Fix bug in collecting total_latencies from all threads in pgbench.

hlinnaka · hlinnaka · commit b2ed8edeecd7 · 2015-07-28T11:30:23.000+03:00
This was broken in 1bc90f7, which removed the thread-emulation. With modest -j and -c settings the result were usually close enough that you wouldn't notice it easily, but with a high enough thread count it would access uninitialized memory and crash. Per report from Andres Freund offlist.
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
@@ -3456,8 +3456,8 @@ main(int argc, char **argv)
 		for (j = 0; j < thread->nstate; j++)
 		{
 			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[i].txn_latencies;
-			total_sqlats += thread->state[i].txn_sqlats;
+			total_latencies += thread->state[j].txn_latencies;
+			total_sqlats += thread->state[j].txn_sqlats;
 		}
 	}
 	disconnect_all(state, nclients);

Original file line number	Diff line number	Diff line change
`@@ -3456,8 +3456,8 @@ main(int argc, char **argv)`
`3456`	`3456`	`for (j = 0; j < thread->nstate; j++)`
`3457`	`3457`	`{`
`3458`	`3458`	`total_xacts += thread->state[j].cnt;`
`3459`		`- total_latencies += thread->state[i].txn_latencies;`
`3460`		`- total_sqlats += thread->state[i].txn_sqlats;`
	`3459`	`+ total_latencies += thread->state[j].txn_latencies;`
	`3460`	`+ total_sqlats += thread->state[j].txn_sqlats;`
`3461`	`3461`	`}`
`3462`	`3462`	`}`
`3463`	`3463`	`disconnect_all(state, nclients);`