '10'::numeric))::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
+   Sort Key: ft1.c2
+   ->  Foreign Scan
+         Output: c2, (rank('10'::character varying) WITHIN GROUP (ORDER BY c6)), (percentile_cont((((c2)::numeric / '10'::numeric))::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
+         Relations: Aggregate on (public.ft1)
+         Remote SQL: SELECT c2, rank('10'::character varying) WITHIN GROUP (ORDER BY c6 ASC NULLS LAST), percentile_cont((c2 / 10::numeric)) WITHIN GROUP (ORDER BY ("C 1") ASC NULLS LAST) FROM "S 1"."T 1" WHERE ((c2 < 10)) GROUP BY 1 HAVING ((percentile_cont((c2 / 10::numeric)) WITHIN GROUP (ORDER BY ("C 1") ASC NULLS LAST) < 500::double precision))
+(7 rows)
+
+select c2, rank('10'::varchar) within group (order by c6), percentile_cont(c2/10::numeric) within group (order by c1) from ft1 where c2 < 10 group by c2 having percentile_cont(c2/10::numeric) within group (order by c1) < 500 order by c2;
+ c2 | rank | percentile_cont 
+----+------+-----------------
+  0 |  101 |              10
+  1 |  101 |             100
+  2 |    1 |             200
+  3 |    1 |             300
+  4 |    1 |             400
+(5 rows)
+
+-- Using multiple arguments within aggregates
+explain (verbose, costs off)
+select c1, rank(c1, c2) within group (order by c1, c2) from ft1 group by c1, c2 having c1 = 6 order by 1;
+                                                                             QUERY PLAN                                                                             
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: c1, (rank(c1, c2) WITHIN GROUP (ORDER BY c1, c2)), c2
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT "C 1", rank("C 1", c2) WITHIN GROUP (ORDER BY "C 1" ASC NULLS LAST, c2 ASC NULLS LAST), c2 FROM "S 1"."T 1" WHERE (("C 1" = 6)) GROUP BY 1, 3
+(4 rows)
+
+select c1, rank(c1, c2) within group (order by c1, c2) from ft1 group by c1, c2 having c1 = 6 order by 1;
+ c1 | rank 
+----+------
+  6 |    1
+(1 row)
+
+-- User defined function for user defined aggregate, VARIADIC
+create function least_accum(anyelement, variadic anyarray)
+returns anyelement language sql as
+  'select least($1, min($2[i])) from generate_subscripts($2,1) g(i)';
+create aggregate least_agg(variadic items anyarray) (
+  stype = anyelement, sfunc = least_accum
+);
+-- Disable hash aggregation for plan stability.
+set enable_hashagg to false;
+-- Not pushed down due to user defined aggregate
+explain (verbose, costs off)
+select c2, least_agg(c1) from ft1 group by c2 order by c2;
+                                    QUERY PLAN                                    
+----------------------------------------------------------------------------------
+ GroupAggregate
+   Output: c2, least_agg(VARIADIC ARRAY[c1])
+   Group Key: ft1.c2
+   ->  Foreign Scan on public.ft1
+         Output: c2, c1
+         Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" ORDER BY c2 ASC NULLS LAST
+(6 rows)
+
+-- Add function and aggregate into extension
+alter extension postgres_fdw add function least_accum(anyelement, variadic anyarray);
+alter extension postgres_fdw add aggregate least_agg(variadic items anyarray);
+alter server loopback options (set extensions 'postgres_fdw');
+-- Now aggregate will be pushed.  Aggregate will display VARIADIC argument.
+explain (verbose, costs off)
+select c2, least_agg(c1) from ft1 where c2 < 100 group by c2 order by c2;
+                                                      QUERY PLAN                                                       
+-----------------------------------------------------------------------------------------------------------------------
+ Sort
+   Output: c2, (least_agg(VARIADIC ARRAY[c1]))
+   Sort Key: ft1.c2
+   ->  Foreign Scan
+         Output: c2, (least_agg(VARIADIC ARRAY[c1]))
+         Relations: Aggregate on (public.ft1)
+         Remote SQL: SELECT c2, public.least_agg(VARIADIC ARRAY["C 1"]) FROM "S 1"."T 1" WHERE ((c2 < 100)) GROUP BY 1
+(7 rows)
+
+select c2, least_agg(c1) from ft1 where c2 < 100 group by c2 order by c2;
+ c2 | least_agg 
+----+-----------
+  0 |        10
+  1 |         1
+  2 |         2
+  3 |         3
+  4 |         4
+  5 |         5
+  6 |         6
+  7 |         7
+  8 |         8
+  9 |         9
+(10 rows)
+
+-- Remove function and aggregate from extension
+alter extension postgres_fdw drop function least_accum(anyelement, variadic anyarray);
+alter extension postgres_fdw drop aggregate least_agg(variadic items anyarray);
+alter server loopback options (set extensions 'postgres_fdw');
+-- Not pushed down as we have dropped objects from extension.
+explain (verbose, costs off)
+select c2, least_agg(c1) from ft1 group by c2 order by c2;
+                                    QUERY PLAN                                    
+----------------------------------------------------------------------------------
+ GroupAggregate
+   Output: c2, least_agg(VARIADIC ARRAY[c1])
+   Group Key: ft1.c2
+   ->  Foreign Scan on public.ft1
+         Output: c2, c1
+         Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" ORDER BY c2 ASC NULLS LAST
+(6 rows)
+
+-- Cleanup
+reset enable_hashagg;
+drop aggregate least_agg(variadic items anyarray);
+drop function least_accum(anyelement, variadic anyarray);
+-- Testing USING OPERATOR() in ORDER BY within aggregate.
+-- For this, we need user defined operators along with operator family and
+-- operator class.  Create those and then add them in extension.  Note that
+-- user defined objects are considered unshippable unless they are part of
+-- the extension.
+create operator public.<^ (
+ leftarg = int4,
+ rightarg = int4,
+ procedure = int4eq
+);
+create operator public.=^ (
+ leftarg = int4,
+ rightarg = int4,
+ procedure = int4lt
+);
+create operator public.>^ (
+ leftarg = int4,
+ rightarg = int4,
+ procedure = int4gt
+);
+create operator family my_op_family using btree;
+create function my_op_cmp(a int, b int) returns int as
+  $$begin return btint4cmp(a, b); end $$ language plpgsql;
+create operator class my_op_class for type int using btree family my_op_family as
+ operator 1 public.<^,
+ operator 3 public.=^,
+ operator 5 public.>^,
+ function 1 my_op_cmp(int, int);
+-- This will not be pushed as user defined sort operator is not part of the
+-- extension yet.
+explain (verbose, costs off)
+select array_agg(c1 order by c1 using operator(public.<^)) from ft2 where c2 = 6 and c1 < 100 group by c2;
+                                            QUERY PLAN                                            
+--------------------------------------------------------------------------------------------------
+ GroupAggregate
+   Output: array_agg(c1 ORDER BY c1 USING <^ NULLS LAST), c2
+   Group Key: ft2.c2
+   ->  Sort
+         Output: c2, c1
+         Sort Key: ft2.c1 USING <^
+         ->  Foreign Scan on public.ft2
+               Output: c2, c1
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND ((c2 = 6))
+(9 rows)
+
+-- This should not be pushed either.
+explain (verbose, costs off)
+select * from ft2 order by c1 using operator(public.<^);
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Sort
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Sort Key: ft2.c1 USING <^
+   ->  Foreign Scan on public.ft2
+         Output: c1, c2, c3, c4, c5, c6, c7, c8
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(6 rows)
+
+-- Update local stats on ft2
+ANALYZE ft2;
+-- Add into extension
+alter extension postgres_fdw add operator class my_op_class using btree;
+alter extension postgres_fdw add function my_op_cmp(a int, b int);
+alter extension postgres_fdw add operator family my_op_family using btree;
+alter extension postgres_fdw add operator public.<^(int, int);
+alter extension postgres_fdw add operator public.=^(int, int);
+alter extension postgres_fdw add operator public.>^(int, int);
+alter server loopback options (set extensions 'postgres_fdw');
+-- Now this will be pushed as sort operator is part of the extension.
+alter server loopback options (add fdw_tuple_cost '0.5');
+explain (verbose, costs off)
+select array_agg(c1 order by c1 using operator(public.<^)) from ft2 where c2 = 6 and c1 < 100 group by c2;
+                                                                           QUERY PLAN                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (array_agg(c1 ORDER BY c1 USING <^ NULLS LAST)), c2
+   Relations: Aggregate on (public.ft2)
+   Remote SQL: SELECT array_agg("C 1" ORDER BY "C 1" USING OPERATOR(public.<^) NULLS LAST), c2 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND ((c2 = 6)) GROUP BY 2
+(4 rows)
+
+select array_agg(c1 order by c1 using operator(public.<^)) from ft2 where c2 = 6 and c1 < 100 group by c2;
+           array_agg            
+--------------------------------
+ {6,16,26,36,46,56,66,76,86,96}
+(1 row)
+
+alter server loopback options (drop fdw_tuple_cost);
+-- This should be pushed too.
+explain (verbose, costs off)
+select * from ft2 order by c1 using operator(public.<^);
+                                                         QUERY PLAN                                                          
+-----------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft2
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" ORDER BY "C 1" USING OPERATOR(public.<^) NULLS LAST
+(3 rows)
+
+-- Remove from extension
+alter extension postgres_fdw drop operator class my_op_class using btree;
+alter extension postgres_fdw drop function my_op_cmp(a int, b int);
+alter extension postgres_fdw drop operator family my_op_family using btree;
+alter extension postgres_fdw drop operator public.<^(int, int);
+alter extension postgres_fdw drop operator public.=^(int, int);
+alter extension postgres_fdw drop operator public.>^(int, int);
+alter server loopback options (set extensions 'postgres_fdw');
+-- This will not be pushed as sort operator is now removed from the extension.
+explain (verbose, costs off)
+select array_agg(c1 order by c1 using operator(public.<^)) from ft2 where c2 = 6 and c1 < 100 group by c2;
+                                            QUERY PLAN                                            
+--------------------------------------------------------------------------------------------------
+ GroupAggregate
+   Output: array_agg(c1 ORDER BY c1 USING <^ NULLS LAST), c2
+   Group Key: ft2.c2
+   ->  Sort
+         Output: c2, c1
+         Sort Key: ft2.c1 USING <^
+         ->  Foreign Scan on public.ft2
+               Output: c2, c1
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND ((c2 = 6))
+(9 rows)
+
+-- Cleanup
+drop operator class my_op_class using btree;
+drop function my_op_cmp(a int, b int);
+drop operator family my_op_family using btree;
+drop operator public.>^(int, int);
+drop operator public.=^(int, int);
+drop operator public.<^(int, int);
+-- Input relation to aggregate push down hook is not safe to pushdown and thus
+-- the aggregate cannot be pushed down to foreign server.
+explain (verbose, costs off)
+select count(t1.c3) from ft2 t1 left join ft2 t2 on (t1.c1 = random() * t2.c2);
+                                        QUERY PLAN                                         
+-------------------------------------------------------------------------------------------
+ Aggregate
+   Output: count(t1.c3)
+   ->  Nested Loop Left Join
+         Output: t1.c3
+         Join Filter: ((t1.c1)::double precision = (random() * (t2.c2)::double precision))
+         ->  Foreign Scan on public.ft2 t1
+               Output: t1.c3, t1.c1
+               Remote SQL: SELECT "C 1", c3 FROM "S 1"."T 1"
+         ->  Materialize
+               Output: t2.c2
+               ->  Foreign Scan on public.ft2 t2
+                     Output: t2.c2
+                     Remote SQL: SELECT c2 FROM "S 1"."T 1"
+(13 rows)
+
+-- Subquery in FROM clause having aggregate
+explain (verbose, costs off)
+select count(*), x.b from ft1, (select c2 a, sum(c1) b from ft1 group by c2) x where ft1.c2 = x.a group by x.b order by 1, 2;
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
+ Sort
+   Output: (count(*)), x.b
+   Sort Key: (count(*)), x.b
+   ->  HashAggregate
+         Output: count(*), x.b
+         Group Key: x.b
+         ->  Hash Join
+               Output: x.b
+               Inner Unique: true
+               Hash Cond: (ft1.c2 = x.a)
+               ->  Foreign Scan on public.ft1
+                     Output: ft1.c2
+                     Remote SQL: SELECT c2 FROM "S 1"."T 1"
+               ->  Hash
+                     Output: x.b, x.a
+                     ->  Subquery Scan on x
+                           Output: x.b, x.a
+                           ->  Foreign Scan
+                                 Output: ft1_1.c2, (sum(ft1_1.c1))
+                                 Relations: Aggregate on (public.ft1 ft1_1)
+                                 Remote SQL: SELECT c2, sum("C 1") FROM "S 1"."T 1" GROUP BY 1
+(21 rows)
+
+select count(*), x.b from ft1, (select c2 a, sum(c1) b from ft1 group by c2) x where ft1.c2 = x.a group by x.b order by 1, 2;
+ count |   b   
+-------+-------
+   100 | 49600
+   100 | 49700
+   100 | 49800
+   100 | 49900
+   100 | 50000
+   100 | 50100
+   100 | 50200
+   100 | 50300
+   100 | 50400
+   100 | 50500
+(10 rows)
+
+-- FULL join with IS NULL check in HAVING
+explain (verbose, costs off)
+select avg(t1.c1), sum(t2.c1) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) group by t2.c1 having (avg(t1.c1) is null and sum(t2.c1) < 10) or sum(t2.c1) is null order by 1 nulls last, 2;
+                                                                                                                                    QUERY PLAN                                                                                                                                     
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (avg(t1.c1)), (sum(t2.c1)), t2.c1
+   Relations: Aggregate on ((public.ft4 t1) FULL JOIN (public.ft5 t2))
+   Remote SQL: SELECT avg(r1.c1), sum(r2.c1), r2.c1 FROM ("S 1"."T 3" r1 FULL JOIN "S 1"."T 4" r2 ON (((r1.c1 = r2.c1)))) GROUP BY 3 HAVING ((((avg(r1.c1) IS NULL) AND (sum(r2.c1) < 10)) OR (sum(r2.c1) IS NULL))) ORDER BY avg(r1.c1) ASC NULLS LAST, sum(r2.c1) ASC NULLS LAST
+(4 rows)
+
+select avg(t1.c1), sum(t2.c1) from ft4 t1 full join ft5 t2 on (t1.c1 = t2.c1) group by t2.c1 having (avg(t1.c1) is null and sum(t2.c1) < 10) or sum(t2.c1) is null order by 1 nulls last, 2;
+         avg         | sum 
+---------------------+-----
+ 51.0000000000000000 |    
+                     |   3
+                     |   9
+(3 rows)
+
+-- Aggregate over FULL join needing to deparse the joining relations as
+-- subqueries.
+explain (verbose, costs off)
+select count(*), sum(t1.c1), avg(t2.c1) from (select c1 from ft4 where c1 between 50 and 60) t1 full join (select c1 from ft5 where c1 between 50 and 60) t2 on (t1.c1 = t2.c1);
+                                                                                                                  QUERY PLAN                                                                                                                   
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(*)), (sum(ft4.c1)), (avg(ft5.c1))
+   Relations: Aggregate on ((public.ft4) FULL JOIN (public.ft5))
+   Remote SQL: SELECT count(*), sum(s4.c1), avg(s5.c1) FROM ((SELECT c1 FROM "S 1"."T 3" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s4(c1) FULL JOIN (SELECT c1 FROM "S 1"."T 4" WHERE ((c1 >= 50)) AND ((c1 <= 60))) s5(c1) ON (((s4.c1 = s5.c1))))
+(4 rows)
+
+select count(*), sum(t1.c1), avg(t2.c1) from (select c1 from ft4 where c1 between 50 and 60) t1 full join (select c1 from ft5 where c1 between 50 and 60) t2 on (t1.c1 = t2.c1);
+ count | sum |         avg         
+-------+-----+---------------------
+     8 | 330 | 55.5000000000000000
+(1 row)
+
+-- ORDER BY expression is part of the target list but not pushed down to
+-- foreign server.
+explain (verbose, costs off)
+select sum(c2) * (random() <= 1)::int as sum from ft1 order by 1;
+                                   QUERY PLAN                                   
+--------------------------------------------------------------------------------
+ Sort
+   Output: (((sum(c2)) * ((random() <= '1'::double precision))::integer))
+   Sort Key: (((sum(ft1.c2)) * ((random() <= '1'::double precision))::integer))
+   ->  Foreign Scan
+         Output: ((sum(c2)) * ((random() <= '1'::double precision))::integer)
+         Relations: Aggregate on (public.ft1)
+         Remote SQL: SELECT sum(c2) FROM "S 1"."T 1"
+(7 rows)
+
+select sum(c2) * (random() <= 1)::int as sum from ft1 order by 1;
+ sum  
+------
+ 4500
+(1 row)
+
+-- LATERAL join, with parameterization
+set enable_hashagg to false;
+explain (verbose, costs off)
+select c2, sum from "S 1"."T 1" t1, lateral (select sum(t2.c1 + t1."C 1") sum from ft2 t2 group by t2.c1) qry where t1.c2 * 2 = qry.sum and t1.c2 < 3 and t1."C 1" < 100 order by 1;
+                                              QUERY PLAN                                              
+------------------------------------------------------------------------------------------------------
+ Sort
+   Output: t1.c2, qry.sum
+   Sort Key: t1.c2
+   ->  Nested Loop
+         Output: t1.c2, qry.sum
+         ->  Index Scan using t1_pkey on "S 1"."T 1" t1
+               Output: t1."C 1", t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+               Index Cond: (t1."C 1" < 100)
+               Filter: (t1.c2 < 3)
+         ->  Subquery Scan on qry
+               Output: qry.sum, t2.c1
+               Filter: ((t1.c2 * 2) = qry.sum)
+               ->  Foreign Scan
+                     Output: (sum((t2.c1 + t1."C 1"))), t2.c1
+                     Relations: Aggregate on (public.ft2 t2)
+                     Remote SQL: SELECT sum(("C 1" + $1::integer)), "C 1" FROM "S 1"."T 1" GROUP BY 2
+(16 rows)
+
+select c2, sum from "S 1"."T 1" t1, lateral (select sum(t2.c1 + t1."C 1") sum from ft2 t2 group by t2.c1) qry where t1.c2 * 2 = qry.sum and t1.c2 < 3 and t1."C 1" < 100 order by 1;
+ c2 | sum 
+----+-----
+  1 |   2
+  2 |   4
+(2 rows)
+
+reset enable_hashagg;
+-- bug #15613: bad plan for foreign table scan with lateral reference
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT ref_0.c2, subq_1.*
+FROM
+    "S 1"."T 1" AS ref_0,
+    LATERAL (
+        SELECT ref_0."C 1" c1, subq_0.*
+        FROM (SELECT ref_0.c2, ref_1.c3
+              FROM ft1 AS ref_1) AS subq_0
+             RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3)
+    ) AS subq_1
+WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001'
+ORDER BY ref_0."C 1";
+                                               QUERY PLAN                                                
+---------------------------------------------------------------------------------------------------------
+ Nested Loop
+   Output: ref_0.c2, ref_0."C 1", (ref_0.c2), ref_1.c3, ref_0."C 1"
+   ->  Nested Loop
+         Output: ref_0.c2, ref_0."C 1", ref_1.c3, (ref_0.c2)
+         ->  Index Scan using t1_pkey on "S 1"."T 1" ref_0
+               Output: ref_0."C 1", ref_0.c2, ref_0.c3, ref_0.c4, ref_0.c5, ref_0.c6, ref_0.c7, ref_0.c8
+               Index Cond: (ref_0."C 1" < 10)
+         ->  Foreign Scan on public.ft1 ref_1
+               Output: ref_1.c3, ref_0.c2
+               Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'))
+   ->  Materialize
+         Output: ref_3.c3
+         ->  Foreign Scan on public.ft2 ref_3
+               Output: ref_3.c3
+               Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'))
+(15 rows)
+
+SELECT ref_0.c2, subq_1.*
+FROM
+    "S 1"."T 1" AS ref_0,
+    LATERAL (
+        SELECT ref_0."C 1" c1, subq_0.*
+        FROM (SELECT ref_0.c2, ref_1.c3
+              FROM ft1 AS ref_1) AS subq_0
+             RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3)
+    ) AS subq_1
+WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001'
+ORDER BY ref_0."C 1";
+ c2 | c1 | c2 |  c3   
+----+----+----+-------
+  1 |  1 |  1 | 00001
+  2 |  2 |  2 | 00001
+  3 |  3 |  3 | 00001
+  4 |  4 |  4 | 00001
+  5 |  5 |  5 | 00001
+  6 |  6 |  6 | 00001
+  7 |  7 |  7 | 00001
+  8 |  8 |  8 | 00001
+  9 |  9 |  9 | 00001
+(9 rows)
+
+-- Check with placeHolderVars
+explain (verbose, costs off)
+select sum(q.a), count(q.b) from ft4 left join (select 13, avg(ft1.c1), sum(ft2.c1) from ft1 right join ft2 on (ft1.c1 = ft2.c1)) q(a, b, c) on (ft4.c1 <= q.b);
+                                                                        QUERY PLAN                                                                        
+----------------------------------------------------------------------------------------------------------------------------------------------------------
+ Aggregate
+   Output: sum(q.a), count(q.b)
+   ->  Nested Loop Left Join
+         Output: q.a, q.b
+         Inner Unique: true
+         Join Filter: ((ft4.c1)::numeric <= q.b)
+         ->  Foreign Scan on public.ft4
+               Output: ft4.c1, ft4.c2, ft4.c3
+               Remote SQL: SELECT c1 FROM "S 1"."T 3"
+         ->  Materialize
+               Output: q.a, q.b
+               ->  Subquery Scan on q
+                     Output: q.a, q.b
+                     ->  Foreign Scan
+                           Output: 13, (avg(ft1.c1)), NULL::bigint
+                           Relations: Aggregate on ((public.ft2) LEFT JOIN (public.ft1))
+                           Remote SQL: SELECT 13, avg(r1."C 1"), NULL::bigint FROM ("S 1"."T 1" r2 LEFT JOIN "S 1"."T 1" r1 ON (((r1."C 1" = r2."C 1"))))
+(17 rows)
+
+select sum(q.a), count(q.b) from ft4 left join (select 13, avg(ft1.c1), sum(ft2.c1) from ft1 right join ft2 on (ft1.c1 = ft2.c1)) q(a, b, c) on (ft4.c1 <= q.b);
+ sum | count 
+-----+-------
+ 650 |    50
+(1 row)
+
+-- Not supported cases
+-- Grouping sets
+explain (verbose, costs off)
+select c2, sum(c1) from ft1 where c2 < 3 group by rollup(c2) order by 1 nulls last;
+                                  QUERY PLAN                                  
+------------------------------------------------------------------------------
+ Sort
+   Output: c2, (sum(c1))
+   Sort Key: ft1.c2
+   ->  MixedAggregate
+         Output: c2, sum(c1)
+         Hash Key: ft1.c2
+         Group Key: ()
+         ->  Foreign Scan on public.ft1
+               Output: c2, c1
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" WHERE ((c2 < 3))
+(10 rows)
+
+select c2, sum(c1) from ft1 where c2 < 3 group by rollup(c2) order by 1 nulls last;
+ c2 |  sum   
+----+--------
+  0 |  50500
+  1 |  49600
+  2 |  49700
+    | 149800
+(4 rows)
+
+explain (verbose, costs off)
+select c2, sum(c1) from ft1 where c2 < 3 group by cube(c2) order by 1 nulls last;
+                                  QUERY PLAN                                  
+------------------------------------------------------------------------------
+ Sort
+   Output: c2, (sum(c1))
+   Sort Key: ft1.c2
+   ->  MixedAggregate
+         Output: c2, sum(c1)
+         Hash Key: ft1.c2
+         Group Key: ()
+         ->  Foreign Scan on public.ft1
+               Output: c2, c1
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" WHERE ((c2 < 3))
+(10 rows)
+
+select c2, sum(c1) from ft1 where c2 < 3 group by cube(c2) order by 1 nulls last;
+ c2 |  sum   
+----+--------
+  0 |  50500
+  1 |  49600
+  2 |  49700
+    | 149800
+(4 rows)
+
+explain (verbose, costs off)
+select c2, c6, sum(c1) from ft1 where c2 < 3 group by grouping sets(c2, c6) order by 1 nulls last, 2 nulls last;
+                                    QUERY PLAN                                    
+----------------------------------------------------------------------------------
+ Sort
+   Output: c2, c6, (sum(c1))
+   Sort Key: ft1.c2, ft1.c6
+   ->  HashAggregate
+         Output: c2, c6, sum(c1)
+         Hash Key: ft1.c2
+         Hash Key: ft1.c6
+         ->  Foreign Scan on public.ft1
+               Output: c2, c6, c1
+               Remote SQL: SELECT "C 1", c2, c6 FROM "S 1"."T 1" WHERE ((c2 < 3))
+(10 rows)
+
+select c2, c6, sum(c1) from ft1 where c2 < 3 group by grouping sets(c2, c6) order by 1 nulls last, 2 nulls last;
+ c2 | c6 |  sum  
+----+----+-------
+  0 |    | 50500
+  1 |    | 49600
+  2 |    | 49700
+    | 0  | 50500
+    | 1  | 49600
+    | 2  | 49700
+(6 rows)
+
+explain (verbose, costs off)
+select c2, sum(c1), grouping(c2) from ft1 where c2 < 3 group by c2 order by 1 nulls last;
+                                  QUERY PLAN                                  
+------------------------------------------------------------------------------
+ Sort
+   Output: c2, (sum(c1)), (GROUPING(c2))
+   Sort Key: ft1.c2
+   ->  HashAggregate
+         Output: c2, sum(c1), GROUPING(c2)
+         Group Key: ft1.c2
+         ->  Foreign Scan on public.ft1
+               Output: c2, c1
+               Remote SQL: SELECT "C 1", c2 FROM "S 1"."T 1" WHERE ((c2 < 3))
+(9 rows)
+
+select c2, sum(c1), grouping(c2) from ft1 where c2 < 3 group by c2 order by 1 nulls last;
+ c2 |  sum  | grouping 
+----+-------+----------
+  0 | 50500 |        0
+  1 | 49600 |        0
+  2 | 49700 |        0
+(3 rows)
+
+-- DISTINCT itself is not pushed down, whereas underneath aggregate is pushed
+explain (verbose, costs off)
+select distinct sum(c1)/1000 s from ft2 where c2 < 6 group by c2 order by 1;
+                                              QUERY PLAN                                               
+-------------------------------------------------------------------------------------------------------
+ Unique
+   Output: ((sum(c1) / 1000)), c2
+   ->  Sort
+         Output: ((sum(c1) / 1000)), c2
+         Sort Key: ((sum(ft2.c1) / 1000))
+         ->  Foreign Scan
+               Output: ((sum(c1) / 1000)), c2
+               Relations: Aggregate on (public.ft2)
+               Remote SQL: SELECT (sum("C 1") / 1000), c2 FROM "S 1"."T 1" WHERE ((c2 < 6)) GROUP BY 2
+(9 rows)
+
+select distinct sum(c1)/1000 s from ft2 where c2 < 6 group by c2 order by 1;
+ s  
+----
+ 49
+ 50
+(2 rows)
+
+-- WindowAgg
+explain (verbose, costs off)
+select c2, sum(c2), count(c2) over (partition by c2%2) from ft2 where c2 < 10 group by c2 order by 1;
+                                                 QUERY PLAN                                                 
+------------------------------------------------------------------------------------------------------------
+ Sort
+   Output: c2, (sum(c2)), (count(c2) OVER (?)), ((c2 % 2))
+   Sort Key: ft2.c2
+   ->  WindowAgg
+         Output: c2, (sum(c2)), count(c2) OVER (?), ((c2 % 2))
+         ->  Sort
+               Output: c2, ((c2 % 2)), (sum(c2))
+               Sort Key: ((ft2.c2 % 2))
+               ->  Foreign Scan
+                     Output: c2, ((c2 % 2)), (sum(c2))
+                     Relations: Aggregate on (public.ft2)
+                     Remote SQL: SELECT c2, (c2 % 2), sum(c2) FROM "S 1"."T 1" WHERE ((c2 < 10)) GROUP BY 1
+(12 rows)
+
+select c2, sum(c2), count(c2) over (partition by c2%2) from ft2 where c2 < 10 group by c2 order by 1;
+ c2 | sum | count 
+----+-----+-------
+  0 |   0 |     5
+  1 | 100 |     5
+  2 | 200 |     5
+  3 | 300 |     5
+  4 | 400 |     5
+  5 | 500 |     5
+  6 | 600 |     5
+  7 | 700 |     5
+  8 | 800 |     5
+  9 | 900 |     5
+(10 rows)
+
+explain (verbose, costs off)
+select c2, array_agg(c2) over (partition by c2%2 order by c2 desc) from ft1 where c2 < 10 group by c2 order by 1;
+                                            QUERY PLAN                                             
+---------------------------------------------------------------------------------------------------
+ Sort
+   Output: c2, (array_agg(c2) OVER (?)), ((c2 % 2))
+   Sort Key: ft1.c2
+   ->  WindowAgg
+         Output: c2, array_agg(c2) OVER (?), ((c2 % 2))
+         ->  Sort
+               Output: c2, ((c2 % 2))
+               Sort Key: ((ft1.c2 % 2)), ft1.c2 DESC
+               ->  Foreign Scan
+                     Output: c2, ((c2 % 2))
+                     Relations: Aggregate on (public.ft1)
+                     Remote SQL: SELECT c2, (c2 % 2) FROM "S 1"."T 1" WHERE ((c2 < 10)) GROUP BY 1
+(12 rows)
+
+select c2, array_agg(c2) over (partition by c2%2 order by c2 desc) from ft1 where c2 < 10 group by c2 order by 1;
+ c2 |  array_agg  
+----+-------------
+  0 | {8,6,4,2,0}
+  1 | {9,7,5,3,1}
+  2 | {8,6,4,2}
+  3 | {9,7,5,3}
+  4 | {8,6,4}
+  5 | {9,7,5}
+  6 | {8,6}
+  7 | {9,7}
+  8 | {8}
+  9 | {9}
+(10 rows)
+
+explain (verbose, costs off)
+select c2, array_agg(c2) over (partition by c2%2 order by c2 range between current row and unbounded following) from ft1 where c2 < 10 group by c2 order by 1;
+                                            QUERY PLAN                                             
+---------------------------------------------------------------------------------------------------
+ Sort
+   Output: c2, (array_agg(c2) OVER (?)), ((c2 % 2))
+   Sort Key: ft1.c2
+   ->  WindowAgg
+         Output: c2, array_agg(c2) OVER (?), ((c2 % 2))
+         ->  Sort
+               Output: c2, ((c2 % 2))
+               Sort Key: ((ft1.c2 % 2)), ft1.c2
+               ->  Foreign Scan
+                     Output: c2, ((c2 % 2))
+                     Relations: Aggregate on (public.ft1)
+                     Remote SQL: SELECT c2, (c2 % 2) FROM "S 1"."T 1" WHERE ((c2 < 10)) GROUP BY 1
+(12 rows)
+
+select c2, array_agg(c2) over (partition by c2%2 order by c2 range between current row and unbounded following) from ft1 where c2 < 10 group by c2 order by 1;
+ c2 |  array_agg  
+----+-------------
+  0 | {0,2,4,6,8}
+  1 | {1,3,5,7,9}
+  2 | {2,4,6,8}
+  3 | {3,5,7,9}
+  4 | {4,6,8}
+  5 | {5,7,9}
+  6 | {6,8}
+  7 | {7,9}
+  8 | {8}
+  9 | {9}
+(10 rows)
+
+-- ===================================================================
+-- parameterized queries
+-- ===================================================================
+-- simple join
+PREPARE st1(int, int) AS SELECT t1.c3, t2.c3 FROM ft1 t1, ft2 t2 WHERE t1.c1 = $1 AND t2.c1 = $2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st1(1, 2);
+                                                          QUERY PLAN                                                          
+------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.c3, t2.c3
+   Relations: (public.ft1 t1) INNER JOIN (public.ft2 t2)
+   Remote SQL: SELECT r1.c3, r2.c3 FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r2."C 1" = 2)) AND ((r1."C 1" = 1))))
+(4 rows)
+
+EXECUTE st1(1, 1);
+  c3   |  c3   
+-------+-------
+ 00001 | 00001
+(1 row)
+
+EXECUTE st1(101, 101);
+  c3   |  c3   
+-------+-------
+ 00101 | 00101
+(1 row)
+
+-- subquery using stable function (can't be sent to remote)
+PREPARE st2(int) AS SELECT * FROM ft1 t1 WHERE t1.c1 < $2 AND t1.c3 IN (SELECT c3 FROM ft2 t2 WHERE c1 > $1 AND date(c4) = '1970-01-17'::date) ORDER BY c1;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st2(10, 20);
+                                                QUERY PLAN                                                
+----------------------------------------------------------------------------------------------------------
+ Sort
+   Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+   Sort Key: t1.c1
+   ->  Nested Loop Semi Join
+         Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+         Join Filter: (t1.c3 = t2.c3)
+         ->  Foreign Scan on public.ft1 t1
+               Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+               Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 20))
+         ->  Materialize
+               Output: t2.c3
+               ->  Foreign Scan on public.ft2 t2
+                     Output: t2.c3
+                     Filter: (date(t2.c4) = '01-17-1970'::date)
+                     Remote SQL: SELECT c3, c4 FROM "S 1"."T 1" WHERE (("C 1" > 10))
+(15 rows)
+
+EXECUTE st2(10, 20);
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 16 |  6 | 00016 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+(1 row)
+
+EXECUTE st2(101, 121);
+ c1  | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 116 |  6 | 00116 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+(1 row)
+
+-- subquery using immutable function (can be sent to remote)
+PREPARE st3(int) AS SELECT * FROM ft1 t1 WHERE t1.c1 < $2 AND t1.c3 IN (SELECT c3 FROM ft2 t2 WHERE c1 > $1 AND date(c5) = '1970-01-17'::date) ORDER BY c1;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st3(10, 20);
+                                                      QUERY PLAN                                                       
+-----------------------------------------------------------------------------------------------------------------------
+ Sort
+   Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+   Sort Key: t1.c1
+   ->  Nested Loop Semi Join
+         Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+         Join Filter: (t1.c3 = t2.c3)
+         ->  Foreign Scan on public.ft1 t1
+               Output: t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t1.c6, t1.c7, t1.c8
+               Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 20))
+         ->  Materialize
+               Output: t2.c3
+               ->  Foreign Scan on public.ft2 t2
+                     Output: t2.c3
+                     Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE (("C 1" > 10)) AND ((date(c5) = '1970-01-17'::date))
+(14 rows)
+
+EXECUTE st3(10, 20);
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 16 |  6 | 00016 | Sat Jan 17 00:00:00 1970 PST | Sat Jan 17 00:00:00 1970 | 6  | 6          | foo
+(1 row)
+
+EXECUTE st3(20, 30);
+ c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8 
+----+----+----+----+----+----+----+----
+(0 rows)
+
+-- custom plan should be chosen initially
+PREPARE st4(int) AS SELECT * FROM ft1 t1 WHERE t1.c1 = $1;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st4(1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st4(1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st4(1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st4(1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st4(1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(3 rows)
+
+-- once we try it enough times, should switch to generic plan
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st4(1);
+                                              QUERY PLAN                                               
+-------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = $1::integer))
+(3 rows)
+
+-- value of $1 should not be sent to remote
+PREPARE st5(user_enum,int) AS SELECT * FROM ft1 t1 WHERE c8 = $1 and c1 = $2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st5('foo', 1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (t1.c8 = 'foo'::user_enum)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(4 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st5('foo', 1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (t1.c8 = 'foo'::user_enum)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(4 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st5('foo', 1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (t1.c8 = 'foo'::user_enum)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(4 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st5('foo', 1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (t1.c8 = 'foo'::user_enum)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(4 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st5('foo', 1);
+                                         QUERY PLAN                                          
+---------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (t1.c8 = 'foo'::user_enum)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 1))
+(4 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st5('foo', 1);
+                                              QUERY PLAN                                               
+-------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Filter: (t1.c8 = $1)
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = $1::integer))
+(4 rows)
+
+EXECUTE st5('foo', 1);
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+-- altering FDW options requires replanning
+PREPARE st6 AS SELECT * FROM ft1 t1 WHERE t1.c1 = t1.c2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st6;
+                                          QUERY PLAN                                          
+----------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = c2))
+(3 rows)
+
+PREPARE st7 AS INSERT INTO ft1 (c1,c2,c3) VALUES (1001,101,'foo');
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st7;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.ft1
+   Remote SQL: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+   Batch Size: 1
+   ->  Result
+         Output: NULL::integer, 1001, 101, 'foo'::text, NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying, 'ft1       '::character(10), NULL::user_enum
+(5 rows)
+
+ALTER TABLE "S 1"."T 1" RENAME TO "T 0";
+ALTER FOREIGN TABLE ft1 OPTIONS (SET table_name 'T 0');
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st6;
+                                          QUERY PLAN                                          
+----------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 0" WHERE (("C 1" = c2))
+(3 rows)
+
+EXECUTE st6;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+  3 |  3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+  4 |  4 | 00004 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4  | 4          | foo
+  5 |  5 | 00005 | Tue Jan 06 00:00:00 1970 PST | Tue Jan 06 00:00:00 1970 | 5  | 5          | foo
+  6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+  7 |  7 | 00007 | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  8 |  8 | 00008 | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  9 |  9 | 00009 | Sat Jan 10 00:00:00 1970 PST | Sat Jan 10 00:00:00 1970 | 9  | 9          | foo
+(9 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st7;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.ft1
+   Remote SQL: INSERT INTO "S 1"."T 0"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+   Batch Size: 1
+   ->  Result
+         Output: NULL::integer, 1001, 101, 'foo'::text, NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying, 'ft1       '::character(10), NULL::user_enum
+(5 rows)
+
+ALTER TABLE "S 1"."T 0" RENAME TO "T 1";
+ALTER FOREIGN TABLE ft1 OPTIONS (SET table_name 'T 1');
+PREPARE st8 AS SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st8;
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c3))
+   Relations: Aggregate on (public.ft1 t1)
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" OPERATOR(public.===) c2))
+(4 rows)
+
+ALTER SERVER loopback OPTIONS (DROP extensions);
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st8;
+                        QUERY PLAN                         
+-----------------------------------------------------------
+ Aggregate
+   Output: count(c3)
+   ->  Foreign Scan on public.ft1 t1
+         Output: c3
+         Filter: (t1.c1 === t1.c2)
+         Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1"
+(6 rows)
+
+EXECUTE st8;
+ count 
+-------
+     9
+(1 row)
+
+ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
+-- cleanup
+DEALLOCATE st1;
+DEALLOCATE st2;
+DEALLOCATE st3;
+DEALLOCATE st4;
+DEALLOCATE st5;
+DEALLOCATE st6;
+DEALLOCATE st7;
+DEALLOCATE st8;
+-- System columns, except ctid and oid, should not be sent to remote
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 t1 WHERE t1.tableoid = 'pg_class'::regclass LIMIT 1;
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Limit
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   ->  Foreign Scan on public.ft1 t1
+         Output: c1, c2, c3, c4, c5, c6, c7, c8
+         Filter: (t1.tableoid = '1259'::oid)
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(6 rows)
+
+SELECT * FROM ft1 t1 WHERE t1.tableoid = 'ft1'::regclass LIMIT 1;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT tableoid::regclass, * FROM ft1 t1 LIMIT 1;
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: (tableoid)::regclass, c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" LIMIT 1::bigint
+(3 rows)
+
+SELECT tableoid::regclass, * FROM ft1 t1 LIMIT 1;
+ tableoid | c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----------+----+----+-------+------------------------------+--------------------------+----+------------+-----
+ ft1      |  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 t1 WHERE t1.ctid = '(0,2)';
+                                            QUERY PLAN                                            
+--------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((ctid = '(0,2)'))
+(3 rows)
+
+SELECT * FROM ft1 t1 WHERE t1.ctid = '(0,2)';
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT ctid, * FROM ft1 t1 LIMIT 1;
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: ctid, c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" LIMIT 1::bigint
+(3 rows)
+
+SELECT ctid, * FROM ft1 t1 LIMIT 1;
+ ctid  | c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+-------+----+----+-------+------------------------------+--------------------------+----+------------+-----
+ (0,1) |  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+-- ===================================================================
+-- used in PL/pgSQL function
+-- ===================================================================
+CREATE OR REPLACE FUNCTION f_test(p_c1 int) RETURNS int AS $$
+DECLARE
+	v_c1 int;
+BEGIN
+    SELECT c1 INTO v_c1 FROM ft1 WHERE c1 = p_c1 LIMIT 1;
+    PERFORM c1 FROM ft1 WHERE c1 = p_c1 AND p_c1 = v_c1 LIMIT 1;
+    RETURN v_c1;
+END;
+$$ LANGUAGE plpgsql;
+SELECT f_test(100);
+ f_test 
+--------
+    100
+(1 row)
+
+DROP FUNCTION f_test(int);
+-- ===================================================================
+-- REINDEX
+-- ===================================================================
+-- remote table is not created here
+CREATE FOREIGN TABLE reindex_foreign (c1 int, c2 int)
+  SERVER loopback2 OPTIONS (table_name 'reindex_local');
+REINDEX TABLE reindex_foreign; -- error
+ERROR:  "reindex_foreign" is not a table or materialized view
+REINDEX TABLE CONCURRENTLY reindex_foreign; -- error
+ERROR:  "reindex_foreign" is not a table or materialized view
+DROP FOREIGN TABLE reindex_foreign;
+-- partitions and foreign tables
+CREATE TABLE reind_fdw_parent (c1 int) PARTITION BY RANGE (c1);
+CREATE TABLE reind_fdw_0_10 PARTITION OF reind_fdw_parent
+  FOR VALUES FROM (0) TO (10);
+CREATE FOREIGN TABLE reind_fdw_10_20 PARTITION OF reind_fdw_parent
+  FOR VALUES FROM (10) TO (20)
+  SERVER loopback OPTIONS (table_name 'reind_local_10_20');
+REINDEX TABLE reind_fdw_parent; -- ok
+REINDEX TABLE CONCURRENTLY reind_fdw_parent; -- ok
+DROP TABLE reind_fdw_parent;
+-- ===================================================================
+-- conversion error
+-- ===================================================================
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE int;
+SELECT * FROM ft1 ftx(x1,x2,x3,x4,x5,x6,x7,x8) WHERE x1 = 1;  -- ERROR
+ERROR:  invalid input syntax for type integer: "foo"
+CONTEXT:  column "x8" of foreign table "ftx"
+SELECT ftx.x1, ft2.c2, ftx.x8 FROM ft1 ftx(x1,x2,x3,x4,x5,x6,x7,x8), ft2
+  WHERE ftx.x1 = ft2.c1 AND ftx.x1 = 1; -- ERROR
+ERROR:  invalid input syntax for type integer: "foo"
+CONTEXT:  column "x8" of foreign table "ftx"
+SELECT ftx.x1, ft2.c2, ftx FROM ft1 ftx(x1,x2,x3,x4,x5,x6,x7,x8), ft2
+  WHERE ftx.x1 = ft2.c1 AND ftx.x1 = 1; -- ERROR
+ERROR:  invalid input syntax for type integer: "foo"
+CONTEXT:  whole-row reference to foreign table "ftx"
+SELECT sum(c2), array_agg(c8) FROM ft1 GROUP BY c8; -- ERROR
+ERROR:  invalid input syntax for type integer: "foo"
+CONTEXT:  processing expression at position 2 in select list
+ANALYZE ft1; -- ERROR
+ERROR:  invalid input syntax for type integer: "foo"
+CONTEXT:  column "c8" of foreign table "ft1"
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE user_enum;
+-- ===================================================================
+-- local type can be different from remote type in some cases,
+-- in particular if similarly-named operators do equivalent things
+-- ===================================================================
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE text;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE c8 = 'foo' LIMIT 1;
+                                                  QUERY PLAN                                                  
+--------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 = 'foo')) LIMIT 1::bigint
+(3 rows)
+
+SELECT * FROM ft1 WHERE c8 = 'foo' LIMIT 1;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE 'foo' = c8 LIMIT 1;
+                                                  QUERY PLAN                                                  
+--------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (('foo' = c8)) LIMIT 1::bigint
+(3 rows)
+
+SELECT * FROM ft1 WHERE 'foo' = c8 LIMIT 1;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+-- we declared c8 to be text locally, but it's still the same type on
+-- the remote which will balk if we try to do anything incompatible
+-- with that remote type
+SELECT * FROM ft1 WHERE c8 LIKE 'foo' LIMIT 1; -- ERROR
+ERROR:  operator does not exist: public.user_enum ~~ unknown
+HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+CONTEXT:  remote SQL command: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 ~~ 'foo')) LIMIT 1::bigint
+SELECT * FROM ft1 WHERE c8::text LIKE 'foo' LIMIT 1; -- ERROR; cast not pushed down
+ERROR:  operator does not exist: public.user_enum ~~ unknown
+HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+CONTEXT:  remote SQL command: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 ~~ 'foo')) LIMIT 1::bigint
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE user_enum;
+-- ===================================================================
+-- subtransaction
+--  + local/remote error doesn't break cursor
+-- ===================================================================
+BEGIN;
+DECLARE c CURSOR FOR SELECT * FROM ft1 ORDER BY c1;
+FETCH c;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+SAVEPOINT s;
+ERROR OUT;          -- ERROR
+ERROR:  syntax error at or near "ERROR"
+LINE 1: ERROR OUT;
+        ^
+ROLLBACK TO s;
+FETCH c;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+(1 row)
+
+SAVEPOINT s;
+SELECT * FROM ft1 WHERE 1 / (c1 - 1) > 0;  -- ERROR
+ERROR:  division by zero
+CONTEXT:  remote SQL command: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (((1 / ("C 1" - 1)) > 0))
+ROLLBACK TO s;
+FETCH c;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  3 |  3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+(1 row)
+
+SELECT * FROM ft1 ORDER BY c1 LIMIT 1;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+(1 row)
+
+COMMIT;
+-- ===================================================================
+-- test handling of collations
+-- ===================================================================
+create table loct3 (f1 text collate "C" unique, f2 text, f3 varchar(10) unique);
+create foreign table ft3 (f1 text collate "C", f2 text, f3 varchar(10))
+  server loopback options (table_name 'loct3', use_remote_estimate 'true');
+-- can be sent to remote
+explain (verbose, costs off) select * from ft3 where f1 = 'foo';
+                               QUERY PLAN                               
+------------------------------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f1 = 'foo'))
+(3 rows)
+
+explain (verbose, costs off) select * from ft3 where f1 COLLATE "C" = 'foo';
+                               QUERY PLAN                               
+------------------------------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f1 = 'foo'))
+(3 rows)
+
+explain (verbose, costs off) select * from ft3 where f2 = 'foo';
+                               QUERY PLAN                               
+------------------------------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f2 = 'foo'))
+(3 rows)
+
+explain (verbose, costs off) select * from ft3 where f3 = 'foo';
+                               QUERY PLAN                               
+------------------------------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f3 = 'foo'))
+(3 rows)
+
+explain (verbose, costs off) select * from ft3 f, loct3 l
+  where f.f3 = l.f3 and l.f1 = 'foo';
+                                            QUERY PLAN                                            
+--------------------------------------------------------------------------------------------------
+ Nested Loop
+   Output: f.f1, f.f2, f.f3, l.f1, l.f2, l.f3
+   ->  Index Scan using loct3_f1_key on public.loct3 l
+         Output: l.f1, l.f2, l.f3
+         Index Cond: (l.f1 = 'foo'::text)
+   ->  Foreign Scan on public.ft3 f
+         Output: f.f1, f.f2, f.f3
+         Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE (($1::character varying(10) = f3))
+(8 rows)
+
+-- can't be sent to remote
+explain (verbose, costs off) select * from ft3 where f1 COLLATE "POSIX" = 'foo';
+                    QUERY PLAN                     
+---------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Filter: ((ft3.f1)::text = 'foo'::text)
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3
+(4 rows)
+
+explain (verbose, costs off) select * from ft3 where f1 = 'foo' COLLATE "C";
+                    QUERY PLAN                     
+---------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Filter: (ft3.f1 = 'foo'::text COLLATE "C")
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3
+(4 rows)
+
+explain (verbose, costs off) select * from ft3 where f2 COLLATE "C" = 'foo';
+                    QUERY PLAN                     
+---------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Filter: ((ft3.f2)::text = 'foo'::text)
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3
+(4 rows)
+
+explain (verbose, costs off) select * from ft3 where f2 = 'foo' COLLATE "C";
+                    QUERY PLAN                     
+---------------------------------------------------
+ Foreign Scan on public.ft3
+   Output: f1, f2, f3
+   Filter: (ft3.f2 = 'foo'::text COLLATE "C")
+   Remote SQL: SELECT f1, f2, f3 FROM public.loct3
+(4 rows)
+
+explain (verbose, costs off) select * from ft3 f, loct3 l
+  where f.f3 = l.f3 COLLATE "POSIX" and l.f1 = 'foo';
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Hash Join
+   Output: f.f1, f.f2, f.f3, l.f1, l.f2, l.f3
+   Inner Unique: true
+   Hash Cond: ((f.f3)::text = (l.f3)::text)
+   ->  Foreign Scan on public.ft3 f
+         Output: f.f1, f.f2, f.f3
+         Remote SQL: SELECT f1, f2, f3 FROM public.loct3
+   ->  Hash
+         Output: l.f1, l.f2, l.f3
+         ->  Index Scan using loct3_f1_key on public.loct3 l
+               Output: l.f1, l.f2, l.f3
+               Index Cond: (l.f1 = 'foo'::text)
+(12 rows)
+
+-- ===================================================================
+-- test writable foreign table stuff
+-- ===================================================================
+EXPLAIN (verbose, costs off)
+INSERT INTO ft2 (c1,c2,c3) SELECT c1+1000,c2+100, c3 || c3 FROM ft2 LIMIT 20;
+                                                                                                                    QUERY PLAN                                                                                                                    
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.ft2
+   Remote SQL: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+   Batch Size: 1
+   ->  Subquery Scan on "*SELECT*"
+         Output: "*SELECT*"."?column?", "*SELECT*"."?column?_1", NULL::integer, "*SELECT*"."?column?_2", NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying, 'ft2       '::character(10), NULL::user_enum
+         ->  Foreign Scan on public.ft2 ft2_1
+               Output: (ft2_1.c1 + 1000), (ft2_1.c2 + 100), (ft2_1.c3 || ft2_1.c3)
+               Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1" LIMIT 20::bigint
+(8 rows)
+
+INSERT INTO ft2 (c1,c2,c3) SELECT c1+1000,c2+100, c3 || c3 FROM ft2 LIMIT 20;
+INSERT INTO ft2 (c1,c2,c3)
+  VALUES (1101,201,'aaa'), (1102,202,'bbb'), (1103,203,'ccc') RETURNING *;
+  c1  | c2  | c3  | c4 | c5 | c6 |     c7     | c8 
+------+-----+-----+----+----+----+------------+----
+ 1101 | 201 | aaa |    |    |    | ft2        | 
+ 1102 | 202 | bbb |    |    |    | ft2        | 
+ 1103 | 203 | ccc |    |    |    | ft2        | 
+(3 rows)
+
+INSERT INTO ft2 (c1,c2,c3) VALUES (1104,204,'ddd'), (1105,205,'eee');
+EXPLAIN (verbose, costs off)
+UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;              -- can be pushed down
+                                                   QUERY PLAN                                                   
+----------------------------------------------------------------------------------------------------------------
+ Update on public.ft2
+   ->  Foreign Update on public.ft2
+         Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 300), c3 = (c3 || '_update3') WHERE ((("C 1" % 10) = 3))
+(3 rows)
+
+UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;
+EXPLAIN (verbose, costs off)
+UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;  -- can be pushed down
+                                                                         QUERY PLAN                                                                         
+------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Update on public.ft2
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   ->  Foreign Update on public.ft2
+         Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 400), c3 = (c3 || '_update7') WHERE ((("C 1" % 10) = 7)) RETURNING "C 1", c2, c3, c4, c5, c6, c7, c8
+(4 rows)
+
+UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;
+  c1  | c2  |         c3         |              c4              |            c5            | c6 |     c7     | c8  
+------+-----+--------------------+------------------------------+--------------------------+----+------------+-----
+    7 | 407 | 00007_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+   17 | 407 | 00017_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+   27 | 407 | 00027_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+   37 | 407 | 00037_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+   47 | 407 | 00047_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+   57 | 407 | 00057_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+   67 | 407 | 00067_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+   77 | 407 | 00077_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+   87 | 407 | 00087_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+   97 | 407 | 00097_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  107 | 407 | 00107_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  117 | 407 | 00117_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  127 | 407 | 00127_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  137 | 407 | 00137_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  147 | 407 | 00147_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  157 | 407 | 00157_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  167 | 407 | 00167_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  177 | 407 | 00177_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  187 | 407 | 00187_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  197 | 407 | 00197_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  207 | 407 | 00207_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  217 | 407 | 00217_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  227 | 407 | 00227_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  237 | 407 | 00237_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  247 | 407 | 00247_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  257 | 407 | 00257_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  267 | 407 | 00267_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  277 | 407 | 00277_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  287 | 407 | 00287_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  297 | 407 | 00297_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  307 | 407 | 00307_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  317 | 407 | 00317_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  327 | 407 | 00327_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  337 | 407 | 00337_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  347 | 407 | 00347_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  357 | 407 | 00357_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  367 | 407 | 00367_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  377 | 407 | 00377_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  387 | 407 | 00387_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  397 | 407 | 00397_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  407 | 407 | 00407_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  417 | 407 | 00417_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  427 | 407 | 00427_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  437 | 407 | 00437_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  447 | 407 | 00447_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  457 | 407 | 00457_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  467 | 407 | 00467_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  477 | 407 | 00477_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  487 | 407 | 00487_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  497 | 407 | 00497_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  507 | 407 | 00507_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  517 | 407 | 00517_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  527 | 407 | 00527_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  537 | 407 | 00537_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  547 | 407 | 00547_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  557 | 407 | 00557_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  567 | 407 | 00567_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  577 | 407 | 00577_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  587 | 407 | 00587_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  597 | 407 | 00597_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  607 | 407 | 00607_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  617 | 407 | 00617_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  627 | 407 | 00627_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  637 | 407 | 00637_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  647 | 407 | 00647_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  657 | 407 | 00657_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  667 | 407 | 00667_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  677 | 407 | 00677_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  687 | 407 | 00687_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  697 | 407 | 00697_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  707 | 407 | 00707_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  717 | 407 | 00717_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  727 | 407 | 00727_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  737 | 407 | 00737_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  747 | 407 | 00747_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  757 | 407 | 00757_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  767 | 407 | 00767_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  777 | 407 | 00777_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  787 | 407 | 00787_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  797 | 407 | 00797_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  807 | 407 | 00807_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  817 | 407 | 00817_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  827 | 407 | 00827_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  837 | 407 | 00837_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  847 | 407 | 00847_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  857 | 407 | 00857_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  867 | 407 | 00867_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  877 | 407 | 00877_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  887 | 407 | 00887_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  897 | 407 | 00897_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+  907 | 407 | 00907_update7      | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  917 | 407 | 00917_update7      | Sun Jan 18 00:00:00 1970 PST | Sun Jan 18 00:00:00 1970 | 7  | 7          | foo
+  927 | 407 | 00927_update7      | Wed Jan 28 00:00:00 1970 PST | Wed Jan 28 00:00:00 1970 | 7  | 7          | foo
+  937 | 407 | 00937_update7      | Sat Feb 07 00:00:00 1970 PST | Sat Feb 07 00:00:00 1970 | 7  | 7          | foo
+  947 | 407 | 00947_update7      | Tue Feb 17 00:00:00 1970 PST | Tue Feb 17 00:00:00 1970 | 7  | 7          | foo
+  957 | 407 | 00957_update7      | Fri Feb 27 00:00:00 1970 PST | Fri Feb 27 00:00:00 1970 | 7  | 7          | foo
+  967 | 407 | 00967_update7      | Mon Mar 09 00:00:00 1970 PST | Mon Mar 09 00:00:00 1970 | 7  | 7          | foo
+  977 | 407 | 00977_update7      | Thu Mar 19 00:00:00 1970 PST | Thu Mar 19 00:00:00 1970 | 7  | 7          | foo
+  987 | 407 | 00987_update7      | Sun Mar 29 00:00:00 1970 PST | Sun Mar 29 00:00:00 1970 | 7  | 7          | foo
+  997 | 407 | 00997_update7      | Wed Apr 08 00:00:00 1970 PST | Wed Apr 08 00:00:00 1970 | 7  | 7          | foo
+ 1007 | 507 | 0000700007_update7 |                              |                          |    | ft2        | 
+ 1017 | 507 | 0001700017_update7 |                              |                          |    | ft2        | 
+(102 rows)
+
+EXPLAIN (verbose, costs off)
+UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
+  FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;                               -- can be pushed down
+                                                                                                QUERY PLAN                                                                                                 
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Update on public.ft2
+   ->  Foreign Update
+         Remote SQL: UPDATE "S 1"."T 1" r1 SET c2 = (r1.c2 + 500), c3 = (r1.c3 || '_update9'), c7 = 'ft2       '::character(10) FROM "S 1"."T 1" r2 WHERE ((r1.c2 = r2."C 1")) AND (((r2."C 1" % 10) = 9))
+(3 rows)
+
+UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
+  FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;
+EXPLAIN (verbose, costs off)
+  DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;                               -- can be pushed down
+                                         QUERY PLAN                                         
+--------------------------------------------------------------------------------------------
+ Delete on public.ft2
+   Output: c1, c4
+   ->  Foreign Delete on public.ft2
+         Remote SQL: DELETE FROM "S 1"."T 1" WHERE ((("C 1" % 10) = 5)) RETURNING "C 1", c4
+(4 rows)
+
+DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
+  c1  |              c4              
+------+------------------------------
+    5 | Tue Jan 06 00:00:00 1970 PST
+   15 | Fri Jan 16 00:00:00 1970 PST
+   25 | Mon Jan 26 00:00:00 1970 PST
+   35 | Thu Feb 05 00:00:00 1970 PST
+   45 | Sun Feb 15 00:00:00 1970 PST
+   55 | Wed Feb 25 00:00:00 1970 PST
+   65 | Sat Mar 07 00:00:00 1970 PST
+   75 | Tue Mar 17 00:00:00 1970 PST
+   85 | Fri Mar 27 00:00:00 1970 PST
+   95 | Mon Apr 06 00:00:00 1970 PST
+  105 | Tue Jan 06 00:00:00 1970 PST
+  115 | Fri Jan 16 00:00:00 1970 PST
+  125 | Mon Jan 26 00:00:00 1970 PST
+  135 | Thu Feb 05 00:00:00 1970 PST
+  145 | Sun Feb 15 00:00:00 1970 PST
+  155 | Wed Feb 25 00:00:00 1970 PST
+  165 | Sat Mar 07 00:00:00 1970 PST
+  175 | Tue Mar 17 00:00:00 1970 PST
+  185 | Fri Mar 27 00:00:00 1970 PST
+  195 | Mon Apr 06 00:00:00 1970 PST
+  205 | Tue Jan 06 00:00:00 1970 PST
+  215 | Fri Jan 16 00:00:00 1970 PST
+  225 | Mon Jan 26 00:00:00 1970 PST
+  235 | Thu Feb 05 00:00:00 1970 PST
+  245 | Sun Feb 15 00:00:00 1970 PST
+  255 | Wed Feb 25 00:00:00 1970 PST
+  265 | Sat Mar 07 00:00:00 1970 PST
+  275 | Tue Mar 17 00:00:00 1970 PST
+  285 | Fri Mar 27 00:00:00 1970 PST
+  295 | Mon Apr 06 00:00:00 1970 PST
+  305 | Tue Jan 06 00:00:00 1970 PST
+  315 | Fri Jan 16 00:00:00 1970 PST
+  325 | Mon Jan 26 00:00:00 1970 PST
+  335 | Thu Feb 05 00:00:00 1970 PST
+  345 | Sun Feb 15 00:00:00 1970 PST
+  355 | Wed Feb 25 00:00:00 1970 PST
+  365 | Sat Mar 07 00:00:00 1970 PST
+  375 | Tue Mar 17 00:00:00 1970 PST
+  385 | Fri Mar 27 00:00:00 1970 PST
+  395 | Mon Apr 06 00:00:00 1970 PST
+  405 | Tue Jan 06 00:00:00 1970 PST
+  415 | Fri Jan 16 00:00:00 1970 PST
+  425 | Mon Jan 26 00:00:00 1970 PST
+  435 | Thu Feb 05 00:00:00 1970 PST
+  445 | Sun Feb 15 00:00:00 1970 PST
+  455 | Wed Feb 25 00:00:00 1970 PST
+  465 | Sat Mar 07 00:00:00 1970 PST
+  475 | Tue Mar 17 00:00:00 1970 PST
+  485 | Fri Mar 27 00:00:00 1970 PST
+  495 | Mon Apr 06 00:00:00 1970 PST
+  505 | Tue Jan 06 00:00:00 1970 PST
+  515 | Fri Jan 16 00:00:00 1970 PST
+  525 | Mon Jan 26 00:00:00 1970 PST
+  535 | Thu Feb 05 00:00:00 1970 PST
+  545 | Sun Feb 15 00:00:00 1970 PST
+  555 | Wed Feb 25 00:00:00 1970 PST
+  565 | Sat Mar 07 00:00:00 1970 PST
+  575 | Tue Mar 17 00:00:00 1970 PST
+  585 | Fri Mar 27 00:00:00 1970 PST
+  595 | Mon Apr 06 00:00:00 1970 PST
+  605 | Tue Jan 06 00:00:00 1970 PST
+  615 | Fri Jan 16 00:00:00 1970 PST
+  625 | Mon Jan 26 00:00:00 1970 PST
+  635 | Thu Feb 05 00:00:00 1970 PST
+  645 | Sun Feb 15 00:00:00 1970 PST
+  655 | Wed Feb 25 00:00:00 1970 PST
+  665 | Sat Mar 07 00:00:00 1970 PST
+  675 | Tue Mar 17 00:00:00 1970 PST
+  685 | Fri Mar 27 00:00:00 1970 PST
+  695 | Mon Apr 06 00:00:00 1970 PST
+  705 | Tue Jan 06 00:00:00 1970 PST
+  715 | Fri Jan 16 00:00:00 1970 PST
+  725 | Mon Jan 26 00:00:00 1970 PST
+  735 | Thu Feb 05 00:00:00 1970 PST
+  745 | Sun Feb 15 00:00:00 1970 PST
+  755 | Wed Feb 25 00:00:00 1970 PST
+  765 | Sat Mar 07 00:00:00 1970 PST
+  775 | Tue Mar 17 00:00:00 1970 PST
+  785 | Fri Mar 27 00:00:00 1970 PST
+  795 | Mon Apr 06 00:00:00 1970 PST
+  805 | Tue Jan 06 00:00:00 1970 PST
+  815 | Fri Jan 16 00:00:00 1970 PST
+  825 | Mon Jan 26 00:00:00 1970 PST
+  835 | Thu Feb 05 00:00:00 1970 PST
+  845 | Sun Feb 15 00:00:00 1970 PST
+  855 | Wed Feb 25 00:00:00 1970 PST
+  865 | Sat Mar 07 00:00:00 1970 PST
+  875 | Tue Mar 17 00:00:00 1970 PST
+  885 | Fri Mar 27 00:00:00 1970 PST
+  895 | Mon Apr 06 00:00:00 1970 PST
+  905 | Tue Jan 06 00:00:00 1970 PST
+  915 | Fri Jan 16 00:00:00 1970 PST
+  925 | Mon Jan 26 00:00:00 1970 PST
+  935 | Thu Feb 05 00:00:00 1970 PST
+  945 | Sun Feb 15 00:00:00 1970 PST
+  955 | Wed Feb 25 00:00:00 1970 PST
+  965 | Sat Mar 07 00:00:00 1970 PST
+  975 | Tue Mar 17 00:00:00 1970 PST
+  985 | Fri Mar 27 00:00:00 1970 PST
+  995 | Mon Apr 06 00:00:00 1970 PST
+ 1005 | 
+ 1015 | 
+ 1105 | 
+(103 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;                -- can be pushed down
+                                                         QUERY PLAN                                                         
+----------------------------------------------------------------------------------------------------------------------------
+ Delete on public.ft2
+   ->  Foreign Delete
+         Remote SQL: DELETE FROM "S 1"."T 1" r1 USING "S 1"."T 1" r2 WHERE ((r1.c2 = r2."C 1")) AND (((r2."C 1" % 10) = 2))
+(3 rows)
+
+DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;
+SELECT c1,c2,c3,c4 FROM ft2 ORDER BY c1;
+  c1  | c2  |         c3         |              c4              
+------+-----+--------------------+------------------------------
+    1 |   1 | 00001              | Fri Jan 02 00:00:00 1970 PST
+    3 | 303 | 00003_update3      | Sun Jan 04 00:00:00 1970 PST
+    4 |   4 | 00004              | Mon Jan 05 00:00:00 1970 PST
+    6 |   6 | 00006              | Wed Jan 07 00:00:00 1970 PST
+    7 | 407 | 00007_update7      | Thu Jan 08 00:00:00 1970 PST
+    8 |   8 | 00008              | Fri Jan 09 00:00:00 1970 PST
+    9 | 509 | 00009_update9      | Sat Jan 10 00:00:00 1970 PST
+   10 |   0 | 00010              | Sun Jan 11 00:00:00 1970 PST
+   11 |   1 | 00011              | Mon Jan 12 00:00:00 1970 PST
+   13 | 303 | 00013_update3      | Wed Jan 14 00:00:00 1970 PST
+   14 |   4 | 00014              | Thu Jan 15 00:00:00 1970 PST
+   16 |   6 | 00016              | Sat Jan 17 00:00:00 1970 PST
+   17 | 407 | 00017_update7      | Sun Jan 18 00:00:00 1970 PST
+   18 |   8 | 00018              | Mon Jan 19 00:00:00 1970 PST
+   19 | 509 | 00019_update9      | Tue Jan 20 00:00:00 1970 PST
+   20 |   0 | 00020              | Wed Jan 21 00:00:00 1970 PST
+   21 |   1 | 00021              | Thu Jan 22 00:00:00 1970 PST
+   23 | 303 | 00023_update3      | Sat Jan 24 00:00:00 1970 PST
+   24 |   4 | 00024              | Sun Jan 25 00:00:00 1970 PST
+   26 |   6 | 00026              | Tue Jan 27 00:00:00 1970 PST
+   27 | 407 | 00027_update7      | Wed Jan 28 00:00:00 1970 PST
+   28 |   8 | 00028              | Thu Jan 29 00:00:00 1970 PST
+   29 | 509 | 00029_update9      | Fri Jan 30 00:00:00 1970 PST
+   30 |   0 | 00030              | Sat Jan 31 00:00:00 1970 PST
+   31 |   1 | 00031              | Sun Feb 01 00:00:00 1970 PST
+   33 | 303 | 00033_update3      | Tue Feb 03 00:00:00 1970 PST
+   34 |   4 | 00034              | Wed Feb 04 00:00:00 1970 PST
+   36 |   6 | 00036              | Fri Feb 06 00:00:00 1970 PST
+   37 | 407 | 00037_update7      | Sat Feb 07 00:00:00 1970 PST
+   38 |   8 | 00038              | Sun Feb 08 00:00:00 1970 PST
+   39 | 509 | 00039_update9      | Mon Feb 09 00:00:00 1970 PST
+   40 |   0 | 00040              | Tue Feb 10 00:00:00 1970 PST
+   41 |   1 | 00041              | Wed Feb 11 00:00:00 1970 PST
+   43 | 303 | 00043_update3      | Fri Feb 13 00:00:00 1970 PST
+   44 |   4 | 00044              | Sat Feb 14 00:00:00 1970 PST
+   46 |   6 | 00046              | Mon Feb 16 00:00:00 1970 PST
+   47 | 407 | 00047_update7      | Tue Feb 17 00:00:00 1970 PST
+   48 |   8 | 00048              | Wed Feb 18 00:00:00 1970 PST
+   49 | 509 | 00049_update9      | Thu Feb 19 00:00:00 1970 PST
+   50 |   0 | 00050              | Fri Feb 20 00:00:00 1970 PST
+   51 |   1 | 00051              | Sat Feb 21 00:00:00 1970 PST
+   53 | 303 | 00053_update3      | Mon Feb 23 00:00:00 1970 PST
+   54 |   4 | 00054              | Tue Feb 24 00:00:00 1970 PST
+   56 |   6 | 00056              | Thu Feb 26 00:00:00 1970 PST
+   57 | 407 | 00057_update7      | Fri Feb 27 00:00:00 1970 PST
+   58 |   8 | 00058              | Sat Feb 28 00:00:00 1970 PST
+   59 | 509 | 00059_update9      | Sun Mar 01 00:00:00 1970 PST
+   60 |   0 | 00060              | Mon Mar 02 00:00:00 1970 PST
+   61 |   1 | 00061              | Tue Mar 03 00:00:00 1970 PST
+   63 | 303 | 00063_update3      | Thu Mar 05 00:00:00 1970 PST
+   64 |   4 | 00064              | Fri Mar 06 00:00:00 1970 PST
+   66 |   6 | 00066              | Sun Mar 08 00:00:00 1970 PST
+   67 | 407 | 00067_update7      | Mon Mar 09 00:00:00 1970 PST
+   68 |   8 | 00068              | Tue Mar 10 00:00:00 1970 PST
+   69 | 509 | 00069_update9      | Wed Mar 11 00:00:00 1970 PST
+   70 |   0 | 00070              | Thu Mar 12 00:00:00 1970 PST
+   71 |   1 | 00071              | Fri Mar 13 00:00:00 1970 PST
+   73 | 303 | 00073_update3      | Sun Mar 15 00:00:00 1970 PST
+   74 |   4 | 00074              | Mon Mar 16 00:00:00 1970 PST
+   76 |   6 | 00076              | Wed Mar 18 00:00:00 1970 PST
+   77 | 407 | 00077_update7      | Thu Mar 19 00:00:00 1970 PST
+   78 |   8 | 00078              | Fri Mar 20 00:00:00 1970 PST
+   79 | 509 | 00079_update9      | Sat Mar 21 00:00:00 1970 PST
+   80 |   0 | 00080              | Sun Mar 22 00:00:00 1970 PST
+   81 |   1 | 00081              | Mon Mar 23 00:00:00 1970 PST
+   83 | 303 | 00083_update3      | Wed Mar 25 00:00:00 1970 PST
+   84 |   4 | 00084              | Thu Mar 26 00:00:00 1970 PST
+   86 |   6 | 00086              | Sat Mar 28 00:00:00 1970 PST
+   87 | 407 | 00087_update7      | Sun Mar 29 00:00:00 1970 PST
+   88 |   8 | 00088              | Mon Mar 30 00:00:00 1970 PST
+   89 | 509 | 00089_update9      | Tue Mar 31 00:00:00 1970 PST
+   90 |   0 | 00090              | Wed Apr 01 00:00:00 1970 PST
+   91 |   1 | 00091              | Thu Apr 02 00:00:00 1970 PST
+   93 | 303 | 00093_update3      | Sat Apr 04 00:00:00 1970 PST
+   94 |   4 | 00094              | Sun Apr 05 00:00:00 1970 PST
+   96 |   6 | 00096              | Tue Apr 07 00:00:00 1970 PST
+   97 | 407 | 00097_update7      | Wed Apr 08 00:00:00 1970 PST
+   98 |   8 | 00098              | Thu Apr 09 00:00:00 1970 PST
+   99 | 509 | 00099_update9      | Fri Apr 10 00:00:00 1970 PST
+  100 |   0 | 00100              | Thu Jan 01 00:00:00 1970 PST
+  101 |   1 | 00101              | Fri Jan 02 00:00:00 1970 PST
+  103 | 303 | 00103_update3      | Sun Jan 04 00:00:00 1970 PST
+  104 |   4 | 00104              | Mon Jan 05 00:00:00 1970 PST
+  106 |   6 | 00106              | Wed Jan 07 00:00:00 1970 PST
+  107 | 407 | 00107_update7      | Thu Jan 08 00:00:00 1970 PST
+  108 |   8 | 00108              | Fri Jan 09 00:00:00 1970 PST
+  109 | 509 | 00109_update9      | Sat Jan 10 00:00:00 1970 PST
+  110 |   0 | 00110              | Sun Jan 11 00:00:00 1970 PST
+  111 |   1 | 00111              | Mon Jan 12 00:00:00 1970 PST
+  113 | 303 | 00113_update3      | Wed Jan 14 00:00:00 1970 PST
+  114 |   4 | 00114              | Thu Jan 15 00:00:00 1970 PST
+  116 |   6 | 00116              | Sat Jan 17 00:00:00 1970 PST
+  117 | 407 | 00117_update7      | Sun Jan 18 00:00:00 1970 PST
+  118 |   8 | 00118              | Mon Jan 19 00:00:00 1970 PST
+  119 | 509 | 00119_update9      | Tue Jan 20 00:00:00 1970 PST
+  120 |   0 | 00120              | Wed Jan 21 00:00:00 1970 PST
+  121 |   1 | 00121              | Thu Jan 22 00:00:00 1970 PST
+  123 | 303 | 00123_update3      | Sat Jan 24 00:00:00 1970 PST
+  124 |   4 | 00124              | Sun Jan 25 00:00:00 1970 PST
+  126 |   6 | 00126              | Tue Jan 27 00:00:00 1970 PST
+  127 | 407 | 00127_update7      | Wed Jan 28 00:00:00 1970 PST
+  128 |   8 | 00128              | Thu Jan 29 00:00:00 1970 PST
+  129 | 509 | 00129_update9      | Fri Jan 30 00:00:00 1970 PST
+  130 |   0 | 00130              | Sat Jan 31 00:00:00 1970 PST
+  131 |   1 | 00131              | Sun Feb 01 00:00:00 1970 PST
+  133 | 303 | 00133_update3      | Tue Feb 03 00:00:00 1970 PST
+  134 |   4 | 00134              | Wed Feb 04 00:00:00 1970 PST
+  136 |   6 | 00136              | Fri Feb 06 00:00:00 1970 PST
+  137 | 407 | 00137_update7      | Sat Feb 07 00:00:00 1970 PST
+  138 |   8 | 00138              | Sun Feb 08 00:00:00 1970 PST
+  139 | 509 | 00139_update9      | Mon Feb 09 00:00:00 1970 PST
+  140 |   0 | 00140              | Tue Feb 10 00:00:00 1970 PST
+  141 |   1 | 00141              | Wed Feb 11 00:00:00 1970 PST
+  143 | 303 | 00143_update3      | Fri Feb 13 00:00:00 1970 PST
+  144 |   4 | 00144              | Sat Feb 14 00:00:00 1970 PST
+  146 |   6 | 00146              | Mon Feb 16 00:00:00 1970 PST
+  147 | 407 | 00147_update7      | Tue Feb 17 00:00:00 1970 PST
+  148 |   8 | 00148              | Wed Feb 18 00:00:00 1970 PST
+  149 | 509 | 00149_update9      | Thu Feb 19 00:00:00 1970 PST
+  150 |   0 | 00150              | Fri Feb 20 00:00:00 1970 PST
+  151 |   1 | 00151              | Sat Feb 21 00:00:00 1970 PST
+  153 | 303 | 00153_update3      | Mon Feb 23 00:00:00 1970 PST
+  154 |   4 | 00154              | Tue Feb 24 00:00:00 1970 PST
+  156 |   6 | 00156              | Thu Feb 26 00:00:00 1970 PST
+  157 | 407 | 00157_update7      | Fri Feb 27 00:00:00 1970 PST
+  158 |   8 | 00158              | Sat Feb 28 00:00:00 1970 PST
+  159 | 509 | 00159_update9      | Sun Mar 01 00:00:00 1970 PST
+  160 |   0 | 00160              | Mon Mar 02 00:00:00 1970 PST
+  161 |   1 | 00161              | Tue Mar 03 00:00:00 1970 PST
+  163 | 303 | 00163_update3      | Thu Mar 05 00:00:00 1970 PST
+  164 |   4 | 00164              | Fri Mar 06 00:00:00 1970 PST
+  166 |   6 | 00166              | Sun Mar 08 00:00:00 1970 PST
+  167 | 407 | 00167_update7      | Mon Mar 09 00:00:00 1970 PST
+  168 |   8 | 00168              | Tue Mar 10 00:00:00 1970 PST
+  169 | 509 | 00169_update9      | Wed Mar 11 00:00:00 1970 PST
+  170 |   0 | 00170              | Thu Mar 12 00:00:00 1970 PST
+  171 |   1 | 00171              | Fri Mar 13 00:00:00 1970 PST
+  173 | 303 | 00173_update3      | Sun Mar 15 00:00:00 1970 PST
+  174 |   4 | 00174              | Mon Mar 16 00:00:00 1970 PST
+  176 |   6 | 00176              | Wed Mar 18 00:00:00 1970 PST
+  177 | 407 | 00177_update7      | Thu Mar 19 00:00:00 1970 PST
+  178 |   8 | 00178              | Fri Mar 20 00:00:00 1970 PST
+  179 | 509 | 00179_update9      | Sat Mar 21 00:00:00 1970 PST
+  180 |   0 | 00180              | Sun Mar 22 00:00:00 1970 PST
+  181 |   1 | 00181              | Mon Mar 23 00:00:00 1970 PST
+  183 | 303 | 00183_update3      | Wed Mar 25 00:00:00 1970 PST
+  184 |   4 | 00184              | Thu Mar 26 00:00:00 1970 PST
+  186 |   6 | 00186              | Sat Mar 28 00:00:00 1970 PST
+  187 | 407 | 00187_update7      | Sun Mar 29 00:00:00 1970 PST
+  188 |   8 | 00188              | Mon Mar 30 00:00:00 1970 PST
+  189 | 509 | 00189_update9      | Tue Mar 31 00:00:00 1970 PST
+  190 |   0 | 00190              | Wed Apr 01 00:00:00 1970 PST
+  191 |   1 | 00191              | Thu Apr 02 00:00:00 1970 PST
+  193 | 303 | 00193_update3      | Sat Apr 04 00:00:00 1970 PST
+  194 |   4 | 00194              | Sun Apr 05 00:00:00 1970 PST
+  196 |   6 | 00196              | Tue Apr 07 00:00:00 1970 PST
+  197 | 407 | 00197_update7      | Wed Apr 08 00:00:00 1970 PST
+  198 |   8 | 00198              | Thu Apr 09 00:00:00 1970 PST
+  199 | 509 | 00199_update9      | Fri Apr 10 00:00:00 1970 PST
+  200 |   0 | 00200              | Thu Jan 01 00:00:00 1970 PST
+  201 |   1 | 00201              | Fri Jan 02 00:00:00 1970 PST
+  203 | 303 | 00203_update3      | Sun Jan 04 00:00:00 1970 PST
+  204 |   4 | 00204              | Mon Jan 05 00:00:00 1970 PST
+  206 |   6 | 00206              | Wed Jan 07 00:00:00 1970 PST
+  207 | 407 | 00207_update7      | Thu Jan 08 00:00:00 1970 PST
+  208 |   8 | 00208              | Fri Jan 09 00:00:00 1970 PST
+  209 | 509 | 00209_update9      | Sat Jan 10 00:00:00 1970 PST
+  210 |   0 | 00210              | Sun Jan 11 00:00:00 1970 PST
+  211 |   1 | 00211              | Mon Jan 12 00:00:00 1970 PST
+  213 | 303 | 00213_update3      | Wed Jan 14 00:00:00 1970 PST
+  214 |   4 | 00214              | Thu Jan 15 00:00:00 1970 PST
+  216 |   6 | 00216              | Sat Jan 17 00:00:00 1970 PST
+  217 | 407 | 00217_update7      | Sun Jan 18 00:00:00 1970 PST
+  218 |   8 | 00218              | Mon Jan 19 00:00:00 1970 PST
+  219 | 509 | 00219_update9      | Tue Jan 20 00:00:00 1970 PST
+  220 |   0 | 00220              | Wed Jan 21 00:00:00 1970 PST
+  221 |   1 | 00221              | Thu Jan 22 00:00:00 1970 PST
+  223 | 303 | 00223_update3      | Sat Jan 24 00:00:00 1970 PST
+  224 |   4 | 00224              | Sun Jan 25 00:00:00 1970 PST
+  226 |   6 | 00226              | Tue Jan 27 00:00:00 1970 PST
+  227 | 407 | 00227_update7      | Wed Jan 28 00:00:00 1970 PST
+  228 |   8 | 00228              | Thu Jan 29 00:00:00 1970 PST
+  229 | 509 | 00229_update9      | Fri Jan 30 00:00:00 1970 PST
+  230 |   0 | 00230              | Sat Jan 31 00:00:00 1970 PST
+  231 |   1 | 00231              | Sun Feb 01 00:00:00 1970 PST
+  233 | 303 | 00233_update3      | Tue Feb 03 00:00:00 1970 PST
+  234 |   4 | 00234              | Wed Feb 04 00:00:00 1970 PST
+  236 |   6 | 00236              | Fri Feb 06 00:00:00 1970 PST
+  237 | 407 | 00237_update7      | Sat Feb 07 00:00:00 1970 PST
+  238 |   8 | 00238              | Sun Feb 08 00:00:00 1970 PST
+  239 | 509 | 00239_update9      | Mon Feb 09 00:00:00 1970 PST
+  240 |   0 | 00240              | Tue Feb 10 00:00:00 1970 PST
+  241 |   1 | 00241              | Wed Feb 11 00:00:00 1970 PST
+  243 | 303 | 00243_update3      | Fri Feb 13 00:00:00 1970 PST
+  244 |   4 | 00244              | Sat Feb 14 00:00:00 1970 PST
+  246 |   6 | 00246              | Mon Feb 16 00:00:00 1970 PST
+  247 | 407 | 00247_update7      | Tue Feb 17 00:00:00 1970 PST
+  248 |   8 | 00248              | Wed Feb 18 00:00:00 1970 PST
+  249 | 509 | 00249_update9      | Thu Feb 19 00:00:00 1970 PST
+  250 |   0 | 00250              | Fri Feb 20 00:00:00 1970 PST
+  251 |   1 | 00251              | Sat Feb 21 00:00:00 1970 PST
+  253 | 303 | 00253_update3      | Mon Feb 23 00:00:00 1970 PST
+  254 |   4 | 00254              | Tue Feb 24 00:00:00 1970 PST
+  256 |   6 | 00256              | Thu Feb 26 00:00:00 1970 PST
+  257 | 407 | 00257_update7      | Fri Feb 27 00:00:00 1970 PST
+  258 |   8 | 00258              | Sat Feb 28 00:00:00 1970 PST
+  259 | 509 | 00259_update9      | Sun Mar 01 00:00:00 1970 PST
+  260 |   0 | 00260              | Mon Mar 02 00:00:00 1970 PST
+  261 |   1 | 00261              | Tue Mar 03 00:00:00 1970 PST
+  263 | 303 | 00263_update3      | Thu Mar 05 00:00:00 1970 PST
+  264 |   4 | 00264              | Fri Mar 06 00:00:00 1970 PST
+  266 |   6 | 00266              | Sun Mar 08 00:00:00 1970 PST
+  267 | 407 | 00267_update7      | Mon Mar 09 00:00:00 1970 PST
+  268 |   8 | 00268              | Tue Mar 10 00:00:00 1970 PST
+  269 | 509 | 00269_update9      | Wed Mar 11 00:00:00 1970 PST
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+  271 |   1 | 00271              | Fri Mar 13 00:00:00 1970 PST
+  273 | 303 | 00273_update3      | Sun Mar 15 00:00:00 1970 PST
+  274 |   4 | 00274              | Mon Mar 16 00:00:00 1970 PST
+  276 |   6 | 00276              | Wed Mar 18 00:00:00 1970 PST
+  277 | 407 | 00277_update7      | Thu Mar 19 00:00:00 1970 PST
+  278 |   8 | 00278              | Fri Mar 20 00:00:00 1970 PST
+  279 | 509 | 00279_update9      | Sat Mar 21 00:00:00 1970 PST
+  280 |   0 | 00280              | Sun Mar 22 00:00:00 1970 PST
+  281 |   1 | 00281              | Mon Mar 23 00:00:00 1970 PST
+  283 | 303 | 00283_update3      | Wed Mar 25 00:00:00 1970 PST
+  284 |   4 | 00284              | Thu Mar 26 00:00:00 1970 PST
+  286 |   6 | 00286              | Sat Mar 28 00:00:00 1970 PST
+  287 | 407 | 00287_update7      | Sun Mar 29 00:00:00 1970 PST
+  288 |   8 | 00288              | Mon Mar 30 00:00:00 1970 PST
+  289 | 509 | 00289_update9      | Tue Mar 31 00:00:00 1970 PST
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+  293 | 303 | 00293_update3      | Sat Apr 04 00:00:00 1970 PST
+  294 |   4 | 00294              | Sun Apr 05 00:00:00 1970 PST
+  296 |   6 | 00296              | Tue Apr 07 00:00:00 1970 PST
+  297 | 407 | 00297_update7      | Wed Apr 08 00:00:00 1970 PST
+  298 |   8 | 00298              | Thu Apr 09 00:00:00 1970 PST
+  299 | 509 | 00299_update9      | Fri Apr 10 00:00:00 1970 PST
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+  303 | 303 | 00303_update3      | Sun Jan 04 00:00:00 1970 PST
+  304 |   4 | 00304              | Mon Jan 05 00:00:00 1970 PST
+  306 |   6 | 00306              | Wed Jan 07 00:00:00 1970 PST
+  307 | 407 | 00307_update7      | Thu Jan 08 00:00:00 1970 PST
+  308 |   8 | 00308              | Fri Jan 09 00:00:00 1970 PST
+  309 | 509 | 00309_update9      | Sat Jan 10 00:00:00 1970 PST
+  310 |   0 | 00310              | Sun Jan 11 00:00:00 1970 PST
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+  313 | 303 | 00313_update3      | Wed Jan 14 00:00:00 1970 PST
+  314 |   4 | 00314              | Thu Jan 15 00:00:00 1970 PST
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+  317 | 407 | 00317_update7      | Sun Jan 18 00:00:00 1970 PST
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+  319 | 509 | 00319_update9      | Tue Jan 20 00:00:00 1970 PST
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+  323 | 303 | 00323_update3      | Sat Jan 24 00:00:00 1970 PST
+  324 |   4 | 00324              | Sun Jan 25 00:00:00 1970 PST
+  326 |   6 | 00326              | Tue Jan 27 00:00:00 1970 PST
+  327 | 407 | 00327_update7      | Wed Jan 28 00:00:00 1970 PST
+  328 |   8 | 00328              | Thu Jan 29 00:00:00 1970 PST
+  329 | 509 | 00329_update9      | Fri Jan 30 00:00:00 1970 PST
+  330 |   0 | 00330              | Sat Jan 31 00:00:00 1970 PST
+  331 |   1 | 00331              | Sun Feb 01 00:00:00 1970 PST
+  333 | 303 | 00333_update3      | Tue Feb 03 00:00:00 1970 PST
+  334 |   4 | 00334              | Wed Feb 04 00:00:00 1970 PST
+  336 |   6 | 00336              | Fri Feb 06 00:00:00 1970 PST
+  337 | 407 | 00337_update7      | Sat Feb 07 00:00:00 1970 PST
+  338 |   8 | 00338              | Sun Feb 08 00:00:00 1970 PST
+  339 | 509 | 00339_update9      | Mon Feb 09 00:00:00 1970 PST
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+  343 | 303 | 00343_update3      | Fri Feb 13 00:00:00 1970 PST
+  344 |   4 | 00344              | Sat Feb 14 00:00:00 1970 PST
+  346 |   6 | 00346              | Mon Feb 16 00:00:00 1970 PST
+  347 | 407 | 00347_update7      | Tue Feb 17 00:00:00 1970 PST
+  348 |   8 | 00348              | Wed Feb 18 00:00:00 1970 PST
+  349 | 509 | 00349_update9      | Thu Feb 19 00:00:00 1970 PST
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+  353 | 303 | 00353_update3      | Mon Feb 23 00:00:00 1970 PST
+  354 |   4 | 00354              | Tue Feb 24 00:00:00 1970 PST
+  356 |   6 | 00356              | Thu Feb 26 00:00:00 1970 PST
+  357 | 407 | 00357_update7      | Fri Feb 27 00:00:00 1970 PST
+  358 |   8 | 00358              | Sat Feb 28 00:00:00 1970 PST
+  359 | 509 | 00359_update9      | Sun Mar 01 00:00:00 1970 PST
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+  363 | 303 | 00363_update3      | Thu Mar 05 00:00:00 1970 PST
+  364 |   4 | 00364              | Fri Mar 06 00:00:00 1970 PST
+  366 |   6 | 00366              | Sun Mar 08 00:00:00 1970 PST
+  367 | 407 | 00367_update7      | Mon Mar 09 00:00:00 1970 PST
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+  373 | 303 | 00373_update3      | Sun Mar 15 00:00:00 1970 PST
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+  377 | 407 | 00377_update7      | Thu Mar 19 00:00:00 1970 PST
+  378 |   8 | 00378              | Fri Mar 20 00:00:00 1970 PST
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+  383 | 303 | 00383_update3      | Wed Mar 25 00:00:00 1970 PST
+  384 |   4 | 00384              | Thu Mar 26 00:00:00 1970 PST
+  386 |   6 | 00386              | Sat Mar 28 00:00:00 1970 PST
+  387 | 407 | 00387_update7      | Sun Mar 29 00:00:00 1970 PST
+  388 |   8 | 00388              | Mon Mar 30 00:00:00 1970 PST
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+  393 | 303 | 00393_update3      | Sat Apr 04 00:00:00 1970 PST
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+  397 | 407 | 00397_update7      | Wed Apr 08 00:00:00 1970 PST
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+  417 | 407 | 00417_update7      | Sun Jan 18 00:00:00 1970 PST
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+  423 | 303 | 00423_update3      | Sat Jan 24 00:00:00 1970 PST
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+  427 | 407 | 00427_update7      | Wed Jan 28 00:00:00 1970 PST
+  428 |   8 | 00428              | Thu Jan 29 00:00:00 1970 PST
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+  431 |   1 | 00431              | Sun Feb 01 00:00:00 1970 PST
+  433 | 303 | 00433_update3      | Tue Feb 03 00:00:00 1970 PST
+  434 |   4 | 00434              | Wed Feb 04 00:00:00 1970 PST
+  436 |   6 | 00436              | Fri Feb 06 00:00:00 1970 PST
+  437 | 407 | 00437_update7      | Sat Feb 07 00:00:00 1970 PST
+  438 |   8 | 00438              | Sun Feb 08 00:00:00 1970 PST
+  439 | 509 | 00439_update9      | Mon Feb 09 00:00:00 1970 PST
+  440 |   0 | 00440              | Tue Feb 10 00:00:00 1970 PST
+  441 |   1 | 00441              | Wed Feb 11 00:00:00 1970 PST
+  443 | 303 | 00443_update3      | Fri Feb 13 00:00:00 1970 PST
+  444 |   4 | 00444              | Sat Feb 14 00:00:00 1970 PST
+  446 |   6 | 00446              | Mon Feb 16 00:00:00 1970 PST
+  447 | 407 | 00447_update7      | Tue Feb 17 00:00:00 1970 PST
+  448 |   8 | 00448              | Wed Feb 18 00:00:00 1970 PST
+  449 | 509 | 00449_update9      | Thu Feb 19 00:00:00 1970 PST
+  450 |   0 | 00450              | Fri Feb 20 00:00:00 1970 PST
+  451 |   1 | 00451              | Sat Feb 21 00:00:00 1970 PST
+  453 | 303 | 00453_update3      | Mon Feb 23 00:00:00 1970 PST
+  454 |   4 | 00454              | Tue Feb 24 00:00:00 1970 PST
+  456 |   6 | 00456              | Thu Feb 26 00:00:00 1970 PST
+  457 | 407 | 00457_update7      | Fri Feb 27 00:00:00 1970 PST
+  458 |   8 | 00458              | Sat Feb 28 00:00:00 1970 PST
+  459 | 509 | 00459_update9      | Sun Mar 01 00:00:00 1970 PST
+  460 |   0 | 00460              | Mon Mar 02 00:00:00 1970 PST
+  461 |   1 | 00461              | Tue Mar 03 00:00:00 1970 PST
+  463 | 303 | 00463_update3      | Thu Mar 05 00:00:00 1970 PST
+  464 |   4 | 00464              | Fri Mar 06 00:00:00 1970 PST
+  466 |   6 | 00466              | Sun Mar 08 00:00:00 1970 PST
+  467 | 407 | 00467_update7      | Mon Mar 09 00:00:00 1970 PST
+  468 |   8 | 00468              | Tue Mar 10 00:00:00 1970 PST
+  469 | 509 | 00469_update9      | Wed Mar 11 00:00:00 1970 PST
+  470 |   0 | 00470              | Thu Mar 12 00:00:00 1970 PST
+  471 |   1 | 00471              | Fri Mar 13 00:00:00 1970 PST
+  473 | 303 | 00473_update3      | Sun Mar 15 00:00:00 1970 PST
+  474 |   4 | 00474              | Mon Mar 16 00:00:00 1970 PST
+  476 |   6 | 00476              | Wed Mar 18 00:00:00 1970 PST
+  477 | 407 | 00477_update7      | Thu Mar 19 00:00:00 1970 PST
+  478 |   8 | 00478              | Fri Mar 20 00:00:00 1970 PST
+  479 | 509 | 00479_update9      | Sat Mar 21 00:00:00 1970 PST
+  480 |   0 | 00480              | Sun Mar 22 00:00:00 1970 PST
+  481 |   1 | 00481              | Mon Mar 23 00:00:00 1970 PST
+  483 | 303 | 00483_update3      | Wed Mar 25 00:00:00 1970 PST
+  484 |   4 | 00484              | Thu Mar 26 00:00:00 1970 PST
+  486 |   6 | 00486              | Sat Mar 28 00:00:00 1970 PST
+  487 | 407 | 00487_update7      | Sun Mar 29 00:00:00 1970 PST
+  488 |   8 | 00488              | Mon Mar 30 00:00:00 1970 PST
+  489 | 509 | 00489_update9      | Tue Mar 31 00:00:00 1970 PST
+  490 |   0 | 00490              | Wed Apr 01 00:00:00 1970 PST
+  491 |   1 | 00491              | Thu Apr 02 00:00:00 1970 PST
+  493 | 303 | 00493_update3      | Sat Apr 04 00:00:00 1970 PST
+  494 |   4 | 00494              | Sun Apr 05 00:00:00 1970 PST
+  496 |   6 | 00496              | Tue Apr 07 00:00:00 1970 PST
+  497 | 407 | 00497_update7      | Wed Apr 08 00:00:00 1970 PST
+  498 |   8 | 00498              | Thu Apr 09 00:00:00 1970 PST
+  499 | 509 | 00499_update9      | Fri Apr 10 00:00:00 1970 PST
+  500 |   0 | 00500              | Thu Jan 01 00:00:00 1970 PST
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+  503 | 303 | 00503_update3      | Sun Jan 04 00:00:00 1970 PST
+  504 |   4 | 00504              | Mon Jan 05 00:00:00 1970 PST
+  506 |   6 | 00506              | Wed Jan 07 00:00:00 1970 PST
+  507 | 407 | 00507_update7      | Thu Jan 08 00:00:00 1970 PST
+  508 |   8 | 00508              | Fri Jan 09 00:00:00 1970 PST
+  509 | 509 | 00509_update9      | Sat Jan 10 00:00:00 1970 PST
+  510 |   0 | 00510              | Sun Jan 11 00:00:00 1970 PST
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+  513 | 303 | 00513_update3      | Wed Jan 14 00:00:00 1970 PST
+  514 |   4 | 00514              | Thu Jan 15 00:00:00 1970 PST
+  516 |   6 | 00516              | Sat Jan 17 00:00:00 1970 PST
+  517 | 407 | 00517_update7      | Sun Jan 18 00:00:00 1970 PST
+  518 |   8 | 00518              | Mon Jan 19 00:00:00 1970 PST
+  519 | 509 | 00519_update9      | Tue Jan 20 00:00:00 1970 PST
+  520 |   0 | 00520              | Wed Jan 21 00:00:00 1970 PST
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+  523 | 303 | 00523_update3      | Sat Jan 24 00:00:00 1970 PST
+  524 |   4 | 00524              | Sun Jan 25 00:00:00 1970 PST
+  526 |   6 | 00526              | Tue Jan 27 00:00:00 1970 PST
+  527 | 407 | 00527_update7      | Wed Jan 28 00:00:00 1970 PST
+  528 |   8 | 00528              | Thu Jan 29 00:00:00 1970 PST
+  529 | 509 | 00529_update9      | Fri Jan 30 00:00:00 1970 PST
+  530 |   0 | 00530              | Sat Jan 31 00:00:00 1970 PST
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+  533 | 303 | 00533_update3      | Tue Feb 03 00:00:00 1970 PST
+  534 |   4 | 00534              | Wed Feb 04 00:00:00 1970 PST
+  536 |   6 | 00536              | Fri Feb 06 00:00:00 1970 PST
+  537 | 407 | 00537_update7      | Sat Feb 07 00:00:00 1970 PST
+  538 |   8 | 00538              | Sun Feb 08 00:00:00 1970 PST
+  539 | 509 | 00539_update9      | Mon Feb 09 00:00:00 1970 PST
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+  543 | 303 | 00543_update3      | Fri Feb 13 00:00:00 1970 PST
+  544 |   4 | 00544              | Sat Feb 14 00:00:00 1970 PST
+  546 |   6 | 00546              | Mon Feb 16 00:00:00 1970 PST
+  547 | 407 | 00547_update7      | Tue Feb 17 00:00:00 1970 PST
+  548 |   8 | 00548              | Wed Feb 18 00:00:00 1970 PST
+  549 | 509 | 00549_update9      | Thu Feb 19 00:00:00 1970 PST
+  550 |   0 | 00550              | Fri Feb 20 00:00:00 1970 PST
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+  553 | 303 | 00553_update3      | Mon Feb 23 00:00:00 1970 PST
+  554 |   4 | 00554              | Tue Feb 24 00:00:00 1970 PST
+  556 |   6 | 00556              | Thu Feb 26 00:00:00 1970 PST
+  557 | 407 | 00557_update7      | Fri Feb 27 00:00:00 1970 PST
+  558 |   8 | 00558              | Sat Feb 28 00:00:00 1970 PST
+  559 | 509 | 00559_update9      | Sun Mar 01 00:00:00 1970 PST
+  560 |   0 | 00560              | Mon Mar 02 00:00:00 1970 PST
+  561 |   1 | 00561              | Tue Mar 03 00:00:00 1970 PST
+  563 | 303 | 00563_update3      | Thu Mar 05 00:00:00 1970 PST
+  564 |   4 | 00564              | Fri Mar 06 00:00:00 1970 PST
+  566 |   6 | 00566              | Sun Mar 08 00:00:00 1970 PST
+  567 | 407 | 00567_update7      | Mon Mar 09 00:00:00 1970 PST
+  568 |   8 | 00568              | Tue Mar 10 00:00:00 1970 PST
+  569 | 509 | 00569_update9      | Wed Mar 11 00:00:00 1970 PST
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+  573 | 303 | 00573_update3      | Sun Mar 15 00:00:00 1970 PST
+  574 |   4 | 00574              | Mon Mar 16 00:00:00 1970 PST
+  576 |   6 | 00576              | Wed Mar 18 00:00:00 1970 PST
+  577 | 407 | 00577_update7      | Thu Mar 19 00:00:00 1970 PST
+  578 |   8 | 00578              | Fri Mar 20 00:00:00 1970 PST
+  579 | 509 | 00579_update9      | Sat Mar 21 00:00:00 1970 PST
+  580 |   0 | 00580              | Sun Mar 22 00:00:00 1970 PST
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+  583 | 303 | 00583_update3      | Wed Mar 25 00:00:00 1970 PST
+  584 |   4 | 00584              | Thu Mar 26 00:00:00 1970 PST
+  586 |   6 | 00586              | Sat Mar 28 00:00:00 1970 PST
+  587 | 407 | 00587_update7      | Sun Mar 29 00:00:00 1970 PST
+  588 |   8 | 00588              | Mon Mar 30 00:00:00 1970 PST
+  589 | 509 | 00589_update9      | Tue Mar 31 00:00:00 1970 PST
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+  593 | 303 | 00593_update3      | Sat Apr 04 00:00:00 1970 PST
+  594 |   4 | 00594              | Sun Apr 05 00:00:00 1970 PST
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+  597 | 407 | 00597_update7      | Wed Apr 08 00:00:00 1970 PST
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+  599 | 509 | 00599_update9      | Fri Apr 10 00:00:00 1970 PST
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+  607 | 407 | 00607_update7      | Thu Jan 08 00:00:00 1970 PST
+  608 |   8 | 00608              | Fri Jan 09 00:00:00 1970 PST
+  609 | 509 | 00609_update9      | Sat Jan 10 00:00:00 1970 PST
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+  614 |   4 | 00614              | Thu Jan 15 00:00:00 1970 PST
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+  617 | 407 | 00617_update7      | Sun Jan 18 00:00:00 1970 PST
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+  623 | 303 | 00623_update3      | Sat Jan 24 00:00:00 1970 PST
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+  627 | 407 | 00627_update7      | Wed Jan 28 00:00:00 1970 PST
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+  629 | 509 | 00629_update9      | Fri Jan 30 00:00:00 1970 PST
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+  637 | 407 | 00637_update7      | Sat Feb 07 00:00:00 1970 PST
+  638 |   8 | 00638              | Sun Feb 08 00:00:00 1970 PST
+  639 | 509 | 00639_update9      | Mon Feb 09 00:00:00 1970 PST
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+  657 | 407 | 00657_update7      | Fri Feb 27 00:00:00 1970 PST
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+  667 | 407 | 00667_update7      | Mon Mar 09 00:00:00 1970 PST
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+  849 | 509 | 00849_update9      | Thu Feb 19 00:00:00 1970 PST
+  850 |   0 | 00850              | Fri Feb 20 00:00:00 1970 PST
+  851 |   1 | 00851              | Sat Feb 21 00:00:00 1970 PST
+  853 | 303 | 00853_update3      | Mon Feb 23 00:00:00 1970 PST
+  854 |   4 | 00854              | Tue Feb 24 00:00:00 1970 PST
+  856 |   6 | 00856              | Thu Feb 26 00:00:00 1970 PST
+  857 | 407 | 00857_update7      | Fri Feb 27 00:00:00 1970 PST
+  858 |   8 | 00858              | Sat Feb 28 00:00:00 1970 PST
+  859 | 509 | 00859_update9      | Sun Mar 01 00:00:00 1970 PST
+  860 |   0 | 00860              | Mon Mar 02 00:00:00 1970 PST
+  861 |   1 | 00861              | Tue Mar 03 00:00:00 1970 PST
+  863 | 303 | 00863_update3      | Thu Mar 05 00:00:00 1970 PST
+  864 |   4 | 00864              | Fri Mar 06 00:00:00 1970 PST
+  866 |   6 | 00866              | Sun Mar 08 00:00:00 1970 PST
+  867 | 407 | 00867_update7      | Mon Mar 09 00:00:00 1970 PST
+  868 |   8 | 00868              | Tue Mar 10 00:00:00 1970 PST
+  869 | 509 | 00869_update9      | Wed Mar 11 00:00:00 1970 PST
+  870 |   0 | 00870              | Thu Mar 12 00:00:00 1970 PST
+  871 |   1 | 00871              | Fri Mar 13 00:00:00 1970 PST
+  873 | 303 | 00873_update3      | Sun Mar 15 00:00:00 1970 PST
+  874 |   4 | 00874              | Mon Mar 16 00:00:00 1970 PST
+  876 |   6 | 00876              | Wed Mar 18 00:00:00 1970 PST
+  877 | 407 | 00877_update7      | Thu Mar 19 00:00:00 1970 PST
+  878 |   8 | 00878              | Fri Mar 20 00:00:00 1970 PST
+  879 | 509 | 00879_update9      | Sat Mar 21 00:00:00 1970 PST
+  880 |   0 | 00880              | Sun Mar 22 00:00:00 1970 PST
+  881 |   1 | 00881              | Mon Mar 23 00:00:00 1970 PST
+  883 | 303 | 00883_update3      | Wed Mar 25 00:00:00 1970 PST
+  884 |   4 | 00884              | Thu Mar 26 00:00:00 1970 PST
+  886 |   6 | 00886              | Sat Mar 28 00:00:00 1970 PST
+  887 | 407 | 00887_update7      | Sun Mar 29 00:00:00 1970 PST
+  888 |   8 | 00888              | Mon Mar 30 00:00:00 1970 PST
+  889 | 509 | 00889_update9      | Tue Mar 31 00:00:00 1970 PST
+  890 |   0 | 00890              | Wed Apr 01 00:00:00 1970 PST
+  891 |   1 | 00891              | Thu Apr 02 00:00:00 1970 PST
+  893 | 303 | 00893_update3      | Sat Apr 04 00:00:00 1970 PST
+  894 |   4 | 00894              | Sun Apr 05 00:00:00 1970 PST
+  896 |   6 | 00896              | Tue Apr 07 00:00:00 1970 PST
+  897 | 407 | 00897_update7      | Wed Apr 08 00:00:00 1970 PST
+  898 |   8 | 00898              | Thu Apr 09 00:00:00 1970 PST
+  899 | 509 | 00899_update9      | Fri Apr 10 00:00:00 1970 PST
+  900 |   0 | 00900              | Thu Jan 01 00:00:00 1970 PST
+  901 |   1 | 00901              | Fri Jan 02 00:00:00 1970 PST
+  903 | 303 | 00903_update3      | Sun Jan 04 00:00:00 1970 PST
+  904 |   4 | 00904              | Mon Jan 05 00:00:00 1970 PST
+  906 |   6 | 00906              | Wed Jan 07 00:00:00 1970 PST
+  907 | 407 | 00907_update7      | Thu Jan 08 00:00:00 1970 PST
+  908 |   8 | 00908              | Fri Jan 09 00:00:00 1970 PST
+  909 | 509 | 00909_update9      | Sat Jan 10 00:00:00 1970 PST
+  910 |   0 | 00910              | Sun Jan 11 00:00:00 1970 PST
+  911 |   1 | 00911              | Mon Jan 12 00:00:00 1970 PST
+  913 | 303 | 00913_update3      | Wed Jan 14 00:00:00 1970 PST
+  914 |   4 | 00914              | Thu Jan 15 00:00:00 1970 PST
+  916 |   6 | 00916              | Sat Jan 17 00:00:00 1970 PST
+  917 | 407 | 00917_update7      | Sun Jan 18 00:00:00 1970 PST
+  918 |   8 | 00918              | Mon Jan 19 00:00:00 1970 PST
+  919 | 509 | 00919_update9      | Tue Jan 20 00:00:00 1970 PST
+  920 |   0 | 00920              | Wed Jan 21 00:00:00 1970 PST
+  921 |   1 | 00921              | Thu Jan 22 00:00:00 1970 PST
+  923 | 303 | 00923_update3      | Sat Jan 24 00:00:00 1970 PST
+  924 |   4 | 00924              | Sun Jan 25 00:00:00 1970 PST
+  926 |   6 | 00926              | Tue Jan 27 00:00:00 1970 PST
+  927 | 407 | 00927_update7      | Wed Jan 28 00:00:00 1970 PST
+  928 |   8 | 00928              | Thu Jan 29 00:00:00 1970 PST
+  929 | 509 | 00929_update9      | Fri Jan 30 00:00:00 1970 PST
+  930 |   0 | 00930              | Sat Jan 31 00:00:00 1970 PST
+  931 |   1 | 00931              | Sun Feb 01 00:00:00 1970 PST
+  933 | 303 | 00933_update3      | Tue Feb 03 00:00:00 1970 PST
+  934 |   4 | 00934              | Wed Feb 04 00:00:00 1970 PST
+  936 |   6 | 00936              | Fri Feb 06 00:00:00 1970 PST
+  937 | 407 | 00937_update7      | Sat Feb 07 00:00:00 1970 PST
+  938 |   8 | 00938              | Sun Feb 08 00:00:00 1970 PST
+  939 | 509 | 00939_update9      | Mon Feb 09 00:00:00 1970 PST
+  940 |   0 | 00940              | Tue Feb 10 00:00:00 1970 PST
+  941 |   1 | 00941              | Wed Feb 11 00:00:00 1970 PST
+  943 | 303 | 00943_update3      | Fri Feb 13 00:00:00 1970 PST
+  944 |   4 | 00944              | Sat Feb 14 00:00:00 1970 PST
+  946 |   6 | 00946              | Mon Feb 16 00:00:00 1970 PST
+  947 | 407 | 00947_update7      | Tue Feb 17 00:00:00 1970 PST
+  948 |   8 | 00948              | Wed Feb 18 00:00:00 1970 PST
+  949 | 509 | 00949_update9      | Thu Feb 19 00:00:00 1970 PST
+  950 |   0 | 00950              | Fri Feb 20 00:00:00 1970 PST
+  951 |   1 | 00951              | Sat Feb 21 00:00:00 1970 PST
+  953 | 303 | 00953_update3      | Mon Feb 23 00:00:00 1970 PST
+  954 |   4 | 00954              | Tue Feb 24 00:00:00 1970 PST
+  956 |   6 | 00956              | Thu Feb 26 00:00:00 1970 PST
+  957 | 407 | 00957_update7      | Fri Feb 27 00:00:00 1970 PST
+  958 |   8 | 00958              | Sat Feb 28 00:00:00 1970 PST
+  959 | 509 | 00959_update9      | Sun Mar 01 00:00:00 1970 PST
+  960 |   0 | 00960              | Mon Mar 02 00:00:00 1970 PST
+  961 |   1 | 00961              | Tue Mar 03 00:00:00 1970 PST
+  963 | 303 | 00963_update3      | Thu Mar 05 00:00:00 1970 PST
+  964 |   4 | 00964              | Fri Mar 06 00:00:00 1970 PST
+  966 |   6 | 00966              | Sun Mar 08 00:00:00 1970 PST
+  967 | 407 | 00967_update7      | Mon Mar 09 00:00:00 1970 PST
+  968 |   8 | 00968              | Tue Mar 10 00:00:00 1970 PST
+  969 | 509 | 00969_update9      | Wed Mar 11 00:00:00 1970 PST
+  970 |   0 | 00970              | Thu Mar 12 00:00:00 1970 PST
+  971 |   1 | 00971              | Fri Mar 13 00:00:00 1970 PST
+  973 | 303 | 00973_update3      | Sun Mar 15 00:00:00 1970 PST
+  974 |   4 | 00974              | Mon Mar 16 00:00:00 1970 PST
+  976 |   6 | 00976              | Wed Mar 18 00:00:00 1970 PST
+  977 | 407 | 00977_update7      | Thu Mar 19 00:00:00 1970 PST
+  978 |   8 | 00978              | Fri Mar 20 00:00:00 1970 PST
+  979 | 509 | 00979_update9      | Sat Mar 21 00:00:00 1970 PST
+  980 |   0 | 00980              | Sun Mar 22 00:00:00 1970 PST
+  981 |   1 | 00981              | Mon Mar 23 00:00:00 1970 PST
+  983 | 303 | 00983_update3      | Wed Mar 25 00:00:00 1970 PST
+  984 |   4 | 00984              | Thu Mar 26 00:00:00 1970 PST
+  986 |   6 | 00986              | Sat Mar 28 00:00:00 1970 PST
+  987 | 407 | 00987_update7      | Sun Mar 29 00:00:00 1970 PST
+  988 |   8 | 00988              | Mon Mar 30 00:00:00 1970 PST
+  989 | 509 | 00989_update9      | Tue Mar 31 00:00:00 1970 PST
+  990 |   0 | 00990              | Wed Apr 01 00:00:00 1970 PST
+  991 |   1 | 00991              | Thu Apr 02 00:00:00 1970 PST
+  993 | 303 | 00993_update3      | Sat Apr 04 00:00:00 1970 PST
+  994 |   4 | 00994              | Sun Apr 05 00:00:00 1970 PST
+  996 |   6 | 00996              | Tue Apr 07 00:00:00 1970 PST
+  997 | 407 | 00997_update7      | Wed Apr 08 00:00:00 1970 PST
+  998 |   8 | 00998              | Thu Apr 09 00:00:00 1970 PST
+  999 | 509 | 00999_update9      | Fri Apr 10 00:00:00 1970 PST
+ 1000 |   0 | 01000              | Thu Jan 01 00:00:00 1970 PST
+ 1001 | 101 | 0000100001         | 
+ 1003 | 403 | 0000300003_update3 | 
+ 1004 | 104 | 0000400004         | 
+ 1006 | 106 | 0000600006         | 
+ 1007 | 507 | 0000700007_update7 | 
+ 1008 | 108 | 0000800008         | 
+ 1009 | 609 | 0000900009_update9 | 
+ 1010 | 100 | 0001000010         | 
+ 1011 | 101 | 0001100011         | 
+ 1013 | 403 | 0001300013_update3 | 
+ 1014 | 104 | 0001400014         | 
+ 1016 | 106 | 0001600016         | 
+ 1017 | 507 | 0001700017_update7 | 
+ 1018 | 108 | 0001800018         | 
+ 1019 | 609 | 0001900019_update9 | 
+ 1020 | 100 | 0002000020         | 
+ 1101 | 201 | aaa                | 
+ 1103 | 503 | ccc_update3        | 
+ 1104 | 204 | ddd                | 
+(819 rows)
+
+EXPLAIN (verbose, costs off)
+INSERT INTO ft2 (c1,c2,c3) VALUES (1200,999,'foo') RETURNING tableoid::regclass;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.ft2
+   Output: (ft2.tableoid)::regclass
+   Remote SQL: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+   Batch Size: 1
+   ->  Result
+         Output: 1200, 999, NULL::integer, 'foo'::text, NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying, 'ft2       '::character(10), NULL::user_enum
+(6 rows)
+
+INSERT INTO ft2 (c1,c2,c3) VALUES (1200,999,'foo') RETURNING tableoid::regclass;
+ tableoid 
+----------
+ ft2
+(1 row)
+
+EXPLAIN (verbose, costs off)
+UPDATE ft2 SET c3 = 'bar' WHERE c1 = 1200 RETURNING tableoid::regclass;             -- can be pushed down
+                                     QUERY PLAN                                     
+------------------------------------------------------------------------------------
+ Update on public.ft2
+   Output: (tableoid)::regclass
+   ->  Foreign Update on public.ft2
+         Remote SQL: UPDATE "S 1"."T 1" SET c3 = 'bar'::text WHERE (("C 1" = 1200))
+(4 rows)
+
+UPDATE ft2 SET c3 = 'bar' WHERE c1 = 1200 RETURNING tableoid::regclass;
+ tableoid 
+----------
+ ft2
+(1 row)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM ft2 WHERE c1 = 1200 RETURNING tableoid::regclass;                       -- can be pushed down
+                             QUERY PLAN                             
+--------------------------------------------------------------------
+ Delete on public.ft2
+   Output: (tableoid)::regclass
+   ->  Foreign Delete on public.ft2
+         Remote SQL: DELETE FROM "S 1"."T 1" WHERE (("C 1" = 1200))
+(4 rows)
+
+DELETE FROM ft2 WHERE c1 = 1200 RETURNING tableoid::regclass;
+ tableoid 
+----------
+ ft2
+(1 row)
+
+-- Test UPDATE/DELETE with RETURNING on a three-table join
+INSERT INTO ft2 (c1,c2,c3)
+  SELECT id, id - 1200, to_char(id, 'FM00000') FROM generate_series(1201, 1300) id;
+EXPLAIN (verbose, costs off)
+UPDATE ft2 SET c3 = 'foo'
+  FROM ft4 INNER JOIN ft5 ON (ft4.c1 = ft5.c1)
+  WHERE ft2.c1 > 1200 AND ft2.c2 = ft4.c1
+  RETURNING ft2, ft2.*, ft4, ft4.*;       -- can be pushed down
+                                                                                                                                                                          QUERY PLAN                                                                                                                                                                           
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Update on public.ft2
+   Output: ft2.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.*, ft4.c1, ft4.c2, ft4.c3
+   ->  Foreign Update
+         Remote SQL: UPDATE "S 1"."T 1" r1 SET c3 = 'foo'::text FROM ("S 1"."T 3" r2 INNER JOIN "S 1"."T 4" r3 ON (TRUE)) WHERE ((r2.c1 = r3.c1)) AND ((r1.c2 = r2.c1)) AND ((r1."C 1" > 1200)) RETURNING r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2.c1, r2.c2, r2.c3) END, r2.c1, r2.c2, r2.c3
+(4 rows)
+
+UPDATE ft2 SET c3 = 'foo'
+  FROM ft4 INNER JOIN ft5 ON (ft4.c1 = ft5.c1)
+  WHERE ft2.c1 > 1200 AND ft2.c2 = ft4.c1
+  RETURNING ft2, ft2.*, ft4, ft4.*;
+              ft2               |  c1  | c2 | c3  | c4 | c5 | c6 |     c7     | c8 |      ft4       | c1 | c2 |   c3   
+--------------------------------+------+----+-----+----+----+----+------------+----+----------------+----+----+--------
+ (1206,6,foo,,,,"ft2       ",)  | 1206 |  6 | foo |    |    |    | ft2        |    | (6,7,AAA006)   |  6 |  7 | AAA006
+ (1212,12,foo,,,,"ft2       ",) | 1212 | 12 | foo |    |    |    | ft2        |    | (12,13,AAA012) | 12 | 13 | AAA012
+ (1218,18,foo,,,,"ft2       ",) | 1218 | 18 | foo |    |    |    | ft2        |    | (18,19,AAA018) | 18 | 19 | AAA018
+ (1224,24,foo,,,,"ft2       ",) | 1224 | 24 | foo |    |    |    | ft2        |    | (24,25,AAA024) | 24 | 25 | AAA024
+ (1230,30,foo,,,,"ft2       ",) | 1230 | 30 | foo |    |    |    | ft2        |    | (30,31,AAA030) | 30 | 31 | AAA030
+ (1236,36,foo,,,,"ft2       ",) | 1236 | 36 | foo |    |    |    | ft2        |    | (36,37,AAA036) | 36 | 37 | AAA036
+ (1242,42,foo,,,,"ft2       ",) | 1242 | 42 | foo |    |    |    | ft2        |    | (42,43,AAA042) | 42 | 43 | AAA042
+ (1248,48,foo,,,,"ft2       ",) | 1248 | 48 | foo |    |    |    | ft2        |    | (48,49,AAA048) | 48 | 49 | AAA048
+ (1254,54,foo,,,,"ft2       ",) | 1254 | 54 | foo |    |    |    | ft2        |    | (54,55,AAA054) | 54 | 55 | AAA054
+ (1260,60,foo,,,,"ft2       ",) | 1260 | 60 | foo |    |    |    | ft2        |    | (60,61,AAA060) | 60 | 61 | AAA060
+ (1266,66,foo,,,,"ft2       ",) | 1266 | 66 | foo |    |    |    | ft2        |    | (66,67,AAA066) | 66 | 67 | AAA066
+ (1272,72,foo,,,,"ft2       ",) | 1272 | 72 | foo |    |    |    | ft2        |    | (72,73,AAA072) | 72 | 73 | AAA072
+ (1278,78,foo,,,,"ft2       ",) | 1278 | 78 | foo |    |    |    | ft2        |    | (78,79,AAA078) | 78 | 79 | AAA078
+ (1284,84,foo,,,,"ft2       ",) | 1284 | 84 | foo |    |    |    | ft2        |    | (84,85,AAA084) | 84 | 85 | AAA084
+ (1290,90,foo,,,,"ft2       ",) | 1290 | 90 | foo |    |    |    | ft2        |    | (90,91,AAA090) | 90 | 91 | AAA090
+ (1296,96,foo,,,,"ft2       ",) | 1296 | 96 | foo |    |    |    | ft2        |    | (96,97,AAA096) | 96 | 97 | AAA096
+(16 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM ft2
+  USING ft4 LEFT JOIN ft5 ON (ft4.c1 = ft5.c1)
+  WHERE ft2.c1 > 1200 AND ft2.c1 % 10 = 0 AND ft2.c2 = ft4.c1
+  RETURNING 100;                          -- can be pushed down
+                                                                                            QUERY PLAN                                                                                             
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Delete on public.ft2
+   Output: 100
+   ->  Foreign Delete
+         Remote SQL: DELETE FROM "S 1"."T 1" r1 USING ("S 1"."T 3" r2 LEFT JOIN "S 1"."T 4" r3 ON (((r2.c1 = r3.c1)))) WHERE ((r1.c2 = r2.c1)) AND ((r1."C 1" > 1200)) AND (((r1."C 1" % 10) = 0))
+(4 rows)
+
+DELETE FROM ft2
+  USING ft4 LEFT JOIN ft5 ON (ft4.c1 = ft5.c1)
+  WHERE ft2.c1 > 1200 AND ft2.c1 % 10 = 0 AND ft2.c2 = ft4.c1
+  RETURNING 100;
+ ?column? 
+----------
+      100
+      100
+      100
+      100
+      100
+      100
+      100
+      100
+      100
+      100
+(10 rows)
+
+DELETE FROM ft2 WHERE ft2.c1 > 1200;
+-- Test UPDATE with a MULTIEXPR sub-select
+-- (maybe someday this'll be remotely executable, but not today)
+EXPLAIN (verbose, costs off)
+UPDATE ft2 AS target SET (c2, c7) = (
+    SELECT c2 * 10, c7
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+                                                      QUERY PLAN                                                       
+-----------------------------------------------------------------------------------------------------------------------
+ Update on public.ft2 target
+   Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2, c7 = $3 WHERE ctid = $1
+   ->  Foreign Scan on public.ft2 target
+         Output: $1, $2, (SubPlan 1 (returns $1,$2)), target.ctid, target.*
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1100)) FOR UPDATE
+         SubPlan 1 (returns $1,$2)
+           ->  Foreign Scan on public.ft2 src
+                 Output: (src.c2 * 10), src.c7
+                 Remote SQL: SELECT c2, c7 FROM "S 1"."T 1" WHERE (($1::integer = "C 1"))
+(9 rows)
+
+UPDATE ft2 AS target SET (c2, c7) = (
+    SELECT c2 * 10, c7
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+UPDATE ft2 AS target SET (c2) = (
+    SELECT c2 / 10
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+-- Test UPDATE involving a join that can be pushed down,
+-- but a SET clause that can't be
+EXPLAIN (VERBOSE, COSTS OFF)
+UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
+  FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
+                                                                                                                                                                                       QUERY PLAN                                                                                                                                                                                        
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Update on public.ft2 d
+   Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
+   ->  Foreign Scan
+         Output: CASE WHEN (random() >= '0'::double precision) THEN d.c2 ELSE 0 END, d.ctid, d.*, t.*
+         Relations: (public.ft2 d) INNER JOIN (public.ft2 t)
+         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
+         ->  Hash Join
+               Output: d.c2, d.ctid, d.*, t.*
+               Hash Cond: (d.c1 = t.c1)
+               ->  Foreign Scan on public.ft2 d
+                     Output: d.c2, d.ctid, d.*, d.c1
+                     Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+               ->  Hash
+                     Output: t.*, t.c1
+                     ->  Foreign Scan on public.ft2 t
+                           Output: t.*, t.c1
+                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(17 rows)
+
+UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
+  FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
+-- Test UPDATE/DELETE with WHERE or JOIN/ON conditions containing
+-- user-defined operators/functions
+ALTER SERVER loopback OPTIONS (DROP extensions);
+INSERT INTO ft2 (c1,c2,c3)
+  SELECT id, id % 10, to_char(id, 'FM00000') FROM generate_series(2001, 2010) id;
+EXPLAIN (verbose, costs off)
+UPDATE ft2 SET c3 = 'bar' WHERE postgres_fdw_abs(c1) > 2000 RETURNING *;            -- can't be pushed down
+                                                QUERY PLAN                                                
+----------------------------------------------------------------------------------------------------------
+ Update on public.ft2
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: UPDATE "S 1"."T 1" SET c3 = $2 WHERE ctid = $1 RETURNING "C 1", c2, c3, c4, c5, c6, c7, c8
+   ->  Foreign Scan on public.ft2
+         Output: 'bar'::text, ctid, ft2.*
+         Filter: (postgres_fdw_abs(ft2.c1) > 2000)
+         Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" FOR UPDATE
+(7 rows)
+
+UPDATE ft2 SET c3 = 'bar' WHERE postgres_fdw_abs(c1) > 2000 RETURNING *;
+  c1  | c2 | c3  | c4 | c5 | c6 |     c7     | c8 
+------+----+-----+----+----+----+------------+----
+ 2001 |  1 | bar |    |    |    | ft2        | 
+ 2002 |  2 | bar |    |    |    | ft2        | 
+ 2003 |  3 | bar |    |    |    | ft2        | 
+ 2004 |  4 | bar |    |    |    | ft2        | 
+ 2005 |  5 | bar |    |    |    | ft2        | 
+ 2006 |  6 | bar |    |    |    | ft2        | 
+ 2007 |  7 | bar |    |    |    | ft2        | 
+ 2008 |  8 | bar |    |    |    | ft2        | 
+ 2009 |  9 | bar |    |    |    | ft2        | 
+ 2010 |  0 | bar |    |    |    | ft2        | 
+(10 rows)
+
+EXPLAIN (verbose, costs off)
+UPDATE ft2 SET c3 = 'baz'
+  FROM ft4 INNER JOIN ft5 ON (ft4.c1 = ft5.c1)
+  WHERE ft2.c1 > 2000 AND ft2.c2 === ft4.c1
+  RETURNING ft2.*, ft4.*, ft5.*;                                                    -- can't be pushed down
+                                                                                                                                          QUERY PLAN                                                                                                                                          
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Update on public.ft2
+   Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3
+   Remote SQL: UPDATE "S 1"."T 1" SET c3 = $2 WHERE ctid = $1 RETURNING "C 1", c2, c3, c4, c5, c6, c7, c8
+   ->  Nested Loop
+         Output: 'baz'::text, ft2.ctid, ft2.*, ft4.*, ft5.*, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3
+         Join Filter: (ft2.c2 === ft4.c1)
+         ->  Foreign Scan on public.ft2
+               Output: ft2.ctid, ft2.*, ft2.c2
+               Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 2000)) FOR UPDATE
+         ->  Foreign Scan
+               Output: ft4.*, ft4.c1, ft4.c2, ft4.c3, ft5.*, ft5.c1, ft5.c2, ft5.c3
+               Relations: (public.ft4) INNER JOIN (public.ft5)
+               Remote SQL: SELECT CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2.c1, r2.c2, r2.c3) END, r2.c1, r2.c2, r2.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r3.c1, r3.c2, r3.c3 FROM ("S 1"."T 3" r2 INNER JOIN "S 1"."T 4" r3 ON (((r2.c1 = r3.c1))))
+               ->  Hash Join
+                     Output: ft4.*, ft4.c1, ft4.c2, ft4.c3, ft5.*, ft5.c1, ft5.c2, ft5.c3
+                     Hash Cond: (ft4.c1 = ft5.c1)
+                     ->  Foreign Scan on public.ft4
+                           Output: ft4.*, ft4.c1, ft4.c2, ft4.c3
+                           Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 3"
+                     ->  Hash
+                           Output: ft5.*, ft5.c1, ft5.c2, ft5.c3
+                           ->  Foreign Scan on public.ft5
+                                 Output: ft5.*, ft5.c1, ft5.c2, ft5.c3
+                                 Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 4"
+(24 rows)
+
+UPDATE ft2 SET c3 = 'baz'
+  FROM ft4 INNER JOIN ft5 ON (ft4.c1 = ft5.c1)
+  WHERE ft2.c1 > 2000 AND ft2.c2 === ft4.c1
+  RETURNING ft2.*, ft4.*, ft5.*;
+  c1  | c2 | c3  | c4 | c5 | c6 |     c7     | c8 | c1 | c2 |   c3   | c1 | c2 |   c3   
+------+----+-----+----+----+----+------------+----+----+----+--------+----+----+--------
+ 2006 |  6 | baz |    |    |    | ft2        |    |  6 |  7 | AAA006 |  6 |  7 | AAA006
+(1 row)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM ft2
+  USING ft4 INNER JOIN ft5 ON (ft4.c1 === ft5.c1)
+  WHERE ft2.c1 > 2000 AND ft2.c2 = ft4.c1
+  RETURNING ft2.c1, ft2.c2, ft2.c3;       -- can't be pushed down
+                                                                                                                                                                     QUERY PLAN                                                                                                                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Delete on public.ft2
+   Output: ft2.c1, ft2.c2, ft2.c3
+   Remote SQL: DELETE FROM "S 1"."T 1" WHERE ctid = $1 RETURNING "C 1", c2, c3
+   ->  Foreign Scan
+         Output: ft2.ctid, ft4.*, ft5.*
+         Filter: (ft4.c1 === ft5.c1)
+         Relations: ((public.ft2) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
+         Remote SQL: SELECT r1.ctid, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2.c1, r2.c2, r2.c3) END, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r2.c1, r3.c1 FROM (("S 1"."T 1" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c2 = r2.c1)) AND ((r1."C 1" > 2000)))) INNER JOIN "S 1"."T 4" r3 ON (TRUE)) FOR UPDATE OF r1
+         ->  Nested Loop
+               Output: ft2.ctid, ft4.*, ft5.*, ft4.c1, ft5.c1
+               ->  Nested Loop
+                     Output: ft2.ctid, ft4.*, ft4.c1
+                     Join Filter: (ft2.c2 = ft4.c1)
+                     ->  Foreign Scan on public.ft2
+                           Output: ft2.ctid, ft2.c2
+                           Remote SQL: SELECT c2, ctid FROM "S 1"."T 1" WHERE (("C 1" > 2000)) FOR UPDATE
+                     ->  Foreign Scan on public.ft4
+                           Output: ft4.*, ft4.c1
+                           Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 3"
+               ->  Foreign Scan on public.ft5
+                     Output: ft5.*, ft5.c1
+                     Remote SQL: SELECT c1, c2, c3 FROM "S 1"."T 4"
+(22 rows)
+
+DELETE FROM ft2
+  USING ft4 INNER JOIN ft5 ON (ft4.c1 === ft5.c1)
+  WHERE ft2.c1 > 2000 AND ft2.c2 = ft4.c1
+  RETURNING ft2.c1, ft2.c2, ft2.c3;
+  c1  | c2 | c3  
+------+----+-----
+ 2006 |  6 | baz
+(1 row)
+
+DELETE FROM ft2 WHERE ft2.c1 > 2000;
+ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
+-- Test that trigger on remote table works as expected
+CREATE OR REPLACE FUNCTION "S 1".F_BRTRIG() RETURNS trigger AS $$
+BEGIN
+    NEW.c3 = NEW.c3 || '_trig_update';
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+CREATE TRIGGER t1_br_insert BEFORE INSERT OR UPDATE
+    ON "S 1"."T 1" FOR EACH ROW EXECUTE PROCEDURE "S 1".F_BRTRIG();
+INSERT INTO ft2 (c1,c2,c3) VALUES (1208, 818, 'fff') RETURNING *;
+  c1  | c2  |       c3        | c4 | c5 | c6 |     c7     | c8 
+------+-----+-----------------+----+----+----+------------+----
+ 1208 | 818 | fff_trig_update |    |    |    | ft2        | 
+(1 row)
+
+INSERT INTO ft2 (c1,c2,c3,c6) VALUES (1218, 818, 'ggg', '(--;') RETURNING *;
+  c1  | c2  |       c3        | c4 | c5 |  c6  |     c7     | c8 
+------+-----+-----------------+----+----+------+------------+----
+ 1218 | 818 | ggg_trig_update |    |    | (--; | ft2        | 
+(1 row)
+
+UPDATE ft2 SET c2 = c2 + 600 WHERE c1 % 10 = 8 AND c1 < 1200 RETURNING *;
+  c1  | c2  |           c3           |              c4              |            c5            | c6 |     c7     | c8  
+------+-----+------------------------+------------------------------+--------------------------+----+------------+-----
+    8 | 608 | 00008_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+   18 | 608 | 00018_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+   28 | 608 | 00028_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+   38 | 608 | 00038_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+   48 | 608 | 00048_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+   58 | 608 | 00058_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+   68 | 608 | 00068_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+   78 | 608 | 00078_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+   88 | 608 | 00088_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+   98 | 608 | 00098_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  108 | 608 | 00108_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  118 | 608 | 00118_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  128 | 608 | 00128_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  138 | 608 | 00138_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  148 | 608 | 00148_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  158 | 608 | 00158_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  168 | 608 | 00168_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  178 | 608 | 00178_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  188 | 608 | 00188_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  198 | 608 | 00198_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  208 | 608 | 00208_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  218 | 608 | 00218_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  228 | 608 | 00228_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  238 | 608 | 00238_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  248 | 608 | 00248_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  258 | 608 | 00258_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  268 | 608 | 00268_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  278 | 608 | 00278_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  288 | 608 | 00288_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  298 | 608 | 00298_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  308 | 608 | 00308_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  318 | 608 | 00318_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  328 | 608 | 00328_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  338 | 608 | 00338_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  348 | 608 | 00348_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  358 | 608 | 00358_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  368 | 608 | 00368_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  378 | 608 | 00378_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  388 | 608 | 00388_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  398 | 608 | 00398_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  408 | 608 | 00408_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  418 | 608 | 00418_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  428 | 608 | 00428_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  438 | 608 | 00438_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  448 | 608 | 00448_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  458 | 608 | 00458_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  468 | 608 | 00468_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  478 | 608 | 00478_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  488 | 608 | 00488_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  498 | 608 | 00498_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  508 | 608 | 00508_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  518 | 608 | 00518_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  528 | 608 | 00528_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  538 | 608 | 00538_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  548 | 608 | 00548_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  558 | 608 | 00558_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  568 | 608 | 00568_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  578 | 608 | 00578_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  588 | 608 | 00588_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  598 | 608 | 00598_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  608 | 608 | 00608_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  618 | 608 | 00618_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  628 | 608 | 00628_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  638 | 608 | 00638_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  648 | 608 | 00648_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  658 | 608 | 00658_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  668 | 608 | 00668_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  678 | 608 | 00678_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  688 | 608 | 00688_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  698 | 608 | 00698_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  708 | 608 | 00708_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  718 | 608 | 00718_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  728 | 608 | 00728_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  738 | 608 | 00738_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  748 | 608 | 00748_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  758 | 608 | 00758_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  768 | 608 | 00768_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  778 | 608 | 00778_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  788 | 608 | 00788_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  798 | 608 | 00798_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  808 | 608 | 00808_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  818 | 608 | 00818_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  828 | 608 | 00828_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  838 | 608 | 00838_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  848 | 608 | 00848_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  858 | 608 | 00858_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  868 | 608 | 00868_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  878 | 608 | 00878_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  888 | 608 | 00888_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  898 | 608 | 00898_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+  908 | 608 | 00908_trig_update      | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  918 | 608 | 00918_trig_update      | Mon Jan 19 00:00:00 1970 PST | Mon Jan 19 00:00:00 1970 | 8  | 8          | foo
+  928 | 608 | 00928_trig_update      | Thu Jan 29 00:00:00 1970 PST | Thu Jan 29 00:00:00 1970 | 8  | 8          | foo
+  938 | 608 | 00938_trig_update      | Sun Feb 08 00:00:00 1970 PST | Sun Feb 08 00:00:00 1970 | 8  | 8          | foo
+  948 | 608 | 00948_trig_update      | Wed Feb 18 00:00:00 1970 PST | Wed Feb 18 00:00:00 1970 | 8  | 8          | foo
+  958 | 608 | 00958_trig_update      | Sat Feb 28 00:00:00 1970 PST | Sat Feb 28 00:00:00 1970 | 8  | 8          | foo
+  968 | 608 | 00968_trig_update      | Tue Mar 10 00:00:00 1970 PST | Tue Mar 10 00:00:00 1970 | 8  | 8          | foo
+  978 | 608 | 00978_trig_update      | Fri Mar 20 00:00:00 1970 PST | Fri Mar 20 00:00:00 1970 | 8  | 8          | foo
+  988 | 608 | 00988_trig_update      | Mon Mar 30 00:00:00 1970 PST | Mon Mar 30 00:00:00 1970 | 8  | 8          | foo
+  998 | 608 | 00998_trig_update      | Thu Apr 09 00:00:00 1970 PST | Thu Apr 09 00:00:00 1970 | 8  | 8          | foo
+ 1008 | 708 | 0000800008_trig_update |                              |                          |    | ft2        | 
+ 1018 | 708 | 0001800018_trig_update |                              |                          |    | ft2        | 
+(102 rows)
+
+-- Test errors thrown on remote side during update
+ALTER TABLE "S 1"."T 1" ADD CONSTRAINT c2positive CHECK (c2 >= 0);
+INSERT INTO ft1(c1, c2) VALUES(11, 12);  -- duplicate key
+ERROR:  duplicate key value violates unique constraint "t1_pkey"
+DETAIL:  Key ("C 1")=(11) already exists.
+CONTEXT:  remote SQL command: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+INSERT INTO ft1(c1, c2) VALUES(11, 12) ON CONFLICT DO NOTHING; -- works
+INSERT INTO ft1(c1, c2) VALUES(11, 12) ON CONFLICT (c1, c2) DO NOTHING; -- unsupported
+ERROR:  there is no unique or exclusion constraint matching the ON CONFLICT specification
+INSERT INTO ft1(c1, c2) VALUES(11, 12) ON CONFLICT (c1, c2) DO UPDATE SET c3 = 'ffg'; -- unsupported
+ERROR:  there is no unique or exclusion constraint matching the ON CONFLICT specification
+INSERT INTO ft1(c1, c2) VALUES(1111, -2);  -- c2positive
+ERROR:  new row for relation "T 1" violates check constraint "c2positive"
+DETAIL:  Failing row contains (1111, -2, null, null, null, null, ft1       , null).
+CONTEXT:  remote SQL command: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+UPDATE ft1 SET c2 = -c2 WHERE c1 = 1;  -- c2positive
+ERROR:  new row for relation "T 1" violates check constraint "c2positive"
+DETAIL:  Failing row contains (1, -1, 00001_trig_update, 1970-01-02 08:00:00+00, 1970-01-02 00:00:00, 1, 1         , foo).
+CONTEXT:  remote SQL command: UPDATE "S 1"."T 1" SET c2 = (- c2) WHERE (("C 1" = 1))
+-- Test savepoint/rollback behavior
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   0 |   100
+   1 |   100
+   4 |   100
+   6 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+select c2, count(*) from "S 1"."T 1" where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   0 |   100
+   1 |   100
+   4 |   100
+   6 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+begin;
+update ft2 set c2 = 42 where c2 = 0;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   4 |   100
+   6 |   100
+  42 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+savepoint s1;
+update ft2 set c2 = 44 where c2 = 4;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+release savepoint s1;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+savepoint s2;
+update ft2 set c2 = 46 where c2 = 6;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+  42 |   100
+  44 |   100
+  46 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+rollback to savepoint s2;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+release savepoint s2;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+savepoint s3;
+update ft2 set c2 = -2 where c2 = 42 and c1 = 10; -- fail on remote side
+ERROR:  new row for relation "T 1" violates check constraint "c2positive"
+DETAIL:  Failing row contains (10, -2, 00010_trig_update_trig_update, 1970-01-11 08:00:00+00, 1970-01-11 00:00:00, 0, 0         , foo).
+CONTEXT:  remote SQL command: UPDATE "S 1"."T 1" SET c2 = (-2) WHERE ((c2 = 42)) AND (("C 1" = 10))
+rollback to savepoint s3;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+release savepoint s3;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+-- none of the above is committed yet remotely
+select c2, count(*) from "S 1"."T 1" where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   0 |   100
+   1 |   100
+   4 |   100
+   6 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+commit;
+select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+select c2, count(*) from "S 1"."T 1" where c2 < 500 group by 1 order by 1;
+ c2  | count 
+-----+-------
+   1 |   100
+   6 |   100
+  42 |   100
+  44 |   100
+ 100 |     2
+ 101 |     2
+ 104 |     2
+ 106 |     2
+ 201 |     1
+ 204 |     1
+ 303 |   100
+ 403 |     2
+ 407 |   100
+(13 rows)
+
+VACUUM ANALYZE "S 1"."T 1";
+-- Above DMLs add data with c6 as NULL in ft1, so test ORDER BY NULLS LAST and NULLs
+-- FIRST behavior here.
+-- ORDER BY DESC NULLS LAST options
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 ORDER BY c6 DESC NULLS LAST, c1 OFFSET 795 LIMIT 10;
+                                                                          QUERY PLAN                                                                           
+---------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" ORDER BY c6 DESC NULLS LAST, "C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 795::bigint
+(3 rows)
+
+SELECT * FROM ft1 ORDER BY c6 DESC NULLS LAST, c1 OFFSET 795  LIMIT 10;
+  c1  | c2  |         c3         |              c4              |            c5            |  c6  |     c7     | c8  
+------+-----+--------------------+------------------------------+--------------------------+------+------------+-----
+  960 |  42 | 00960_trig_update  | Mon Mar 02 00:00:00 1970 PST | Mon Mar 02 00:00:00 1970 | 0    | 0          | foo
+  970 |  42 | 00970_trig_update  | Thu Mar 12 00:00:00 1970 PST | Thu Mar 12 00:00:00 1970 | 0    | 0          | foo
+  980 |  42 | 00980_trig_update  | Sun Mar 22 00:00:00 1970 PST | Sun Mar 22 00:00:00 1970 | 0    | 0          | foo
+  990 |  42 | 00990_trig_update  | Wed Apr 01 00:00:00 1970 PST | Wed Apr 01 00:00:00 1970 | 0    | 0          | foo
+ 1000 |  42 | 01000_trig_update  | Thu Jan 01 00:00:00 1970 PST | Thu Jan 01 00:00:00 1970 | 0    | 0          | foo
+ 1218 | 818 | ggg_trig_update    |                              |                          | (--; | ft2        | 
+ 1001 | 101 | 0000100001         |                              |                          |      | ft2        | 
+ 1003 | 403 | 0000300003_update3 |                              |                          |      | ft2        | 
+ 1004 | 104 | 0000400004         |                              |                          |      | ft2        | 
+ 1006 | 106 | 0000600006         |                              |                          |      | ft2        | 
+(10 rows)
+
+-- ORDER BY DESC NULLS FIRST options
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 ORDER BY c6 DESC NULLS FIRST, c1 OFFSET 15 LIMIT 10;
+                                                                          QUERY PLAN                                                                           
+---------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" ORDER BY c6 DESC NULLS FIRST, "C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 15::bigint
+(3 rows)
+
+SELECT * FROM ft1 ORDER BY c6 DESC NULLS FIRST, c1 OFFSET 15 LIMIT 10;
+  c1  | c2  |       c3        |              c4              |            c5            | c6 |     c7     | c8  
+------+-----+-----------------+------------------------------+--------------------------+----+------------+-----
+ 1020 | 100 | 0002000020      |                              |                          |    | ft2        | 
+ 1101 | 201 | aaa             |                              |                          |    | ft2        | 
+ 1103 | 503 | ccc_update3     |                              |                          |    | ft2        | 
+ 1104 | 204 | ddd             |                              |                          |    | ft2        | 
+ 1208 | 818 | fff_trig_update |                              |                          |    | ft2        | 
+    9 | 509 | 00009_update9   | Sat Jan 10 00:00:00 1970 PST | Sat Jan 10 00:00:00 1970 | 9  | ft2        | foo
+   19 | 509 | 00019_update9   | Tue Jan 20 00:00:00 1970 PST | Tue Jan 20 00:00:00 1970 | 9  | ft2        | foo
+   29 | 509 | 00029_update9   | Fri Jan 30 00:00:00 1970 PST | Fri Jan 30 00:00:00 1970 | 9  | ft2        | foo
+   39 | 509 | 00039_update9   | Mon Feb 09 00:00:00 1970 PST | Mon Feb 09 00:00:00 1970 | 9  | ft2        | foo
+   49 | 509 | 00049_update9   | Thu Feb 19 00:00:00 1970 PST | Thu Feb 19 00:00:00 1970 | 9  | ft2        | foo
+(10 rows)
+
+-- ORDER BY ASC NULLS FIRST options
+EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 ORDER BY c6 ASC NULLS FIRST, c1 OFFSET 15 LIMIT 10;
+                                                                          QUERY PLAN                                                                          
+--------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" ORDER BY c6 ASC NULLS FIRST, "C 1" ASC NULLS LAST LIMIT 10::bigint OFFSET 15::bigint
+(3 rows)
+
+SELECT * FROM ft1 ORDER BY c6 ASC NULLS FIRST, c1 OFFSET 15 LIMIT 10;
+  c1  | c2  |        c3         |              c4              |            c5            |  c6  |     c7     | c8  
+------+-----+-------------------+------------------------------+--------------------------+------+------------+-----
+ 1020 | 100 | 0002000020        |                              |                          |      | ft2        | 
+ 1101 | 201 | aaa               |                              |                          |      | ft2        | 
+ 1103 | 503 | ccc_update3       |                              |                          |      | ft2        | 
+ 1104 | 204 | ddd               |                              |                          |      | ft2        | 
+ 1208 | 818 | fff_trig_update   |                              |                          |      | ft2        | 
+ 1218 | 818 | ggg_trig_update   |                              |                          | (--; | ft2        | 
+   10 |  42 | 00010_trig_update | Sun Jan 11 00:00:00 1970 PST | Sun Jan 11 00:00:00 1970 | 0    | 0          | foo
+   20 |  42 | 00020_trig_update | Wed Jan 21 00:00:00 1970 PST | Wed Jan 21 00:00:00 1970 | 0    | 0          | foo
+   30 |  42 | 00030_trig_update | Sat Jan 31 00:00:00 1970 PST | Sat Jan 31 00:00:00 1970 | 0    | 0          | foo
+   40 |  42 | 00040_trig_update | Tue Feb 10 00:00:00 1970 PST | Tue Feb 10 00:00:00 1970 | 0    | 0          | foo
+(10 rows)
+
+-- ===================================================================
+-- test check constraints
+-- ===================================================================
+-- Consistent check constraints provide consistent results
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2positive CHECK (c2 >= 0);
+EXPLAIN (VERBOSE, COSTS OFF) SELECT count(*) FROM ft1 WHERE c2 < 0;
+                           QUERY PLAN                            
+-----------------------------------------------------------------
+ Foreign Scan
+   Output: (count(*))
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT count(*) FROM "S 1"."T 1" WHERE ((c2 < 0))
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 < 0;
+ count 
+-------
+     0
+(1 row)
+
+SET constraint_exclusion = 'on';
+EXPLAIN (VERBOSE, COSTS OFF) SELECT count(*) FROM ft1 WHERE c2 < 0;
+           QUERY PLAN           
+--------------------------------
+ Aggregate
+   Output: count(*)
+   ->  Result
+         One-Time Filter: false
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 < 0;
+ count 
+-------
+     0
+(1 row)
+
+RESET constraint_exclusion;
+-- check constraint is enforced on the remote side, not locally
+INSERT INTO ft1(c1, c2) VALUES(1111, -2);  -- c2positive
+ERROR:  new row for relation "T 1" violates check constraint "c2positive"
+DETAIL:  Failing row contains (1111, -2, null, null, null, null, ft1       , null).
+CONTEXT:  remote SQL command: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+UPDATE ft1 SET c2 = -c2 WHERE c1 = 1;  -- c2positive
+ERROR:  new row for relation "T 1" violates check constraint "c2positive"
+DETAIL:  Failing row contains (1, -1, 00001_trig_update, 1970-01-02 08:00:00+00, 1970-01-02 00:00:00, 1, 1         , foo).
+CONTEXT:  remote SQL command: UPDATE "S 1"."T 1" SET c2 = (- c2) WHERE (("C 1" = 1))
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2positive;
+-- But inconsistent check constraints provide inconsistent results
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2negative CHECK (c2 < 0);
+EXPLAIN (VERBOSE, COSTS OFF) SELECT count(*) FROM ft1 WHERE c2 >= 0;
+                            QUERY PLAN                            
+------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(*))
+   Relations: Aggregate on (public.ft1)
+   Remote SQL: SELECT count(*) FROM "S 1"."T 1" WHERE ((c2 >= 0))
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 >= 0;
+ count 
+-------
+   821
+(1 row)
+
+SET constraint_exclusion = 'on';
+EXPLAIN (VERBOSE, COSTS OFF) SELECT count(*) FROM ft1 WHERE c2 >= 0;
+           QUERY PLAN           
+--------------------------------
+ Aggregate
+   Output: count(*)
+   ->  Result
+         One-Time Filter: false
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 >= 0;
+ count 
+-------
+     0
+(1 row)
+
+RESET constraint_exclusion;
+-- local check constraint is not actually enforced
+INSERT INTO ft1(c1, c2) VALUES(1111, 2);
+UPDATE ft1 SET c2 = c2 + 1 WHERE c1 = 1;
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2negative;
+-- ===================================================================
+-- test WITH CHECK OPTION constraints
+-- ===================================================================
+CREATE FUNCTION row_before_insupd_trigfunc() RETURNS trigger AS $$BEGIN NEW.a := NEW.a + 10; RETURN NEW; END$$ LANGUAGE plpgsql;
+CREATE TABLE base_tbl (a int, b int);
+ALTER TABLE base_tbl SET (autovacuum_enabled = 'false');
+CREATE TRIGGER row_before_insupd_trigger BEFORE INSERT OR UPDATE ON base_tbl FOR EACH ROW EXECUTE PROCEDURE row_before_insupd_trigfunc();
+CREATE FOREIGN TABLE foreign_tbl (a int, b int)
+  SERVER loopback OPTIONS (table_name 'base_tbl');
+CREATE VIEW rw_view AS SELECT * FROM foreign_tbl
+  WHERE a < b WITH CHECK OPTION;
+\d+ rw_view
+                           View "public.rw_view"
+ Column |  Type   | Collation | Nullable | Default | Storage | Description 
+--------+---------+-----------+----------+---------+---------+-------------
+ a      | integer |           |          |         | plain   | 
+ b      | integer |           |          |         | plain   | 
+View definition:
+ SELECT foreign_tbl.a,
+    foreign_tbl.b
+   FROM foreign_tbl
+  WHERE foreign_tbl.a < foreign_tbl.b;
+Options: check_option=cascaded
+
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 5);
+                                   QUERY PLAN                                   
+--------------------------------------------------------------------------------
+ Insert on public.foreign_tbl
+   Remote SQL: INSERT INTO public.base_tbl(a, b) VALUES ($1, $2) RETURNING a, b
+   Batch Size: 1
+   ->  Result
+         Output: 0, 5
+(5 rows)
+
+INSERT INTO rw_view VALUES (0, 5); -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (10, 5).
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15);
+                                   QUERY PLAN                                   
+--------------------------------------------------------------------------------
+ Insert on public.foreign_tbl
+   Remote SQL: INSERT INTO public.base_tbl(a, b) VALUES ($1, $2) RETURNING a, b
+   Batch Size: 1
+   ->  Result
+         Output: 0, 15
+(5 rows)
+
+INSERT INTO rw_view VALUES (0, 15); -- ok
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 10 | 15
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+UPDATE rw_view SET b = b + 5;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Update on public.foreign_tbl
+   Remote SQL: UPDATE public.base_tbl SET b = $2 WHERE ctid = $1 RETURNING a, b
+   ->  Foreign Scan on public.foreign_tbl
+         Output: (foreign_tbl.b + 5), foreign_tbl.ctid, foreign_tbl.*
+         Remote SQL: SELECT a, b, ctid FROM public.base_tbl WHERE ((a < b)) FOR UPDATE
+(5 rows)
+
+UPDATE rw_view SET b = b + 5; -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (20, 20).
+EXPLAIN (VERBOSE, COSTS OFF)
+UPDATE rw_view SET b = b + 15;
+                                      QUERY PLAN                                       
+---------------------------------------------------------------------------------------
+ Update on public.foreign_tbl
+   Remote SQL: UPDATE public.base_tbl SET b = $2 WHERE ctid = $1 RETURNING a, b
+   ->  Foreign Scan on public.foreign_tbl
+         Output: (foreign_tbl.b + 15), foreign_tbl.ctid, foreign_tbl.*
+         Remote SQL: SELECT a, b, ctid FROM public.base_tbl WHERE ((a < b)) FOR UPDATE
+(5 rows)
+
+UPDATE rw_view SET b = b + 15; -- ok
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 20 | 30
+(1 row)
+
+-- We don't allow batch insert when there are any WCO constraints
+ALTER SERVER loopback OPTIONS (ADD batch_size '10');
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15), (0, 5);
+                                   QUERY PLAN                                   
+--------------------------------------------------------------------------------
+ Insert on public.foreign_tbl
+   Remote SQL: INSERT INTO public.base_tbl(a, b) VALUES ($1, $2) RETURNING a, b
+   Batch Size: 1
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1, "*VALUES*".column2
+(5 rows)
+
+INSERT INTO rw_view VALUES (0, 15), (0, 5); -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (10, 5).
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 20 | 30
+(1 row)
+
+ALTER SERVER loopback OPTIONS (DROP batch_size);
+DROP FOREIGN TABLE foreign_tbl CASCADE;
+NOTICE:  drop cascades to view rw_view
+DROP TRIGGER row_before_insupd_trigger ON base_tbl;
+DROP TABLE base_tbl;
+-- test WCO for partitions
+CREATE TABLE child_tbl (a int, b int);
+ALTER TABLE child_tbl SET (autovacuum_enabled = 'false');
+CREATE TRIGGER row_before_insupd_trigger BEFORE INSERT OR UPDATE ON child_tbl FOR EACH ROW EXECUTE PROCEDURE row_before_insupd_trigfunc();
+CREATE FOREIGN TABLE foreign_tbl (a int, b int)
+  SERVER loopback OPTIONS (table_name 'child_tbl');
+CREATE TABLE parent_tbl (a int, b int) PARTITION BY RANGE(a);
+ALTER TABLE parent_tbl ATTACH PARTITION foreign_tbl FOR VALUES FROM (0) TO (100);
+-- Detach and re-attach once, to stress the concurrent detach case.
+ALTER TABLE parent_tbl DETACH PARTITION foreign_tbl CONCURRENTLY;
+ALTER TABLE parent_tbl ATTACH PARTITION foreign_tbl FOR VALUES FROM (0) TO (100);
+CREATE VIEW rw_view AS SELECT * FROM parent_tbl
+  WHERE a < b WITH CHECK OPTION;
+\d+ rw_view
+                           View "public.rw_view"
+ Column |  Type   | Collation | Nullable | Default | Storage | Description 
+--------+---------+-----------+----------+---------+---------+-------------
+ a      | integer |           |          |         | plain   | 
+ b      | integer |           |          |         | plain   | 
+View definition:
+ SELECT parent_tbl.a,
+    parent_tbl.b
+   FROM parent_tbl
+  WHERE parent_tbl.a < parent_tbl.b;
+Options: check_option=cascaded
+
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 5);
+         QUERY PLAN          
+-----------------------------
+ Insert on public.parent_tbl
+   ->  Result
+         Output: 0, 5
+(3 rows)
+
+INSERT INTO rw_view VALUES (0, 5); -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (10, 5).
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15);
+         QUERY PLAN          
+-----------------------------
+ Insert on public.parent_tbl
+   ->  Result
+         Output: 0, 15
+(3 rows)
+
+INSERT INTO rw_view VALUES (0, 15); -- ok
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 10 | 15
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+UPDATE rw_view SET b = b + 5;
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
+ Update on public.parent_tbl
+   Foreign Update on public.foreign_tbl parent_tbl_1
+     Remote SQL: UPDATE public.child_tbl SET b = $2 WHERE ctid = $1 RETURNING a, b
+   ->  Foreign Scan on public.foreign_tbl parent_tbl_1
+         Output: (parent_tbl_1.b + 5), parent_tbl_1.tableoid, parent_tbl_1.ctid, parent_tbl_1.*
+         Remote SQL: SELECT a, b, ctid FROM public.child_tbl WHERE ((a < b)) FOR UPDATE
+(6 rows)
+
+UPDATE rw_view SET b = b + 5; -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (20, 20).
+EXPLAIN (VERBOSE, COSTS OFF)
+UPDATE rw_view SET b = b + 15;
+                                           QUERY PLAN                                            
+-------------------------------------------------------------------------------------------------
+ Update on public.parent_tbl
+   Foreign Update on public.foreign_tbl parent_tbl_1
+     Remote SQL: UPDATE public.child_tbl SET b = $2 WHERE ctid = $1 RETURNING a, b
+   ->  Foreign Scan on public.foreign_tbl parent_tbl_1
+         Output: (parent_tbl_1.b + 15), parent_tbl_1.tableoid, parent_tbl_1.ctid, parent_tbl_1.*
+         Remote SQL: SELECT a, b, ctid FROM public.child_tbl WHERE ((a < b)) FOR UPDATE
+(6 rows)
+
+UPDATE rw_view SET b = b + 15; -- ok
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 20 | 30
+(1 row)
+
+-- We don't allow batch insert when there are any WCO constraints
+ALTER SERVER loopback OPTIONS (ADD batch_size '10');
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15), (0, 5);
+                       QUERY PLAN                       
+--------------------------------------------------------
+ Insert on public.parent_tbl
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1, "*VALUES*".column2
+(3 rows)
+
+INSERT INTO rw_view VALUES (0, 15), (0, 5); -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (10, 5).
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 20 | 30
+(1 row)
+
+ALTER SERVER loopback OPTIONS (DROP batch_size);
+DROP FOREIGN TABLE foreign_tbl CASCADE;
+DROP TRIGGER row_before_insupd_trigger ON child_tbl;
+DROP TABLE parent_tbl CASCADE;
+NOTICE:  drop cascades to view rw_view
+DROP FUNCTION row_before_insupd_trigfunc;
+-- ===================================================================
+-- test serial columns (ie, sequence-based defaults)
+-- ===================================================================
+create table loc1 (f1 serial, f2 text);
+alter table loc1 set (autovacuum_enabled = 'false');
+create foreign table rem1 (f1 serial, f2 text)
+  server loopback options(table_name 'loc1');
+select pg_catalog.setval('rem1_f1_seq', 10, false);
+ setval 
+--------
+     10
+(1 row)
+
+insert into loc1(f2) values('hi');
+insert into rem1(f2) values('hi remote');
+insert into loc1(f2) values('bye');
+insert into rem1(f2) values('bye remote');
+select * from loc1;
+ f1 |     f2     
+----+------------
+  1 | hi
+ 10 | hi remote
+  2 | bye
+ 11 | bye remote
+(4 rows)
+
+select * from rem1;
+ f1 |     f2     
+----+------------
+  1 | hi
+ 10 | hi remote
+  2 | bye
+ 11 | bye remote
+(4 rows)
+
+-- ===================================================================
+-- test generated columns
+-- ===================================================================
+create table gloc1 (
+  a int,
+  b int generated always as (a * 2) stored);
+alter table gloc1 set (autovacuum_enabled = 'false');
+create foreign table grem1 (
+  a int,
+  b int generated always as (a * 2) stored)
+  server loopback options(table_name 'gloc1');
+explain (verbose, costs off)
+insert into grem1 (a) values (1), (2);
+                            QUERY PLAN                             
+-------------------------------------------------------------------
+ Insert on public.grem1
+   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Batch Size: 1
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1, NULL::integer
+(5 rows)
+
+insert into grem1 (a) values (1), (2);
+explain (verbose, costs off)
+update grem1 set a = 22 where a = 2;
+                                     QUERY PLAN                                     
+------------------------------------------------------------------------------------
+ Update on public.grem1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   ->  Foreign Scan on public.grem1
+         Output: 22, ctid, grem1.*
+         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+(5 rows)
+
+update grem1 set a = 22 where a = 2;
+select * from gloc1;
+ a  | b  
+----+----
+  1 |  2
+ 22 | 44
+(2 rows)
+
+select * from grem1;
+ a  | b  
+----+----
+  1 |  2
+ 22 | 44
+(2 rows)
+
+delete from grem1;
+-- test copy from
+copy grem1 from stdin;
+select * from gloc1;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+(2 rows)
+
+select * from grem1;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+(2 rows)
+
+delete from grem1;
+-- test batch insert
+alter server loopback options (add batch_size '10');
+explain (verbose, costs off)
+insert into grem1 (a) values (1), (2);
+                            QUERY PLAN                             
+-------------------------------------------------------------------
+ Insert on public.grem1
+   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Batch Size: 10
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1, NULL::integer
+(5 rows)
+
+insert into grem1 (a) values (1), (2);
+select * from gloc1;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+(2 rows)
+
+select * from grem1;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+(2 rows)
+
+delete from grem1;
+alter server loopback options (drop batch_size);
+-- ===================================================================
+-- test local triggers
+-- ===================================================================
+-- Trigger functions "borrowed" from triggers regress test.
+CREATE FUNCTION trigger_func() RETURNS trigger LANGUAGE plpgsql AS $$
+BEGIN
+	RAISE NOTICE 'trigger_func(%) called: action = %, when = %, level = %',
+		TG_ARGV[0], TG_OP, TG_WHEN, TG_LEVEL;
+	RETURN NULL;
+END;$$;
+CREATE TRIGGER trig_stmt_before BEFORE DELETE OR INSERT OR UPDATE OR TRUNCATE ON rem1
+	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+CREATE TRIGGER trig_stmt_after AFTER DELETE OR INSERT OR UPDATE OR TRUNCATE ON rem1
+	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+CREATE OR REPLACE FUNCTION trigger_data()  RETURNS trigger
+LANGUAGE plpgsql AS $$
+
+declare
+	oldnew text[];
+	relid text;
+    argstr text;
+begin
+
+	relid := TG_relid::regclass;
+	argstr := '';
+	for i in 0 .. TG_nargs - 1 loop
+		if i > 0 then
+			argstr := argstr || ', ';
+		end if;
+		argstr := argstr || TG_argv[i];
+	end loop;
+
+    RAISE NOTICE '%(%) % % % ON %',
+		tg_name, argstr, TG_when, TG_level, TG_OP, relid;
+    oldnew := '{}'::text[];
+	if TG_OP != 'INSERT' then
+		oldnew := array_append(oldnew, format('OLD: %s', OLD));
+	end if;
+
+	if TG_OP != 'DELETE' then
+		oldnew := array_append(oldnew, format('NEW: %s', NEW));
+	end if;
+
+    RAISE NOTICE '%', array_to_string(oldnew, ',');
+
+	if TG_OP = 'DELETE' then
+		return OLD;
+	else
+		return NEW;
+	end if;
+end;
+$$;
+-- Test basic functionality
+CREATE TRIGGER trig_row_before
+BEFORE INSERT OR UPDATE OR DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+CREATE TRIGGER trig_row_after
+AFTER INSERT OR UPDATE OR DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+delete from rem1;
+NOTICE:  trigger_func(<NULL>) called: action = DELETE, when = BEFORE, level = STATEMENT
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW DELETE ON rem1
+NOTICE:  OLD: (1,hi)
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW DELETE ON rem1
+NOTICE:  OLD: (10,"hi remote")
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW DELETE ON rem1
+NOTICE:  OLD: (2,bye)
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW DELETE ON rem1
+NOTICE:  OLD: (11,"bye remote")
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW DELETE ON rem1
+NOTICE:  OLD: (1,hi)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW DELETE ON rem1
+NOTICE:  OLD: (10,"hi remote")
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW DELETE ON rem1
+NOTICE:  OLD: (2,bye)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW DELETE ON rem1
+NOTICE:  OLD: (11,"bye remote")
+NOTICE:  trigger_func(<NULL>) called: action = DELETE, when = AFTER, level = STATEMENT
+insert into rem1 values(1,'insert');
+NOTICE:  trigger_func(<NULL>) called: action = INSERT, when = BEFORE, level = STATEMENT
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW INSERT ON rem1
+NOTICE:  NEW: (1,insert)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW INSERT ON rem1
+NOTICE:  NEW: (1,insert)
+NOTICE:  trigger_func(<NULL>) called: action = INSERT, when = AFTER, level = STATEMENT
+update rem1 set f2  = 'update' where f1 = 1;
+NOTICE:  trigger_func(<NULL>) called: action = UPDATE, when = BEFORE, level = STATEMENT
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW UPDATE ON rem1
+NOTICE:  OLD: (1,insert),NEW: (1,update)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (1,insert),NEW: (1,update)
+NOTICE:  trigger_func(<NULL>) called: action = UPDATE, when = AFTER, level = STATEMENT
+update rem1 set f2 = f2 || f2;
+NOTICE:  trigger_func(<NULL>) called: action = UPDATE, when = BEFORE, level = STATEMENT
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW UPDATE ON rem1
+NOTICE:  OLD: (1,update),NEW: (1,updateupdate)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (1,update),NEW: (1,updateupdate)
+NOTICE:  trigger_func(<NULL>) called: action = UPDATE, when = AFTER, level = STATEMENT
+truncate rem1;
+NOTICE:  trigger_func(<NULL>) called: action = TRUNCATE, when = BEFORE, level = STATEMENT
+NOTICE:  trigger_func(<NULL>) called: action = TRUNCATE, when = AFTER, level = STATEMENT
+-- cleanup
+DROP TRIGGER trig_row_before ON rem1;
+DROP TRIGGER trig_row_after ON rem1;
+DROP TRIGGER trig_stmt_before ON rem1;
+DROP TRIGGER trig_stmt_after ON rem1;
+DELETE from rem1;
+-- Test multiple AFTER ROW triggers on a foreign table
+CREATE TRIGGER trig_row_after1
+AFTER INSERT OR UPDATE OR DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+CREATE TRIGGER trig_row_after2
+AFTER INSERT OR UPDATE OR DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+insert into rem1 values(1,'insert');
+NOTICE:  trig_row_after1(23, skidoo) AFTER ROW INSERT ON rem1
+NOTICE:  NEW: (1,insert)
+NOTICE:  trig_row_after2(23, skidoo) AFTER ROW INSERT ON rem1
+NOTICE:  NEW: (1,insert)
+update rem1 set f2  = 'update' where f1 = 1;
+NOTICE:  trig_row_after1(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (1,insert),NEW: (1,update)
+NOTICE:  trig_row_after2(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (1,insert),NEW: (1,update)
+update rem1 set f2 = f2 || f2;
+NOTICE:  trig_row_after1(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (1,update),NEW: (1,updateupdate)
+NOTICE:  trig_row_after2(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (1,update),NEW: (1,updateupdate)
+delete from rem1;
+NOTICE:  trig_row_after1(23, skidoo) AFTER ROW DELETE ON rem1
+NOTICE:  OLD: (1,updateupdate)
+NOTICE:  trig_row_after2(23, skidoo) AFTER ROW DELETE ON rem1
+NOTICE:  OLD: (1,updateupdate)
+-- cleanup
+DROP TRIGGER trig_row_after1 ON rem1;
+DROP TRIGGER trig_row_after2 ON rem1;
+-- Test WHEN conditions
+CREATE TRIGGER trig_row_before_insupd
+BEFORE INSERT OR UPDATE ON rem1
+FOR EACH ROW
+WHEN (NEW.f2 like '%update%')
+EXECUTE PROCEDURE trigger_data(23,'skidoo');
+CREATE TRIGGER trig_row_after_insupd
+AFTER INSERT OR UPDATE ON rem1
+FOR EACH ROW
+WHEN (NEW.f2 like '%update%')
+EXECUTE PROCEDURE trigger_data(23,'skidoo');
+-- Insert or update not matching: nothing happens
+INSERT INTO rem1 values(1, 'insert');
+UPDATE rem1 set f2 = 'test';
+-- Insert or update matching: triggers are fired
+INSERT INTO rem1 values(2, 'update');
+NOTICE:  trig_row_before_insupd(23, skidoo) BEFORE ROW INSERT ON rem1
+NOTICE:  NEW: (2,update)
+NOTICE:  trig_row_after_insupd(23, skidoo) AFTER ROW INSERT ON rem1
+NOTICE:  NEW: (2,update)
+UPDATE rem1 set f2 = 'update update' where f1 = '2';
+NOTICE:  trig_row_before_insupd(23, skidoo) BEFORE ROW UPDATE ON rem1
+NOTICE:  OLD: (2,update),NEW: (2,"update update")
+NOTICE:  trig_row_after_insupd(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (2,update),NEW: (2,"update update")
+CREATE TRIGGER trig_row_before_delete
+BEFORE DELETE ON rem1
+FOR EACH ROW
+WHEN (OLD.f2 like '%update%')
+EXECUTE PROCEDURE trigger_data(23,'skidoo');
+CREATE TRIGGER trig_row_after_delete
+AFTER DELETE ON rem1
+FOR EACH ROW
+WHEN (OLD.f2 like '%update%')
+EXECUTE PROCEDURE trigger_data(23,'skidoo');
+-- Trigger is fired for f1=2, not for f1=1
+DELETE FROM rem1;
+NOTICE:  trig_row_before_delete(23, skidoo) BEFORE ROW DELETE ON rem1
+NOTICE:  OLD: (2,"update update")
+NOTICE:  trig_row_after_delete(23, skidoo) AFTER ROW DELETE ON rem1
+NOTICE:  OLD: (2,"update update")
+-- cleanup
+DROP TRIGGER trig_row_before_insupd ON rem1;
+DROP TRIGGER trig_row_after_insupd ON rem1;
+DROP TRIGGER trig_row_before_delete ON rem1;
+DROP TRIGGER trig_row_after_delete ON rem1;
+-- Test various RETURN statements in BEFORE triggers.
+CREATE FUNCTION trig_row_before_insupdate() RETURNS TRIGGER AS $$
+  BEGIN
+    NEW.f2 := NEW.f2 || ' triggered !';
+    RETURN NEW;
+  END
+$$ language plpgsql;
+CREATE TRIGGER trig_row_before_insupd
+BEFORE INSERT OR UPDATE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trig_row_before_insupdate();
+-- The new values should have 'triggered' appended
+INSERT INTO rem1 values(1, 'insert');
+SELECT * from loc1;
+ f1 |         f2         
+----+--------------------
+  1 | insert triggered !
+(1 row)
+
+INSERT INTO rem1 values(2, 'insert') RETURNING f2;
+         f2         
+--------------------
+ insert triggered !
+(1 row)
+
+SELECT * from loc1;
+ f1 |         f2         
+----+--------------------
+  1 | insert triggered !
+  2 | insert triggered !
+(2 rows)
+
+UPDATE rem1 set f2 = '';
+SELECT * from loc1;
+ f1 |      f2      
+----+--------------
+  1 |  triggered !
+  2 |  triggered !
+(2 rows)
+
+UPDATE rem1 set f2 = 'skidoo' RETURNING f2;
+         f2         
+--------------------
+ skidoo triggered !
+ skidoo triggered !
+(2 rows)
+
+SELECT * from loc1;
+ f1 |         f2         
+----+--------------------
+  1 | skidoo triggered !
+  2 | skidoo triggered !
+(2 rows)
+
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f1 = 10;          -- all columns should be transmitted
+                              QUERY PLAN                               
+-----------------------------------------------------------------------
+ Update on public.rem1
+   Remote SQL: UPDATE public.loc1 SET f1 = $2, f2 = $3 WHERE ctid = $1
+   ->  Foreign Scan on public.rem1
+         Output: 10, ctid, rem1.*
+         Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+(5 rows)
+
+UPDATE rem1 set f1 = 10;
+SELECT * from loc1;
+ f1 |               f2               
+----+--------------------------------
+ 10 | skidoo triggered ! triggered !
+ 10 | skidoo triggered ! triggered !
+(2 rows)
+
+DELETE FROM rem1;
+-- Add a second trigger, to check that the changes are propagated correctly
+-- from trigger to trigger
+CREATE TRIGGER trig_row_before_insupd2
+BEFORE INSERT OR UPDATE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trig_row_before_insupdate();
+INSERT INTO rem1 values(1, 'insert');
+SELECT * from loc1;
+ f1 |               f2               
+----+--------------------------------
+  1 | insert triggered ! triggered !
+(1 row)
+
+INSERT INTO rem1 values(2, 'insert') RETURNING f2;
+               f2               
+--------------------------------
+ insert triggered ! triggered !
+(1 row)
+
+SELECT * from loc1;
+ f1 |               f2               
+----+--------------------------------
+  1 | insert triggered ! triggered !
+  2 | insert triggered ! triggered !
+(2 rows)
+
+UPDATE rem1 set f2 = '';
+SELECT * from loc1;
+ f1 |            f2            
+----+--------------------------
+  1 |  triggered ! triggered !
+  2 |  triggered ! triggered !
+(2 rows)
+
+UPDATE rem1 set f2 = 'skidoo' RETURNING f2;
+               f2               
+--------------------------------
+ skidoo triggered ! triggered !
+ skidoo triggered ! triggered !
+(2 rows)
+
+SELECT * from loc1;
+ f1 |               f2               
+----+--------------------------------
+  1 | skidoo triggered ! triggered !
+  2 | skidoo triggered ! triggered !
+(2 rows)
+
+DROP TRIGGER trig_row_before_insupd ON rem1;
+DROP TRIGGER trig_row_before_insupd2 ON rem1;
+DELETE from rem1;
+INSERT INTO rem1 VALUES (1, 'test');
+-- Test with a trigger returning NULL
+CREATE FUNCTION trig_null() RETURNS TRIGGER AS $$
+  BEGIN
+    RETURN NULL;
+  END
+$$ language plpgsql;
+CREATE TRIGGER trig_null
+BEFORE INSERT OR UPDATE OR DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trig_null();
+-- Nothing should have changed.
+INSERT INTO rem1 VALUES (2, 'test2');
+SELECT * from loc1;
+ f1 |  f2  
+----+------
+  1 | test
+(1 row)
+
+UPDATE rem1 SET f2 = 'test2';
+SELECT * from loc1;
+ f1 |  f2  
+----+------
+  1 | test
+(1 row)
+
+DELETE from rem1;
+SELECT * from loc1;
+ f1 |  f2  
+----+------
+  1 | test
+(1 row)
+
+DROP TRIGGER trig_null ON rem1;
+DELETE from rem1;
+-- Test a combination of local and remote triggers
+CREATE TRIGGER trig_row_before
+BEFORE INSERT OR UPDATE OR DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+CREATE TRIGGER trig_row_after
+AFTER INSERT OR UPDATE OR DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+CREATE TRIGGER trig_local_before BEFORE INSERT OR UPDATE ON loc1
+FOR EACH ROW EXECUTE PROCEDURE trig_row_before_insupdate();
+INSERT INTO rem1(f2) VALUES ('test');
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW INSERT ON rem1
+NOTICE:  NEW: (12,test)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW INSERT ON rem1
+NOTICE:  NEW: (12,"test triggered !")
+UPDATE rem1 SET f2 = 'testo';
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW UPDATE ON rem1
+NOTICE:  OLD: (12,"test triggered !"),NEW: (12,testo)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW UPDATE ON rem1
+NOTICE:  OLD: (12,"test triggered !"),NEW: (12,"testo triggered !")
+-- Test returning a system attribute
+INSERT INTO rem1(f2) VALUES ('test') RETURNING ctid;
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW INSERT ON rem1
+NOTICE:  NEW: (13,test)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW INSERT ON rem1
+NOTICE:  NEW: (13,"test triggered !")
+  ctid  
+--------
+ (0,25)
+(1 row)
+
+-- cleanup
+DROP TRIGGER trig_row_before ON rem1;
+DROP TRIGGER trig_row_after ON rem1;
+DROP TRIGGER trig_local_before ON loc1;
+-- Test direct foreign table modification functionality
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can be pushed down
+                 QUERY PLAN                  
+---------------------------------------------
+ Delete on public.rem1
+   ->  Foreign Delete on public.rem1
+         Remote SQL: DELETE FROM public.loc1
+(3 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1 WHERE false;     -- currently can't be pushed down
+                      QUERY PLAN                       
+-------------------------------------------------------
+ Delete on public.rem1
+   Remote SQL: DELETE FROM public.loc1 WHERE ctid = $1
+   ->  Result
+         Output: ctid
+         One-Time Filter: false
+(5 rows)
+
+-- Test with statement-level triggers
+CREATE TRIGGER trig_stmt_before
+	BEFORE DELETE OR INSERT OR UPDATE ON rem1
+	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can be pushed down
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Update on public.rem1
+   ->  Foreign Update on public.rem1
+         Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+(3 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can be pushed down
+                 QUERY PLAN                  
+---------------------------------------------
+ Delete on public.rem1
+   ->  Foreign Delete on public.rem1
+         Remote SQL: DELETE FROM public.loc1
+(3 rows)
+
+DROP TRIGGER trig_stmt_before ON rem1;
+CREATE TRIGGER trig_stmt_after
+	AFTER DELETE OR INSERT OR UPDATE ON rem1
+	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can be pushed down
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Update on public.rem1
+   ->  Foreign Update on public.rem1
+         Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+(3 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can be pushed down
+                 QUERY PLAN                  
+---------------------------------------------
+ Delete on public.rem1
+   ->  Foreign Delete on public.rem1
+         Remote SQL: DELETE FROM public.loc1
+(3 rows)
+
+DROP TRIGGER trig_stmt_after ON rem1;
+-- Test with row-level ON INSERT triggers
+CREATE TRIGGER trig_row_before_insert
+BEFORE INSERT ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can be pushed down
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Update on public.rem1
+   ->  Foreign Update on public.rem1
+         Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+(3 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can be pushed down
+                 QUERY PLAN                  
+---------------------------------------------
+ Delete on public.rem1
+   ->  Foreign Delete on public.rem1
+         Remote SQL: DELETE FROM public.loc1
+(3 rows)
+
+DROP TRIGGER trig_row_before_insert ON rem1;
+CREATE TRIGGER trig_row_after_insert
+AFTER INSERT ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can be pushed down
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Update on public.rem1
+   ->  Foreign Update on public.rem1
+         Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+(3 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can be pushed down
+                 QUERY PLAN                  
+---------------------------------------------
+ Delete on public.rem1
+   ->  Foreign Delete on public.rem1
+         Remote SQL: DELETE FROM public.loc1
+(3 rows)
+
+DROP TRIGGER trig_row_after_insert ON rem1;
+-- Test with row-level ON UPDATE triggers
+CREATE TRIGGER trig_row_before_update
+BEFORE UPDATE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can't be pushed down
+                              QUERY PLAN                               
+-----------------------------------------------------------------------
+ Update on public.rem1
+   Remote SQL: UPDATE public.loc1 SET f1 = $2, f2 = $3 WHERE ctid = $1
+   ->  Foreign Scan on public.rem1
+         Output: ''::text, ctid, rem1.*
+         Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+(5 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can be pushed down
+                 QUERY PLAN                  
+---------------------------------------------
+ Delete on public.rem1
+   ->  Foreign Delete on public.rem1
+         Remote SQL: DELETE FROM public.loc1
+(3 rows)
+
+DROP TRIGGER trig_row_before_update ON rem1;
+CREATE TRIGGER trig_row_after_update
+AFTER UPDATE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can't be pushed down
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Update on public.rem1
+   Remote SQL: UPDATE public.loc1 SET f2 = $2 WHERE ctid = $1 RETURNING f1, f2
+   ->  Foreign Scan on public.rem1
+         Output: ''::text, ctid, rem1.*
+         Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+(5 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can be pushed down
+                 QUERY PLAN                  
+---------------------------------------------
+ Delete on public.rem1
+   ->  Foreign Delete on public.rem1
+         Remote SQL: DELETE FROM public.loc1
+(3 rows)
+
+DROP TRIGGER trig_row_after_update ON rem1;
+-- Test with row-level ON DELETE triggers
+CREATE TRIGGER trig_row_before_delete
+BEFORE DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can be pushed down
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Update on public.rem1
+   ->  Foreign Update on public.rem1
+         Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+(3 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can't be pushed down
+                             QUERY PLAN                              
+---------------------------------------------------------------------
+ Delete on public.rem1
+   Remote SQL: DELETE FROM public.loc1 WHERE ctid = $1
+   ->  Foreign Scan on public.rem1
+         Output: ctid, rem1.*
+         Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+(5 rows)
+
+DROP TRIGGER trig_row_before_delete ON rem1;
+CREATE TRIGGER trig_row_after_delete
+AFTER DELETE ON rem1
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f2 = '';          -- can be pushed down
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Update on public.rem1
+   ->  Foreign Update on public.rem1
+         Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+(3 rows)
+
+EXPLAIN (verbose, costs off)
+DELETE FROM rem1;                 -- can't be pushed down
+                               QUERY PLAN                               
+------------------------------------------------------------------------
+ Delete on public.rem1
+   Remote SQL: DELETE FROM public.loc1 WHERE ctid = $1 RETURNING f1, f2
+   ->  Foreign Scan on public.rem1
+         Output: ctid, rem1.*
+         Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+(5 rows)
+
+DROP TRIGGER trig_row_after_delete ON rem1;
+-- ===================================================================
+-- test inheritance features
+-- ===================================================================
+CREATE TABLE a (aa TEXT);
+CREATE TABLE loct (aa TEXT, bb TEXT);
+ALTER TABLE a SET (autovacuum_enabled = 'false');
+ALTER TABLE loct SET (autovacuum_enabled = 'false');
+CREATE FOREIGN TABLE b (bb TEXT) INHERITS (a)
+  SERVER loopback OPTIONS (table_name 'loct');
+INSERT INTO a(aa) VALUES('aaa');
+INSERT INTO a(aa) VALUES('aaaa');
+INSERT INTO a(aa) VALUES('aaaaa');
+INSERT INTO b(aa) VALUES('bbb');
+INSERT INTO b(aa) VALUES('bbbb');
+INSERT INTO b(aa) VALUES('bbbbb');
+SELECT tableoid::regclass, * FROM a;
+ tableoid |  aa   
+----------+-------
+ a        | aaa
+ a        | aaaa
+ a        | aaaaa
+ b        | bbb
+ b        | bbbb
+ b        | bbbbb
+(6 rows)
+
+SELECT tableoid::regclass, * FROM b;
+ tableoid |  aa   | bb 
+----------+-------+----
+ b        | bbb   | 
+ b        | bbbb  | 
+ b        | bbbbb | 
+(3 rows)
+
+SELECT tableoid::regclass, * FROM ONLY a;
+ tableoid |  aa   
+----------+-------
+ a        | aaa
+ a        | aaaa
+ a        | aaaaa
+(3 rows)
+
+UPDATE a SET aa = 'zzzzzz' WHERE aa LIKE 'aaaa%';
+SELECT tableoid::regclass, * FROM a;
+ tableoid |   aa   
+----------+--------
+ a        | aaa
+ a        | zzzzzz
+ a        | zzzzzz
+ b        | bbb
+ b        | bbbb
+ b        | bbbbb
+(6 rows)
+
+SELECT tableoid::regclass, * FROM b;
+ tableoid |  aa   | bb 
+----------+-------+----
+ b        | bbb   | 
+ b        | bbbb  | 
+ b        | bbbbb | 
+(3 rows)
+
+SELECT tableoid::regclass, * FROM ONLY a;
+ tableoid |   aa   
+----------+--------
+ a        | aaa
+ a        | zzzzzz
+ a        | zzzzzz
+(3 rows)
+
+UPDATE b SET aa = 'new';
+SELECT tableoid::regclass, * FROM a;
+ tableoid |   aa   
+----------+--------
+ a        | aaa
+ a        | zzzzzz
+ a        | zzzzzz
+ b        | new
+ b        | new
+ b        | new
+(6 rows)
+
+SELECT tableoid::regclass, * FROM b;
+ tableoid | aa  | bb 
+----------+-----+----
+ b        | new | 
+ b        | new | 
+ b        | new | 
+(3 rows)
+
+SELECT tableoid::regclass, * FROM ONLY a;
+ tableoid |   aa   
+----------+--------
+ a        | aaa
+ a        | zzzzzz
+ a        | zzzzzz
+(3 rows)
+
+UPDATE a SET aa = 'newtoo';
+SELECT tableoid::regclass, * FROM a;
+ tableoid |   aa   
+----------+--------
+ a        | newtoo
+ a        | newtoo
+ a        | newtoo
+ b        | newtoo
+ b        | newtoo
+ b        | newtoo
+(6 rows)
+
+SELECT tableoid::regclass, * FROM b;
+ tableoid |   aa   | bb 
+----------+--------+----
+ b        | newtoo | 
+ b        | newtoo | 
+ b        | newtoo | 
+(3 rows)
+
+SELECT tableoid::regclass, * FROM ONLY a;
+ tableoid |   aa   
+----------+--------
+ a        | newtoo
+ a        | newtoo
+ a        | newtoo
+(3 rows)
+
+DELETE FROM a;
+SELECT tableoid::regclass, * FROM a;
+ tableoid | aa 
+----------+----
+(0 rows)
+
+SELECT tableoid::regclass, * FROM b;
+ tableoid | aa | bb 
+----------+----+----
+(0 rows)
+
+SELECT tableoid::regclass, * FROM ONLY a;
+ tableoid | aa 
+----------+----
+(0 rows)
+
+DROP TABLE a CASCADE;
+NOTICE:  drop cascades to foreign table b
+DROP TABLE loct;
+-- Check SELECT FOR UPDATE/SHARE with an inherited source table
+create table loct1 (f1 int, f2 int, f3 int);
+create table loct2 (f1 int, f2 int, f3 int);
+alter table loct1 set (autovacuum_enabled = 'false');
+alter table loct2 set (autovacuum_enabled = 'false');
+create table foo (f1 int, f2 int);
+create foreign table foo2 (f3 int) inherits (foo)
+  server loopback options (table_name 'loct1');
+create table bar (f1 int, f2 int);
+create foreign table bar2 (f3 int) inherits (bar)
+  server loopback options (table_name 'loct2');
+alter table foo set (autovacuum_enabled = 'false');
+alter table bar set (autovacuum_enabled = 'false');
+insert into foo values(1,1);
+insert into foo values(3,3);
+insert into foo2 values(2,2,2);
+insert into foo2 values(4,4,4);
+insert into bar values(1,11);
+insert into bar values(2,22);
+insert into bar values(6,66);
+insert into bar2 values(3,33,33);
+insert into bar2 values(4,44,44);
+insert into bar2 values(7,77,77);
+explain (verbose, costs off)
+select * from bar where f1 in (select f1 from foo) for update;
+                                          QUERY PLAN                                          
+----------------------------------------------------------------------------------------------
+ LockRows
+   Output: bar.f1, bar.f2, bar.ctid, foo.ctid, bar.*, bar.tableoid, foo.*, foo.tableoid
+   ->  Hash Join
+         Output: bar.f1, bar.f2, bar.ctid, foo.ctid, bar.*, bar.tableoid, foo.*, foo.tableoid
+         Inner Unique: true
+         Hash Cond: (bar.f1 = foo.f1)
+         ->  Append
+               ->  Seq Scan on public.bar bar_1
+                     Output: bar_1.f1, bar_1.f2, bar_1.ctid, bar_1.*, bar_1.tableoid
+               ->  Foreign Scan on public.bar2 bar_2
+                     Output: bar_2.f1, bar_2.f2, bar_2.ctid, bar_2.*, bar_2.tableoid
+                     Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 FOR UPDATE
+         ->  Hash
+               Output: foo.ctid, foo.f1, foo.*, foo.tableoid
+               ->  HashAggregate
+                     Output: foo.ctid, foo.f1, foo.*, foo.tableoid
+                     Group Key: foo.f1
+                     ->  Append
+                           ->  Seq Scan on public.foo foo_1
+                                 Output: foo_1.ctid, foo_1.f1, foo_1.*, foo_1.tableoid
+                           ->  Foreign Scan on public.foo2 foo_2
+                                 Output: foo_2.ctid, foo_2.f1, foo_2.*, foo_2.tableoid
+                                 Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct1
+(23 rows)
+
+select * from bar where f1 in (select f1 from foo) for update;
+ f1 | f2 
+----+----
+  1 | 11
+  2 | 22
+  3 | 33
+  4 | 44
+(4 rows)
+
+explain (verbose, costs off)
+select * from bar where f1 in (select f1 from foo) for share;
+                                          QUERY PLAN                                          
+----------------------------------------------------------------------------------------------
+ LockRows
+   Output: bar.f1, bar.f2, bar.ctid, foo.ctid, bar.*, bar.tableoid, foo.*, foo.tableoid
+   ->  Hash Join
+         Output: bar.f1, bar.f2, bar.ctid, foo.ctid, bar.*, bar.tableoid, foo.*, foo.tableoid
+         Inner Unique: true
+         Hash Cond: (bar.f1 = foo.f1)
+         ->  Append
+               ->  Seq Scan on public.bar bar_1
+                     Output: bar_1.f1, bar_1.f2, bar_1.ctid, bar_1.*, bar_1.tableoid
+               ->  Foreign Scan on public.bar2 bar_2
+                     Output: bar_2.f1, bar_2.f2, bar_2.ctid, bar_2.*, bar_2.tableoid
+                     Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 FOR SHARE
+         ->  Hash
+               Output: foo.ctid, foo.f1, foo.*, foo.tableoid
+               ->  HashAggregate
+                     Output: foo.ctid, foo.f1, foo.*, foo.tableoid
+                     Group Key: foo.f1
+                     ->  Append
+                           ->  Seq Scan on public.foo foo_1
+                                 Output: foo_1.ctid, foo_1.f1, foo_1.*, foo_1.tableoid
+                           ->  Foreign Scan on public.foo2 foo_2
+                                 Output: foo_2.ctid, foo_2.f1, foo_2.*, foo_2.tableoid
+                                 Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct1
+(23 rows)
+
+select * from bar where f1 in (select f1 from foo) for share;
+ f1 | f2 
+----+----
+  1 | 11
+  2 | 22
+  3 | 33
+  4 | 44
+(4 rows)
+
+-- Now check SELECT FOR UPDATE/SHARE with an inherited source table,
+-- where the parent is itself a foreign table
+create table loct4 (f1 int, f2 int, f3 int);
+create foreign table foo2child (f3 int) inherits (foo2)
+  server loopback options (table_name 'loct4');
+NOTICE:  moving and merging column "f3" with inherited definition
+DETAIL:  User-specified column moved to the position of the inherited column.
+explain (verbose, costs off)
+select * from bar where f1 in (select f1 from foo2) for share;
+                                      QUERY PLAN                                      
+--------------------------------------------------------------------------------------
+ LockRows
+   Output: bar.f1, bar.f2, bar.ctid, foo2.*, bar.*, bar.tableoid, foo2.tableoid
+   ->  Hash Join
+         Output: bar.f1, bar.f2, bar.ctid, foo2.*, bar.*, bar.tableoid, foo2.tableoid
+         Inner Unique: true
+         Hash Cond: (bar.f1 = foo2.f1)
+         ->  Append
+               ->  Seq Scan on public.bar bar_1
+                     Output: bar_1.f1, bar_1.f2, bar_1.ctid, bar_1.*, bar_1.tableoid
+               ->  Foreign Scan on public.bar2 bar_2
+                     Output: bar_2.f1, bar_2.f2, bar_2.ctid, bar_2.*, bar_2.tableoid
+                     Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 FOR SHARE
+         ->  Hash
+               Output: foo2.*, foo2.f1, foo2.tableoid
+               ->  HashAggregate
+                     Output: foo2.*, foo2.f1, foo2.tableoid
+                     Group Key: foo2.f1
+                     ->  Append
+                           ->  Foreign Scan on public.foo2 foo2_1
+                                 Output: foo2_1.*, foo2_1.f1, foo2_1.tableoid
+                                 Remote SQL: SELECT f1, f2, f3 FROM public.loct1
+                           ->  Foreign Scan on public.foo2child foo2_2
+                                 Output: foo2_2.*, foo2_2.f1, foo2_2.tableoid
+                                 Remote SQL: SELECT f1, f2, f3 FROM public.loct4
+(24 rows)
+
+select * from bar where f1 in (select f1 from foo2) for share;
+ f1 | f2 
+----+----
+  2 | 22
+  4 | 44
+(2 rows)
+
+drop foreign table foo2child;
+-- And with a local child relation of the foreign table parent
+create table foo2child (f3 int) inherits (foo2);
+NOTICE:  moving and merging column "f3" with inherited definition
+DETAIL:  User-specified column moved to the position of the inherited column.
+explain (verbose, costs off)
+select * from bar where f1 in (select f1 from foo2) for share;
+                                           QUERY PLAN                                            
+-------------------------------------------------------------------------------------------------
+ LockRows
+   Output: bar.f1, bar.f2, bar.ctid, foo2.*, bar.*, bar.tableoid, foo2.ctid, foo2.tableoid
+   ->  Hash Join
+         Output: bar.f1, bar.f2, bar.ctid, foo2.*, bar.*, bar.tableoid, foo2.ctid, foo2.tableoid
+         Inner Unique: true
+         Hash Cond: (bar.f1 = foo2.f1)
+         ->  Append
+               ->  Seq Scan on public.bar bar_1
+                     Output: bar_1.f1, bar_1.f2, bar_1.ctid, bar_1.*, bar_1.tableoid
+               ->  Foreign Scan on public.bar2 bar_2
+                     Output: bar_2.f1, bar_2.f2, bar_2.ctid, bar_2.*, bar_2.tableoid
+                     Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 FOR SHARE
+         ->  Hash
+               Output: foo2.*, foo2.f1, foo2.ctid, foo2.tableoid
+               ->  HashAggregate
+                     Output: foo2.*, foo2.f1, foo2.ctid, foo2.tableoid
+                     Group Key: foo2.f1
+                     ->  Append
+                           ->  Foreign Scan on public.foo2 foo2_1
+                                 Output: foo2_1.*, foo2_1.f1, foo2_1.ctid, foo2_1.tableoid
+                                 Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct1
+                           ->  Seq Scan on public.foo2child foo2_2
+                                 Output: foo2_2.*, foo2_2.f1, foo2_2.ctid, foo2_2.tableoid
+(23 rows)
+
+select * from bar where f1 in (select f1 from foo2) for share;
+ f1 | f2 
+----+----
+  2 | 22
+  4 | 44
+(2 rows)
+
+drop table foo2child;
+-- Check UPDATE with inherited target and an inherited source table
+explain (verbose, costs off)
+update bar set f2 = f2 + 100 where f1 in (select f1 from foo);
+                                              QUERY PLAN                                               
+-------------------------------------------------------------------------------------------------------
+ Update on public.bar
+   Update on public.bar bar_1
+   Foreign Update on public.bar2 bar_2
+     Remote SQL: UPDATE public.loct2 SET f2 = $2 WHERE ctid = $1
+   ->  Hash Join
+         Output: (bar.f2 + 100), foo.ctid, bar.tableoid, bar.ctid, (NULL::record), foo.*, foo.tableoid
+         Inner Unique: true
+         Hash Cond: (bar.f1 = foo.f1)
+         ->  Append
+               ->  Seq Scan on public.bar bar_1
+                     Output: bar_1.f2, bar_1.f1, bar_1.tableoid, bar_1.ctid, NULL::record
+               ->  Foreign Scan on public.bar2 bar_2
+                     Output: bar_2.f2, bar_2.f1, bar_2.tableoid, bar_2.ctid, bar_2.*
+                     Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 FOR UPDATE
+         ->  Hash
+               Output: foo.ctid, foo.f1, foo.*, foo.tableoid
+               ->  HashAggregate
+                     Output: foo.ctid, foo.f1, foo.*, foo.tableoid
+                     Group Key: foo.f1
+                     ->  Append
+                           ->  Seq Scan on public.foo foo_1
+                                 Output: foo_1.ctid, foo_1.f1, foo_1.*, foo_1.tableoid
+                           ->  Foreign Scan on public.foo2 foo_2
+                                 Output: foo_2.ctid, foo_2.f1, foo_2.*, foo_2.tableoid
+                                 Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct1
+(25 rows)
+
+update bar set f2 = f2 + 100 where f1 in (select f1 from foo);
+select tableoid::regclass, * from bar order by 1,2;
+ tableoid | f1 | f2  
+----------+----+-----
+ bar      |  1 | 111
+ bar      |  2 | 122
+ bar      |  6 |  66
+ bar2     |  3 | 133
+ bar2     |  4 | 144
+ bar2     |  7 |  77
+(6 rows)
+
+-- Check UPDATE with inherited target and an appendrel subquery
+explain (verbose, costs off)
+update bar set f2 = f2 + 100
+from
+  ( select f1 from foo union all select f1+3 from foo ) ss
+where bar.f1 = ss.f1;
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
+ Update on public.bar
+   Update on public.bar bar_1
+   Foreign Update on public.bar2 bar_2
+     Remote SQL: UPDATE public.loct2 SET f2 = $2 WHERE ctid = $1
+   ->  Merge Join
+         Output: (bar.f2 + 100), (ROW(foo.f1)), bar.tableoid, bar.ctid, (NULL::record)
+         Merge Cond: (bar.f1 = foo.f1)
+         ->  Sort
+               Output: bar.f2, bar.f1, bar.tableoid, bar.ctid, (NULL::record)
+               Sort Key: bar.f1
+               ->  Append
+                     ->  Seq Scan on public.bar bar_1
+                           Output: bar_1.f2, bar_1.f1, bar_1.tableoid, bar_1.ctid, NULL::record
+                     ->  Foreign Scan on public.bar2 bar_2
+                           Output: bar_2.f2, bar_2.f1, bar_2.tableoid, bar_2.ctid, bar_2.*
+                           Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 FOR UPDATE
+         ->  Sort
+               Output: (ROW(foo.f1)), foo.f1
+               Sort Key: foo.f1
+               ->  Append
+                     ->  Seq Scan on public.foo
+                           Output: ROW(foo.f1), foo.f1
+                     ->  Foreign Scan on public.foo2 foo_1
+                           Output: ROW(foo_1.f1), foo_1.f1
+                           Remote SQL: SELECT f1 FROM public.loct1
+                     ->  Seq Scan on public.foo foo_2
+                           Output: ROW((foo_2.f1 + 3)), (foo_2.f1 + 3)
+                     ->  Foreign Scan on public.foo2 foo_3
+                           Output: ROW((foo_3.f1 + 3)), (foo_3.f1 + 3)
+                           Remote SQL: SELECT f1 FROM public.loct1
+(30 rows)
+
+update bar set f2 = f2 + 100
+from
+  ( select f1 from foo union all select f1+3 from foo ) ss
+where bar.f1 = ss.f1;
+select tableoid::regclass, * from bar order by 1,2;
+ tableoid | f1 | f2  
+----------+----+-----
+ bar      |  1 | 211
+ bar      |  2 | 222
+ bar      |  6 | 166
+ bar2     |  3 | 233
+ bar2     |  4 | 244
+ bar2     |  7 | 177
+(6 rows)
+
+-- Test forcing the remote server to produce sorted data for a merge join,
+-- but the foreign table is an inheritance child.
+truncate table loct1;
+truncate table only foo;
+\set num_rows_foo 2000
+insert into loct1 select generate_series(0, :num_rows_foo, 2), generate_series(0, :num_rows_foo, 2), generate_series(0, :num_rows_foo, 2);
+insert into foo select generate_series(1, :num_rows_foo, 2), generate_series(1, :num_rows_foo, 2);
+SET enable_hashjoin to false;
+SET enable_nestloop to false;
+alter foreign table foo2 options (use_remote_estimate 'true');
+create index i_loct1_f1 on loct1(f1);
+create index i_foo_f1 on foo(f1);
+analyze foo;
+analyze loct1;
+-- inner join; expressions in the clauses appear in the equivalence class list
+explain (verbose, costs off)
+	select foo.f1, loct1.f1 from foo join loct1 on (foo.f1 = loct1.f1) order by foo.f2 offset 10 limit 10;
+                                            QUERY PLAN                                            
+--------------------------------------------------------------------------------------------------
+ Limit
+   Output: foo.f1, loct1.f1, foo.f2
+   ->  Sort
+         Output: foo.f1, loct1.f1, foo.f2
+         Sort Key: foo.f2
+         ->  Merge Join
+               Output: foo.f1, loct1.f1, foo.f2
+               Merge Cond: (foo.f1 = loct1.f1)
+               ->  Merge Append
+                     Sort Key: foo.f1
+                     ->  Index Scan using i_foo_f1 on public.foo foo_1
+                           Output: foo_1.f1, foo_1.f2
+                     ->  Foreign Scan on public.foo2 foo_2
+                           Output: foo_2.f1, foo_2.f2
+                           Remote SQL: SELECT f1, f2 FROM public.loct1 ORDER BY f1 ASC NULLS LAST
+               ->  Index Only Scan using i_loct1_f1 on public.loct1
+                     Output: loct1.f1
+(17 rows)
+
+select foo.f1, loct1.f1 from foo join loct1 on (foo.f1 = loct1.f1) order by foo.f2 offset 10 limit 10;
+ f1 | f1 
+----+----
+ 20 | 20
+ 22 | 22
+ 24 | 24
+ 26 | 26
+ 28 | 28
+ 30 | 30
+ 32 | 32
+ 34 | 34
+ 36 | 36
+ 38 | 38
+(10 rows)
+
+-- outer join; expressions in the clauses do not appear in equivalence class
+-- list but no output change as compared to the previous query
+explain (verbose, costs off)
+	select foo.f1, loct1.f1 from foo left join loct1 on (foo.f1 = loct1.f1) order by foo.f2 offset 10 limit 10;
+                                            QUERY PLAN                                            
+--------------------------------------------------------------------------------------------------
+ Limit
+   Output: foo.f1, loct1.f1, foo.f2
+   ->  Sort
+         Output: foo.f1, loct1.f1, foo.f2
+         Sort Key: foo.f2
+         ->  Merge Left Join
+               Output: foo.f1, loct1.f1, foo.f2
+               Merge Cond: (foo.f1 = loct1.f1)
+               ->  Merge Append
+                     Sort Key: foo.f1
+                     ->  Index Scan using i_foo_f1 on public.foo foo_1
+                           Output: foo_1.f1, foo_1.f2
+                     ->  Foreign Scan on public.foo2 foo_2
+                           Output: foo_2.f1, foo_2.f2
+                           Remote SQL: SELECT f1, f2 FROM public.loct1 ORDER BY f1 ASC NULLS LAST
+               ->  Index Only Scan using i_loct1_f1 on public.loct1
+                     Output: loct1.f1
+(17 rows)
+
+select foo.f1, loct1.f1 from foo left join loct1 on (foo.f1 = loct1.f1) order by foo.f2 offset 10 limit 10;
+ f1 | f1 
+----+----
+ 10 | 10
+ 11 |   
+ 12 | 12
+ 13 |   
+ 14 | 14
+ 15 |   
+ 16 | 16
+ 17 |   
+ 18 | 18
+ 19 |   
+(10 rows)
+
+RESET enable_hashjoin;
+RESET enable_nestloop;
+-- Test that WHERE CURRENT OF is not supported
+begin;
+declare c cursor for select * from bar where f1 = 7;
+fetch from c;
+ f1 | f2  
+----+-----
+  7 | 177
+(1 row)
+
+update bar set f2 = null where current of c;
+ERROR:  WHERE CURRENT OF is not supported for this table type
+rollback;
+explain (verbose, costs off)
+delete from foo where f1 < 5 returning *;
+                                      QUERY PLAN                                      
+--------------------------------------------------------------------------------------
+ Delete on public.foo
+   Output: foo_1.f1, foo_1.f2
+   Delete on public.foo foo_1
+   Foreign Delete on public.foo2 foo_2
+   ->  Append
+         ->  Index Scan using i_foo_f1 on public.foo foo_1
+               Output: foo_1.tableoid, foo_1.ctid
+               Index Cond: (foo_1.f1 < 5)
+         ->  Foreign Delete on public.foo2 foo_2
+               Remote SQL: DELETE FROM public.loct1 WHERE ((f1 < 5)) RETURNING f1, f2
+(10 rows)
+
+delete from foo where f1 < 5 returning *;
+ f1 | f2 
+----+----
+  1 |  1
+  3 |  3
+  0 |  0
+  2 |  2
+  4 |  4
+(5 rows)
+
+explain (verbose, costs off)
+update bar set f2 = f2 + 100 returning *;
+                                        QUERY PLAN                                        
+------------------------------------------------------------------------------------------
+ Update on public.bar
+   Output: bar_1.f1, bar_1.f2
+   Update on public.bar bar_1
+   Foreign Update on public.bar2 bar_2
+   ->  Result
+         Output: (bar.f2 + 100), bar.tableoid, bar.ctid, (NULL::record)
+         ->  Append
+               ->  Seq Scan on public.bar bar_1
+                     Output: bar_1.f2, bar_1.tableoid, bar_1.ctid, NULL::record
+               ->  Foreign Update on public.bar2 bar_2
+                     Remote SQL: UPDATE public.loct2 SET f2 = (f2 + 100) RETURNING f1, f2
+(11 rows)
+
+update bar set f2 = f2 + 100 returning *;
+ f1 | f2  
+----+-----
+  1 | 311
+  2 | 322
+  6 | 266
+  3 | 333
+  4 | 344
+  7 | 277
+(6 rows)
+
+-- Test that UPDATE/DELETE with inherited target works with row-level triggers
+CREATE TRIGGER trig_row_before
+BEFORE UPDATE OR DELETE ON bar2
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+CREATE TRIGGER trig_row_after
+AFTER UPDATE OR DELETE ON bar2
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+explain (verbose, costs off)
+update bar set f2 = f2 + 100;
+                                               QUERY PLAN                                               
+--------------------------------------------------------------------------------------------------------
+ Update on public.bar
+   Update on public.bar bar_1
+   Foreign Update on public.bar2 bar_2
+     Remote SQL: UPDATE public.loct2 SET f1 = $2, f2 = $3, f3 = $4 WHERE ctid = $1 RETURNING f1, f2, f3
+   ->  Result
+         Output: (bar.f2 + 100), bar.tableoid, bar.ctid, (NULL::record)
+         ->  Append
+               ->  Seq Scan on public.bar bar_1
+                     Output: bar_1.f2, bar_1.tableoid, bar_1.ctid, NULL::record
+               ->  Foreign Scan on public.bar2 bar_2
+                     Output: bar_2.f2, bar_2.tableoid, bar_2.ctid, bar_2.*
+                     Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 FOR UPDATE
+(12 rows)
+
+update bar set f2 = f2 + 100;
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW UPDATE ON bar2
+NOTICE:  OLD: (3,333,33),NEW: (3,433,33)
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW UPDATE ON bar2
+NOTICE:  OLD: (4,344,44),NEW: (4,444,44)
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW UPDATE ON bar2
+NOTICE:  OLD: (7,277,77),NEW: (7,377,77)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW UPDATE ON bar2
+NOTICE:  OLD: (3,333,33),NEW: (3,433,33)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW UPDATE ON bar2
+NOTICE:  OLD: (4,344,44),NEW: (4,444,44)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW UPDATE ON bar2
+NOTICE:  OLD: (7,277,77),NEW: (7,377,77)
+explain (verbose, costs off)
+delete from bar where f2 < 400;
+                                            QUERY PLAN                                             
+---------------------------------------------------------------------------------------------------
+ Delete on public.bar
+   Delete on public.bar bar_1
+   Foreign Delete on public.bar2 bar_2
+     Remote SQL: DELETE FROM public.loct2 WHERE ctid = $1 RETURNING f1, f2, f3
+   ->  Append
+         ->  Seq Scan on public.bar bar_1
+               Output: bar_1.tableoid, bar_1.ctid, NULL::record
+               Filter: (bar_1.f2 < 400)
+         ->  Foreign Scan on public.bar2 bar_2
+               Output: bar_2.tableoid, bar_2.ctid, bar_2.*
+               Remote SQL: SELECT f1, f2, f3, ctid FROM public.loct2 WHERE ((f2 < 400)) FOR UPDATE
+(11 rows)
+
+delete from bar where f2 < 400;
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW DELETE ON bar2
+NOTICE:  OLD: (7,377,77)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW DELETE ON bar2
+NOTICE:  OLD: (7,377,77)
+-- cleanup
+drop table foo cascade;
+NOTICE:  drop cascades to foreign table foo2
+drop table bar cascade;
+NOTICE:  drop cascades to foreign table bar2
+drop table loct1;
+drop table loct2;
+-- Test pushing down UPDATE/DELETE joins to the remote server
+create table parent (a int, b text);
+create table loct1 (a int, b text);
+create table loct2 (a int, b text);
+create foreign table remt1 (a int, b text)
+  server loopback options (table_name 'loct1');
+create foreign table remt2 (a int, b text)
+  server loopback options (table_name 'loct2');
+alter foreign table remt1 inherit parent;
+insert into remt1 values (1, 'foo');
+insert into remt1 values (2, 'bar');
+insert into remt2 values (1, 'foo');
+insert into remt2 values (2, 'bar');
+analyze remt1;
+analyze remt2;
+explain (verbose, costs off)
+update parent set b = parent.b || remt2.b from remt2 where parent.a = remt2.a returning *;
+                                                   QUERY PLAN                                                   
+----------------------------------------------------------------------------------------------------------------
+ Update on public.parent
+   Output: parent_1.a, parent_1.b, remt2.a, remt2.b
+   Update on public.parent parent_1
+   Foreign Update on public.remt1 parent_2
+     Remote SQL: UPDATE public.loct1 SET b = $2 WHERE ctid = $1 RETURNING a, b
+   ->  Nested Loop
+         Output: (parent.b || remt2.b), remt2.*, remt2.a, remt2.b, parent.tableoid, parent.ctid, (NULL::record)
+         Join Filter: (parent.a = remt2.a)
+         ->  Append
+               ->  Seq Scan on public.parent parent_1
+                     Output: parent_1.b, parent_1.a, parent_1.tableoid, parent_1.ctid, NULL::record
+               ->  Foreign Scan on public.remt1 parent_2
+                     Output: parent_2.b, parent_2.a, parent_2.tableoid, parent_2.ctid, parent_2.*
+                     Remote SQL: SELECT a, b, ctid FROM public.loct1 FOR UPDATE
+         ->  Materialize
+               Output: remt2.b, remt2.*, remt2.a
+               ->  Foreign Scan on public.remt2
+                     Output: remt2.b, remt2.*, remt2.a
+                     Remote SQL: SELECT a, b FROM public.loct2
+(19 rows)
+
+update parent set b = parent.b || remt2.b from remt2 where parent.a = remt2.a returning *;
+ a |   b    | a |  b  
+---+--------+---+-----
+ 1 | foofoo | 1 | foo
+ 2 | barbar | 2 | bar
+(2 rows)
+
+explain (verbose, costs off)
+delete from parent using remt2 where parent.a = remt2.a returning parent;
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
+ Delete on public.parent
+   Output: parent_1.*
+   Delete on public.parent parent_1
+   Foreign Delete on public.remt1 parent_2
+     Remote SQL: DELETE FROM public.loct1 WHERE ctid = $1 RETURNING a, b
+   ->  Nested Loop
+         Output: remt2.*, parent.tableoid, parent.ctid
+         Join Filter: (parent.a = remt2.a)
+         ->  Append
+               ->  Seq Scan on public.parent parent_1
+                     Output: parent_1.a, parent_1.tableoid, parent_1.ctid
+               ->  Foreign Scan on public.remt1 parent_2
+                     Output: parent_2.a, parent_2.tableoid, parent_2.ctid
+                     Remote SQL: SELECT a, ctid FROM public.loct1 FOR UPDATE
+         ->  Materialize
+               Output: remt2.*, remt2.a
+               ->  Foreign Scan on public.remt2
+                     Output: remt2.*, remt2.a
+                     Remote SQL: SELECT a, b FROM public.loct2
+(19 rows)
+
+delete from parent using remt2 where parent.a = remt2.a returning parent;
+   parent   
+------------
+ (1,foofoo)
+ (2,barbar)
+(2 rows)
+
+-- cleanup
+drop foreign table remt1;
+drop foreign table remt2;
+drop table loct1;
+drop table loct2;
+drop table parent;
+-- ===================================================================
+-- test tuple routing for foreign-table partitions
+-- ===================================================================
+-- Test insert tuple routing
+create table itrtest (a int, b text) partition by list (a);
+create table loct1 (a int check (a in (1)), b text);
+create foreign table remp1 (a int check (a in (1)), b text) server loopback options (table_name 'loct1');
+create table loct2 (a int check (a in (2)), b text);
+create foreign table remp2 (b text, a int check (a in (2))) server loopback options (table_name 'loct2');
+alter table itrtest attach partition remp1 for values in (1);
+alter table itrtest attach partition remp2 for values in (2);
+insert into itrtest values (1, 'foo');
+insert into itrtest values (1, 'bar') returning *;
+ a |  b  
+---+-----
+ 1 | bar
+(1 row)
+
+insert into itrtest values (2, 'baz');
+insert into itrtest values (2, 'qux') returning *;
+ a |  b  
+---+-----
+ 2 | qux
+(1 row)
+
+insert into itrtest values (1, 'test1'), (2, 'test2') returning *;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+select tableoid::regclass, * FROM itrtest;
+ tableoid | a |   b   
+----------+---+-------
+ remp1    | 1 | foo
+ remp1    | 1 | bar
+ remp1    | 1 | test1
+ remp2    | 2 | baz
+ remp2    | 2 | qux
+ remp2    | 2 | test2
+(6 rows)
+
+select tableoid::regclass, * FROM remp1;
+ tableoid | a |   b   
+----------+---+-------
+ remp1    | 1 | foo
+ remp1    | 1 | bar
+ remp1    | 1 | test1
+(3 rows)
+
+select tableoid::regclass, * FROM remp2;
+ tableoid |   b   | a 
+----------+-------+---
+ remp2    | baz   | 2
+ remp2    | qux   | 2
+ remp2    | test2 | 2
+(3 rows)
+
+delete from itrtest;
+create unique index loct1_idx on loct1 (a);
+-- DO NOTHING without an inference specification is supported
+insert into itrtest values (1, 'foo') on conflict do nothing returning *;
+ a |  b  
+---+-----
+ 1 | foo
+(1 row)
+
+insert into itrtest values (1, 'foo') on conflict do nothing returning *;
+ a | b 
+---+---
+(0 rows)
+
+-- But other cases are not supported
+insert into itrtest values (1, 'bar') on conflict (a) do nothing;
+ERROR:  there is no unique or exclusion constraint matching the ON CONFLICT specification
+insert into itrtest values (1, 'bar') on conflict (a) do update set b = excluded.b;
+ERROR:  there is no unique or exclusion constraint matching the ON CONFLICT specification
+select tableoid::regclass, * FROM itrtest;
+ tableoid | a |  b  
+----------+---+-----
+ remp1    | 1 | foo
+(1 row)
+
+delete from itrtest;
+drop index loct1_idx;
+-- Test that remote triggers work with insert tuple routing
+create function br_insert_trigfunc() returns trigger as $$
+begin
+	new.b := new.b || ' triggered !';
+	return new;
+end
+$$ language plpgsql;
+create trigger loct1_br_insert_trigger before insert on loct1
+	for each row execute procedure br_insert_trigfunc();
+create trigger loct2_br_insert_trigger before insert on loct2
+	for each row execute procedure br_insert_trigfunc();
+-- The new values are concatenated with ' triggered !'
+insert into itrtest values (1, 'foo') returning *;
+ a |        b        
+---+-----------------
+ 1 | foo triggered !
+(1 row)
+
+insert into itrtest values (2, 'qux') returning *;
+ a |        b        
+---+-----------------
+ 2 | qux triggered !
+(1 row)
+
+insert into itrtest values (1, 'test1'), (2, 'test2') returning *;
+ a |         b         
+---+-------------------
+ 1 | test1 triggered !
+ 2 | test2 triggered !
+(2 rows)
+
+with result as (insert into itrtest values (1, 'test1'), (2, 'test2') returning *) select * from result;
+ a |         b         
+---+-------------------
+ 1 | test1 triggered !
+ 2 | test2 triggered !
+(2 rows)
+
+drop trigger loct1_br_insert_trigger on loct1;
+drop trigger loct2_br_insert_trigger on loct2;
+drop table itrtest;
+drop table loct1;
+drop table loct2;
+-- Test update tuple routing
+create table utrtest (a int, b text) partition by list (a);
+create table loct (a int check (a in (1)), b text);
+create foreign table remp (a int check (a in (1)), b text) server loopback options (table_name 'loct');
+create table locp (a int check (a in (2)), b text);
+alter table utrtest attach partition remp for values in (1);
+alter table utrtest attach partition locp for values in (2);
+insert into utrtest values (1, 'foo');
+insert into utrtest values (2, 'qux');
+select tableoid::regclass, * FROM utrtest;
+ tableoid | a |  b  
+----------+---+-----
+ remp     | 1 | foo
+ locp     | 2 | qux
+(2 rows)
+
+select tableoid::regclass, * FROM remp;
+ tableoid | a |  b  
+----------+---+-----
+ remp     | 1 | foo
+(1 row)
+
+select tableoid::regclass, * FROM locp;
+ tableoid | a |  b  
+----------+---+-----
+ locp     | 2 | qux
+(1 row)
+
+-- It's not allowed to move a row from a partition that is foreign to another
+update utrtest set a = 2 where b = 'foo' returning *;
+ERROR:  new row for relation "loct" violates check constraint "loct_a_check"
+DETAIL:  Failing row contains (2, foo).
+CONTEXT:  remote SQL command: UPDATE public.loct SET a = 2 WHERE ((b = 'foo')) RETURNING a, b
+-- But the reverse is allowed
+update utrtest set a = 1 where b = 'qux' returning *;
+ERROR:  cannot route tuples into foreign table to be updated "remp"
+select tableoid::regclass, * FROM utrtest;
+ tableoid | a |  b  
+----------+---+-----
+ remp     | 1 | foo
+ locp     | 2 | qux
+(2 rows)
+
+select tableoid::regclass, * FROM remp;
+ tableoid | a |  b  
+----------+---+-----
+ remp     | 1 | foo
+(1 row)
+
+select tableoid::regclass, * FROM locp;
+ tableoid | a |  b  
+----------+---+-----
+ locp     | 2 | qux
+(1 row)
+
+-- The executor should not let unexercised FDWs shut down
+update utrtest set a = 1 where b = 'foo';
+-- Test that remote triggers work with update tuple routing
+create trigger loct_br_insert_trigger before insert on loct
+	for each row execute procedure br_insert_trigfunc();
+delete from utrtest;
+insert into utrtest values (2, 'qux');
+-- Check case where the foreign partition is a subplan target rel
+explain (verbose, costs off)
+update utrtest set a = 1 where a = 1 or a = 2 returning *;
+                                             QUERY PLAN                                             
+----------------------------------------------------------------------------------------------------
+ Update on public.utrtest
+   Output: utrtest_1.a, utrtest_1.b
+   Foreign Update on public.remp utrtest_1
+   Update on public.locp utrtest_2
+   ->  Append
+         ->  Foreign Update on public.remp utrtest_1
+               Remote SQL: UPDATE public.loct SET a = 1 WHERE (((a = 1) OR (a = 2))) RETURNING a, b
+         ->  Seq Scan on public.locp utrtest_2
+               Output: 1, utrtest_2.tableoid, utrtest_2.ctid, NULL::record
+               Filter: ((utrtest_2.a = 1) OR (utrtest_2.a = 2))
+(10 rows)
+
+-- The new values are concatenated with ' triggered !'
+update utrtest set a = 1 where a = 1 or a = 2 returning *;
+ERROR:  cannot route tuples into foreign table to be updated "remp"
+delete from utrtest;
+insert into utrtest values (2, 'qux');
+-- Check case where the foreign partition isn't a subplan target rel
+explain (verbose, costs off)
+update utrtest set a = 1 where a = 2 returning *;
+                      QUERY PLAN                       
+-------------------------------------------------------
+ Update on public.utrtest
+   Output: utrtest_1.a, utrtest_1.b
+   Update on public.locp utrtest_1
+   ->  Seq Scan on public.locp utrtest_1
+         Output: 1, utrtest_1.tableoid, utrtest_1.ctid
+         Filter: (utrtest_1.a = 2)
+(6 rows)
+
+-- The new values are concatenated with ' triggered !'
+update utrtest set a = 1 where a = 2 returning *;
+ a |        b        
+---+-----------------
+ 1 | qux triggered !
+(1 row)
+
+drop trigger loct_br_insert_trigger on loct;
+-- We can move rows to a foreign partition that has been updated already,
+-- but can't move rows to a foreign partition that hasn't been updated yet
+delete from utrtest;
+insert into utrtest values (1, 'foo');
+insert into utrtest values (2, 'qux');
+-- Test the former case:
+-- with a direct modification plan
+explain (verbose, costs off)
+update utrtest set a = 1 returning *;
+                                QUERY PLAN                                 
+---------------------------------------------------------------------------
+ Update on public.utrtest
+   Output: utrtest_1.a, utrtest_1.b
+   Foreign Update on public.remp utrtest_1
+   Update on public.locp utrtest_2
+   ->  Append
+         ->  Foreign Update on public.remp utrtest_1
+               Remote SQL: UPDATE public.loct SET a = 1 RETURNING a, b
+         ->  Seq Scan on public.locp utrtest_2
+               Output: 1, utrtest_2.tableoid, utrtest_2.ctid, NULL::record
+(9 rows)
+
+update utrtest set a = 1 returning *;
+ERROR:  cannot route tuples into foreign table to be updated "remp"
+delete from utrtest;
+insert into utrtest values (1, 'foo');
+insert into utrtest values (2, 'qux');
+-- with a non-direct modification plan
+explain (verbose, costs off)
+update utrtest set a = 1 from (values (1), (2)) s(x) where a = s.x returning *;
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
+ Update on public.utrtest
+   Output: utrtest_1.a, utrtest_1.b, "*VALUES*".column1
+   Foreign Update on public.remp utrtest_1
+     Remote SQL: UPDATE public.loct SET a = $2 WHERE ctid = $1 RETURNING a, b
+   Update on public.locp utrtest_2
+   ->  Hash Join
+         Output: 1, "*VALUES*".*, "*VALUES*".column1, utrtest.tableoid, utrtest.ctid, utrtest.*
+         Hash Cond: (utrtest.a = "*VALUES*".column1)
+         ->  Append
+               ->  Foreign Scan on public.remp utrtest_1
+                     Output: utrtest_1.a, utrtest_1.tableoid, utrtest_1.ctid, utrtest_1.*
+                     Remote SQL: SELECT a, b, ctid FROM public.loct FOR UPDATE
+               ->  Seq Scan on public.locp utrtest_2
+                     Output: utrtest_2.a, utrtest_2.tableoid, utrtest_2.ctid, NULL::record
+         ->  Hash
+               Output: "*VALUES*".*, "*VALUES*".column1
+               ->  Values Scan on "*VALUES*"
+                     Output: "*VALUES*".*, "*VALUES*".column1
+(18 rows)
+
+update utrtest set a = 1 from (values (1), (2)) s(x) where a = s.x returning *;
+ERROR:  cannot route tuples into foreign table to be updated "remp"
+-- Change the definition of utrtest so that the foreign partition get updated
+-- after the local partition
+delete from utrtest;
+alter table utrtest detach partition remp;
+drop foreign table remp;
+alter table loct drop constraint loct_a_check;
+alter table loct add check (a in (3));
+create foreign table remp (a int check (a in (3)), b text) server loopback options (table_name 'loct');
+alter table utrtest attach partition remp for values in (3);
+insert into utrtest values (2, 'qux');
+insert into utrtest values (3, 'xyzzy');
+-- Test the latter case:
+-- with a direct modification plan
+explain (verbose, costs off)
+update utrtest set a = 3 returning *;
+                                QUERY PLAN                                 
+---------------------------------------------------------------------------
+ Update on public.utrtest
+   Output: utrtest_1.a, utrtest_1.b
+   Update on public.locp utrtest_1
+   Foreign Update on public.remp utrtest_2
+   ->  Append
+         ->  Seq Scan on public.locp utrtest_1
+               Output: 3, utrtest_1.tableoid, utrtest_1.ctid, NULL::record
+         ->  Foreign Update on public.remp utrtest_2
+               Remote SQL: UPDATE public.loct SET a = 3 RETURNING a, b
+(9 rows)
+
+update utrtest set a = 3 returning *; -- ERROR
+ERROR:  cannot route tuples into foreign table to be updated "remp"
+-- with a non-direct modification plan
+explain (verbose, costs off)
+update utrtest set a = 3 from (values (2), (3)) s(x) where a = s.x returning *;
+                                             QUERY PLAN                                              
+-----------------------------------------------------------------------------------------------------
+ Update on public.utrtest
+   Output: utrtest_1.a, utrtest_1.b, "*VALUES*".column1
+   Update on public.locp utrtest_1
+   Foreign Update on public.remp utrtest_2
+     Remote SQL: UPDATE public.loct SET a = $2 WHERE ctid = $1 RETURNING a, b
+   ->  Hash Join
+         Output: 3, "*VALUES*".*, "*VALUES*".column1, utrtest.tableoid, utrtest.ctid, (NULL::record)
+         Hash Cond: (utrtest.a = "*VALUES*".column1)
+         ->  Append
+               ->  Seq Scan on public.locp utrtest_1
+                     Output: utrtest_1.a, utrtest_1.tableoid, utrtest_1.ctid, NULL::record
+               ->  Foreign Scan on public.remp utrtest_2
+                     Output: utrtest_2.a, utrtest_2.tableoid, utrtest_2.ctid, utrtest_2.*
+                     Remote SQL: SELECT a, b, ctid FROM public.loct FOR UPDATE
+         ->  Hash
+               Output: "*VALUES*".*, "*VALUES*".column1
+               ->  Values Scan on "*VALUES*"
+                     Output: "*VALUES*".*, "*VALUES*".column1
+(18 rows)
+
+update utrtest set a = 3 from (values (2), (3)) s(x) where a = s.x returning *; -- ERROR
+ERROR:  cannot route tuples into foreign table to be updated "remp"
+drop table utrtest;
+drop table loct;
+-- Test copy tuple routing
+create table ctrtest (a int, b text) partition by list (a);
+create table loct1 (a int check (a in (1)), b text);
+create foreign table remp1 (a int check (a in (1)), b text) server loopback options (table_name 'loct1');
+create table loct2 (a int check (a in (2)), b text);
+create foreign table remp2 (b text, a int check (a in (2))) server loopback options (table_name 'loct2');
+alter table ctrtest attach partition remp1 for values in (1);
+alter table ctrtest attach partition remp2 for values in (2);
+copy ctrtest from stdin;
+select tableoid::regclass, * FROM ctrtest;
+ tableoid | a |  b  
+----------+---+-----
+ remp1    | 1 | foo
+ remp2    | 2 | qux
+(2 rows)
+
+select tableoid::regclass, * FROM remp1;
+ tableoid | a |  b  
+----------+---+-----
+ remp1    | 1 | foo
+(1 row)
+
+select tableoid::regclass, * FROM remp2;
+ tableoid |  b  | a 
+----------+-----+---
+ remp2    | qux | 2
+(1 row)
+
+-- Copying into foreign partitions directly should work as well
+copy remp1 from stdin;
+select tableoid::regclass, * FROM remp1;
+ tableoid | a |  b  
+----------+---+-----
+ remp1    | 1 | foo
+ remp1    | 1 | bar
+(2 rows)
+
+drop table ctrtest;
+drop table loct1;
+drop table loct2;
+-- ===================================================================
+-- test COPY FROM
+-- ===================================================================
+create table loc2 (f1 int, f2 text);
+alter table loc2 set (autovacuum_enabled = 'false');
+create foreign table rem2 (f1 int, f2 text) server loopback options(table_name 'loc2');
+-- Test basic functionality
+copy rem2 from stdin;
+select * from rem2;
+ f1 | f2  
+----+-----
+  1 | foo
+  2 | bar
+(2 rows)
+
+delete from rem2;
+-- Test check constraints
+alter table loc2 add constraint loc2_f1positive check (f1 >= 0);
+alter foreign table rem2 add constraint rem2_f1positive check (f1 >= 0);
+-- check constraint is enforced on the remote side, not locally
+copy rem2 from stdin;
+copy rem2 from stdin; -- ERROR
+ERROR:  new row for relation "loc2" violates check constraint "loc2_f1positive"
+DETAIL:  Failing row contains (-1, xyzzy).
+CONTEXT:  remote SQL command: INSERT INTO public.loc2(f1, f2) VALUES ($1, $2)
+COPY rem2, line 1: "-1	xyzzy"
+select * from rem2;
+ f1 | f2  
+----+-----
+  1 | foo
+  2 | bar
+(2 rows)
+
+alter foreign table rem2 drop constraint rem2_f1positive;
+alter table loc2 drop constraint loc2_f1positive;
+delete from rem2;
+-- Test local triggers
+create trigger trig_stmt_before before insert on rem2
+	for each statement execute procedure trigger_func();
+create trigger trig_stmt_after after insert on rem2
+	for each statement execute procedure trigger_func();
+create trigger trig_row_before before insert on rem2
+	for each row execute procedure trigger_data(23,'skidoo');
+create trigger trig_row_after after insert on rem2
+	for each row execute procedure trigger_data(23,'skidoo');
+copy rem2 from stdin;
+NOTICE:  trigger_func(<NULL>) called: action = INSERT, when = BEFORE, level = STATEMENT
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW INSERT ON rem2
+NOTICE:  NEW: (1,foo)
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW INSERT ON rem2
+NOTICE:  NEW: (2,bar)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW INSERT ON rem2
+NOTICE:  NEW: (1,foo)
+NOTICE:  trig_row_after(23, skidoo) AFTER ROW INSERT ON rem2
+NOTICE:  NEW: (2,bar)
+NOTICE:  trigger_func(<NULL>) called: action = INSERT, when = AFTER, level = STATEMENT
+select * from rem2;
+ f1 | f2  
+----+-----
+  1 | foo
+  2 | bar
+(2 rows)
+
+drop trigger trig_row_before on rem2;
+drop trigger trig_row_after on rem2;
+drop trigger trig_stmt_before on rem2;
+drop trigger trig_stmt_after on rem2;
+delete from rem2;
+create trigger trig_row_before_insert before insert on rem2
+	for each row execute procedure trig_row_before_insupdate();
+-- The new values are concatenated with ' triggered !'
+copy rem2 from stdin;
+select * from rem2;
+ f1 |       f2        
+----+-----------------
+  1 | foo triggered !
+  2 | bar triggered !
+(2 rows)
+
+drop trigger trig_row_before_insert on rem2;
+delete from rem2;
+create trigger trig_null before insert on rem2
+	for each row execute procedure trig_null();
+-- Nothing happens
+copy rem2 from stdin;
+select * from rem2;
+ f1 | f2 
+----+----
+(0 rows)
+
+drop trigger trig_null on rem2;
+delete from rem2;
+-- Test remote triggers
+create trigger trig_row_before_insert before insert on loc2
+	for each row execute procedure trig_row_before_insupdate();
+-- The new values are concatenated with ' triggered !'
+copy rem2 from stdin;
+select * from rem2;
+ f1 |       f2        
+----+-----------------
+  1 | foo triggered !
+  2 | bar triggered !
+(2 rows)
+
+drop trigger trig_row_before_insert on loc2;
+delete from rem2;
+create trigger trig_null before insert on loc2
+	for each row execute procedure trig_null();
+-- Nothing happens
+copy rem2 from stdin;
+select * from rem2;
+ f1 | f2 
+----+----
+(0 rows)
+
+drop trigger trig_null on loc2;
+delete from rem2;
+-- Test a combination of local and remote triggers
+create trigger rem2_trig_row_before before insert on rem2
+	for each row execute procedure trigger_data(23,'skidoo');
+create trigger rem2_trig_row_after after insert on rem2
+	for each row execute procedure trigger_data(23,'skidoo');
+create trigger loc2_trig_row_before_insert before insert on loc2
+	for each row execute procedure trig_row_before_insupdate();
+copy rem2 from stdin;
+NOTICE:  rem2_trig_row_before(23, skidoo) BEFORE ROW INSERT ON rem2
+NOTICE:  NEW: (1,foo)
+NOTICE:  rem2_trig_row_before(23, skidoo) BEFORE ROW INSERT ON rem2
+NOTICE:  NEW: (2,bar)
+NOTICE:  rem2_trig_row_after(23, skidoo) AFTER ROW INSERT ON rem2
+NOTICE:  NEW: (1,"foo triggered !")
+NOTICE:  rem2_trig_row_after(23, skidoo) AFTER ROW INSERT ON rem2
+NOTICE:  NEW: (2,"bar triggered !")
+select * from rem2;
+ f1 |       f2        
+----+-----------------
+  1 | foo triggered !
+  2 | bar triggered !
+(2 rows)
+
+drop trigger rem2_trig_row_before on rem2;
+drop trigger rem2_trig_row_after on rem2;
+drop trigger loc2_trig_row_before_insert on loc2;
+delete from rem2;
+-- test COPY FROM with foreign table created in the same transaction
+create table loc3 (f1 int, f2 text);
+begin;
+create foreign table rem3 (f1 int, f2 text)
+	server loopback options(table_name 'loc3');
+copy rem3 from stdin;
+commit;
+select * from rem3;
+ f1 | f2  
+----+-----
+  1 | foo
+  2 | bar
+(2 rows)
+
+drop foreign table rem3;
+drop table loc3;
+-- ===================================================================
+-- test for TRUNCATE
+-- ===================================================================
+CREATE TABLE tru_rtable0 (id int primary key);
+CREATE FOREIGN TABLE tru_ftable (id int)
+       SERVER loopback OPTIONS (table_name 'tru_rtable0');
+INSERT INTO tru_rtable0 (SELECT x FROM generate_series(1,10) x);
+CREATE TABLE tru_ptable (id int) PARTITION BY HASH(id);
+CREATE TABLE tru_ptable__p0 PARTITION OF tru_ptable
+                            FOR VALUES WITH (MODULUS 2, REMAINDER 0);
+CREATE TABLE tru_rtable1 (id int primary key);
+CREATE FOREIGN TABLE tru_ftable__p1 PARTITION OF tru_ptable
+                                    FOR VALUES WITH (MODULUS 2, REMAINDER 1)
+       SERVER loopback OPTIONS (table_name 'tru_rtable1');
+INSERT INTO tru_ptable (SELECT x FROM generate_series(11,20) x);
+CREATE TABLE tru_pk_table(id int primary key);
+CREATE TABLE tru_fk_table(fkey int references tru_pk_table(id));
+INSERT INTO tru_pk_table (SELECT x FROM generate_series(1,10) x);
+INSERT INTO tru_fk_table (SELECT x % 10 + 1 FROM generate_series(5,25) x);
+CREATE FOREIGN TABLE tru_pk_ftable (id int)
+       SERVER loopback OPTIONS (table_name 'tru_pk_table');
+CREATE TABLE tru_rtable_parent (id int);
+CREATE TABLE tru_rtable_child (id int);
+CREATE FOREIGN TABLE tru_ftable_parent (id int)
+       SERVER loopback OPTIONS (table_name 'tru_rtable_parent');
+CREATE FOREIGN TABLE tru_ftable_child () INHERITS (tru_ftable_parent)
+       SERVER loopback OPTIONS (table_name 'tru_rtable_child');
+INSERT INTO tru_rtable_parent (SELECT x FROM generate_series(1,8) x);
+INSERT INTO tru_rtable_child  (SELECT x FROM generate_series(10, 18) x);
+-- normal truncate
+SELECT sum(id) FROM tru_ftable;        -- 55
+ sum 
+-----
+  55
+(1 row)
+
+TRUNCATE tru_ftable;
+SELECT count(*) FROM tru_rtable0;		-- 0
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM tru_ftable;		-- 0
+ count 
+-------
+     0
+(1 row)
+
+-- 'truncatable' option
+ALTER SERVER loopback OPTIONS (ADD truncatable 'false');
+TRUNCATE tru_ftable;			-- error
+ERROR:  foreign table "tru_ftable" does not allow truncates
+ALTER FOREIGN TABLE tru_ftable OPTIONS (ADD truncatable 'true');
+TRUNCATE tru_ftable;			-- accepted
+ALTER FOREIGN TABLE tru_ftable OPTIONS (SET truncatable 'false');
+TRUNCATE tru_ftable;			-- error
+ERROR:  foreign table "tru_ftable" does not allow truncates
+ALTER SERVER loopback OPTIONS (DROP truncatable);
+ALTER FOREIGN TABLE tru_ftable OPTIONS (SET truncatable 'false');
+TRUNCATE tru_ftable;			-- error
+ERROR:  foreign table "tru_ftable" does not allow truncates
+ALTER FOREIGN TABLE tru_ftable OPTIONS (SET truncatable 'true');
+TRUNCATE tru_ftable;			-- accepted
+-- partitioned table with both local and foreign tables as partitions
+SELECT sum(id) FROM tru_ptable;        -- 155
+ sum 
+-----
+ 155
+(1 row)
+
+TRUNCATE tru_ptable;
+SELECT count(*) FROM tru_ptable;		-- 0
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM tru_ptable__p0;	-- 0
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM tru_ftable__p1;	-- 0
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM tru_rtable1;		-- 0
+ count 
+-------
+     0
+(1 row)
+
+-- 'CASCADE' option
+SELECT sum(id) FROM tru_pk_ftable;      -- 55
+ sum 
+-----
+  55
+(1 row)
+
+TRUNCATE tru_pk_ftable;	-- failed by FK reference
+ERROR:  cannot truncate a table referenced in a foreign key constraint
+DETAIL:  Table "tru_fk_table" references "tru_pk_table".
+HINT:  Truncate table "tru_fk_table" at the same time, or use TRUNCATE ... CASCADE.
+CONTEXT:  remote SQL command: TRUNCATE public.tru_pk_table CONTINUE IDENTITY RESTRICT
+TRUNCATE tru_pk_ftable CASCADE;
+SELECT count(*) FROM tru_pk_ftable;    -- 0
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM tru_fk_table;		-- also truncated,0
+ count 
+-------
+     0
+(1 row)
+
+-- truncate two tables at a command
+INSERT INTO tru_ftable (SELECT x FROM generate_series(1,8) x);
+INSERT INTO tru_pk_ftable (SELECT x FROM generate_series(3,10) x);
+SELECT count(*) from tru_ftable; -- 8
+ count 
+-------
+     8
+(1 row)
+
+SELECT count(*) from tru_pk_ftable; -- 8
+ count 
+-------
+     8
+(1 row)
+
+TRUNCATE tru_ftable, tru_pk_ftable CASCADE;
+SELECT count(*) from tru_ftable; -- 0
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) from tru_pk_ftable; -- 0
+ count 
+-------
+     0
+(1 row)
+
+-- truncate with ONLY clause
+-- Since ONLY is specified, the table tru_ftable_child that inherits
+-- tru_ftable_parent locally is not truncated.
+TRUNCATE ONLY tru_ftable_parent;
+SELECT sum(id) FROM tru_ftable_parent;  -- 126
+ sum 
+-----
+ 126
+(1 row)
+
+TRUNCATE tru_ftable_parent;
+SELECT count(*) FROM tru_ftable_parent; -- 0
+ count 
+-------
+     0
+(1 row)
+
+-- in case when remote table has inherited children
+CREATE TABLE tru_rtable0_child () INHERITS (tru_rtable0);
+INSERT INTO tru_rtable0 (SELECT x FROM generate_series(5,9) x);
+INSERT INTO tru_rtable0_child (SELECT x FROM generate_series(10,14) x);
+SELECT sum(id) FROM tru_ftable;   -- 95
+ sum 
+-----
+  95
+(1 row)
+
+-- Both parent and child tables in the foreign server are truncated
+-- even though ONLY is specified because ONLY has no effect
+-- when truncating a foreign table.
+TRUNCATE ONLY tru_ftable;
+SELECT count(*) FROM tru_ftable;   -- 0
+ count 
+-------
+     0
+(1 row)
+
+INSERT INTO tru_rtable0 (SELECT x FROM generate_series(21,25) x);
+INSERT INTO tru_rtable0_child (SELECT x FROM generate_series(26,30) x);
+SELECT sum(id) FROM tru_ftable;		-- 255
+ sum 
+-----
+ 255
+(1 row)
+
+TRUNCATE tru_ftable;			-- truncate both of parent and child
+SELECT count(*) FROM tru_ftable;    -- 0
+ count 
+-------
+     0
+(1 row)
+
+-- cleanup
+DROP FOREIGN TABLE tru_ftable_parent, tru_ftable_child, tru_pk_ftable,tru_ftable__p1,tru_ftable;
+DROP TABLE tru_rtable0, tru_rtable1, tru_ptable, tru_ptable__p0, tru_pk_table, tru_fk_table,
+tru_rtable_parent,tru_rtable_child, tru_rtable0_child;
+-- ===================================================================
+-- test IMPORT FOREIGN SCHEMA
+-- ===================================================================
+CREATE SCHEMA import_source;
+CREATE TABLE import_source.t1 (c1 int, c2 varchar NOT NULL);
+CREATE TABLE import_source.t2 (c1 int default 42, c2 varchar NULL, c3 text collate "POSIX");
+CREATE TYPE typ1 AS (m1 int, m2 varchar);
+CREATE TABLE import_source.t3 (c1 timestamptz default now(), c2 typ1);
+CREATE TABLE import_source."x 4" (c1 float8, "C 2" text, c3 varchar(42));
+CREATE TABLE import_source."x 5" (c1 float8);
+ALTER TABLE import_source."x 5" DROP COLUMN c1;
+CREATE TABLE import_source."x 6" (c1 int, c2 int generated always as (c1 * 2) stored);
+CREATE TABLE import_source.t4 (c1 int) PARTITION BY RANGE (c1);
+CREATE TABLE import_source.t4_part PARTITION OF import_source.t4
+  FOR VALUES FROM (1) TO (100);
+CREATE TABLE import_source.t4_part2 PARTITION OF import_source.t4
+  FOR VALUES FROM (100) TO (200);
+CREATE SCHEMA import_dest1;
+IMPORT FOREIGN SCHEMA import_source FROM SERVER loopback INTO import_dest1;
+\det+ import_dest1.*
+                                     List of foreign tables
+    Schema    | Table |  Server  |                   FDW options                   | Description 
+--------------+-------+----------+-------------------------------------------------+-------------
+ import_dest1 | t1    | loopback | (schema_name 'import_source', table_name 't1')  | 
+ import_dest1 | t2    | loopback | (schema_name 'import_source', table_name 't2')  | 
+ import_dest1 | t3    | loopback | (schema_name 'import_source', table_name 't3')  | 
+ import_dest1 | t4    | loopback | (schema_name 'import_source', table_name 't4')  | 
+ import_dest1 | x 4   | loopback | (schema_name 'import_source', table_name 'x 4') | 
+ import_dest1 | x 5   | loopback | (schema_name 'import_source', table_name 'x 5') | 
+ import_dest1 | x 6   | loopback | (schema_name 'import_source', table_name 'x 6') | 
+(7 rows)
+
+\d import_dest1.*
+                         Foreign table "import_dest1.t1"
+ Column |       Type        | Collation | Nullable | Default |    FDW options     
+--------+-------------------+-----------+----------+---------+--------------------
+ c1     | integer           |           |          |         | (column_name 'c1')
+ c2     | character varying |           | not null |         | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't1')
+
+                         Foreign table "import_dest1.t2"
+ Column |       Type        | Collation | Nullable | Default |    FDW options     
+--------+-------------------+-----------+----------+---------+--------------------
+ c1     | integer           |           |          |         | (column_name 'c1')
+ c2     | character varying |           |          |         | (column_name 'c2')
+ c3     | text              | POSIX     |          |         | (column_name 'c3')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't2')
+
+                             Foreign table "import_dest1.t3"
+ Column |           Type           | Collation | Nullable | Default |    FDW options     
+--------+--------------------------+-----------+----------+---------+--------------------
+ c1     | timestamp with time zone |           |          |         | (column_name 'c1')
+ c2     | typ1                     |           |          |         | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't3')
+
+                    Foreign table "import_dest1.t4"
+ Column |  Type   | Collation | Nullable | Default |    FDW options     
+--------+---------+-----------+----------+---------+--------------------
+ c1     | integer |           |          |         | (column_name 'c1')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't4')
+
+                           Foreign table "import_dest1.x 4"
+ Column |         Type          | Collation | Nullable | Default |     FDW options     
+--------+-----------------------+-----------+----------+---------+---------------------
+ c1     | double precision      |           |          |         | (column_name 'c1')
+ C 2    | text                  |           |          |         | (column_name 'C 2')
+ c3     | character varying(42) |           |          |         | (column_name 'c3')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 4')
+
+               Foreign table "import_dest1.x 5"
+ Column | Type | Collation | Nullable | Default | FDW options 
+--------+------+-----------+----------+---------+-------------
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 5')
+
+                                  Foreign table "import_dest1.x 6"
+ Column |  Type   | Collation | Nullable |               Default               |    FDW options     
+--------+---------+-----------+----------+-------------------------------------+--------------------
+ c1     | integer |           |          |                                     | (column_name 'c1')
+ c2     | integer |           |          | generated always as (c1 * 2) stored | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 6')
+
+-- Options
+CREATE SCHEMA import_dest2;
+IMPORT FOREIGN SCHEMA import_source FROM SERVER loopback INTO import_dest2
+  OPTIONS (import_default 'true');
+\det+ import_dest2.*
+                                     List of foreign tables
+    Schema    | Table |  Server  |                   FDW options                   | Description 
+--------------+-------+----------+-------------------------------------------------+-------------
+ import_dest2 | t1    | loopback | (schema_name 'import_source', table_name 't1')  | 
+ import_dest2 | t2    | loopback | (schema_name 'import_source', table_name 't2')  | 
+ import_dest2 | t3    | loopback | (schema_name 'import_source', table_name 't3')  | 
+ import_dest2 | t4    | loopback | (schema_name 'import_source', table_name 't4')  | 
+ import_dest2 | x 4   | loopback | (schema_name 'import_source', table_name 'x 4') | 
+ import_dest2 | x 5   | loopback | (schema_name 'import_source', table_name 'x 5') | 
+ import_dest2 | x 6   | loopback | (schema_name 'import_source', table_name 'x 6') | 
+(7 rows)
+
+\d import_dest2.*
+                         Foreign table "import_dest2.t1"
+ Column |       Type        | Collation | Nullable | Default |    FDW options     
+--------+-------------------+-----------+----------+---------+--------------------
+ c1     | integer           |           |          |         | (column_name 'c1')
+ c2     | character varying |           | not null |         | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't1')
+
+                         Foreign table "import_dest2.t2"
+ Column |       Type        | Collation | Nullable | Default |    FDW options     
+--------+-------------------+-----------+----------+---------+--------------------
+ c1     | integer           |           |          | 42      | (column_name 'c1')
+ c2     | character varying |           |          |         | (column_name 'c2')
+ c3     | text              | POSIX     |          |         | (column_name 'c3')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't2')
+
+                             Foreign table "import_dest2.t3"
+ Column |           Type           | Collation | Nullable | Default |    FDW options     
+--------+--------------------------+-----------+----------+---------+--------------------
+ c1     | timestamp with time zone |           |          | now()   | (column_name 'c1')
+ c2     | typ1                     |           |          |         | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't3')
+
+                    Foreign table "import_dest2.t4"
+ Column |  Type   | Collation | Nullable | Default |    FDW options     
+--------+---------+-----------+----------+---------+--------------------
+ c1     | integer |           |          |         | (column_name 'c1')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't4')
+
+                           Foreign table "import_dest2.x 4"
+ Column |         Type          | Collation | Nullable | Default |     FDW options     
+--------+-----------------------+-----------+----------+---------+---------------------
+ c1     | double precision      |           |          |         | (column_name 'c1')
+ C 2    | text                  |           |          |         | (column_name 'C 2')
+ c3     | character varying(42) |           |          |         | (column_name 'c3')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 4')
+
+               Foreign table "import_dest2.x 5"
+ Column | Type | Collation | Nullable | Default | FDW options 
+--------+------+-----------+----------+---------+-------------
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 5')
+
+                                  Foreign table "import_dest2.x 6"
+ Column |  Type   | Collation | Nullable |               Default               |    FDW options     
+--------+---------+-----------+----------+-------------------------------------+--------------------
+ c1     | integer |           |          |                                     | (column_name 'c1')
+ c2     | integer |           |          | generated always as (c1 * 2) stored | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 6')
+
+CREATE SCHEMA import_dest3;
+IMPORT FOREIGN SCHEMA import_source FROM SERVER loopback INTO import_dest3
+  OPTIONS (import_collate 'false', import_generated 'false', import_not_null 'false');
+\det+ import_dest3.*
+                                     List of foreign tables
+    Schema    | Table |  Server  |                   FDW options                   | Description 
+--------------+-------+----------+-------------------------------------------------+-------------
+ import_dest3 | t1    | loopback | (schema_name 'import_source', table_name 't1')  | 
+ import_dest3 | t2    | loopback | (schema_name 'import_source', table_name 't2')  | 
+ import_dest3 | t3    | loopback | (schema_name 'import_source', table_name 't3')  | 
+ import_dest3 | t4    | loopback | (schema_name 'import_source', table_name 't4')  | 
+ import_dest3 | x 4   | loopback | (schema_name 'import_source', table_name 'x 4') | 
+ import_dest3 | x 5   | loopback | (schema_name 'import_source', table_name 'x 5') | 
+ import_dest3 | x 6   | loopback | (schema_name 'import_source', table_name 'x 6') | 
+(7 rows)
+
+\d import_dest3.*
+                         Foreign table "import_dest3.t1"
+ Column |       Type        | Collation | Nullable | Default |    FDW options     
+--------+-------------------+-----------+----------+---------+--------------------
+ c1     | integer           |           |          |         | (column_name 'c1')
+ c2     | character varying |           |          |         | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't1')
+
+                         Foreign table "import_dest3.t2"
+ Column |       Type        | Collation | Nullable | Default |    FDW options     
+--------+-------------------+-----------+----------+---------+--------------------
+ c1     | integer           |           |          |         | (column_name 'c1')
+ c2     | character varying |           |          |         | (column_name 'c2')
+ c3     | text              |           |          |         | (column_name 'c3')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't2')
+
+                             Foreign table "import_dest3.t3"
+ Column |           Type           | Collation | Nullable | Default |    FDW options     
+--------+--------------------------+-----------+----------+---------+--------------------
+ c1     | timestamp with time zone |           |          |         | (column_name 'c1')
+ c2     | typ1                     |           |          |         | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't3')
+
+                    Foreign table "import_dest3.t4"
+ Column |  Type   | Collation | Nullable | Default |    FDW options     
+--------+---------+-----------+----------+---------+--------------------
+ c1     | integer |           |          |         | (column_name 'c1')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 't4')
+
+                           Foreign table "import_dest3.x 4"
+ Column |         Type          | Collation | Nullable | Default |     FDW options     
+--------+-----------------------+-----------+----------+---------+---------------------
+ c1     | double precision      |           |          |         | (column_name 'c1')
+ C 2    | text                  |           |          |         | (column_name 'C 2')
+ c3     | character varying(42) |           |          |         | (column_name 'c3')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 4')
+
+               Foreign table "import_dest3.x 5"
+ Column | Type | Collation | Nullable | Default | FDW options 
+--------+------+-----------+----------+---------+-------------
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 5')
+
+                    Foreign table "import_dest3.x 6"
+ Column |  Type   | Collation | Nullable | Default |    FDW options     
+--------+---------+-----------+----------+---------+--------------------
+ c1     | integer |           |          |         | (column_name 'c1')
+ c2     | integer |           |          |         | (column_name 'c2')
+Server: loopback
+FDW options: (schema_name 'import_source', table_name 'x 6')
+
+-- Check LIMIT TO and EXCEPT
+CREATE SCHEMA import_dest4;
+IMPORT FOREIGN SCHEMA import_source LIMIT TO (t1, nonesuch, t4_part)
+  FROM SERVER loopback INTO import_dest4;
+\det+ import_dest4.*
+                                        List of foreign tables
+    Schema    |  Table  |  Server  |                     FDW options                     | Description 
+--------------+---------+----------+-----------------------------------------------------+-------------
+ import_dest4 | t1      | loopback | (schema_name 'import_source', table_name 't1')      | 
+ import_dest4 | t4_part | loopback | (schema_name 'import_source', table_name 't4_part') | 
+(2 rows)
+
+IMPORT FOREIGN SCHEMA import_source EXCEPT (t1, "x 4", nonesuch, t4_part)
+  FROM SERVER loopback INTO import_dest4;
+\det+ import_dest4.*
+                                        List of foreign tables
+    Schema    |  Table  |  Server  |                     FDW options                     | Description 
+--------------+---------+----------+-----------------------------------------------------+-------------
+ import_dest4 | t1      | loopback | (schema_name 'import_source', table_name 't1')      | 
+ import_dest4 | t2      | loopback | (schema_name 'import_source', table_name 't2')      | 
+ import_dest4 | t3      | loopback | (schema_name 'import_source', table_name 't3')      | 
+ import_dest4 | t4      | loopback | (schema_name 'import_source', table_name 't4')      | 
+ import_dest4 | t4_part | loopback | (schema_name 'import_source', table_name 't4_part') | 
+ import_dest4 | x 5     | loopback | (schema_name 'import_source', table_name 'x 5')     | 
+ import_dest4 | x 6     | loopback | (schema_name 'import_source', table_name 'x 6')     | 
+(7 rows)
+
+-- Assorted error cases
+IMPORT FOREIGN SCHEMA import_source FROM SERVER loopback INTO import_dest4;
+ERROR:  relation "t1" already exists
+CONTEXT:  importing foreign table "t1"
+IMPORT FOREIGN SCHEMA nonesuch FROM SERVER loopback INTO import_dest4;
+ERROR:  schema "nonesuch" is not present on foreign server "loopback"
+IMPORT FOREIGN SCHEMA nonesuch FROM SERVER loopback INTO notthere;
+ERROR:  schema "notthere" does not exist
+IMPORT FOREIGN SCHEMA nonesuch FROM SERVER nowhere INTO notthere;
+ERROR:  server "nowhere" does not exist
+-- Check case of a type present only on the remote server.
+-- We can fake this by dropping the type locally in our transaction.
+CREATE TYPE "Colors" AS ENUM ('red', 'green', 'blue');
+CREATE TABLE import_source.t5 (c1 int, c2 text collate "C", "Col" "Colors");
+CREATE SCHEMA import_dest5;
+BEGIN;
+DROP TYPE "Colors" CASCADE;
+NOTICE:  drop cascades to column Col of table import_source.t5
+IMPORT FOREIGN SCHEMA import_source LIMIT TO (t5)
+  FROM SERVER loopback INTO import_dest5;  -- ERROR
+ERROR:  type "public.Colors" does not exist
+LINE 4:   "Col" public."Colors" OPTIONS (column_name 'Col')
+                ^
+QUERY:  CREATE FOREIGN TABLE t5 (
+  c1 integer OPTIONS (column_name 'c1'),
+  c2 text OPTIONS (column_name 'c2') COLLATE pg_catalog."C",
+  "Col" public."Colors" OPTIONS (column_name 'Col')
+) SERVER loopback
+OPTIONS (schema_name 'import_source', table_name 't5');
+CONTEXT:  importing foreign table "t5"
+ROLLBACK;
+BEGIN;
+CREATE SERVER fetch101 FOREIGN DATA WRAPPER postgres_fdw OPTIONS( fetch_size '101' );
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=101'];
+ count 
+-------
+     1
+(1 row)
+
+ALTER SERVER fetch101 OPTIONS( SET fetch_size '202' );
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=101'];
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=202'];
+ count 
+-------
+     1
+(1 row)
+
+CREATE FOREIGN TABLE table30000 ( x int ) SERVER fetch101 OPTIONS ( fetch_size '30000' );
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=30000'];
+ count 
+-------
+     1
+(1 row)
+
+ALTER FOREIGN TABLE table30000 OPTIONS ( SET fetch_size '60000');
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=30000'];
+ count 
+-------
+     0
+(1 row)
+
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=60000'];
+ count 
+-------
+     1
+(1 row)
+
+ROLLBACK;
+-- ===================================================================
+-- test partitionwise joins
+-- ===================================================================
+SET enable_partitionwise_join=on;
+CREATE TABLE fprt1 (a int, b int, c varchar) PARTITION BY RANGE(a);
+CREATE TABLE fprt1_p1 (LIKE fprt1);
+CREATE TABLE fprt1_p2 (LIKE fprt1);
+ALTER TABLE fprt1_p1 SET (autovacuum_enabled = 'false');
+ALTER TABLE fprt1_p2 SET (autovacuum_enabled = 'false');
+INSERT INTO fprt1_p1 SELECT i, i, to_char(i/50, 'FM0000') FROM generate_series(0, 249, 2) i;
+INSERT INTO fprt1_p2 SELECT i, i, to_char(i/50, 'FM0000') FROM generate_series(250, 499, 2) i;
+CREATE FOREIGN TABLE ftprt1_p1 PARTITION OF fprt1 FOR VALUES FROM (0) TO (250)
+	SERVER loopback OPTIONS (table_name 'fprt1_p1', use_remote_estimate 'true');
+CREATE FOREIGN TABLE ftprt1_p2 PARTITION OF fprt1 FOR VALUES FROM (250) TO (500)
+	SERVER loopback OPTIONS (TABLE_NAME 'fprt1_p2');
+ANALYZE fprt1;
+ANALYZE fprt1_p1;
+ANALYZE fprt1_p2;
+CREATE TABLE fprt2 (a int, b int, c varchar) PARTITION BY RANGE(b);
+CREATE TABLE fprt2_p1 (LIKE fprt2);
+CREATE TABLE fprt2_p2 (LIKE fprt2);
+ALTER TABLE fprt2_p1 SET (autovacuum_enabled = 'false');
+ALTER TABLE fprt2_p2 SET (autovacuum_enabled = 'false');
+INSERT INTO fprt2_p1 SELECT i, i, to_char(i/50, 'FM0000') FROM generate_series(0, 249, 3) i;
+INSERT INTO fprt2_p2 SELECT i, i, to_char(i/50, 'FM0000') FROM generate_series(250, 499, 3) i;
+CREATE FOREIGN TABLE ftprt2_p1 (b int, c varchar, a int)
+	SERVER loopback OPTIONS (table_name 'fprt2_p1', use_remote_estimate 'true');
+ALTER TABLE fprt2 ATTACH PARTITION ftprt2_p1 FOR VALUES FROM (0) TO (250);
+CREATE FOREIGN TABLE ftprt2_p2 PARTITION OF fprt2 FOR VALUES FROM (250) TO (500)
+	SERVER loopback OPTIONS (table_name 'fprt2_p2', use_remote_estimate 'true');
+ANALYZE fprt2;
+ANALYZE fprt2_p1;
+ANALYZE fprt2_p2;
+-- inner join three tables
+EXPLAIN (COSTS OFF)
+SELECT t1.a,t2.b,t3.c FROM fprt1 t1 INNER JOIN fprt2 t2 ON (t1.a = t2.b) INNER JOIN fprt1 t3 ON (t2.b = t3.a) WHERE t1.a % 25 =0 ORDER BY 1,2,3;
+                                             QUERY PLAN                                              
+-----------------------------------------------------------------------------------------------------
+ Sort
+   Sort Key: t1.a, t3.c
+   ->  Append
+         ->  Foreign Scan
+               Relations: ((ftprt1_p1 t1_1) INNER JOIN (ftprt2_p1 t2_1)) INNER JOIN (ftprt1_p1 t3_1)
+         ->  Foreign Scan
+               Relations: ((ftprt1_p2 t1_2) INNER JOIN (ftprt2_p2 t2_2)) INNER JOIN (ftprt1_p2 t3_2)
+(7 rows)
+
+SELECT t1.a,t2.b,t3.c FROM fprt1 t1 INNER JOIN fprt2 t2 ON (t1.a = t2.b) INNER JOIN fprt1 t3 ON (t2.b = t3.a) WHERE t1.a % 25 =0 ORDER BY 1,2,3;
+  a  |  b  |  c   
+-----+-----+------
+   0 |   0 | 0000
+ 150 | 150 | 0003
+ 250 | 250 | 0005
+ 400 | 400 | 0008
+(4 rows)
+
+-- left outer join + nullable clause
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT t1.a,t2.b,t2.c FROM fprt1 t1 LEFT JOIN (SELECT * FROM fprt2 WHERE a < 10) t2 ON (t1.a = t2.b and t1.b = t2.a) WHERE t1.a < 10 ORDER BY 1,2,3;
+                                                                                                                     QUERY PLAN                                                                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: t1.a, fprt2.b, fprt2.c
+   Relations: (public.ftprt1_p1 t1) LEFT JOIN (public.ftprt2_p1 fprt2)
+   Remote SQL: SELECT r5.a, r6.b, r6.c FROM (public.fprt1_p1 r5 LEFT JOIN public.fprt2_p1 r6 ON (((r5.a = r6.b)) AND ((r5.b = r6.a)) AND ((r6.a < 10)))) WHERE ((r5.a < 10)) ORDER BY r5.a ASC NULLS LAST, r6.b ASC NULLS LAST, r6.c ASC NULLS LAST
+(4 rows)
+
+SELECT t1.a,t2.b,t2.c FROM fprt1 t1 LEFT JOIN (SELECT * FROM fprt2 WHERE a < 10) t2 ON (t1.a = t2.b and t1.b = t2.a) WHERE t1.a < 10 ORDER BY 1,2,3;
+ a | b |  c   
+---+---+------
+ 0 | 0 | 0000
+ 2 |   | 
+ 4 |   | 
+ 6 | 6 | 0000
+ 8 |   | 
+(5 rows)
+
+-- with whole-row reference; partitionwise join does not apply
+EXPLAIN (COSTS OFF)
+SELECT t1.wr, t2.wr FROM (SELECT t1 wr, a FROM fprt1 t1 WHERE t1.a % 25 = 0) t1 FULL JOIN (SELECT t2 wr, b FROM fprt2 t2 WHERE t2.b % 25 = 0) t2 ON (t1.a = t2.b) ORDER BY 1,2;
+                       QUERY PLAN                       
+--------------------------------------------------------
+ Sort
+   Sort Key: ((t1.*)::fprt1), ((t2.*)::fprt2)
+   ->  Hash Full Join
+         Hash Cond: (t1.a = t2.b)
+         ->  Append
+               ->  Foreign Scan on ftprt1_p1 t1_1
+               ->  Foreign Scan on ftprt1_p2 t1_2
+         ->  Hash
+               ->  Append
+                     ->  Foreign Scan on ftprt2_p1 t2_1
+                     ->  Foreign Scan on ftprt2_p2 t2_2
+(11 rows)
+
+SELECT t1.wr, t2.wr FROM (SELECT t1 wr, a FROM fprt1 t1 WHERE t1.a % 25 = 0) t1 FULL JOIN (SELECT t2 wr, b FROM fprt2 t2 WHERE t2.b % 25 = 0) t2 ON (t1.a = t2.b) ORDER BY 1,2;
+       wr       |       wr       
+----------------+----------------
+ (0,0,0000)     | (0,0,0000)
+ (50,50,0001)   | 
+ (100,100,0002) | 
+ (150,150,0003) | (150,150,0003)
+ (200,200,0004) | 
+ (250,250,0005) | (250,250,0005)
+ (300,300,0006) | 
+ (350,350,0007) | 
+ (400,400,0008) | (400,400,0008)
+ (450,450,0009) | 
+                | (75,75,0001)
+                | (225,225,0004)
+                | (325,325,0006)
+                | (475,475,0009)
+(14 rows)
+
+-- join with lateral reference
+EXPLAIN (COSTS OFF)
+SELECT t1.a,t1.b FROM fprt1 t1, LATERAL (SELECT t2.a, t2.b FROM fprt2 t2 WHERE t1.a = t2.b AND t1.b = t2.a) q WHERE t1.a%25 = 0 ORDER BY 1,2;
+                              QUERY PLAN                               
+-----------------------------------------------------------------------
+ Sort
+   Sort Key: t1.a, t1.b
+   ->  Append
+         ->  Foreign Scan
+               Relations: (ftprt1_p1 t1_1) INNER JOIN (ftprt2_p1 t2_1)
+         ->  Foreign Scan
+               Relations: (ftprt1_p2 t1_2) INNER JOIN (ftprt2_p2 t2_2)
+(7 rows)
+
+SELECT t1.a,t1.b FROM fprt1 t1, LATERAL (SELECT t2.a, t2.b FROM fprt2 t2 WHERE t1.a = t2.b AND t1.b = t2.a) q WHERE t1.a%25 = 0 ORDER BY 1,2;
+  a  |  b  
+-----+-----
+   0 |   0
+ 150 | 150
+ 250 | 250
+ 400 | 400
+(4 rows)
+
+-- with PHVs, partitionwise join selected but no join pushdown
+EXPLAIN (COSTS OFF)
+SELECT t1.a, t1.phv, t2.b, t2.phv FROM (SELECT 't1_phv' phv, * FROM fprt1 WHERE a % 25 = 0) t1 FULL JOIN (SELECT 't2_phv' phv, * FROM fprt2 WHERE b % 25 = 0) t2 ON (t1.a = t2.b) ORDER BY t1.a, t2.b;
+                        QUERY PLAN                         
+-----------------------------------------------------------
+ Sort
+   Sort Key: fprt1.a, fprt2.b
+   ->  Append
+         ->  Hash Full Join
+               Hash Cond: (fprt1_1.a = fprt2_1.b)
+               ->  Foreign Scan on ftprt1_p1 fprt1_1
+               ->  Hash
+                     ->  Foreign Scan on ftprt2_p1 fprt2_1
+         ->  Hash Full Join
+               Hash Cond: (fprt1_2.a = fprt2_2.b)
+               ->  Foreign Scan on ftprt1_p2 fprt1_2
+               ->  Hash
+                     ->  Foreign Scan on ftprt2_p2 fprt2_2
+(13 rows)
+
+SELECT t1.a, t1.phv, t2.b, t2.phv FROM (SELECT 't1_phv' phv, * FROM fprt1 WHERE a % 25 = 0) t1 FULL JOIN (SELECT 't2_phv' phv, * FROM fprt2 WHERE b % 25 = 0) t2 ON (t1.a = t2.b) ORDER BY t1.a, t2.b;
+  a  |  phv   |  b  |  phv   
+-----+--------+-----+--------
+   0 | t1_phv |   0 | t2_phv
+  50 | t1_phv |     | 
+ 100 | t1_phv |     | 
+ 150 | t1_phv | 150 | t2_phv
+ 200 | t1_phv |     | 
+ 250 | t1_phv | 250 | t2_phv
+ 300 | t1_phv |     | 
+ 350 | t1_phv |     | 
+ 400 | t1_phv | 400 | t2_phv
+ 450 | t1_phv |     | 
+     |        |  75 | t2_phv
+     |        | 225 | t2_phv
+     |        | 325 | t2_phv
+     |        | 475 | t2_phv
+(14 rows)
+
+-- test FOR UPDATE; partitionwise join does not apply
+EXPLAIN (COSTS OFF)
+SELECT t1.a, t2.b FROM fprt1 t1 INNER JOIN fprt2 t2 ON (t1.a = t2.b) WHERE t1.a % 25 = 0 ORDER BY 1,2 FOR UPDATE OF t1;
+                          QUERY PLAN                          
+--------------------------------------------------------------
+ LockRows
+   ->  Sort
+         Sort Key: t1.a
+         ->  Hash Join
+               Hash Cond: (t2.b = t1.a)
+               ->  Append
+                     ->  Foreign Scan on ftprt2_p1 t2_1
+                     ->  Foreign Scan on ftprt2_p2 t2_2
+               ->  Hash
+                     ->  Append
+                           ->  Foreign Scan on ftprt1_p1 t1_1
+                           ->  Foreign Scan on ftprt1_p2 t1_2
+(12 rows)
+
+SELECT t1.a, t2.b FROM fprt1 t1 INNER JOIN fprt2 t2 ON (t1.a = t2.b) WHERE t1.a % 25 = 0 ORDER BY 1,2 FOR UPDATE OF t1;
+  a  |  b  
+-----+-----
+   0 |   0
+ 150 | 150
+ 250 | 250
+ 400 | 400
+(4 rows)
+
+RESET enable_partitionwise_join;
+-- ===================================================================
+-- test partitionwise aggregates
+-- ===================================================================
+CREATE TABLE pagg_tab (a int, b int, c text) PARTITION BY RANGE(a);
+CREATE TABLE pagg_tab_p1 (LIKE pagg_tab);
+CREATE TABLE pagg_tab_p2 (LIKE pagg_tab);
+CREATE TABLE pagg_tab_p3 (LIKE pagg_tab);
+INSERT INTO pagg_tab_p1 SELECT i % 30, i % 50, to_char(i/30, 'FM0000') FROM generate_series(1, 3000) i WHERE (i % 30) < 10;
+INSERT INTO pagg_tab_p2 SELECT i % 30, i % 50, to_char(i/30, 'FM0000') FROM generate_series(1, 3000) i WHERE (i % 30) < 20 and (i % 30) >= 10;
+INSERT INTO pagg_tab_p3 SELECT i % 30, i % 50, to_char(i/30, 'FM0000') FROM generate_series(1, 3000) i WHERE (i % 30) < 30 and (i % 30) >= 20;
+-- Create foreign partitions
+CREATE FOREIGN TABLE fpagg_tab_p1 PARTITION OF pagg_tab FOR VALUES FROM (0) TO (10) SERVER loopback OPTIONS (table_name 'pagg_tab_p1');
+CREATE FOREIGN TABLE fpagg_tab_p2 PARTITION OF pagg_tab FOR VALUES FROM (10) TO (20) SERVER loopback OPTIONS (table_name 'pagg_tab_p2');
+CREATE FOREIGN TABLE fpagg_tab_p3 PARTITION OF pagg_tab FOR VALUES FROM (20) TO (30) SERVER loopback OPTIONS (table_name 'pagg_tab_p3');
+ANALYZE pagg_tab;
+ANALYZE fpagg_tab_p1;
+ANALYZE fpagg_tab_p2;
+ANALYZE fpagg_tab_p3;
+-- When GROUP BY clause matches with PARTITION KEY.
+-- Plan with partitionwise aggregates is disabled
+SET enable_partitionwise_aggregate TO false;
+EXPLAIN (COSTS OFF)
+SELECT a, sum(b), min(b), count(*) FROM pagg_tab GROUP BY a HAVING avg(b) < 22 ORDER BY 1;
+                        QUERY PLAN                         
+-----------------------------------------------------------
+ Sort
+   Sort Key: pagg_tab.a
+   ->  HashAggregate
+         Group Key: pagg_tab.a
+         Filter: (avg(pagg_tab.b) < '22'::numeric)
+         ->  Append
+               ->  Foreign Scan on fpagg_tab_p1 pagg_tab_1
+               ->  Foreign Scan on fpagg_tab_p2 pagg_tab_2
+               ->  Foreign Scan on fpagg_tab_p3 pagg_tab_3
+(9 rows)
+
+-- Plan with partitionwise aggregates is enabled
+SET enable_partitionwise_aggregate TO true;
+EXPLAIN (COSTS OFF)
+SELECT a, sum(b), min(b), count(*) FROM pagg_tab GROUP BY a HAVING avg(b) < 22 ORDER BY 1;
+                           QUERY PLAN                            
+-----------------------------------------------------------------
+ Sort
+   Sort Key: pagg_tab.a
+   ->  Append
+         ->  Foreign Scan
+               Relations: Aggregate on (fpagg_tab_p1 pagg_tab)
+         ->  Foreign Scan
+               Relations: Aggregate on (fpagg_tab_p2 pagg_tab_1)
+         ->  Foreign Scan
+               Relations: Aggregate on (fpagg_tab_p3 pagg_tab_2)
+(9 rows)
+
+SELECT a, sum(b), min(b), count(*) FROM pagg_tab GROUP BY a HAVING avg(b) < 22 ORDER BY 1;
+ a  | sum  | min | count 
+----+------+-----+-------
+  0 | 2000 |   0 |   100
+  1 | 2100 |   1 |   100
+ 10 | 2000 |   0 |   100
+ 11 | 2100 |   1 |   100
+ 20 | 2000 |   0 |   100
+ 21 | 2100 |   1 |   100
+(6 rows)
+
+-- Check with whole-row reference
+-- Should have all the columns in the target list for the given relation
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT a, count(t1) FROM pagg_tab t1 GROUP BY a HAVING avg(b) < 22 ORDER BY 1;
+                               QUERY PLAN                               
+------------------------------------------------------------------------
+ Sort
+   Output: t1.a, (count(((t1.*)::pagg_tab)))
+   Sort Key: t1.a
+   ->  Append
+         ->  HashAggregate
+               Output: t1.a, count(((t1.*)::pagg_tab))
+               Group Key: t1.a
+               Filter: (avg(t1.b) < '22'::numeric)
+               ->  Foreign Scan on public.fpagg_tab_p1 t1
+                     Output: t1.a, t1.*, t1.b
+                     Remote SQL: SELECT a, b, c FROM public.pagg_tab_p1
+         ->  HashAggregate
+               Output: t1_1.a, count(((t1_1.*)::pagg_tab))
+               Group Key: t1_1.a
+               Filter: (avg(t1_1.b) < '22'::numeric)
+               ->  Foreign Scan on public.fpagg_tab_p2 t1_1
+                     Output: t1_1.a, t1_1.*, t1_1.b
+                     Remote SQL: SELECT a, b, c FROM public.pagg_tab_p2
+         ->  HashAggregate
+               Output: t1_2.a, count(((t1_2.*)::pagg_tab))
+               Group Key: t1_2.a
+               Filter: (avg(t1_2.b) < '22'::numeric)
+               ->  Foreign Scan on public.fpagg_tab_p3 t1_2
+                     Output: t1_2.a, t1_2.*, t1_2.b
+                     Remote SQL: SELECT a, b, c FROM public.pagg_tab_p3
+(25 rows)
+
+SELECT a, count(t1) FROM pagg_tab t1 GROUP BY a HAVING avg(b) < 22 ORDER BY 1;
+ a  | count 
+----+-------
+  0 |   100
+  1 |   100
+ 10 |   100
+ 11 |   100
+ 20 |   100
+ 21 |   100
+(6 rows)
+
+-- When GROUP BY clause does not match with PARTITION KEY.
+EXPLAIN (COSTS OFF)
+SELECT b, avg(a), max(a), count(*) FROM pagg_tab GROUP BY b HAVING sum(a) < 700 ORDER BY 1;
+                           QUERY PLAN                            
+-----------------------------------------------------------------
+ Sort
+   Sort Key: pagg_tab.b
+   ->  Finalize HashAggregate
+         Group Key: pagg_tab.b
+         Filter: (sum(pagg_tab.a) < 700)
+         ->  Append
+               ->  Partial HashAggregate
+                     Group Key: pagg_tab.b
+                     ->  Foreign Scan on fpagg_tab_p1 pagg_tab
+               ->  Partial HashAggregate
+                     Group Key: pagg_tab_1.b
+                     ->  Foreign Scan on fpagg_tab_p2 pagg_tab_1
+               ->  Partial HashAggregate
+                     Group Key: pagg_tab_2.b
+                     ->  Foreign Scan on fpagg_tab_p3 pagg_tab_2
+(15 rows)
+
+-- ===================================================================
+-- access rights and superuser
+-- ===================================================================
+-- Non-superuser cannot create a FDW without a password in the connstr
+CREATE ROLE regress_nosuper NOSUPERUSER;
+GRANT USAGE ON FOREIGN DATA WRAPPER postgres_fdw TO regress_nosuper;
+SET ROLE regress_nosuper;
+SHOW is_superuser;
+ is_superuser 
+--------------
+ off
+(1 row)
+
+-- This will be OK, we can create the FDW
+DO $d$
+    BEGIN
+        EXECUTE $$CREATE SERVER loopback_nopw FOREIGN DATA WRAPPER postgres_fdw
+            OPTIONS (dbname '$$||current_database()||$$',
+                     port '$$||current_setting('port')||$$'
+            )$$;
+    END;
+$d$;
+-- But creation of user mappings for non-superusers should fail
+CREATE USER MAPPING FOR public SERVER loopback_nopw;
+CREATE USER MAPPING FOR CURRENT_USER SERVER loopback_nopw;
+CREATE FOREIGN TABLE pg_temp.ft1_nopw (
+	c1 int NOT NULL,
+	c2 int NOT NULL,
+	c3 text,
+	c4 timestamptz,
+	c5 timestamp,
+	c6 varchar(10),
+	c7 char(10) default 'ft1',
+	c8 user_enum
+) SERVER loopback_nopw OPTIONS (schema_name 'public', table_name 'ft1');
+SELECT 1 FROM ft1_nopw LIMIT 1;
+ERROR:  password is required
+DETAIL:  Non-superusers must provide a password in the user mapping.
+-- If we add a password to the connstr it'll fail, because we don't allow passwords
+-- in connstrs only in user mappings.
+ALTER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
+ERROR:  invalid option "password"
+HINT:  Perhaps you meant the option "passfile".
+-- If we add a password for our user mapping instead, we should get a different
+-- error because the password wasn't actually *used* when we run with trust auth.
+--
+-- This won't work with installcheck, but neither will most of the FDW checks.
+ALTER USER MAPPING FOR CURRENT_USER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
+SELECT 1 FROM ft1_nopw LIMIT 1;
+ERROR:  password is required
+DETAIL:  Non-superuser cannot connect if the server does not request a password.
+HINT:  Target server's authentication method must be changed or password_required=false set in the user mapping attributes.
+-- Unpriv user cannot make the mapping passwordless
+ALTER USER MAPPING FOR CURRENT_USER SERVER loopback_nopw OPTIONS (ADD password_required 'false');
+ERROR:  password_required=false is superuser-only
+HINT:  User mappings with the password_required option set to false may only be created or modified by the superuser.
+SELECT 1 FROM ft1_nopw LIMIT 1;
+ERROR:  password is required
+DETAIL:  Non-superuser cannot connect if the server does not request a password.
+HINT:  Target server's authentication method must be changed or password_required=false set in the user mapping attributes.
+RESET ROLE;
+-- But the superuser can
+ALTER USER MAPPING FOR regress_nosuper SERVER loopback_nopw OPTIONS (ADD password_required 'false');
+SET ROLE regress_nosuper;
+-- Should finally work now
+SELECT 1 FROM ft1_nopw LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- unpriv user also cannot set sslcert / sslkey on the user mapping
+-- first set password_required so we see the right error messages
+ALTER USER MAPPING FOR CURRENT_USER SERVER loopback_nopw OPTIONS (SET password_required 'true');
+ALTER USER MAPPING FOR CURRENT_USER SERVER loopback_nopw OPTIONS (ADD sslcert 'foo.crt');
+ERROR:  sslcert and sslkey are superuser-only
+HINT:  User mappings with the sslcert or sslkey options set may only be created or modified by the superuser.
+ALTER USER MAPPING FOR CURRENT_USER SERVER loopback_nopw OPTIONS (ADD sslkey 'foo.key');
+ERROR:  sslcert and sslkey are superuser-only
+HINT:  User mappings with the sslcert or sslkey options set may only be created or modified by the superuser.
+-- We're done with the role named after a specific user and need to check the
+-- changes to the public mapping.
+DROP USER MAPPING FOR CURRENT_USER SERVER loopback_nopw;
+-- This will fail again as it'll resolve the user mapping for public, which
+-- lacks password_required=false
+SELECT 1 FROM ft1_nopw LIMIT 1;
+ERROR:  password is required
+DETAIL:  Non-superusers must provide a password in the user mapping.
+RESET ROLE;
+-- The user mapping for public is passwordless and lacks the password_required=false
+-- mapping option, but will work because the current user is a superuser.
+SELECT 1 FROM ft1_nopw LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- cleanup
+DROP USER MAPPING FOR public SERVER loopback_nopw;
+DROP OWNED BY regress_nosuper;
+DROP ROLE regress_nosuper;
+-- Clean-up
+RESET enable_partitionwise_aggregate;
+-- Two-phase transactions are not supported.
+BEGIN;
+SELECT count(*) FROM ft1;
+ count 
+-------
+   822
+(1 row)
+
+-- error here
+PREPARE TRANSACTION 'fdw_tpc';
+ERROR:  cannot PREPARE a transaction that has operated on postgres_fdw foreign tables
+ROLLBACK;
+WARNING:  there is no transaction in progress
+-- ===================================================================
+-- reestablish new connection
+-- ===================================================================
+-- Change application_name of remote connection to special one
+-- so that we can easily terminate the connection later.
+ALTER SERVER loopback OPTIONS (application_name 'fdw_retry_check');
+-- If debug_discard_caches is active, it results in
+-- dropping remote connections after every transaction, making it
+-- impossible to test termination meaningfully.  So turn that off
+-- for this test.
+SET debug_discard_caches = 0;
+-- Make sure we have a remote connection.
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- Terminate the remote connection and wait for the termination to complete.
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+	WHERE application_name = 'fdw_retry_check';
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+-- This query should detect the broken connection when starting new remote
+-- transaction, reestablish new connection, and then succeed.
+BEGIN;
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- If we detect the broken connection when starting a new remote
+-- subtransaction, we should fail instead of establishing a new connection.
+-- Terminate the remote connection and wait for the termination to complete.
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+	WHERE application_name = 'fdw_retry_check';
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+SAVEPOINT s;
+-- The text of the error might vary across platforms, so only show SQLSTATE.
+\set VERBOSITY sqlstate
+SELECT 1 FROM ft1 LIMIT 1;    -- should fail
+ERROR:  08006
+\set VERBOSITY default
+COMMIT;
+RESET debug_discard_caches;
+-- =============================================================================
+-- test connection invalidation cases and postgres_fdw_get_connections function
+-- =============================================================================
+-- Let's ensure to close all the existing cached connections.
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ ?column? 
+----------
+        1
+(1 row)
+
+-- No cached connections, so no records should be output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+(0 rows)
+
+-- This test case is for closing the connection in pgfdw_xact_callback
+BEGIN;
+-- Connection xact depth becomes 1 i.e. the connection is in midst of the xact.
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+SELECT 1 FROM ft7 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- List all the existing cached connections. loopback and loopback3 should be
+-- output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+ loopback
+ loopback3
+(2 rows)
+
+-- Connections are not closed at the end of the alter and drop statements.
+-- That's because the connections are in midst of this xact,
+-- they are just marked as invalid in pgfdw_inval_callback.
+ALTER SERVER loopback OPTIONS (ADD use_remote_estimate 'off');
+DROP SERVER loopback3 CASCADE;
+NOTICE:  drop cascades to 2 other objects
+DETAIL:  drop cascades to user mapping for public on server loopback3
+drop cascades to foreign table ft7
+-- List all the existing cached connections. loopback and loopback3
+-- should be output as invalid connections. Also the server name for
+-- loopback3 should be NULL because the server was dropped.
+SELECT * FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name | valid 
+-------------+-------
+ loopback    | f
+             | f
+(2 rows)
+
+-- The invalid connections get closed in pgfdw_xact_callback during commit.
+COMMIT;
+-- All cached connections were closed while committing above xact, so no
+-- records should be output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+(0 rows)
+
+-- =======================================================================
+-- test postgres_fdw_disconnect and postgres_fdw_disconnect_all functions
+-- =======================================================================
+BEGIN;
+-- Ensure to cache loopback connection.
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- Ensure to cache loopback2 connection.
+SELECT 1 FROM ft6 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- List all the existing cached connections. loopback and loopback2 should be
+-- output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+ loopback
+ loopback2
+(2 rows)
+
+-- Issue a warning and return false as loopback connection is still in use and
+-- can not be closed.
+SELECT postgres_fdw_disconnect('loopback');
+WARNING:  cannot close connection for server "loopback" because it is still in use
+ postgres_fdw_disconnect 
+-------------------------
+ f
+(1 row)
+
+-- List all the existing cached connections. loopback and loopback2 should be
+-- output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+ loopback
+ loopback2
+(2 rows)
+
+-- Return false as connections are still in use, warnings are issued.
+-- But disable warnings temporarily because the order of them is not stable.
+SET client_min_messages = 'ERROR';
+SELECT postgres_fdw_disconnect_all();
+ postgres_fdw_disconnect_all 
+-----------------------------
+ f
+(1 row)
+
+RESET client_min_messages;
+COMMIT;
+-- Ensure that loopback2 connection is closed.
+SELECT 1 FROM postgres_fdw_disconnect('loopback2');
+ ?column? 
+----------
+        1
+(1 row)
+
+SELECT server_name FROM postgres_fdw_get_connections() WHERE server_name = 'loopback2';
+ server_name 
+-------------
+(0 rows)
+
+-- Return false as loopback2 connection is closed already.
+SELECT postgres_fdw_disconnect('loopback2');
+ postgres_fdw_disconnect 
+-------------------------
+ f
+(1 row)
+
+-- Return an error as there is no foreign server with given name.
+SELECT postgres_fdw_disconnect('unknownserver');
+ERROR:  server "unknownserver" does not exist
+-- Let's ensure to close all the existing cached connections.
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ ?column? 
+----------
+        1
+(1 row)
+
+-- No cached connections, so no records should be output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+(0 rows)
+
+-- =============================================================================
+-- test case for having multiple cached connections for a foreign server
+-- =============================================================================
+CREATE ROLE regress_multi_conn_user1 SUPERUSER;
+CREATE ROLE regress_multi_conn_user2 SUPERUSER;
+CREATE USER MAPPING FOR regress_multi_conn_user1 SERVER loopback;
+CREATE USER MAPPING FOR regress_multi_conn_user2 SERVER loopback;
+BEGIN;
+-- Will cache loopback connection with user mapping for regress_multi_conn_user1
+SET ROLE regress_multi_conn_user1;
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+RESET ROLE;
+-- Will cache loopback connection with user mapping for regress_multi_conn_user2
+SET ROLE regress_multi_conn_user2;
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+RESET ROLE;
+-- Should output two connections for loopback server
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+ loopback
+ loopback
+(2 rows)
+
+COMMIT;
+-- Let's ensure to close all the existing cached connections.
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ ?column? 
+----------
+        1
+(1 row)
+
+-- No cached connections, so no records should be output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+(0 rows)
+
+-- Clean up
+DROP USER MAPPING FOR regress_multi_conn_user1 SERVER loopback;
+DROP USER MAPPING FOR regress_multi_conn_user2 SERVER loopback;
+DROP ROLE regress_multi_conn_user1;
+DROP ROLE regress_multi_conn_user2;
+-- ===================================================================
+-- Test foreign server level option keep_connections
+-- ===================================================================
+-- By default, the connections associated with foreign server are cached i.e.
+-- keep_connections option is on. Set it to off.
+ALTER SERVER loopback OPTIONS (keep_connections 'off');
+-- connection to loopback server is closed at the end of xact
+-- as keep_connections was set to off.
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- No cached connections, so no records should be output.
+SELECT server_name FROM postgres_fdw_get_connections() ORDER BY 1;
+ server_name 
+-------------
+(0 rows)
+
+ALTER SERVER loopback OPTIONS (SET keep_connections 'on');
+-- ===================================================================
+-- batch insert
+-- ===================================================================
+BEGIN;
+CREATE SERVER batch10 FOREIGN DATA WRAPPER postgres_fdw OPTIONS( batch_size '10' );
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'batch10'
+AND srvoptions @> array['batch_size=10'];
+ count 
+-------
+     1
+(1 row)
+
+ALTER SERVER batch10 OPTIONS( SET batch_size '20' );
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'batch10'
+AND srvoptions @> array['batch_size=10'];
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'batch10'
+AND srvoptions @> array['batch_size=20'];
+ count 
+-------
+     1
+(1 row)
+
+CREATE FOREIGN TABLE table30 ( x int ) SERVER batch10 OPTIONS ( batch_size '30' );
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30'::regclass
+AND ftoptions @> array['batch_size=30'];
+ count 
+-------
+     1
+(1 row)
+
+ALTER FOREIGN TABLE table30 OPTIONS ( SET batch_size '40');
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30'::regclass
+AND ftoptions @> array['batch_size=30'];
+ count 
+-------
+     0
+(1 row)
+
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30'::regclass
+AND ftoptions @> array['batch_size=40'];
+ count 
+-------
+     1
+(1 row)
+
+ROLLBACK;
+CREATE TABLE batch_table ( x int );
+CREATE FOREIGN TABLE ftable ( x int ) SERVER loopback OPTIONS ( table_name 'batch_table', batch_size '10' );
+EXPLAIN (VERBOSE, COSTS OFF) INSERT INTO ftable SELECT * FROM generate_series(1, 10) i;
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Insert on public.ftable
+   Remote SQL: INSERT INTO public.batch_table(x) VALUES ($1)
+   Batch Size: 10
+   ->  Function Scan on pg_catalog.generate_series i
+         Output: i.i
+         Function Call: generate_series(1, 10)
+(6 rows)
+
+INSERT INTO ftable SELECT * FROM generate_series(1, 10) i;
+INSERT INTO ftable SELECT * FROM generate_series(11, 31) i;
+INSERT INTO ftable VALUES (32);
+INSERT INTO ftable VALUES (33), (34);
+SELECT COUNT(*) FROM ftable;
+ count 
+-------
+    34
+(1 row)
+
+TRUNCATE batch_table;
+DROP FOREIGN TABLE ftable;
+-- try if large batches exceed max number of bind parameters
+CREATE FOREIGN TABLE ftable ( x int ) SERVER loopback OPTIONS ( table_name 'batch_table', batch_size '100000' );
+INSERT INTO ftable SELECT * FROM generate_series(1, 70000) i;
+SELECT COUNT(*) FROM ftable;
+ count 
+-------
+ 70000
+(1 row)
+
+TRUNCATE batch_table;
+DROP FOREIGN TABLE ftable;
+-- Disable batch insert
+CREATE FOREIGN TABLE ftable ( x int ) SERVER loopback OPTIONS ( table_name 'batch_table', batch_size '1' );
+EXPLAIN (VERBOSE, COSTS OFF) INSERT INTO ftable VALUES (1), (2);
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Insert on public.ftable
+   Remote SQL: INSERT INTO public.batch_table(x) VALUES ($1)
+   Batch Size: 1
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1
+(5 rows)
+
+INSERT INTO ftable VALUES (1), (2);
+SELECT COUNT(*) FROM ftable;
+ count 
+-------
+     2
+(1 row)
+
+-- Disable batch inserting into foreign tables with BEFORE ROW INSERT triggers
+-- even if the batch_size option is enabled.
+ALTER FOREIGN TABLE ftable OPTIONS ( SET batch_size '10' );
+CREATE TRIGGER trig_row_before BEFORE INSERT ON ftable
+FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+EXPLAIN (VERBOSE, COSTS OFF) INSERT INTO ftable VALUES (3), (4);
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Insert on public.ftable
+   Remote SQL: INSERT INTO public.batch_table(x) VALUES ($1)
+   Batch Size: 1
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1
+(5 rows)
+
+INSERT INTO ftable VALUES (3), (4);
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW INSERT ON ftable
+NOTICE:  NEW: (3)
+NOTICE:  trig_row_before(23, skidoo) BEFORE ROW INSERT ON ftable
+NOTICE:  NEW: (4)
+SELECT COUNT(*) FROM ftable;
+ count 
+-------
+     4
+(1 row)
+
+-- Clean up
+DROP TRIGGER trig_row_before ON ftable;
+DROP FOREIGN TABLE ftable;
+DROP TABLE batch_table;
+-- Use partitioning
+CREATE TABLE batch_table ( x int ) PARTITION BY HASH (x);
+CREATE TABLE batch_table_p0 (LIKE batch_table);
+CREATE FOREIGN TABLE batch_table_p0f
+	PARTITION OF batch_table
+	FOR VALUES WITH (MODULUS 3, REMAINDER 0)
+	SERVER loopback
+	OPTIONS (table_name 'batch_table_p0', batch_size '10');
+CREATE TABLE batch_table_p1 (LIKE batch_table);
+CREATE FOREIGN TABLE batch_table_p1f
+	PARTITION OF batch_table
+	FOR VALUES WITH (MODULUS 3, REMAINDER 1)
+	SERVER loopback
+	OPTIONS (table_name 'batch_table_p1', batch_size '1');
+CREATE TABLE batch_table_p2
+	PARTITION OF batch_table
+	FOR VALUES WITH (MODULUS 3, REMAINDER 2);
+INSERT INTO batch_table SELECT * FROM generate_series(1, 66) i;
+SELECT COUNT(*) FROM batch_table;
+ count 
+-------
+    66
+(1 row)
+
+-- Check that enabling batched inserts doesn't interfere with cross-partition
+-- updates
+CREATE TABLE batch_cp_upd_test (a int) PARTITION BY LIST (a);
+CREATE TABLE batch_cp_upd_test1 (LIKE batch_cp_upd_test);
+CREATE FOREIGN TABLE batch_cp_upd_test1_f
+	PARTITION OF batch_cp_upd_test
+	FOR VALUES IN (1)
+	SERVER loopback
+	OPTIONS (table_name 'batch_cp_upd_test1', batch_size '10');
+CREATE TABLE batch_cp_up_test1 PARTITION OF batch_cp_upd_test
+	FOR VALUES IN (2);
+INSERT INTO batch_cp_upd_test VALUES (1), (2);
+-- The following moves a row from the local partition to the foreign one
+UPDATE batch_cp_upd_test t SET a = 1 FROM (VALUES (1), (2)) s(a) WHERE t.a = s.a;
+ERROR:  cannot route tuples into foreign table to be updated "batch_cp_upd_test1_f"
+SELECT tableoid::regclass, * FROM batch_cp_upd_test;
+       tableoid       | a 
+----------------------+---
+ batch_cp_upd_test1_f | 1
+ batch_cp_up_test1    | 2
+(2 rows)
+
+-- Clean up
+DROP TABLE batch_table, batch_cp_upd_test, batch_table_p0, batch_table_p1 CASCADE;
+-- Use partitioning
+ALTER SERVER loopback OPTIONS (ADD batch_size '10');
+CREATE TABLE batch_table ( x int, field1 text, field2 text) PARTITION BY HASH (x);
+CREATE TABLE batch_table_p0 (LIKE batch_table);
+ALTER TABLE batch_table_p0 ADD CONSTRAINT p0_pkey PRIMARY KEY (x);
+CREATE FOREIGN TABLE batch_table_p0f
+	PARTITION OF batch_table
+	FOR VALUES WITH (MODULUS 2, REMAINDER 0)
+	SERVER loopback
+	OPTIONS (table_name 'batch_table_p0');
+CREATE TABLE batch_table_p1 (LIKE batch_table);
+ALTER TABLE batch_table_p1 ADD CONSTRAINT p1_pkey PRIMARY KEY (x);
+CREATE FOREIGN TABLE batch_table_p1f
+	PARTITION OF batch_table
+	FOR VALUES WITH (MODULUS 2, REMAINDER 1)
+	SERVER loopback
+	OPTIONS (table_name 'batch_table_p1');
+INSERT INTO batch_table SELECT i, 'test'||i, 'test'|| i FROM generate_series(1, 50) i;
+SELECT COUNT(*) FROM batch_table;
+ count 
+-------
+    50
+(1 row)
+
+SELECT * FROM batch_table ORDER BY x;
+ x  | field1 | field2 
+----+--------+--------
+  1 | test1  | test1
+  2 | test2  | test2
+  3 | test3  | test3
+  4 | test4  | test4
+  5 | test5  | test5
+  6 | test6  | test6
+  7 | test7  | test7
+  8 | test8  | test8
+  9 | test9  | test9
+ 10 | test10 | test10
+ 11 | test11 | test11
+ 12 | test12 | test12
+ 13 | test13 | test13
+ 14 | test14 | test14
+ 15 | test15 | test15
+ 16 | test16 | test16
+ 17 | test17 | test17
+ 18 | test18 | test18
+ 19 | test19 | test19
+ 20 | test20 | test20
+ 21 | test21 | test21
+ 22 | test22 | test22
+ 23 | test23 | test23
+ 24 | test24 | test24
+ 25 | test25 | test25
+ 26 | test26 | test26
+ 27 | test27 | test27
+ 28 | test28 | test28
+ 29 | test29 | test29
+ 30 | test30 | test30
+ 31 | test31 | test31
+ 32 | test32 | test32
+ 33 | test33 | test33
+ 34 | test34 | test34
+ 35 | test35 | test35
+ 36 | test36 | test36
+ 37 | test37 | test37
+ 38 | test38 | test38
+ 39 | test39 | test39
+ 40 | test40 | test40
+ 41 | test41 | test41
+ 42 | test42 | test42
+ 43 | test43 | test43
+ 44 | test44 | test44
+ 45 | test45 | test45
+ 46 | test46 | test46
+ 47 | test47 | test47
+ 48 | test48 | test48
+ 49 | test49 | test49
+ 50 | test50 | test50
+(50 rows)
+
+ALTER SERVER loopback OPTIONS (DROP batch_size);
+-- ===================================================================
+-- test asynchronous execution
+-- ===================================================================
+ALTER SERVER loopback OPTIONS (DROP extensions);
+ALTER SERVER loopback OPTIONS (ADD async_capable 'true');
+ALTER SERVER loopback2 OPTIONS (ADD async_capable 'true');
+CREATE TABLE async_pt (a int, b int, c text) PARTITION BY RANGE (a);
+CREATE TABLE base_tbl1 (a int, b int, c text);
+CREATE TABLE base_tbl2 (a int, b int, c text);
+CREATE FOREIGN TABLE async_p1 PARTITION OF async_pt FOR VALUES FROM (1000) TO (2000)
+  SERVER loopback OPTIONS (table_name 'base_tbl1');
+CREATE FOREIGN TABLE async_p2 PARTITION OF async_pt FOR VALUES FROM (2000) TO (3000)
+  SERVER loopback2 OPTIONS (table_name 'base_tbl2');
+INSERT INTO async_p1 SELECT 1000 + i, i, to_char(i, 'FM0000') FROM generate_series(0, 999, 5) i;
+INSERT INTO async_p2 SELECT 2000 + i, i, to_char(i, 'FM0000') FROM generate_series(0, 999, 5) i;
+ANALYZE async_pt;
+-- simple queries
+CREATE TABLE result_tbl (a int, b int, c text);
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b % 100 = 0;
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE (((b % 100) = 0))
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE (((b % 100) = 0))
+(8 rows)
+
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b % 100 = 0;
+SELECT * FROM result_tbl ORDER BY a;
+  a   |  b  |  c   
+------+-----+------
+ 1000 |   0 | 0000
+ 1100 | 100 | 0100
+ 1200 | 200 | 0200
+ 1300 | 300 | 0300
+ 1400 | 400 | 0400
+ 1500 | 500 | 0500
+ 1600 | 600 | 0600
+ 1700 | 700 | 0700
+ 1800 | 800 | 0800
+ 1900 | 900 | 0900
+ 2000 |   0 | 0000
+ 2100 | 100 | 0100
+ 2200 | 200 | 0200
+ 2300 | 300 | 0300
+ 2400 | 400 | 0400
+ 2500 | 500 | 0500
+ 2600 | 600 | 0600
+ 2700 | 700 | 0700
+ 2800 | 800 | 0800
+ 2900 | 900 | 0900
+(20 rows)
+
+DELETE FROM result_tbl;
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b === 505;
+                           QUERY PLAN                           
+----------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Filter: (async_pt_1.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+               Filter: (async_pt_2.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+(10 rows)
+
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b === 505;
+SELECT * FROM result_tbl ORDER BY a;
+  a   |  b  |  c   
+------+-----+------
+ 1505 | 505 | 0505
+ 2505 | 505 | 0505
+(2 rows)
+
+DELETE FROM result_tbl;
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO result_tbl SELECT a, b, 'AAA' || c FROM async_pt WHERE b === 505;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, ('AAA'::text || async_pt_1.c)
+               Filter: (async_pt_1.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, ('AAA'::text || async_pt_2.c)
+               Filter: (async_pt_2.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+(10 rows)
+
+INSERT INTO result_tbl SELECT a, b, 'AAA' || c FROM async_pt WHERE b === 505;
+SELECT * FROM result_tbl ORDER BY a;
+  a   |  b  |    c    
+------+-----+---------
+ 1505 | 505 | AAA0505
+ 2505 | 505 | AAA0505
+(2 rows)
+
+DELETE FROM result_tbl;
+-- Check case where multiple partitions use the same connection
+CREATE TABLE base_tbl3 (a int, b int, c text);
+CREATE FOREIGN TABLE async_p3 PARTITION OF async_pt FOR VALUES FROM (3000) TO (4000)
+  SERVER loopback2 OPTIONS (table_name 'base_tbl3');
+INSERT INTO async_p3 SELECT 3000 + i, i, to_char(i, 'FM0000') FROM generate_series(0, 999, 5) i;
+ANALYZE async_pt;
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b === 505;
+                           QUERY PLAN                           
+----------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Filter: (async_pt_1.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+               Filter: (async_pt_2.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+         ->  Async Foreign Scan on public.async_p3 async_pt_3
+               Output: async_pt_3.a, async_pt_3.b, async_pt_3.c
+               Filter: (async_pt_3.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl3
+(14 rows)
+
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b === 505;
+SELECT * FROM result_tbl ORDER BY a;
+  a   |  b  |  c   
+------+-----+------
+ 1505 | 505 | 0505
+ 2505 | 505 | 0505
+ 3505 | 505 | 0505
+(3 rows)
+
+DELETE FROM result_tbl;
+DROP FOREIGN TABLE async_p3;
+DROP TABLE base_tbl3;
+-- Check case where the partitioned table has local/remote partitions
+CREATE TABLE async_p3 PARTITION OF async_pt FOR VALUES FROM (3000) TO (4000);
+INSERT INTO async_p3 SELECT 3000 + i, i, to_char(i, 'FM0000') FROM generate_series(0, 999, 5) i;
+ANALYZE async_pt;
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b === 505;
+                           QUERY PLAN                           
+----------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Filter: (async_pt_1.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+               Filter: (async_pt_2.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+         ->  Seq Scan on public.async_p3 async_pt_3
+               Output: async_pt_3.a, async_pt_3.b, async_pt_3.c
+               Filter: (async_pt_3.b === 505)
+(13 rows)
+
+INSERT INTO result_tbl SELECT * FROM async_pt WHERE b === 505;
+SELECT * FROM result_tbl ORDER BY a;
+  a   |  b  |  c   
+------+-----+------
+ 1505 | 505 | 0505
+ 2505 | 505 | 0505
+ 3505 | 505 | 0505
+(3 rows)
+
+DELETE FROM result_tbl;
+-- partitionwise joins
+SET enable_partitionwise_join TO true;
+CREATE TABLE join_tbl (a1 int, b1 int, c1 text, a2 int, b2 int, c2 text);
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO join_tbl SELECT * FROM async_pt t1, async_pt t2 WHERE t1.a = t2.a AND t1.b = t2.b AND t1.b % 100 = 0;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.join_tbl
+   ->  Append
+         ->  Async Foreign Scan
+               Output: t1_1.a, t1_1.b, t1_1.c, t2_1.a, t2_1.b, t2_1.c
+               Relations: (public.async_p1 t1_1) INNER JOIN (public.async_p1 t2_1)
+               Remote SQL: SELECT r5.a, r5.b, r5.c, r8.a, r8.b, r8.c FROM (public.base_tbl1 r5 INNER JOIN public.base_tbl1 r8 ON (((r5.a = r8.a)) AND ((r5.b = r8.b)) AND (((r5.b % 100) = 0))))
+         ->  Async Foreign Scan
+               Output: t1_2.a, t1_2.b, t1_2.c, t2_2.a, t2_2.b, t2_2.c
+               Relations: (public.async_p2 t1_2) INNER JOIN (public.async_p2 t2_2)
+               Remote SQL: SELECT r6.a, r6.b, r6.c, r9.a, r9.b, r9.c FROM (public.base_tbl2 r6 INNER JOIN public.base_tbl2 r9 ON (((r6.a = r9.a)) AND ((r6.b = r9.b)) AND (((r6.b % 100) = 0))))
+         ->  Hash Join
+               Output: t1_3.a, t1_3.b, t1_3.c, t2_3.a, t2_3.b, t2_3.c
+               Hash Cond: ((t2_3.a = t1_3.a) AND (t2_3.b = t1_3.b))
+               ->  Seq Scan on public.async_p3 t2_3
+                     Output: t2_3.a, t2_3.b, t2_3.c
+               ->  Hash
+                     Output: t1_3.a, t1_3.b, t1_3.c
+                     ->  Seq Scan on public.async_p3 t1_3
+                           Output: t1_3.a, t1_3.b, t1_3.c
+                           Filter: ((t1_3.b % 100) = 0)
+(20 rows)
+
+INSERT INTO join_tbl SELECT * FROM async_pt t1, async_pt t2 WHERE t1.a = t2.a AND t1.b = t2.b AND t1.b % 100 = 0;
+SELECT * FROM join_tbl ORDER BY a1;
+  a1  | b1  |  c1  |  a2  | b2  |  c2  
+------+-----+------+------+-----+------
+ 1000 |   0 | 0000 | 1000 |   0 | 0000
+ 1100 | 100 | 0100 | 1100 | 100 | 0100
+ 1200 | 200 | 0200 | 1200 | 200 | 0200
+ 1300 | 300 | 0300 | 1300 | 300 | 0300
+ 1400 | 400 | 0400 | 1400 | 400 | 0400
+ 1500 | 500 | 0500 | 1500 | 500 | 0500
+ 1600 | 600 | 0600 | 1600 | 600 | 0600
+ 1700 | 700 | 0700 | 1700 | 700 | 0700
+ 1800 | 800 | 0800 | 1800 | 800 | 0800
+ 1900 | 900 | 0900 | 1900 | 900 | 0900
+ 2000 |   0 | 0000 | 2000 |   0 | 0000
+ 2100 | 100 | 0100 | 2100 | 100 | 0100
+ 2200 | 200 | 0200 | 2200 | 200 | 0200
+ 2300 | 300 | 0300 | 2300 | 300 | 0300
+ 2400 | 400 | 0400 | 2400 | 400 | 0400
+ 2500 | 500 | 0500 | 2500 | 500 | 0500
+ 2600 | 600 | 0600 | 2600 | 600 | 0600
+ 2700 | 700 | 0700 | 2700 | 700 | 0700
+ 2800 | 800 | 0800 | 2800 | 800 | 0800
+ 2900 | 900 | 0900 | 2900 | 900 | 0900
+ 3000 |   0 | 0000 | 3000 |   0 | 0000
+ 3100 | 100 | 0100 | 3100 | 100 | 0100
+ 3200 | 200 | 0200 | 3200 | 200 | 0200
+ 3300 | 300 | 0300 | 3300 | 300 | 0300
+ 3400 | 400 | 0400 | 3400 | 400 | 0400
+ 3500 | 500 | 0500 | 3500 | 500 | 0500
+ 3600 | 600 | 0600 | 3600 | 600 | 0600
+ 3700 | 700 | 0700 | 3700 | 700 | 0700
+ 3800 | 800 | 0800 | 3800 | 800 | 0800
+ 3900 | 900 | 0900 | 3900 | 900 | 0900
+(30 rows)
+
+DELETE FROM join_tbl;
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO join_tbl SELECT t1.a, t1.b, 'AAA' || t1.c, t2.a, t2.b, 'AAA' || t2.c FROM async_pt t1, async_pt t2 WHERE t1.a = t2.a AND t1.b = t2.b AND t1.b % 100 = 0;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.join_tbl
+   ->  Append
+         ->  Async Foreign Scan
+               Output: t1_1.a, t1_1.b, ('AAA'::text || t1_1.c), t2_1.a, t2_1.b, ('AAA'::text || t2_1.c)
+               Relations: (public.async_p1 t1_1) INNER JOIN (public.async_p1 t2_1)
+               Remote SQL: SELECT r5.a, r5.b, r5.c, r8.a, r8.b, r8.c FROM (public.base_tbl1 r5 INNER JOIN public.base_tbl1 r8 ON (((r5.a = r8.a)) AND ((r5.b = r8.b)) AND (((r5.b % 100) = 0))))
+         ->  Async Foreign Scan
+               Output: t1_2.a, t1_2.b, ('AAA'::text || t1_2.c), t2_2.a, t2_2.b, ('AAA'::text || t2_2.c)
+               Relations: (public.async_p2 t1_2) INNER JOIN (public.async_p2 t2_2)
+               Remote SQL: SELECT r6.a, r6.b, r6.c, r9.a, r9.b, r9.c FROM (public.base_tbl2 r6 INNER JOIN public.base_tbl2 r9 ON (((r6.a = r9.a)) AND ((r6.b = r9.b)) AND (((r6.b % 100) = 0))))
+         ->  Hash Join
+               Output: t1_3.a, t1_3.b, ('AAA'::text || t1_3.c), t2_3.a, t2_3.b, ('AAA'::text || t2_3.c)
+               Hash Cond: ((t2_3.a = t1_3.a) AND (t2_3.b = t1_3.b))
+               ->  Seq Scan on public.async_p3 t2_3
+                     Output: t2_3.a, t2_3.b, t2_3.c
+               ->  Hash
+                     Output: t1_3.a, t1_3.b, t1_3.c
+                     ->  Seq Scan on public.async_p3 t1_3
+                           Output: t1_3.a, t1_3.b, t1_3.c
+                           Filter: ((t1_3.b % 100) = 0)
+(20 rows)
+
+INSERT INTO join_tbl SELECT t1.a, t1.b, 'AAA' || t1.c, t2.a, t2.b, 'AAA' || t2.c FROM async_pt t1, async_pt t2 WHERE t1.a = t2.a AND t1.b = t2.b AND t1.b % 100 = 0;
+SELECT * FROM join_tbl ORDER BY a1;
+  a1  | b1  |   c1    |  a2  | b2  |   c2    
+------+-----+---------+------+-----+---------
+ 1000 |   0 | AAA0000 | 1000 |   0 | AAA0000
+ 1100 | 100 | AAA0100 | 1100 | 100 | AAA0100
+ 1200 | 200 | AAA0200 | 1200 | 200 | AAA0200
+ 1300 | 300 | AAA0300 | 1300 | 300 | AAA0300
+ 1400 | 400 | AAA0400 | 1400 | 400 | AAA0400
+ 1500 | 500 | AAA0500 | 1500 | 500 | AAA0500
+ 1600 | 600 | AAA0600 | 1600 | 600 | AAA0600
+ 1700 | 700 | AAA0700 | 1700 | 700 | AAA0700
+ 1800 | 800 | AAA0800 | 1800 | 800 | AAA0800
+ 1900 | 900 | AAA0900 | 1900 | 900 | AAA0900
+ 2000 |   0 | AAA0000 | 2000 |   0 | AAA0000
+ 2100 | 100 | AAA0100 | 2100 | 100 | AAA0100
+ 2200 | 200 | AAA0200 | 2200 | 200 | AAA0200
+ 2300 | 300 | AAA0300 | 2300 | 300 | AAA0300
+ 2400 | 400 | AAA0400 | 2400 | 400 | AAA0400
+ 2500 | 500 | AAA0500 | 2500 | 500 | AAA0500
+ 2600 | 600 | AAA0600 | 2600 | 600 | AAA0600
+ 2700 | 700 | AAA0700 | 2700 | 700 | AAA0700
+ 2800 | 800 | AAA0800 | 2800 | 800 | AAA0800
+ 2900 | 900 | AAA0900 | 2900 | 900 | AAA0900
+ 3000 |   0 | AAA0000 | 3000 |   0 | AAA0000
+ 3100 | 100 | AAA0100 | 3100 | 100 | AAA0100
+ 3200 | 200 | AAA0200 | 3200 | 200 | AAA0200
+ 3300 | 300 | AAA0300 | 3300 | 300 | AAA0300
+ 3400 | 400 | AAA0400 | 3400 | 400 | AAA0400
+ 3500 | 500 | AAA0500 | 3500 | 500 | AAA0500
+ 3600 | 600 | AAA0600 | 3600 | 600 | AAA0600
+ 3700 | 700 | AAA0700 | 3700 | 700 | AAA0700
+ 3800 | 800 | AAA0800 | 3800 | 800 | AAA0800
+ 3900 | 900 | AAA0900 | 3900 | 900 | AAA0900
+(30 rows)
+
+DELETE FROM join_tbl;
+RESET enable_partitionwise_join;
+-- Test rescan of an async Append node with do_exec_prune=false
+SET enable_hashjoin TO false;
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO join_tbl SELECT * FROM async_p1 t1, async_pt t2 WHERE t1.a = t2.a AND t1.b = t2.b AND t1.b % 100 = 0;
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
+ Insert on public.join_tbl
+   ->  Nested Loop
+         Output: t1.a, t1.b, t1.c, t2.a, t2.b, t2.c
+         Join Filter: ((t1.a = t2.a) AND (t1.b = t2.b))
+         ->  Foreign Scan on public.async_p1 t1
+               Output: t1.a, t1.b, t1.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE (((b % 100) = 0))
+         ->  Append
+               ->  Async Foreign Scan on public.async_p1 t2_1
+                     Output: t2_1.a, t2_1.b, t2_1.c
+                     Remote SQL: SELECT a, b, c FROM public.base_tbl1
+               ->  Async Foreign Scan on public.async_p2 t2_2
+                     Output: t2_2.a, t2_2.b, t2_2.c
+                     Remote SQL: SELECT a, b, c FROM public.base_tbl2
+               ->  Seq Scan on public.async_p3 t2_3
+                     Output: t2_3.a, t2_3.b, t2_3.c
+(16 rows)
+
+INSERT INTO join_tbl SELECT * FROM async_p1 t1, async_pt t2 WHERE t1.a = t2.a AND t1.b = t2.b AND t1.b % 100 = 0;
+SELECT * FROM join_tbl ORDER BY a1;
+  a1  | b1  |  c1  |  a2  | b2  |  c2  
+------+-----+------+------+-----+------
+ 1000 |   0 | 0000 | 1000 |   0 | 0000
+ 1100 | 100 | 0100 | 1100 | 100 | 0100
+ 1200 | 200 | 0200 | 1200 | 200 | 0200
+ 1300 | 300 | 0300 | 1300 | 300 | 0300
+ 1400 | 400 | 0400 | 1400 | 400 | 0400
+ 1500 | 500 | 0500 | 1500 | 500 | 0500
+ 1600 | 600 | 0600 | 1600 | 600 | 0600
+ 1700 | 700 | 0700 | 1700 | 700 | 0700
+ 1800 | 800 | 0800 | 1800 | 800 | 0800
+ 1900 | 900 | 0900 | 1900 | 900 | 0900
+(10 rows)
+
+DELETE FROM join_tbl;
+RESET enable_hashjoin;
+-- Test interaction of async execution with plan-time partition pruning
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM async_pt WHERE a < 3000;
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
+ Append
+   ->  Async Foreign Scan on public.async_p1 async_pt_1
+         Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+         Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE ((a < 3000))
+   ->  Async Foreign Scan on public.async_p2 async_pt_2
+         Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+         Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE ((a < 3000))
+(7 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM async_pt WHERE a < 2000;
+                              QUERY PLAN                               
+-----------------------------------------------------------------------
+ Foreign Scan on public.async_p1 async_pt
+   Output: async_pt.a, async_pt.b, async_pt.c
+   Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE ((a < 2000))
+(3 rows)
+
+-- Test interaction of async execution with run-time partition pruning
+SET plan_cache_mode TO force_generic_plan;
+PREPARE async_pt_query (int, int) AS
+  INSERT INTO result_tbl SELECT * FROM async_pt WHERE a < $1 AND b === $2;
+EXPLAIN (VERBOSE, COSTS OFF)
+EXECUTE async_pt_query (3000, 505);
+                                        QUERY PLAN                                        
+------------------------------------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         Subplans Removed: 1
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Filter: (async_pt_1.b === $2)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE ((a < $1::integer))
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+               Filter: (async_pt_2.b === $2)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE ((a < $1::integer))
+(11 rows)
+
+EXECUTE async_pt_query (3000, 505);
+SELECT * FROM result_tbl ORDER BY a;
+  a   |  b  |  c   
+------+-----+------
+ 1505 | 505 | 0505
+ 2505 | 505 | 0505
+(2 rows)
+
+DELETE FROM result_tbl;
+EXPLAIN (VERBOSE, COSTS OFF)
+EXECUTE async_pt_query (2000, 505);
+                                        QUERY PLAN                                        
+------------------------------------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         Subplans Removed: 2
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Filter: (async_pt_1.b === $2)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE ((a < $1::integer))
+(7 rows)
+
+EXECUTE async_pt_query (2000, 505);
+SELECT * FROM result_tbl ORDER BY a;
+  a   |  b  |  c   
+------+-----+------
+ 1505 | 505 | 0505
+(1 row)
+
+DELETE FROM result_tbl;
+RESET plan_cache_mode;
+CREATE TABLE local_tbl(a int, b int, c text);
+INSERT INTO local_tbl VALUES (1505, 505, 'foo'), (2505, 505, 'bar');
+ANALYZE local_tbl;
+CREATE INDEX base_tbl1_idx ON base_tbl1 (a);
+CREATE INDEX base_tbl2_idx ON base_tbl2 (a);
+CREATE INDEX async_p3_idx ON async_p3 (a);
+ANALYZE base_tbl1;
+ANALYZE base_tbl2;
+ANALYZE async_p3;
+ALTER FOREIGN TABLE async_p1 OPTIONS (use_remote_estimate 'true');
+ALTER FOREIGN TABLE async_p2 OPTIONS (use_remote_estimate 'true');
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM local_tbl, async_pt WHERE local_tbl.a = async_pt.a AND local_tbl.c = 'bar';
+                                        QUERY PLAN                                        
+------------------------------------------------------------------------------------------
+ Nested Loop
+   Output: local_tbl.a, local_tbl.b, local_tbl.c, async_pt.a, async_pt.b, async_pt.c
+   ->  Seq Scan on public.local_tbl
+         Output: local_tbl.a, local_tbl.b, local_tbl.c
+         Filter: (local_tbl.c = 'bar'::text)
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE (($1::integer = a))
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE (($1::integer = a))
+         ->  Seq Scan on public.async_p3 async_pt_3
+               Output: async_pt_3.a, async_pt_3.b, async_pt_3.c
+               Filter: (local_tbl.a = async_pt_3.a)
+(15 rows)
+
+EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF)
+SELECT * FROM local_tbl, async_pt WHERE local_tbl.a = async_pt.a AND local_tbl.c = 'bar';
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
+ Nested Loop (actual rows=1 loops=1)
+   ->  Seq Scan on local_tbl (actual rows=1 loops=1)
+         Filter: (c = 'bar'::text)
+         Rows Removed by Filter: 1
+   ->  Append (actual rows=1 loops=1)
+         ->  Async Foreign Scan on async_p1 async_pt_1 (never executed)
+         ->  Async Foreign Scan on async_p2 async_pt_2 (actual rows=1 loops=1)
+         ->  Seq Scan on async_p3 async_pt_3 (never executed)
+               Filter: (local_tbl.a = a)
+(9 rows)
+
+SELECT * FROM local_tbl, async_pt WHERE local_tbl.a = async_pt.a AND local_tbl.c = 'bar';
+  a   |  b  |  c  |  a   |  b  |  c   
+------+-----+-----+------+-----+------
+ 2505 | 505 | bar | 2505 | 505 | 0505
+(1 row)
+
+ALTER FOREIGN TABLE async_p1 OPTIONS (DROP use_remote_estimate);
+ALTER FOREIGN TABLE async_p2 OPTIONS (DROP use_remote_estimate);
+DROP TABLE local_tbl;
+DROP INDEX base_tbl1_idx;
+DROP INDEX base_tbl2_idx;
+DROP INDEX async_p3_idx;
+-- UNION queries
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO result_tbl
+(SELECT a, b, 'AAA' || c FROM async_p1 ORDER BY a LIMIT 10)
+UNION
+(SELECT a, b, 'AAA' || c FROM async_p2 WHERE b < 10);
+                                                   QUERY PLAN                                                    
+-----------------------------------------------------------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  HashAggregate
+         Output: async_p1.a, async_p1.b, (('AAA'::text || async_p1.c))
+         Group Key: async_p1.a, async_p1.b, (('AAA'::text || async_p1.c))
+         ->  Append
+               ->  Async Foreign Scan on public.async_p1
+                     Output: async_p1.a, async_p1.b, ('AAA'::text || async_p1.c)
+                     Remote SQL: SELECT a, b, c FROM public.base_tbl1 ORDER BY a ASC NULLS LAST LIMIT 10::bigint
+               ->  Async Foreign Scan on public.async_p2
+                     Output: async_p2.a, async_p2.b, ('AAA'::text || async_p2.c)
+                     Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE ((b < 10))
+(11 rows)
+
+INSERT INTO result_tbl
+(SELECT a, b, 'AAA' || c FROM async_p1 ORDER BY a LIMIT 10)
+UNION
+(SELECT a, b, 'AAA' || c FROM async_p2 WHERE b < 10);
+SELECT * FROM result_tbl ORDER BY a;
+  a   | b  |    c    
+------+----+---------
+ 1000 |  0 | AAA0000
+ 1005 |  5 | AAA0005
+ 1010 | 10 | AAA0010
+ 1015 | 15 | AAA0015
+ 1020 | 20 | AAA0020
+ 1025 | 25 | AAA0025
+ 1030 | 30 | AAA0030
+ 1035 | 35 | AAA0035
+ 1040 | 40 | AAA0040
+ 1045 | 45 | AAA0045
+ 2000 |  0 | AAA0000
+ 2005 |  5 | AAA0005
+(12 rows)
+
+DELETE FROM result_tbl;
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO result_tbl
+(SELECT a, b, 'AAA' || c FROM async_p1 ORDER BY a LIMIT 10)
+UNION ALL
+(SELECT a, b, 'AAA' || c FROM async_p2 WHERE b < 10);
+                                                QUERY PLAN                                                 
+-----------------------------------------------------------------------------------------------------------
+ Insert on public.result_tbl
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1
+               Output: async_p1.a, async_p1.b, ('AAA'::text || async_p1.c)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 ORDER BY a ASC NULLS LAST LIMIT 10::bigint
+         ->  Async Foreign Scan on public.async_p2
+               Output: async_p2.a, async_p2.b, ('AAA'::text || async_p2.c)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE ((b < 10))
+(8 rows)
+
+INSERT INTO result_tbl
+(SELECT a, b, 'AAA' || c FROM async_p1 ORDER BY a LIMIT 10)
+UNION ALL
+(SELECT a, b, 'AAA' || c FROM async_p2 WHERE b < 10);
+SELECT * FROM result_tbl ORDER BY a;
+  a   | b  |    c    
+------+----+---------
+ 1000 |  0 | AAA0000
+ 1005 |  5 | AAA0005
+ 1010 | 10 | AAA0010
+ 1015 | 15 | AAA0015
+ 1020 | 20 | AAA0020
+ 1025 | 25 | AAA0025
+ 1030 | 30 | AAA0030
+ 1035 | 35 | AAA0035
+ 1040 | 40 | AAA0040
+ 1045 | 45 | AAA0045
+ 2000 |  0 | AAA0000
+ 2005 |  5 | AAA0005
+(12 rows)
+
+DELETE FROM result_tbl;
+-- Disable async execution if we use gating Result nodes for pseudoconstant
+-- quals
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM async_pt WHERE CURRENT_USER = SESSION_USER;
+                           QUERY PLAN                           
+----------------------------------------------------------------
+ Append
+   ->  Result
+         Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+         One-Time Filter: (CURRENT_USER = SESSION_USER)
+         ->  Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+   ->  Result
+         Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+         One-Time Filter: (CURRENT_USER = SESSION_USER)
+         ->  Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+   ->  Result
+         Output: async_pt_3.a, async_pt_3.b, async_pt_3.c
+         One-Time Filter: (CURRENT_USER = SESSION_USER)
+         ->  Seq Scan on public.async_p3 async_pt_3
+               Output: async_pt_3.a, async_pt_3.b, async_pt_3.c
+(18 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+(SELECT * FROM async_p1 WHERE CURRENT_USER = SESSION_USER)
+UNION ALL
+(SELECT * FROM async_p2 WHERE CURRENT_USER = SESSION_USER);
+                           QUERY PLAN                           
+----------------------------------------------------------------
+ Append
+   ->  Result
+         Output: async_p1.a, async_p1.b, async_p1.c
+         One-Time Filter: (CURRENT_USER = SESSION_USER)
+         ->  Foreign Scan on public.async_p1
+               Output: async_p1.a, async_p1.b, async_p1.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+   ->  Result
+         Output: async_p2.a, async_p2.b, async_p2.c
+         One-Time Filter: (CURRENT_USER = SESSION_USER)
+         ->  Foreign Scan on public.async_p2
+               Output: async_p2.a, async_p2.b, async_p2.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+(13 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ((SELECT * FROM async_p1 WHERE b < 10) UNION ALL (SELECT * FROM async_p2 WHERE b < 10)) s WHERE CURRENT_USER = SESSION_USER;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Append
+   ->  Result
+         Output: async_p1.a, async_p1.b, async_p1.c
+         One-Time Filter: (CURRENT_USER = SESSION_USER)
+         ->  Foreign Scan on public.async_p1
+               Output: async_p1.a, async_p1.b, async_p1.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE ((b < 10))
+   ->  Result
+         Output: async_p2.a, async_p2.b, async_p2.c
+         One-Time Filter: (CURRENT_USER = SESSION_USER)
+         ->  Foreign Scan on public.async_p2
+               Output: async_p2.a, async_p2.b, async_p2.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE ((b < 10))
+(13 rows)
+
+-- Test that pending requests are processed properly
+SET enable_mergejoin TO false;
+SET enable_hashjoin TO false;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM async_pt t1, async_p2 t2 WHERE t1.a = t2.a AND t1.b === 505;
+                           QUERY PLAN                           
+----------------------------------------------------------------
+ Nested Loop
+   Output: t1.a, t1.b, t1.c, t2.a, t2.b, t2.c
+   Join Filter: (t1.a = t2.a)
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 t1_1
+               Output: t1_1.a, t1_1.b, t1_1.c
+               Filter: (t1_1.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+         ->  Async Foreign Scan on public.async_p2 t1_2
+               Output: t1_2.a, t1_2.b, t1_2.c
+               Filter: (t1_2.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+         ->  Seq Scan on public.async_p3 t1_3
+               Output: t1_3.a, t1_3.b, t1_3.c
+               Filter: (t1_3.b === 505)
+   ->  Materialize
+         Output: t2.a, t2.b, t2.c
+         ->  Foreign Scan on public.async_p2 t2
+               Output: t2.a, t2.b, t2.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+(20 rows)
+
+SELECT * FROM async_pt t1, async_p2 t2 WHERE t1.a = t2.a AND t1.b === 505;
+  a   |  b  |  c   |  a   |  b  |  c   
+------+-----+------+------+-----+------
+ 2505 | 505 | 0505 | 2505 | 505 | 0505
+(1 row)
+
+CREATE TABLE local_tbl (a int, b int, c text);
+INSERT INTO local_tbl VALUES (1505, 505, 'foo');
+ANALYZE local_tbl;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM local_tbl t1 LEFT JOIN (SELECT *, (SELECT count(*) FROM async_pt WHERE a < 3000) FROM async_pt WHERE a < 3000) t2 ON t1.a = t2.a;
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
+ Nested Loop Left Join
+   Output: t1.a, t1.b, t1.c, async_pt.a, async_pt.b, async_pt.c, ($0)
+   Join Filter: (t1.a = async_pt.a)
+   InitPlan 1 (returns $0)
+     ->  Aggregate
+           Output: count(*)
+           ->  Append
+                 ->  Async Foreign Scan on public.async_p1 async_pt_4
+                       Remote SQL: SELECT NULL FROM public.base_tbl1 WHERE ((a < 3000))
+                 ->  Async Foreign Scan on public.async_p2 async_pt_5
+                       Remote SQL: SELECT NULL FROM public.base_tbl2 WHERE ((a < 3000))
+   ->  Seq Scan on public.local_tbl t1
+         Output: t1.a, t1.b, t1.c
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 async_pt_1
+               Output: async_pt_1.a, async_pt_1.b, async_pt_1.c, $0
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1 WHERE ((a < 3000))
+         ->  Async Foreign Scan on public.async_p2 async_pt_2
+               Output: async_pt_2.a, async_pt_2.b, async_pt_2.c, $0
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2 WHERE ((a < 3000))
+(20 rows)
+
+EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF)
+SELECT * FROM local_tbl t1 LEFT JOIN (SELECT *, (SELECT count(*) FROM async_pt WHERE a < 3000) FROM async_pt WHERE a < 3000) t2 ON t1.a = t2.a;
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
+ Nested Loop Left Join (actual rows=1 loops=1)
+   Join Filter: (t1.a = async_pt.a)
+   Rows Removed by Join Filter: 399
+   InitPlan 1 (returns $0)
+     ->  Aggregate (actual rows=1 loops=1)
+           ->  Append (actual rows=400 loops=1)
+                 ->  Async Foreign Scan on async_p1 async_pt_4 (actual rows=200 loops=1)
+                 ->  Async Foreign Scan on async_p2 async_pt_5 (actual rows=200 loops=1)
+   ->  Seq Scan on local_tbl t1 (actual rows=1 loops=1)
+   ->  Append (actual rows=400 loops=1)
+         ->  Async Foreign Scan on async_p1 async_pt_1 (actual rows=200 loops=1)
+         ->  Async Foreign Scan on async_p2 async_pt_2 (actual rows=200 loops=1)
+(12 rows)
+
+SELECT * FROM local_tbl t1 LEFT JOIN (SELECT *, (SELECT count(*) FROM async_pt WHERE a < 3000) FROM async_pt WHERE a < 3000) t2 ON t1.a = t2.a;
+  a   |  b  |  c  |  a   |  b  |  c   | count 
+------+-----+-----+------+-----+------+-------
+ 1505 | 505 | foo | 1505 | 505 | 0505 |   400
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM async_pt t1 WHERE t1.b === 505 LIMIT 1;
+                           QUERY PLAN                           
+----------------------------------------------------------------
+ Limit
+   Output: t1.a, t1.b, t1.c
+   ->  Append
+         ->  Async Foreign Scan on public.async_p1 t1_1
+               Output: t1_1.a, t1_1.b, t1_1.c
+               Filter: (t1_1.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl1
+         ->  Async Foreign Scan on public.async_p2 t1_2
+               Output: t1_2.a, t1_2.b, t1_2.c
+               Filter: (t1_2.b === 505)
+               Remote SQL: SELECT a, b, c FROM public.base_tbl2
+         ->  Seq Scan on public.async_p3 t1_3
+               Output: t1_3.a, t1_3.b, t1_3.c
+               Filter: (t1_3.b === 505)
+(14 rows)
+
+EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF)
+SELECT * FROM async_pt t1 WHERE t1.b === 505 LIMIT 1;
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Limit (actual rows=1 loops=1)
+   ->  Append (actual rows=1 loops=1)
+         ->  Async Foreign Scan on async_p1 t1_1 (actual rows=0 loops=1)
+               Filter: (b === 505)
+         ->  Async Foreign Scan on async_p2 t1_2 (actual rows=0 loops=1)
+               Filter: (b === 505)
+         ->  Seq Scan on async_p3 t1_3 (actual rows=1 loops=1)
+               Filter: (b === 505)
+               Rows Removed by Filter: 101
+(9 rows)
+
+SELECT * FROM async_pt t1 WHERE t1.b === 505 LIMIT 1;
+  a   |  b  |  c   
+------+-----+------
+ 3505 | 505 | 0505
+(1 row)
+
+-- Check with foreign modify
+CREATE TABLE base_tbl3 (a int, b int, c text);
+CREATE FOREIGN TABLE remote_tbl (a int, b int, c text)
+  SERVER loopback OPTIONS (table_name 'base_tbl3');
+INSERT INTO remote_tbl VALUES (2505, 505, 'bar');
+CREATE TABLE base_tbl4 (a int, b int, c text);
+CREATE FOREIGN TABLE insert_tbl (a int, b int, c text)
+  SERVER loopback OPTIONS (table_name 'base_tbl4');
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO insert_tbl (SELECT * FROM local_tbl UNION ALL SELECT * FROM remote_tbl);
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Insert on public.insert_tbl
+   Remote SQL: INSERT INTO public.base_tbl4(a, b, c) VALUES ($1, $2, $3)
+   Batch Size: 1
+   ->  Append
+         ->  Seq Scan on public.local_tbl
+               Output: local_tbl.a, local_tbl.b, local_tbl.c
+         ->  Async Foreign Scan on public.remote_tbl
+               Output: remote_tbl.a, remote_tbl.b, remote_tbl.c
+               Remote SQL: SELECT a, b, c FROM public.base_tbl3
+(9 rows)
+
+INSERT INTO insert_tbl (SELECT * FROM local_tbl UNION ALL SELECT * FROM remote_tbl);
+SELECT * FROM insert_tbl ORDER BY a;
+  a   |  b  |  c  
+------+-----+-----
+ 1505 | 505 | foo
+ 2505 | 505 | bar
+(2 rows)
+
+-- Check with direct modify
+EXPLAIN (VERBOSE, COSTS OFF)
+WITH t AS (UPDATE remote_tbl SET c = c || c RETURNING *)
+INSERT INTO join_tbl SELECT * FROM async_pt LEFT JOIN t ON (async_pt.a = t.a AND async_pt.b = t.b) WHERE async_pt.b === 505;
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
+ Insert on public.join_tbl
+   CTE t
+     ->  Update on public.remote_tbl
+           Output: remote_tbl.a, remote_tbl.b, remote_tbl.c
+           ->  Foreign Update on public.remote_tbl
+                 Remote SQL: UPDATE public.base_tbl3 SET c = (c || c) RETURNING a, b, c
+   ->  Nested Loop Left Join
+         Output: async_pt.a, async_pt.b, async_pt.c, t.a, t.b, t.c
+         Join Filter: ((async_pt.a = t.a) AND (async_pt.b = t.b))
+         ->  Append
+               ->  Async Foreign Scan on public.async_p1 async_pt_1
+                     Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+                     Filter: (async_pt_1.b === 505)
+                     Remote SQL: SELECT a, b, c FROM public.base_tbl1
+               ->  Async Foreign Scan on public.async_p2 async_pt_2
+                     Output: async_pt_2.a, async_pt_2.b, async_pt_2.c
+                     Filter: (async_pt_2.b === 505)
+                     Remote SQL: SELECT a, b, c FROM public.base_tbl2
+               ->  Seq Scan on public.async_p3 async_pt_3
+                     Output: async_pt_3.a, async_pt_3.b, async_pt_3.c
+                     Filter: (async_pt_3.b === 505)
+         ->  CTE Scan on t
+               Output: t.a, t.b, t.c
+(23 rows)
+
+WITH t AS (UPDATE remote_tbl SET c = c || c RETURNING *)
+INSERT INTO join_tbl SELECT * FROM async_pt LEFT JOIN t ON (async_pt.a = t.a AND async_pt.b = t.b) WHERE async_pt.b === 505;
+SELECT * FROM join_tbl ORDER BY a1;
+  a1  | b1  |  c1  |  a2  | b2  |   c2   
+------+-----+------+------+-----+--------
+ 1505 | 505 | 0505 |      |     | 
+ 2505 | 505 | 0505 | 2505 | 505 | barbar
+ 3505 | 505 | 0505 |      |     | 
+(3 rows)
+
+DELETE FROM join_tbl;
+DROP TABLE local_tbl;
+DROP FOREIGN TABLE remote_tbl;
+DROP FOREIGN TABLE insert_tbl;
+DROP TABLE base_tbl3;
+DROP TABLE base_tbl4;
+RESET enable_mergejoin;
+RESET enable_hashjoin;
+-- Test that UPDATE/DELETE with inherited target works with async_capable enabled
+EXPLAIN (VERBOSE, COSTS OFF)
+UPDATE async_pt SET c = c || c WHERE b = 0 RETURNING *;
+                                                QUERY PLAN                                                
+----------------------------------------------------------------------------------------------------------
+ Update on public.async_pt
+   Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+   Foreign Update on public.async_p1 async_pt_1
+   Foreign Update on public.async_p2 async_pt_2
+   Update on public.async_p3 async_pt_3
+   ->  Append
+         ->  Foreign Update on public.async_p1 async_pt_1
+               Remote SQL: UPDATE public.base_tbl1 SET c = (c || c) WHERE ((b = 0)) RETURNING a, b, c
+         ->  Foreign Update on public.async_p2 async_pt_2
+               Remote SQL: UPDATE public.base_tbl2 SET c = (c || c) WHERE ((b = 0)) RETURNING a, b, c
+         ->  Seq Scan on public.async_p3 async_pt_3
+               Output: (async_pt_3.c || async_pt_3.c), async_pt_3.tableoid, async_pt_3.ctid, NULL::record
+               Filter: (async_pt_3.b = 0)
+(13 rows)
+
+UPDATE async_pt SET c = c || c WHERE b = 0 RETURNING *;
+  a   | b |    c     
+------+---+----------
+ 1000 | 0 | 00000000
+ 2000 | 0 | 00000000
+ 3000 | 0 | 00000000
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+DELETE FROM async_pt WHERE b = 0 RETURNING *;
+                                        QUERY PLAN                                        
+------------------------------------------------------------------------------------------
+ Delete on public.async_pt
+   Output: async_pt_1.a, async_pt_1.b, async_pt_1.c
+   Foreign Delete on public.async_p1 async_pt_1
+   Foreign Delete on public.async_p2 async_pt_2
+   Delete on public.async_p3 async_pt_3
+   ->  Append
+         ->  Foreign Delete on public.async_p1 async_pt_1
+               Remote SQL: DELETE FROM public.base_tbl1 WHERE ((b = 0)) RETURNING a, b, c
+         ->  Foreign Delete on public.async_p2 async_pt_2
+               Remote SQL: DELETE FROM public.base_tbl2 WHERE ((b = 0)) RETURNING a, b, c
+         ->  Seq Scan on public.async_p3 async_pt_3
+               Output: async_pt_3.tableoid, async_pt_3.ctid
+               Filter: (async_pt_3.b = 0)
+(13 rows)
+
+DELETE FROM async_pt WHERE b = 0 RETURNING *;
+  a   | b |    c     
+------+---+----------
+ 1000 | 0 | 00000000
+ 2000 | 0 | 00000000
+ 3000 | 0 | 00000000
+(3 rows)
+
+-- Check EXPLAIN ANALYZE for a query that scans empty partitions asynchronously
+DELETE FROM async_p1;
+DELETE FROM async_p2;
+DELETE FROM async_p3;
+EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF)
+SELECT * FROM async_pt;
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Append (actual rows=0 loops=1)
+   ->  Async Foreign Scan on async_p1 async_pt_1 (actual rows=0 loops=1)
+   ->  Async Foreign Scan on async_p2 async_pt_2 (actual rows=0 loops=1)
+   ->  Seq Scan on async_p3 async_pt_3 (actual rows=0 loops=1)
+(4 rows)
+
+-- Clean up
+DROP TABLE async_pt;
+DROP TABLE base_tbl1;
+DROP TABLE base_tbl2;
+DROP TABLE result_tbl;
+DROP TABLE join_tbl;
+-- Test that an asynchronous fetch is processed before restarting the scan in
+-- ReScanForeignScan
+CREATE TABLE base_tbl (a int, b int);
+INSERT INTO base_tbl VALUES (1, 11), (2, 22), (3, 33);
+CREATE FOREIGN TABLE foreign_tbl (b int)
+  SERVER loopback OPTIONS (table_name 'base_tbl');
+CREATE FOREIGN TABLE foreign_tbl2 () INHERITS (foreign_tbl)
+  SERVER loopback OPTIONS (table_name 'base_tbl');
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT a FROM base_tbl WHERE a IN (SELECT a FROM foreign_tbl);
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
+ Seq Scan on public.base_tbl
+   Output: base_tbl.a
+   Filter: (SubPlan 1)
+   SubPlan 1
+     ->  Result
+           Output: base_tbl.a
+           ->  Append
+                 ->  Async Foreign Scan on public.foreign_tbl foreign_tbl_1
+                       Remote SQL: SELECT NULL FROM public.base_tbl
+                 ->  Async Foreign Scan on public.foreign_tbl2 foreign_tbl_2
+                       Remote SQL: SELECT NULL FROM public.base_tbl
+(11 rows)
+
+SELECT a FROM base_tbl WHERE a IN (SELECT a FROM foreign_tbl);
+ a 
+---
+ 1
+ 2
+ 3
+(3 rows)
+
+-- Clean up
+DROP FOREIGN TABLE foreign_tbl CASCADE;
+NOTICE:  drop cascades to foreign table foreign_tbl2
+DROP TABLE base_tbl;
+ALTER SERVER loopback OPTIONS (DROP async_capable);
+ALTER SERVER loopback2 OPTIONS (DROP async_capable);
+-- ===================================================================
+-- test invalid server, foreign table and foreign data wrapper options
+-- ===================================================================
+-- Invalid fdw_startup_cost option
+CREATE SERVER inv_scst FOREIGN DATA WRAPPER postgres_fdw
+	OPTIONS(fdw_startup_cost '100$%$#$#');
+ERROR:  invalid value for floating point option "fdw_startup_cost": 100$%$#$#
+-- Invalid fdw_tuple_cost option
+CREATE SERVER inv_scst FOREIGN DATA WRAPPER postgres_fdw
+	OPTIONS(fdw_tuple_cost '100$%$#$#');
+ERROR:  invalid value for floating point option "fdw_tuple_cost": 100$%$#$#
+-- Invalid fetch_size option
+CREATE FOREIGN TABLE inv_fsz (c1 int )
+	SERVER loopback OPTIONS (fetch_size '100$%$#$#');
+ERROR:  invalid value for integer option "fetch_size": 100$%$#$#
+-- Invalid batch_size option
+CREATE FOREIGN TABLE inv_bsz (c1 int )
+	SERVER loopback OPTIONS (batch_size '100$%$#$#');
+ERROR:  invalid value for integer option "batch_size": 100$%$#$#
+-- No option is allowed to be specified at foreign data wrapper level
+ALTER FOREIGN DATA WRAPPER postgres_fdw OPTIONS (nonexistent 'fdw');
+ERROR:  invalid option "nonexistent"
+HINT:  There are no valid options in this context.
+-- ===================================================================
+-- test postgres_fdw.application_name GUC
+-- ===================================================================
+--- Turn debug_discard_caches off for this test to make sure that
+--- the remote connection is alive when checking its application_name.
+SET debug_discard_caches = 0;
+-- Specify escape sequences in application_name option of a server
+-- object so as to test that they are replaced with status information
+-- expectedly.
+--
+-- Since pg_stat_activity.application_name may be truncated to less than
+-- NAMEDATALEN characters, note that substring() needs to be used
+-- at the condition of test query to make sure that the string consisting
+-- of database name and process ID is also less than that.
+ALTER SERVER loopback2 OPTIONS (application_name 'fdw_%d%p');
+SELECT 1 FROM ft6 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+  WHERE application_name =
+    substring('fdw_' || current_database() || pg_backend_pid() for
+      current_setting('max_identifier_length')::int);
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+-- postgres_fdw.application_name overrides application_name option
+-- of a server object if both settings are present.
+SET postgres_fdw.application_name TO 'fdw_%a%u%%';
+SELECT 1 FROM ft6 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+  WHERE application_name =
+    substring('fdw_' || current_setting('application_name') ||
+      CURRENT_USER || '%' for current_setting('max_identifier_length')::int);
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+-- Test %c (session ID) and %C (cluster name) escape sequences.
+SET postgres_fdw.application_name TO 'fdw_%C%c';
+SELECT 1 FROM ft6 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+  WHERE application_name =
+    substring('fdw_' || current_setting('cluster_name') ||
+      to_hex(trunc(EXTRACT(EPOCH FROM (SELECT backend_start FROM
+      pg_stat_get_activity(pg_backend_pid()))))::integer) || '.' ||
+      to_hex(pg_backend_pid())
+      for current_setting('max_identifier_length')::int);
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+--Clean up
+RESET postgres_fdw.application_name;
+RESET debug_discard_caches;
+-- ===================================================================
+-- test parallel commit
+-- ===================================================================
+ALTER SERVER loopback OPTIONS (ADD parallel_commit 'true');
+ALTER SERVER loopback2 OPTIONS (ADD parallel_commit 'true');
+CREATE TABLE ploc1 (f1 int, f2 text);
+CREATE FOREIGN TABLE prem1 (f1 int, f2 text)
+  SERVER loopback OPTIONS (table_name 'ploc1');
+CREATE TABLE ploc2 (f1 int, f2 text);
+CREATE FOREIGN TABLE prem2 (f1 int, f2 text)
+  SERVER loopback2 OPTIONS (table_name 'ploc2');
+BEGIN;
+INSERT INTO prem1 VALUES (101, 'foo');
+INSERT INTO prem2 VALUES (201, 'bar');
+COMMIT;
+SELECT * FROM prem1;
+ f1  | f2  
+-----+-----
+ 101 | foo
+(1 row)
+
+SELECT * FROM prem2;
+ f1  | f2  
+-----+-----
+ 201 | bar
+(1 row)
+
+BEGIN;
+SAVEPOINT s;
+INSERT INTO prem1 VALUES (102, 'foofoo');
+INSERT INTO prem2 VALUES (202, 'barbar');
+RELEASE SAVEPOINT s;
+COMMIT;
+SELECT * FROM prem1;
+ f1  |   f2   
+-----+--------
+ 101 | foo
+ 102 | foofoo
+(2 rows)
+
+SELECT * FROM prem2;
+ f1  |   f2   
+-----+--------
+ 201 | bar
+ 202 | barbar
+(2 rows)
+
+-- This tests executing DEALLOCATE ALL against foreign servers in parallel
+-- during pre-commit
+BEGIN;
+SAVEPOINT s;
+INSERT INTO prem1 VALUES (103, 'baz');
+INSERT INTO prem2 VALUES (203, 'qux');
+ROLLBACK TO SAVEPOINT s;
+RELEASE SAVEPOINT s;
+INSERT INTO prem1 VALUES (104, 'bazbaz');
+INSERT INTO prem2 VALUES (204, 'quxqux');
+COMMIT;
+SELECT * FROM prem1;
+ f1  |   f2   
+-----+--------
+ 101 | foo
+ 102 | foofoo
+ 104 | bazbaz
+(3 rows)
+
+SELECT * FROM prem2;
+ f1  |   f2   
+-----+--------
+ 201 | bar
+ 202 | barbar
+ 204 | quxqux
+(3 rows)
+
+ALTER SERVER loopback OPTIONS (DROP parallel_commit);
+ALTER SERVER loopback2 OPTIONS (DROP parallel_commit);
+-- ===================================================================
+-- test for health-check feature
+-- ===================================================================
+-- Disable debug_discard_caches in order to manage remote connections
+SET debug_discard_caches TO '0';
+-- Disconnect once and set application_name to an arbitrary value
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ ?column? 
+----------
+        1
+(1 row)
+
+ALTER SERVER loopback OPTIONS (SET application_name 'healthcheck');
+-- Set GUC for checking the health of remote servers
+SET postgres_fdw.health_check_interval TO '1s';
+ERROR:  invalid value for parameter "postgres_fdw.health_check_interval": 1000
+DETAIL:  postgres_fdw.health_check_interval must be set to 0 on this platform
+BEGIN;
+SELECT 1 FROM ft1 LIMIT 1;
+ ?column? 
+----------
+        1
+(1 row)
+
+-- Terminate the remote backend process
+-- FIXME: this should be skipped in some platforms
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+       WHERE application_name = 'healthcheck';
+ pg_terminate_backend 
+----------------------
+ t
+(1 row)
+
+-- While sleeping the process down will be detected.
+SELECT pg_sleep(3);
+ pg_sleep 
+----------
+ 
+(1 row)
+
+COMMIT;
+ERROR:  server closed the connection unexpectedly
+	This probably means the server terminated abnormally
+	before or while processing the request.
+CONTEXT:  remote SQL command: COMMIT TRANSACTION
+-- Clean up
+RESET debug_discard_caches;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index e48ccd286b..375cde1b84 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -3682,3 +3682,30 @@ SELECT * FROM prem2;
 
 ALTER SERVER loopback OPTIONS (DROP parallel_commit);
 ALTER SERVER loopback2 OPTIONS (DROP parallel_commit);
+
+-- ===================================================================
+-- test for health-check feature
+-- ===================================================================
+
+-- Disable debug_discard_caches in order to manage remote connections
+SET debug_discard_caches TO '0';
+
+-- Disconnect once and set application_name to an arbitrary value
+SELECT 1 FROM postgres_fdw_disconnect_all();
+ALTER SERVER loopback OPTIONS (SET application_name 'healthcheck');
+
+-- Set GUC for checking the health of remote servers
+SET postgres_fdw.health_check_interval TO '1s';
+
+BEGIN;
+SELECT 1 FROM ft1 LIMIT 1;
+-- Terminate the remote backend process
+-- FIXME: this should be skipped in some platforms
+SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
+       WHERE application_name = 'healthcheck';
+-- While sleeping the process down will be detected.
+SELECT pg_sleep(3);
+COMMIT;
+
+-- Clean up
+RESET debug_discard_caches;
-- 
2.27.0



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