diff options
| author | Tom Lane | 2018-03-08 16:25:26 +0000 |
|---|---|---|
| committer | Tom Lane | 2018-03-08 16:25:26 +0000 |
| commit | 4e0c743c18bf5435a4850510c5c74b3521c3e1e5 (patch) | |
| tree | 548ba5c052c971a450f9f0bc5db10521b9946a69 /src/backend/postmaster | |
| parent | f9f8784c8b3050aaec52da88a6e41b3e3f576b96 (diff) | |
Fix cross-checking of ReservedBackends/max_wal_senders/MaxConnections.
We were independently checking ReservedBackends < MaxConnections and
max_wal_senders < MaxConnections, but because walsenders aren't allowed
to use superuser-reserved connections, that's really the wrong thing.
Correct behavior is to insist on ReservedBackends + max_wal_senders being
less than MaxConnections. Fix the code and associated documentation.
This has been wrong for a long time, but since the situation probably
hardly ever arises in the field (especially pre-v10, when the default
for max_wal_senders was zero), no back-patch.
Discussion: https://postgr.es/m/28271.1520195491@sss.pgh.pa.us
Diffstat (limited to 'src/backend/postmaster')
| -rw-r--r-- | src/backend/postmaster/postmaster.c | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index f3ddf828bbe..660f3185e6b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -202,9 +202,9 @@ char *ListenAddresses; /* * ReservedBackends is the number of backends reserved for superuser use. - * This number is taken out of the pool size given by MaxBackends so + * This number is taken out of the pool size given by MaxConnections so * number of backend slots available to non-superusers is - * (MaxBackends - ReservedBackends). Note what this really means is + * (MaxConnections - ReservedBackends). Note what this really means is * "if there are <= ReservedBackends connections available, only superusers * can make new connections" --- pre-existing superuser connections don't * count against the limit. @@ -882,14 +882,11 @@ PostmasterMain(int argc, char *argv[]) /* * Check for invalid combinations of GUC settings. */ - if (ReservedBackends >= MaxConnections) + if (ReservedBackends + max_wal_senders >= MaxConnections) { - write_stderr("%s: superuser_reserved_connections must be less than max_connections\n", progname); - ExitPostmaster(1); - } - if (max_wal_senders >= MaxConnections) - { - write_stderr("%s: max_wal_senders must be less than max_connections\n", progname); + write_stderr("%s: superuser_reserved_connections (%d) plus max_wal_senders (%d) must be less than max_connections (%d)\n", + progname, + ReservedBackends, max_wal_senders, MaxConnections); ExitPostmaster(1); } if (XLogArchiveMode > ARCHIVE_MODE_OFF && wal_level == WAL_LEVEL_MINIMAL) |