Rounding up timespec_diff_millis to avoid polling.

Previously diff was rounded down, so we were woken up some nanoseconds ( <=
million) before actual wake time and polled continiously until they passed,
with calculated diff in milliseconds 0.

Besided, some typos fixed.

Author: arssher

postgresql.conf.lord.template

@@ -2,4 +2,4 @@ shardman.shardlord = on # this instance is shardlord?
 shardman.shardlord_dbname = ars # shardlord's dbname
 shardman.shardlord_connstring = 'port=5432' # shardlord's connstring
 shardman.cmd_retry_naptime = 500 # sleep milliseconds after failure
-shardman.poll_interval = 500 # long operations poll frequency
+shardman.poll_interval = 500 # long operations poll frequency in milliseconds

src/copypart.c

@@ -465,7 +465,7 @@ exec_tasks(CopyPartState **tasks, int ntasks)
 				switch (cps->exec_res)
 				{
 					case TASK_WAKEMEUP:
-						/* We need to wake this task again, to keep it in
+						/* We need to wake this task again, so keep it in
 						 * in the list and just continue */
 						continue;
 
@@ -523,7 +523,7 @@ calc_timeout(slist_head *timeout_states)
 		CopyPartState *cps = cps_node->cps;
 
 		/* If waketm is not set, what this node does in this list? */
-		Assert(cps->waketm.tv_nsec != 0);
+		Assert(!(cps->waketm.tv_sec == 0 && cps->waketm.tv_nsec == 0));
 		if (!waketm_set || timespeccmp(cps->waketm, waketm) < 0)
 		{
 			shmn_elog(DEBUG5, "Waketm updated, old %d s, new %d s",
@@ -599,7 +599,7 @@ exec_task(CopyPartState *cps)
 }
 
 /*
- * One iteration of move primary task execution.
+ * One iteration of move partition task execution.
  *
  * Maximum 4 nodes are actively involved here: src, dst, previous replica (or
  * primary) and next replica. The whole task workflow:

src/timeutils.c

@@ -42,12 +42,14 @@ timespec_add_millis(struct timespec t, long millis)
 }
 
 /*
- * Get t1 - t2 difference in milliseconds. Not reliable if time_t is unsigned
+ * Get t1 - t2 difference in milliseconds. Not reliable if time_t is unsigned.
+ * The result is rounded up.
  */
 int
 timespec_diff_millis(struct timespec t1, struct timespec t2)
 {
 	int sec_diff = t1.tv_sec - t2.tv_sec;
 	long nsec_diff = t1.tv_nsec - t2.tv_nsec;
-	return sec_diff * 1000 + nsec_diff / MILLION;
+	/* We add (MILLION - 1) to get the division result rounded up */
+	return sec_diff * 1000 + (nsec_diff + (MILLION - 1)) / MILLION;
 }