Import wiredtiger: 923937e6b2bb7ffc1ff86bfaa8c2f130930286de from branch mongodb-3.6

ref: ce5ee5097b..923937e6b2
for: 3.6.0-rc5

WT-3444       Test format on PPC fails with ENOTSUP when performing an update on an LSM tree
WT-3745       Don't stall reads due to write pressure
WT-3746       Don't busy wait when syncing the log and waiting for writes to complete

1 files changed, 7 insertions, 1 deletions

diff --git a/src/third_party/wiredtiger/src/cache/cache_las.c b/src/third_party/wiredtiger/src/cache/cache_las.c
index 35d9f43b172..9f8aeb7cc9e 100644
--- a/src/third_party/wiredtiger/src/cache/cache_las.c
+++ b/src/third_party/wiredtiger/src/cache/cache_las.c
@@ -518,7 +518,13 @@ __wt_las_insert_block(WT_SESSION_IMPL *session, WT_CURSOR *cursor,
 			cursor->set_value(cursor,
 			    upd->txnid, &las_timestamp, upd->type, &las_value);
 
-			WT_ERR(cursor->insert(cursor));
+			/*
+			 * Using update looks a little strange because the keys
+			 * are guaranteed to not exist, but since we're
+			 * appending, we want the cursor to stay positioned in
+			 * between inserts.
+			 */
+			WT_ERR(cursor->update(cursor));
 			++insert_cnt;
 		} while ((upd = upd->next) != NULL);
 	}