Server won't start with fallback setting by initdb.

Hello.

I'm not sure such a case happens in the real world nowadays,
initdb uses the fallback value of max_connections=10. But it is
out of favor of server since it is not larger than
max_wal_senders(10).

> postgres: max_wal_senders must be less than max_connections

I think that we can safely increase the fallback value to 20 with
which regtests are known not to fail. I believe that is
preferable than explicitly reducing max_wal_senders in the
generated config file. I confirmed that tegtest won't fail with
the value. (Except with permanent failure of dynamic shared
memory)

I don't find documentation about this behavior.

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 2efd3b7..1f7f2aa 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -915,7 +915,7 @@ test_config_settings(void)
 #define MIN_BUFS_FOR_CONNS(nconns)    ((nconns) * 10)
 
     static const int trial_conns[] = {
-        100, 50, 40, 30, 20, 10
+        100, 50, 40, 30, 20
     };
     static const int trial_bufs[] = {
         16384, 8192, 4096, 3584, 3072, 2560, 2048, 1536,