Remove obsolete nbtree relation extension comment.

Commit 0d1fe9f7 improved the approach that vacuumlazy.c takes when it
encounters an empty heap page.  It no acquires the relation extension
lock.

diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index be23395dfbb2e586b344a7c249305b387985ed03..30df2447033e19cb9e2dc690dadda48a6a889d72 100644 (file)
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -963,11 +963,10 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
     * recycled.  Taking the lock synchronizes things enough to prevent a
     * problem: either num_pages won't include the new page, or _bt_getbuf
     * already has write lock on the buffer and it will be fully initialized
-    * before we can examine it.  (See also vacuumlazy.c, which has the same
-    * issue.)  Also, we need not worry if a page is added immediately after
-    * we look; the page splitting code already has write-lock on the left
-    * page before it adds a right page, so we must already have processed any
-    * tuples due to be moved into such a page.
+    * before we can examine it.  Also, we need not worry if a page is added
+    * immediately after we look; the page splitting code already has
+    * write-lock on the left page before it adds a right page, so we must
+    * already have processed any tuples due to be moved into such a page.
     *
     * We can skip locking for new or temp relations, however, since no one
     * else could be accessing them.