Add idle_session_timeout.

This GUC variable works much like idle_in_transaction_session_timeout,
in that it kills sessions that have waited too long for a new client
query.  But it applies when we're not in a transaction, rather than
when we are.

Li Japin, reviewed by David Johnston and Hayato Kuroda, some
fixes by me

Discussion: https://postgr.es/m/763A0689-F189-459E-946F-F0EC4458980B@hotmail.com

10 files changed, 71 insertions, 9 deletions

diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 9b6aa2fe0de..0366a7cc004 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -61,6 +61,7 @@ int			DeadlockTimeout = 1000;
 int			StatementTimeout = 0;
 int			LockTimeout = 0;
 int			IdleInTransactionSessionTimeout = 0;
+int			IdleSessionTimeout = 0;
 bool		log_lock_waits = false;
 
 /* Pointer to this process's PGPROC struct, if any */
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 9d98c028a2d..2b53ebf97dc 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3242,14 +3242,28 @@ ProcessInterrupts(void)
 
 	if (IdleInTransactionSessionTimeoutPending)
 	{
-		/* Has the timeout setting changed since last we looked? */
+		/*
+		 * If the GUC has been reset to zero, ignore the signal.  This is
+		 * important because the GUC update itself won't disable any pending
+		 * interrupt.
+		 */
 		if (IdleInTransactionSessionTimeout > 0)
 			ereport(FATAL,
 					(errcode(ERRCODE_IDLE_IN_TRANSACTION_SESSION_TIMEOUT),
 					 errmsg("terminating connection due to idle-in-transaction timeout")));
 		else
 			IdleInTransactionSessionTimeoutPending = false;
+	}
 
+	if (IdleSessionTimeoutPending)
+	{
+		/* As above, ignore the signal if the GUC has been reset to zero. */
+		if (IdleSessionTimeout > 0)
+			ereport(FATAL,
+					(errcode(ERRCODE_IDLE_SESSION_TIMEOUT),
+					 errmsg("terminating connection due to idle-session timeout")));
+		else
+			IdleSessionTimeoutPending = false;
 	}
 
 	if (ProcSignalBarrierPending)
@@ -3826,7 +3840,8 @@ PostgresMain(int argc, char *argv[],
 	StringInfoData input_message;
 	sigjmp_buf	local_sigjmp_buf;
 	volatile bool send_ready_for_query = true;
-	bool		disable_idle_in_transaction_timeout = false;
+	bool		idle_in_transaction_timeout_enabled = false;
+	bool		idle_session_timeout_enabled = false;
 
 	/* Initialize startup process environment if necessary. */
 	if (!IsUnderPostmaster)
@@ -4228,6 +4243,8 @@ PostgresMain(int argc, char *argv[],
 		 * processing of batched messages, and because we don't want to report
 		 * uncommitted updates (that confuses autovacuum).  The notification
 		 * processor wants a call too, if we are not in a transaction block.
+		 *
+		 * Also, if an idle timeout is enabled, start the timer for that.
 		 */
 		if (send_ready_for_query)
 		{
@@ -4239,7 +4256,7 @@ PostgresMain(int argc, char *argv[],
 				/* Start the idle-in-transaction timer */
 				if (IdleInTransactionSessionTimeout > 0)
 				{
-					disable_idle_in_transaction_timeout = true;
+					idle_in_transaction_timeout_enabled = true;
 					enable_timeout_after(IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
 										 IdleInTransactionSessionTimeout);
 				}
@@ -4252,7 +4269,7 @@ PostgresMain(int argc, char *argv[],
 				/* Start the idle-in-transaction timer */
 				if (IdleInTransactionSessionTimeout > 0)
 				{
-					disable_idle_in_transaction_timeout = true;
+					idle_in_transaction_timeout_enabled = true;
 					enable_timeout_after(IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
 										 IdleInTransactionSessionTimeout);
 				}
@@ -4275,6 +4292,14 @@ PostgresMain(int argc, char *argv[],
 
 				set_ps_display("idle");
 				pgstat_report_activity(STATE_IDLE, NULL);
+
+				/* Start the idle-session timer */
+				if (IdleSessionTimeout > 0)
+				{
+					idle_session_timeout_enabled = true;
+					enable_timeout_after(IDLE_SESSION_TIMEOUT,
+										 IdleSessionTimeout);
+				}
 			}
 
 			/* Report any recently-changed GUC options */
@@ -4310,12 +4335,21 @@ PostgresMain(int argc, char *argv[],
 		DoingCommandRead = false;
 
 		/*
-		 * (5) turn off the idle-in-transaction timeout
+		 * (5) turn off the idle-in-transaction and idle-session timeouts, if
+		 * active.
+		 *
+		 * At most one of these two will be active, so there's no need to
+		 * worry about combining the timeout.c calls into one.
 		 */
-		if (disable_idle_in_transaction_timeout)
+		if (idle_in_transaction_timeout_enabled)
 		{
 			disable_timeout(IDLE_IN_TRANSACTION_SESSION_TIMEOUT, false);
-			disable_idle_in_transaction_timeout = false;
+			idle_in_transaction_timeout_enabled = false;
+		}
+		if (idle_session_timeout_enabled)
+		{
+			disable_timeout(IDLE_SESSION_TIMEOUT, false);
+			idle_session_timeout_enabled = false;
 		}
 
 		/*
diff --git a/src/backend/utils/errcodes.txt b/src/backend/utils/errcodes.txt
index 64ca2deec99..1d5a78e73d6 100644
--- a/src/backend/utils/errcodes.txt
+++ b/src/backend/utils/errcodes.txt
@@ -109,6 +109,7 @@ Section: Class 08 - Connection Exception
 08004    E    ERRCODE_SQLSERVER_REJECTED_ESTABLISHMENT_OF_SQLCONNECTION      sqlserver_rejected_establishment_of_sqlconnection
 08007    E    ERRCODE_TRANSACTION_RESOLUTION_UNKNOWN                         transaction_resolution_unknown
 08P01    E    ERRCODE_PROTOCOL_VIOLATION                                     protocol_violation
+08P02    E    ERRCODE_IDLE_SESSION_TIMEOUT                                   idle_session_timeout
 
 Section: Class 09 - Triggered Action Exception
 
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 3d5d6cc033c..ea28769d6a3 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -32,6 +32,7 @@ volatile sig_atomic_t QueryCancelPending = false;
 volatile sig_atomic_t ProcDiePending = false;
 volatile sig_atomic_t ClientConnectionLost = false;
 volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
+volatile sig_atomic_t IdleSessionTimeoutPending = false;
 volatile sig_atomic_t ProcSignalBarrierPending = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 QueryCancelHoldoffCount = 0;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 59b3f4b1359..e5965bc517d 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -72,6 +72,7 @@ static void ShutdownPostgres(int code, Datum arg);
 static void StatementTimeoutHandler(void);
 static void LockTimeoutHandler(void);
 static void IdleInTransactionSessionTimeoutHandler(void);
+static void IdleSessionTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
@@ -619,6 +620,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 		RegisterTimeout(LOCK_TIMEOUT, LockTimeoutHandler);
 		RegisterTimeout(IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
 						IdleInTransactionSessionTimeoutHandler);
+		RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
 	}
 
 	/*
@@ -1233,6 +1235,14 @@ IdleInTransactionSessionTimeoutHandler(void)
 	SetLatch(MyLatch);
 }
 
+static void
+IdleSessionTimeoutHandler(void)
+{
+	IdleSessionTimeoutPending = 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 1ccf7593eea..daf9c127cde 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2509,7 +2509,7 @@ static struct config_int ConfigureNamesInt[] =
 
 	{
 		{"idle_in_transaction_session_timeout", PGC_USERSET, CLIENT_CONN_STATEMENT,
-			gettext_noop("Sets the maximum allowed duration of any idling transaction."),
+			gettext_noop("Sets the maximum allowed idle time between queries, when in a transaction."),
 			gettext_noop("A value of 0 turns off the timeout."),
 			GUC_UNIT_MS
 		},
@@ -2519,6 +2519,17 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
+		{"idle_session_timeout", PGC_USERSET, CLIENT_CONN_STATEMENT,
+			gettext_noop("Sets the maximum allowed idle time between queries, when not in a transaction."),
+			gettext_noop("A value of 0 turns off the timeout."),
+			GUC_UNIT_MS
+		},
+		&IdleSessionTimeout,
+		0, 0, INT_MAX,
+		NULL, NULL, NULL
+	},
+
+	{
 		{"vacuum_freeze_min_age", PGC_USERSET, CLIENT_CONN_STATEMENT,
 			gettext_noop("Minimum age at which VACUUM should freeze a table row."),
 			NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 5298e18ecd5..033aa335a01 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -663,6 +663,7 @@
 #statement_timeout = 0			# in milliseconds, 0 is disabled
 #lock_timeout = 0			# in milliseconds, 0 is disabled
 #idle_in_transaction_session_timeout = 0	# in milliseconds, 0 is disabled
+#idle_session_timeout = 0		# in milliseconds, 0 is disabled
 #vacuum_freeze_min_age = 50000000
 #vacuum_freeze_table_age = 150000000
 #vacuum_multixact_freeze_min_age = 5000000
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 2c71db79c0a..1bdc97e3082 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -82,6 +82,7 @@ extern PGDLLIMPORT volatile sig_atomic_t InterruptPending;
 extern PGDLLIMPORT volatile sig_atomic_t QueryCancelPending;
 extern PGDLLIMPORT volatile sig_atomic_t ProcDiePending;
 extern PGDLLIMPORT volatile sig_atomic_t IdleInTransactionSessionTimeoutPending;
+extern PGDLLIMPORT volatile sig_atomic_t IdleSessionTimeoutPending;
 extern PGDLLIMPORT volatile sig_atomic_t ProcSignalBarrierPending;
 
 extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 989c5849d45..0786fcf103a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -378,6 +378,7 @@ extern PGDLLIMPORT int DeadlockTimeout;
 extern PGDLLIMPORT int StatementTimeout;
 extern PGDLLIMPORT int LockTimeout;
 extern PGDLLIMPORT int IdleInTransactionSessionTimeout;
+extern PGDLLIMPORT int IdleSessionTimeout;
 extern bool log_lock_waits;
 
 
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 8adb4e14cac..ecb2a366a5f 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -31,10 +31,11 @@ typedef enum TimeoutId
 	STANDBY_TIMEOUT,
 	STANDBY_LOCK_TIMEOUT,
 	IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
+	IDLE_SESSION_TIMEOUT,
 	/* First user-definable timeout reason */
 	USER_TIMEOUT,
 	/* Maximum number of timeout reasons */
-	MAX_TIMEOUTS = 16
+	MAX_TIMEOUTS = USER_TIMEOUT + 10
 } TimeoutId;
 
 /* callback function signature */