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List: postgresql-general
Subject: [HACKERS] Idle In Transaction Session Timeout, revived
From: Vik Fearing <vik () 2ndquadrant ! fr>
Date: 2016-01-31 13:33:04
Message-ID: 56AE0D10.6060805 () 2ndquadrant ! fr
[Download RAW message or body]
Attached is a rebased and revised version of my
idle_in_transaction_session_timeout patch from last year.
This version does not suffer the problems the old one did where it would
jump out of SSL code thanks to Andres' patch in commit
4f85fde8eb860f263384fffdca660e16e77c7f76.
The basic idea is if a session remains idle in a transaction for longer
than the configured time, that connection will be dropped thus releasing
the connection slot and any locks that may have been held by the broken
client.
Added to the March commitfest.
--
Vik Fearing +33 6 46 75 15 36
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
["iitt.v4.patch" (text/x-patch)]
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 392eb70..9cccf0e 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5908,6 +5908,29 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
</listitem>
</varlistentry>
+ <varlistentry id="guc-idle-in-transaction-session-timeout" \
xreflabel="idle_in_transaction_session_timeout"> + \
<term><varname>idle_in_transaction_session_timeout</varname> (<type>integer</type>) + \
<indexterm> + <primary><varname>idle_in_transaction_session_timeout</> \
configuration parameter</primary> + </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Terminate any session with an open transaction that has been idle for
+ longer than the specified duration in milliseconds. This allows any locks to
+ be released and the connection slot to be reused.
+ </para>
+ <para>
+ Sessions in the state "idle in transaction (aborted)" occupy a connection
+ slot but because they hold no locks, they are not considered by this
+ parameter.
+ </para>
+ <para>
+ The default value of 0 means that such sessions will not be terminated.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-vacuum-freeze-table-age" \
xreflabel="vacuum_freeze_table_age">
<term><varname>vacuum_freeze_table_age</varname> (<type>integer</type>)
<indexterm>
diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index dd3c775..6352e12 100644
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -725,7 +725,9 @@ ERROR: could not serialize access due to read/write dependencies \
among transact <listitem>
<para>
Don't leave connections dangling <quote>idle in transaction</quote>
- longer than necessary.
+ longer than necessary. The configuration parameter
+ <xref linkend="guc-idle-in-transaction-session-timeout"> may be used to
+ automatically disconnect lingering sessions.
</para>
</listitem>
<listitem>
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 3690753..b711da4 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -57,6 +57,7 @@
int DeadlockTimeout = 1000;
int StatementTimeout = 0;
int LockTimeout = 0;
+int IdleInTransactionSessionTimeout = 0;
bool log_lock_waits = false;
/* Pointer to this process's PGPROC and PGXACT structs, if any */
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 390816b..7f03d8e 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -2978,6 +2978,11 @@ ProcessInterrupts(void)
}
}
+ if (IdleInTransactionTimeoutSessionPending)
+ ereport(FATAL,
+ (errcode(ERRCODE_IDLE_IN_TRANSACTION_SESSION_TIMEOUT),
+ errmsg("terminating connection due to idle-in-transaction timeout")));
+
if (ParallelMessagePending)
HandleParallelMessages();
}
@@ -3947,6 +3952,11 @@ PostgresMain(int argc, char *argv[],
{
set_ps_display("idle in transaction", false);
pgstat_report_activity(STATE_IDLEINTRANSACTION, NULL);
+
+ /* Start the idle-in-transaction timer */
+ if (IdleInTransactionSessionTimeout > 0)
+ enable_timeout_after(IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
+ IdleInTransactionSessionTimeout);
}
else
{
@@ -3987,7 +3997,13 @@ PostgresMain(int argc, char *argv[],
DoingCommandRead = false;
/*
- * (5) check for any other interesting events that happened while we
+ * (5) turn off the idle-in-transaction timeout
+ */
+ if (IdleInTransactionSessionTimeout > 0)
+ disable_timeout(IDLE_IN_TRANSACTION_SESSION_TIMEOUT, false);
+
+ /*
+ * (6) check for any other interesting events that happened while we
* slept.
*/
if (got_SIGHUP)
@@ -3997,7 +4013,7 @@ PostgresMain(int argc, char *argv[],
}
/*
- * (6) process the command. But ignore it if we're skipping till
+ * (7) process the command. But ignore it if we're skipping till
* Sync.
*/
if (ignore_till_sync && firstchar != EOF)
diff --git a/src/backend/utils/errcodes.txt b/src/backend/utils/errcodes.txt
index 04c9c00..1a920e8 100644
--- a/src/backend/utils/errcodes.txt
+++ b/src/backend/utils/errcodes.txt
@@ -229,6 +229,7 @@ Section: Class 25 - Invalid Transaction State
25007 E ERRCODE_SCHEMA_AND_DATA_STATEMENT_MIXING_NOT_SUPPORTED \
schema_and_data_statement_mixing_not_supported 25P01 E \
ERRCODE_NO_ACTIVE_SQL_TRANSACTION \
no_active_sql_transaction 25P02 E ERRCODE_IN_FAILED_SQL_TRANSACTION \
in_failed_sql_transaction +25P03 E ERRCODE_IDLE_IN_TRANSACTION_SESSION_TIMEOUT \
idle_in_transaction_session_timeout
Section: Class 26 - Invalid SQL Statement Name
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index ccd9c8e..0069255 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -30,6 +30,7 @@ volatile bool InterruptPending = false;
volatile bool QueryCancelPending = false;
volatile bool ProcDiePending = false;
volatile bool ClientConnectionLost = false;
+volatile bool IdleInTransactionTimeoutSessionPending = false;
volatile uint32 InterruptHoldoffCount = 0;
volatile uint32 QueryCancelHoldoffCount = 0;
volatile uint32 CritSectionCount = 0;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index e22d4db..66c1fea 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -70,6 +70,7 @@ static void InitCommunication(void);
static void ShutdownPostgres(int code, Datum arg);
static void StatementTimeoutHandler(void);
static void LockTimeoutHandler(void);
+static void IdleInTransactionSessionTimeoutHandler(void);
static bool ThereIsAtLeastOneRole(void);
static void process_startup_options(Port *port, bool am_superuser);
static void process_settings(Oid databaseid, Oid roleid);
@@ -597,6 +598,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char \
*username, RegisterTimeout(DEADLOCK_TIMEOUT, CheckDeadLockAlert);
RegisterTimeout(STATEMENT_TIMEOUT, StatementTimeoutHandler);
RegisterTimeout(LOCK_TIMEOUT, LockTimeoutHandler);
+ RegisterTimeout(IDLE_IN_TRANSACTION_SESSION_TIMEOUT, \
IdleInTransactionSessionTimeoutHandler); }
/*
@@ -1178,6 +1180,13 @@ LockTimeoutHandler(void)
kill(MyProcPid, SIGINT);
}
+static void
+IdleInTransactionSessionTimeoutHandler(void)
+{
+ IdleInTransactionTimeoutSessionPending = 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 38ba82f..d7322c2 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2052,6 +2052,17 @@ 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("A value of 0 turns off the timeout."),
+ GUC_UNIT_MS
+ },
+ &IdleInTransactionSessionTimeout,
+ 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 029114f..c7044da 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -527,6 +527,7 @@
#session_replication_role = 'origin'
#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
#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 cc7833e..3dd70f1 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -80,6 +80,7 @@
extern PGDLLIMPORT volatile bool InterruptPending;
extern PGDLLIMPORT volatile bool QueryCancelPending;
extern PGDLLIMPORT volatile bool ProcDiePending;
+extern PGDLLIMPORT volatile bool IdleInTransactionTimeoutSessionPending;
extern volatile bool ClientConnectionLost;
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 3441288..d31273c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -241,6 +241,7 @@ extern PGPROC *PreparedXactProcs;
extern int DeadlockTimeout;
extern int StatementTimeout;
extern int LockTimeout;
+extern int IdleInTransactionSessionTimeout;
extern bool log_lock_waits;
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 723b475..59a4afe 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -29,6 +29,7 @@ typedef enum TimeoutId
STATEMENT_TIMEOUT,
STANDBY_DEADLOCK_TIMEOUT,
STANDBY_TIMEOUT,
+ IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
/* First user-definable timeout reason */
USER_TIMEOUT,
/* Maximum number of timeout reasons */
--
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