nbtree: assert no scheduled primscan between pages.

Follow-up to bugfix commit 763d65ae.  Technically this new assertion is
redundant with the assertion recently added to _bt_readpage by that same
commit, but it seems like a good idea to have both.

The new assertion makes it clear that we expect to call _bt_readnextpage
when there's another primitive index scan scheduled, though only when
needed as the final step of ending the current primitive scan.

diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c
index b082cc80f6c854c2c13a6dc309a9d6e75b64f95a..e718668ed6915dfa207e4130f87486e721a07abf 100644 (file)
--- a/src/backend/access/nbtree/nbtsearch.c
+++ b/src/backend/access/nbtree/nbtsearch.c
@@ -2272,6 +2272,8 @@ _bt_readnextpage(IndexScanDesc scan, BlockNumber blkno,
            return false;
        }
 
+       Assert(!so->needPrimScan);
+
        if (ScanDirectionIsForward(dir))
        {
            /* read blkno, but check for interrupts first */