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michaelpqmichaelpq
committedApr 6, 2019
Add support TCP user timeout in libpq and the backend server
Similarly to the set of parameters for keepalive, a connection parameter for libpq is added as well as a backend GUC, called tcp_user_timeout. Increasing the TCP user timeout is useful to allow a connection to survive extended periods without end-to-end connection, and decreasing it allows application to fail faster. By default, the parameter is 0, which makes the connection use the system default, and follows a logic close to the keepalive parameters in its handling. When connecting through a Unix-socket domain, the parameters have no effect. Author: Ryohei Nagaura Reviewed-by: Fabien Coelho, Robert Haas, Kyotaro Horiguchi, Kirk Jamison, Mikalai Keida, Takayuki Tsunakawa, Andrei Yahorau Discussion: https://postgr.es/m/EDA4195584F5064680D8130B1CA91C45367328@G01JPEXMBYT04
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‎contrib/postgres_fdw/expected/postgres_fdw.out

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -151,6 +151,7 @@ ALTER SERVER testserver1 OPTIONS (
151151
keepalives 'value',
152152
keepalives_idle 'value',
153153
keepalives_interval 'value',
154+
tcp_user_timeout 'value',
154155
-- requiressl 'value',
155156
sslcompression 'value',
156157
sslmode 'value',

‎contrib/postgres_fdw/sql/postgres_fdw.sql

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -164,6 +164,7 @@ ALTER SERVER testserver1 OPTIONS (
164164
keepalives 'value',
165165
keepalives_idle 'value',
166166
keepalives_interval 'value',
167+
tcp_user_timeout 'value',
167168
-- requiressl 'value',
168169
sslcompression 'value',
169170
sslmode 'value',

‎doc/src/sgml/config.sgml

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -939,6 +939,31 @@ include_dir 'conf.d'
939939
</listitem>
940940
</varlistentry>
941941

942+
<varlistentry id="guc-tcp-user-timeout" xreflabel="tcp_user_timeout">
943+
<term><varname>tcp_user_timeout</varname> (<type>integer</type>)
944+
<indexterm>
945+
<primary><varname>tcp_user_timeout</varname> configuration parameter</primary>
946+
</indexterm>
947+
</term>
948+
<listitem>
949+
<para>
950+
Specifies the number of milliseconds that transmitted data may
951+
remain unacknowledged before a connection is forcibly closed.
952+
A value of 0 uses the system default.
953+
This parameter is supported only on systems that support
954+
<symbol>TCP_USER_TIMEOUT</symbol>; on other systems, it must be zero.
955+
In sessions connected via a Unix-domain socket, this parameter is
956+
ignored and always reads as zero.
957+
</para>
958+
<note>
959+
<para>
960+
This parameter is not supported on Windows and on Linux version
961+
2.6.36 or older.
962+
</para>
963+
</note>
964+
</listitem>
965+
</varlistentry>
966+
942967
</variablelist>
943968
</sect2>
944969

‎doc/src/sgml/libpq.sgml

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1249,6 +1249,20 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
12491249
</listitem>
12501250
</varlistentry>
12511251

1252+
<varlistentry id="libpq-tcp-user-timeout" xreflabel="libpq_tcp_user_timeout">
1253+
<term><literal>tcp_user_timeout</literal></term>
1254+
<listitem>
1255+
<para>
1256+
Controls the number of milliseconds that transmitted data may
1257+
remain unacknowledged before a connection is forcibly closed.
1258+
A value of zero uses the system default. This parameter is
1259+
ignored for connections made via a Unix-domain socket.
1260+
It is only supported on systems where <symbol>TCP_USER_TIMEOUT</symbol>
1261+
is available; on other systems, it has no effect.
1262+
</para>
1263+
</listitem>
1264+
</varlistentry>
1265+
12521266
<varlistentry id="libpq-connect-tty" xreflabel="tty">
12531267
<term><literal>tty</literal></term>
12541268
<listitem>

‎src/backend/libpq/pqcomm.c

Lines changed: 73 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -825,6 +825,7 @@ StreamConnection(pgsocket server_fd, Port *port)
825825
(void) pq_setkeepalivesidle(tcp_keepalives_idle, port);
826826
(void) pq_setkeepalivesinterval(tcp_keepalives_interval, port);
827827
(void) pq_setkeepalivescount(tcp_keepalives_count, port);
828+
(void) pq_settcpusertimeout(tcp_user_timeout, port);
828829
}
829830

830831
return STATUS_OK;
@@ -1926,3 +1927,75 @@ pq_setkeepalivescount(int count, Port *port)
19261927

19271928
return STATUS_OK;
19281929
}
1930+
1931+
int
1932+
pq_gettcpusertimeout(Port *port)
1933+
{
1934+
#ifdef TCP_USER_TIMEOUT
1935+
if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
1936+
return 0;
1937+
1938+
if (port->tcp_user_timeout != 0)
1939+
return port->tcp_user_timeout;
1940+
1941+
if (port->default_tcp_user_timeout == 0)
1942+
{
1943+
ACCEPT_TYPE_ARG3 size = sizeof(port->default_tcp_user_timeout);
1944+
1945+
if (getsockopt(port->sock, IPPROTO_TCP, TCP_USER_TIMEOUT,
1946+
(char *) &port->default_tcp_user_timeout,
1947+
&size) < 0)
1948+
{
1949+
elog(LOG, "getsockopt(%s) failed: %m", "TCP_USER_TIMEOUT");
1950+
port->default_tcp_user_timeout = -1; /* don't know */
1951+
}
1952+
}
1953+
1954+
return port->default_tcp_user_timeout;
1955+
#else
1956+
return 0;
1957+
#endif
1958+
}
1959+
1960+
int
1961+
pq_settcpusertimeout(int timeout, Port *port)
1962+
{
1963+
if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
1964+
return STATUS_OK;
1965+
1966+
#ifdef TCP_USER_TIMEOUT
1967+
if (timeout == port->tcp_user_timeout)
1968+
return STATUS_OK;
1969+
1970+
if (port->default_tcp_user_timeout <= 0)
1971+
{
1972+
if (pq_gettcpusertimeout(port) < 0)
1973+
{
1974+
if (timeout == 0)
1975+
return STATUS_OK; /* default is set but unknown */
1976+
else
1977+
return STATUS_ERROR;
1978+
}
1979+
}
1980+
1981+
if (timeout == 0)
1982+
timeout = port->default_tcp_user_timeout;
1983+
1984+
if (setsockopt(port->sock, IPPROTO_TCP, TCP_USER_TIMEOUT,
1985+
(char *) &timeout, sizeof(timeout)) < 0)
1986+
{
1987+
elog(LOG, "setsockopt(%s) failed: %m", "TCP_USER_TIMEOUT");
1988+
return STATUS_ERROR;
1989+
}
1990+
1991+
port->tcp_user_timeout = timeout;
1992+
#else
1993+
if (timeout != 0)
1994+
{
1995+
elog(LOG, "setsockopt(%s) not supported", "TCP_USER_TIMEOUT");
1996+
return STATUS_ERROR;
1997+
}
1998+
#endif
1999+
2000+
return STATUS_OK;
2001+
}

‎src/backend/utils/misc/guc.c

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -182,9 +182,11 @@ static const char *show_archive_command(void);
182182
static void assign_tcp_keepalives_idle(int newval, void *extra);
183183
static void assign_tcp_keepalives_interval(int newval, void *extra);
184184
static void assign_tcp_keepalives_count(int newval, void *extra);
185+
static void assign_tcp_user_timeout(int newval, void *extra);
185186
static const char *show_tcp_keepalives_idle(void);
186187
static const char *show_tcp_keepalives_interval(void);
187188
static const char *show_tcp_keepalives_count(void);
189+
static const char *show_tcp_user_timeout(void);
188190
static bool check_maxconnections(int *newval, void **extra, GucSource source);
189191
static bool check_max_worker_processes(int *newval, void **extra, GucSource source);
190192
static bool check_autovacuum_max_workers(int *newval, void **extra, GucSource source);
@@ -530,6 +532,7 @@ char *application_name;
530532
int tcp_keepalives_idle;
531533
int tcp_keepalives_interval;
532534
int tcp_keepalives_count;
535+
int tcp_user_timeout;
533536

534537
/*
535538
* SSL renegotiation was been removed in PostgreSQL 9.5, but we tolerate it
@@ -3182,6 +3185,17 @@ static struct config_int ConfigureNamesInt[] =
31823185
NULL, NULL, NULL
31833186
},
31843187

3188+
{
3189+
{"tcp_user_timeout", PGC_USERSET, CLIENT_CONN_OTHER,
3190+
gettext_noop("TCP user timeout."),
3191+
gettext_noop("A value of 0 uses the system default."),
3192+
GUC_UNIT_MS
3193+
},
3194+
&tcp_user_timeout,
3195+
0, 0, INT_MAX,
3196+
NULL, assign_tcp_user_timeout, show_tcp_user_timeout
3197+
},
3198+
31853199
/* End-of-list marker */
31863200
{
31873201
{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
@@ -11238,6 +11252,23 @@ show_tcp_keepalives_count(void)
1123811252
return nbuf;
1123911253
}
1124011254

11255+
static void
11256+
assign_tcp_user_timeout(int newval, void *extra)
11257+
{
11258+
/* See comments in assign_tcp_keepalives_idle */
11259+
(void) pq_settcpusertimeout(newval, MyProcPort);
11260+
}
11261+
11262+
static const char *
11263+
show_tcp_user_timeout(void)
11264+
{
11265+
/* See comments in assign_tcp_keepalives_idle */
11266+
static char nbuf[16];
11267+
11268+
snprintf(nbuf, sizeof(nbuf), "%d", pq_gettcpusertimeout(MyProcPort));
11269+
return nbuf;
11270+
}
11271+
1124111272
static bool
1124211273
check_maxconnections(int *newval, void **extra, GucSource source)
1124311274
{

‎src/backend/utils/misc/postgresql.conf.sample

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -73,7 +73,7 @@
7373
#bonjour_name = '' # defaults to the computer name
7474
# (change requires restart)
7575

76-
# - TCP Keepalives -
76+
# - TCP settings -
7777
# see "man 7 tcp" for details
7878

7979
#tcp_keepalives_idle = 0 # TCP_KEEPIDLE, in seconds;
@@ -82,6 +82,8 @@
8282
# 0 selects the system default
8383
#tcp_keepalives_count = 0 # TCP_KEEPCNT;
8484
# 0 selects the system default
85+
#tcp_user_timeout = 0 # TCP_USER_TIMEOUT, in milliseconds;
86+
# 0 selects the system default
8587

8688
# - Authentication -
8789

‎src/include/libpq/libpq-be.h

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -155,7 +155,7 @@ typedef struct Port
155155
HbaLine *hba;
156156

157157
/*
158-
* TCP keepalive settings.
158+
* TCP keepalive and user timeout settings.
159159
*
160160
* default values are 0 if AF_UNIX or not yet known; current values are 0
161161
* if AF_UNIX or using the default. Also, -1 in a default value means we
@@ -164,9 +164,11 @@ typedef struct Port
164164
int default_keepalives_idle;
165165
int default_keepalives_interval;
166166
int default_keepalives_count;
167+
int default_tcp_user_timeout;
167168
int keepalives_idle;
168169
int keepalives_interval;
169170
int keepalives_count;
171+
int tcp_user_timeout;
170172

171173
/*
172174
* GSSAPI structures.
@@ -306,9 +308,11 @@ extern ProtocolVersion FrontendProtocol;
306308
extern int pq_getkeepalivesidle(Port *port);
307309
extern int pq_getkeepalivesinterval(Port *port);
308310
extern int pq_getkeepalivescount(Port *port);
311+
extern int pq_gettcpusertimeout(Port *port);
309312

310313
extern int pq_setkeepalivesidle(int idle, Port *port);
311314
extern int pq_setkeepalivesinterval(int interval, Port *port);
312315
extern int pq_setkeepalivescount(int count, Port *port);
316+
extern int pq_settcpusertimeout(int timeout, Port *port);
313317

314318
#endif /* LIBPQ_BE_H */

‎src/include/utils/guc.h

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -271,6 +271,7 @@ extern PGDLLIMPORT char *application_name;
271271
extern int tcp_keepalives_idle;
272272
extern int tcp_keepalives_interval;
273273
extern int tcp_keepalives_count;
274+
extern int tcp_user_timeout;
274275

275276
#ifdef TRACE_SORT
276277
extern bool trace_sort;

‎src/interfaces/libpq/fe-connect.c

Lines changed: 43 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -270,6 +270,10 @@ static const internalPQconninfoOption PQconninfoOptions[] = {
270270
"TCP-Keepalives-Count", "", 10, /* strlen(INT32_MAX) == 10 */
271271
offsetof(struct pg_conn, keepalives_count)},
272272

273+
{"tcp_user_timeout", NULL, NULL, NULL,
274+
"TCP-User-Timeout", "", 10, /* strlen(INT32_MAX) == 10 */
275+
offsetof(struct pg_conn, pgtcp_user_timeout)},
276+
273277
/*
274278
* ssl options are allowed even without client SSL support because the
275279
* client can still handle SSL modes "disable" and "allow". Other
@@ -1833,6 +1837,41 @@ setKeepalivesWin32(PGconn *conn)
18331837
#endif /* SIO_KEEPALIVE_VALS */
18341838
#endif /* WIN32 */
18351839

1840+
/*
1841+
* Set the TCP user timeout.
1842+
*/
1843+
static int
1844+
setTCPUserTimeout(PGconn *conn)
1845+
{
1846+
int timeout;
1847+
1848+
if (conn->pgtcp_user_timeout == NULL)
1849+
return 1;
1850+
1851+
if (!parse_int_param(conn->pgtcp_user_timeout, &timeout, conn,
1852+
"tcp_user_timeout"))
1853+
return 0;
1854+
1855+
if (timeout < 0)
1856+
timeout = 0;
1857+
1858+
#ifdef TCP_USER_TIMEOUT
1859+
if (setsockopt(conn->sock, IPPROTO_TCP, TCP_USER_TIMEOUT,
1860+
(char *) &timeout, sizeof(timeout)) < 0)
1861+
{
1862+
char sebuf[256];
1863+
1864+
appendPQExpBuffer(&conn->errorMessage,
1865+
libpq_gettext("setsockopt(%s) failed: %s\n"),
1866+
"TCP_USER_TIMEOUT",
1867+
SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
1868+
return 0;
1869+
}
1870+
#endif
1871+
1872+
return 1;
1873+
}
1874+
18361875
/* ----------
18371876
* connectDBStart -
18381877
* Begin the process of making a connection to the backend.
@@ -2480,6 +2519,8 @@ PQconnectPoll(PGconn *conn)
24802519
err = 1;
24812520
#endif /* SIO_KEEPALIVE_VALS */
24822521
#endif /* WIN32 */
2522+
else if (!setTCPUserTimeout(conn))
2523+
err = 1;
24832524

24842525
if (err)
24852526
{
@@ -3863,6 +3904,8 @@ freePGconn(PGconn *conn)
38633904
free(conn->pgtty);
38643905
if (conn->connect_timeout)
38653906
free(conn->connect_timeout);
3907+
if (conn->pgtcp_user_timeout)
3908+
free(conn->pgtcp_user_timeout);
38663909
if (conn->pgoptions)
38673910
free(conn->pgoptions);
38683911
if (conn->appname)

‎src/interfaces/libpq/libpq-int.h

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -336,6 +336,7 @@ struct pg_conn
336336
char *pgtty; /* tty on which the backend messages is
337337
* displayed (OBSOLETE, NOT USED) */
338338
char *connect_timeout; /* connection timeout (numeric string) */
339+
char *pgtcp_user_timeout; /* tcp user timeout (numeric string) */
339340
char *client_encoding_initial; /* encoding to use */
340341
char *pgoptions; /* options to start the backend with */
341342
char *appname; /* application name */

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