BUG#46961 - archive engine loses rows during self joining select!

SELECT with join (not only self-join) from archive table may
return incomplete result set, when result set size exceeds
join buffer size.

The problem was that archive row counter was initialzed too
early, when ha_archive::info() method was called. Later,
when optimizer exceeds join buffer, it attempts to reuse
handler without calling ha_archive::info() again (which is
correct).

Fixed by moving row counter initialization from
ha_archive::info() to ha_archive::rnd_init().

mysql-test/r/archive.result:
  A test case for BUG#46961.
mysql-test/t/archive.test:
  A test case for BUG#46961.
storage/archive/ha_archive.cc:
  Since a cursor may get reused without a call to ::info(),
  move assignment of scan_rows to a proper place, that is
  ::rnd_init().

1 files changed, 11 insertions, 0 deletions

diff --git a/mysql-test/r/archive.result b/mysql-test/r/archive.result
index 8c26ea1ff82..9a6edbaa85c 100644
--- a/mysql-test/r/archive.result
+++ b/mysql-test/r/archive.result
@@ -12695,3 +12695,14 @@ a	b
 1	NULL
 2	NULL
 DROP TABLE t1;
+SET @save_join_buffer_size= @@join_buffer_size;
+SET @@join_buffer_size= 8228;
+CREATE TABLE t1(a CHAR(255)) ENGINE=archive;
+INSERT INTO t1 VALUES('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),
+('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),
+('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa');
+SELECT COUNT(t1.a) FROM t1, t1 a, t1 b, t1 c, t1 d, t1 e;
+COUNT(t1.a)
+729
+DROP TABLE t1;
+SET @@join_buffer_size= @save_join_buffer_size;