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

5 files changed, 25 insertions, 1 deletions

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