mirror of
https://github.com/postgres/postgres.git
synced 2025-07-15 19:21:59 +03:00
Move max_wal_senders out of max_connections for connection slot handling
Since its introduction, max_wal_senders is counted as part of max_connections when it comes to define how many connection slots can be used for replication connections with a WAL sender context. This can lead to confusion for some users, as it could be possible to block a base backup or replication from happening because other backend sessions are already taken for other purposes by an application, and superuser-only connection slots are not a correct solution to handle that case. This commit makes max_wal_senders independent of max_connections for its handling of PGPROC entries in ProcGlobal, meaning that connection slots for WAL senders are handled using their own free queue, like autovacuum workers and bgworkers. One compatibility issue that this change creates is that a standby now requires to have a value of max_wal_senders at least equal to its primary. So, if a standby created enforces the value of max_wal_senders to be lower than that, then this could break failovers. Normally this should not be an issue though, as any settings of a standby are inherited from its primary as postgresql.conf gets normally copied as part of a base backup, so parameters would be consistent. Author: Alexander Kukushkin Reviewed-by: Kyotaro Horiguchi, Petr Jelínek, Masahiko Sawada, Oleksii Kliukin Discussion: https://postgr.es/m/CAFh8B=nBzHQeYAu0b8fjK-AF1X4+_p6GRtwG+cCgs6Vci2uRuQ@mail.gmail.com
This commit is contained in:
@ -187,6 +187,7 @@ static const char *show_tcp_keepalives_count(void);
|
||||
static bool check_maxconnections(int *newval, void **extra, GucSource source);
|
||||
static bool check_max_worker_processes(int *newval, void **extra, GucSource source);
|
||||
static bool check_autovacuum_max_workers(int *newval, void **extra, GucSource source);
|
||||
static bool check_max_wal_senders(int *newval, void **extra, GucSource source);
|
||||
static bool check_autovacuum_work_mem(int *newval, void **extra, GucSource source);
|
||||
static bool check_effective_io_concurrency(int *newval, void **extra, GucSource source);
|
||||
static void assign_effective_io_concurrency(int newval, void *extra);
|
||||
@ -2090,7 +2091,7 @@ static struct config_int ConfigureNamesInt[] =
|
||||
},
|
||||
|
||||
{
|
||||
/* see max_connections and max_wal_senders */
|
||||
/* see max_connections */
|
||||
{"superuser_reserved_connections", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
|
||||
gettext_noop("Sets the number of connection slots reserved for superusers."),
|
||||
NULL
|
||||
@ -2608,14 +2609,13 @@ static struct config_int ConfigureNamesInt[] =
|
||||
},
|
||||
|
||||
{
|
||||
/* see max_connections and superuser_reserved_connections */
|
||||
{"max_wal_senders", PGC_POSTMASTER, REPLICATION_SENDING,
|
||||
gettext_noop("Sets the maximum number of simultaneously running WAL sender processes."),
|
||||
NULL
|
||||
},
|
||||
&max_wal_senders,
|
||||
10, 0, MAX_BACKENDS,
|
||||
NULL, NULL, NULL
|
||||
check_max_wal_senders, NULL, NULL
|
||||
},
|
||||
|
||||
{
|
||||
@ -10911,7 +10911,7 @@ static bool
|
||||
check_maxconnections(int *newval, void **extra, GucSource source)
|
||||
{
|
||||
if (*newval + autovacuum_max_workers + 1 +
|
||||
max_worker_processes > MAX_BACKENDS)
|
||||
max_worker_processes + max_wal_senders > MAX_BACKENDS)
|
||||
return false;
|
||||
return true;
|
||||
}
|
||||
@ -10919,7 +10919,17 @@ check_maxconnections(int *newval, void **extra, GucSource source)
|
||||
static bool
|
||||
check_autovacuum_max_workers(int *newval, void **extra, GucSource source)
|
||||
{
|
||||
if (MaxConnections + *newval + 1 + max_worker_processes > MAX_BACKENDS)
|
||||
if (MaxConnections + *newval + 1 +
|
||||
max_worker_processes + max_wal_senders > MAX_BACKENDS)
|
||||
return false;
|
||||
return true;
|
||||
}
|
||||
|
||||
static bool
|
||||
check_max_wal_senders(int *newval, void **extra, GucSource source)
|
||||
{
|
||||
if (MaxConnections + autovacuum_max_workers + 1 +
|
||||
max_worker_processes + *newval > MAX_BACKENDS)
|
||||
return false;
|
||||
return true;
|
||||
}
|
||||
@ -10950,7 +10960,8 @@ check_autovacuum_work_mem(int *newval, void **extra, GucSource source)
|
||||
static bool
|
||||
check_max_worker_processes(int *newval, void **extra, GucSource source)
|
||||
{
|
||||
if (MaxConnections + autovacuum_max_workers + 1 + *newval > MAX_BACKENDS)
|
||||
if (MaxConnections + autovacuum_max_workers + 1 +
|
||||
*newval + max_wal_senders > MAX_BACKENDS)
|
||||
return false;
|
||||
return true;
|
||||
}
|
||||
|
Reference in New Issue
Block a user