index 0813c830269488034eca5a714210c4ecd14860f8..6c87f6087ced287652436d564a5c69480ef06628 100644 (file)
/*
* We only send regular messages to the client for full decoded
* transactions, but a synchronous replication and walsender shutdown
- * possibly are waiting for a later location. So we send pings
- * containing the flush location every now and then.
+ * possibly are waiting for a later location. So, before sleeping, we
+ * send a ping containing the flush location. If the receiver is
+ * otherwise idle, this keepalive will trigger a reply. Processing the
+ * reply will update these MyWalSnd locations.
*/
if (MyWalSnd->flush < sentPtr &&
MyWalSnd->write < sentPtr &&
WalSndKeepaliveIfNecessary();
/*
- * We don't block if not caught up, unless there is unsent data
- * pending in which case we'd better block until the socket is
- * write-ready. This test is only needed for the case where the
- * send_data callback handled a subset of the available data but then
- * pq_flush_if_writable flushed it all --- we should immediately try
- * to send more.
+ * Block if we have unsent data. XXX For logical replication, let
+ * WalSndWaitForWal() handle any other blocking; idle receivers need
+ * its additional actions. For physical replication, also block if
+ * caught up; its send_data does not block.
*/
- if ((WalSndCaughtUp && !streamingDoneSending) || pq_is_send_pending())
+ if ((WalSndCaughtUp && send_data != XLogSendLogical &&
+ !streamingDoneSending) ||
+ pq_is_send_pending())
{
long sleeptime;
int wakeEvents;