Re: [HACKERS] Walsender timeouts and large transactions

The following review has been posted through the commitfest application:
make installcheck-world:  tested, passed
Implements feature:       not tested
Spec compliant:           not tested
Documentation:            not tested

There is no check for (last_reply_timestamp <= 0 || wal_sender_timeout <= 0) as in other places
(in WalSndKeepaliveIfNecessary for example).

I don't think moving update of 'now' down to end of loop body is correct:
there are calls to ProcessConfigFile with SyncRepInitConfig, ProcessRepliesIfAny that can
last non-negligible time. It could lead to over sleeping due to larger computed sleeptime.
Though I could be mistaken.

I'm not sure about moving `if (!pg_is_send_pending())` in a body loop after WalSndKeepaliveIfNecessary.
Is it necessary? But it looks harmless at least.

Could patch be reduced to check after first `if (!pg_is_sendpending())` ? like:
if (!pq_is_send_pending())
-        return;
+    {
+        if (last_reply_timestamp <= 0 || wal_sender_timeout <= 0)
+        {
+            CHECK_FOR_INTERRUPTS();
+            return;
+        }
+        if (now <= TimestampTzPlusMilliseconds(last_reply_timestamp, wal_sender_timeout / 2))
+            return;
+    }

If not, what problem prevents?

The new status of this patch is: Waiting on Author