From c30f54ad732ca5c8762bb68bbe0f51de9137dd72 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Sat, 3 Apr 2021 08:52:30 +1300 Subject: Detect POLLHUP/POLLRDHUP while running queries. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Provide a new GUC check_client_connection_interval that can be used to check whether the client connection has gone away, while running very long queries. It is disabled by default. For now this uses a non-standard Linux extension (also adopted by at least one other OS). POLLRDHUP is not defined by POSIX, and other OSes don't have a reliable way to know if a connection was closed without actually trying to read or write. In future we might consider trying to send a no-op/heartbeat message instead, but that could require protocol changes. Author: Sergey Cherkashin Author: Thomas Munro Reviewed-by: Thomas Munro Reviewed-by: Tatsuo Ishii Reviewed-by: Konstantin Knizhnik Reviewed-by: Zhihong Yu Reviewed-by: Andres Freund Reviewed-by: Maksim Milyutin Reviewed-by: Tsunakawa, Takayuki/綱川 貴之 Reviewed-by: Tom Lane (much earlier version) Discussion: https://postgr.es/m/77def86b27e41f0efcba411460e929ae%40postgrespro.ru --- src/backend/utils/misc/guc.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'src/backend/utils/misc/guc.c') diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 584daffc8a9..60a9c7a2a0b 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -20,6 +20,9 @@ #include #include #include +#ifdef HAVE_POLL_H +#include +#endif #ifndef WIN32 #include #endif @@ -204,6 +207,7 @@ static bool check_autovacuum_work_mem(int *newval, void **extra, GucSource sourc static bool check_effective_io_concurrency(int *newval, void **extra, GucSource source); static bool check_maintenance_io_concurrency(int *newval, void **extra, GucSource source); static bool check_huge_page_size(int *newval, void **extra, GucSource source); +static bool check_client_connection_check_interval(int *newval, void **extra, GucSource source); static void assign_pgstat_temp_directory(const char *newval, void *extra); static bool check_application_name(char **newval, void **extra, GucSource source); static void assign_application_name(const char *newval, void *extra); @@ -3501,6 +3505,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"client_connection_check_interval", PGC_USERSET, CLIENT_CONN_OTHER, + gettext_noop("Sets the time interval between checks for disconnection while running queries."), + NULL, + GUC_UNIT_MS + }, + &client_connection_check_interval, + 0, 0, INT_MAX, + check_client_connection_check_interval, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL @@ -11980,6 +11995,20 @@ check_huge_page_size(int *newval, void **extra, GucSource source) return true; } +static bool +check_client_connection_check_interval(int *newval, void **extra, GucSource source) +{ +#ifndef POLLRDHUP + /* Linux only, for now. See pq_check_connection(). */ + if (*newval != 0) + { + GUC_check_errdetail("client_connection_check_interval must be set to 0 on platforms that lack POLLRDHUP."); + return false; + } +#endif + return true; +} + static void assign_pgstat_temp_directory(const char *newval, void *extra) { -- cgit v1.2.3