MDEV-29947 Spider doesn't return all rows when doing a join of two tables with no usable keys

followup for 57d233e2

storage/spider/ha_spider.cc

@@ -2055,7 +2055,6 @@ int ha_spider::index_first_internal(
       pt_clone_source_handler));
     pt_clone_source_handler->pt_clone_last_searcher = this;
   }
-  if (sql_is_empty(SPIDER_SQL_TYPE_SELECT_SQL))
   {
     /*
         spider_db_free_one_result_for_start_next(this);
@@ -2399,7 +2398,6 @@ int ha_spider::index_last_internal(
       pt_clone_source_handler));
     pt_clone_source_handler->pt_clone_last_searcher = this;
   }
-  if (sql_is_empty(SPIDER_SQL_TYPE_SELECT_SQL))
   {
     /*
         spider_db_free_one_result_for_start_next(this);

storage/spider/mysql-test/spider/r/partition_mrr.result

@@ -104,11 +104,47 @@ pkey
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+SELECT a.pkey FROM tbl_a a, tbl_b b WHERE a.pkey+0 = b.pkey+0 ORDER BY a.pkey;
+pkey
+0
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 connection child2_1;
 SELECT argument FROM mysql.general_log WHERE command_type != 'Execute' AND argument LIKE '%select %';
 argument
 select `pkey` from `auto_test_remote`.`tbl_a` order by `pkey`
 select a.id,b.`pkey` from auto_test_remote.tmp_spider_bka_xxxx a,`auto_test_remote`.`tbl_b` b where a.c0 <=> b.`pkey`
+select `pkey` from `auto_test_remote`.`tbl_a` order by `pkey`
+select `pkey` from `auto_test_remote`.`tbl_b` order by `pkey`
+select `pkey` from `auto_test_remote`.`tbl_b` order by `pkey`
+select `pkey` from `auto_test_remote`.`tbl_b` order by `pkey`
 SELECT argument FROM mysql.general_log WHERE command_type != 'Execute' AND argument LIKE '%select %'
 SELECT pkey FROM tbl_a ORDER BY pkey ;
 SELECT pkey FROM tbl_b ORDER BY pkey;
@@ -139,6 +175,10 @@ SELECT argument FROM mysql.general_log WHERE command_type != 'Execute' AND argum
 argument
 select `pkey` from `auto_test_remote2`.`tbl_a` order by `pkey`
 select a.id,b.`pkey` from auto_test_remote2.tmp_spider_bka_xxxx a,`auto_test_remote2`.`tbl_b` b where a.c0 <=> b.`pkey`
+select `pkey` from `auto_test_remote2`.`tbl_a` order by `pkey`
+select `pkey` from `auto_test_remote2`.`tbl_b` order by `pkey`
+select `pkey` from `auto_test_remote2`.`tbl_b` order by `pkey`
+select `pkey` from `auto_test_remote2`.`tbl_b` order by `pkey`
 SELECT argument FROM mysql.general_log WHERE command_type != 'Execute' AND argument LIKE '%select %'
 SELECT pkey FROM tbl_a ORDER BY pkey ;
 SELECT pkey FROM tbl_b ORDER BY pkey;
@@ -169,6 +209,10 @@ SELECT argument FROM mysql.general_log WHERE command_type != 'Execute' AND argum
 argument
 select `pkey` from `auto_test_remote3`.`tbl_a` order by `pkey`
 select a.id,b.`pkey` from auto_test_remote3.tmp_spider_bka_xxxx a,`auto_test_remote3`.`tbl_b` b where a.c0 <=> b.`pkey`
+select `pkey` from `auto_test_remote3`.`tbl_a` order by `pkey`
+select `pkey` from `auto_test_remote3`.`tbl_b` order by `pkey`
+select `pkey` from `auto_test_remote3`.`tbl_b` order by `pkey`
+select `pkey` from `auto_test_remote3`.`tbl_b` order by `pkey`
 SELECT argument FROM mysql.general_log WHERE command_type != 'Execute' AND argument LIKE '%select %'
 SELECT pkey FROM tbl_a ORDER BY pkey ;
 SELECT pkey FROM tbl_b ORDER BY pkey;

storage/spider/mysql-test/spider/t/partition_mrr.test

@@ -169,6 +169,7 @@ if ($USE_CHILD_GROUP2)
 }
 --connection master_1
 SELECT a.pkey FROM tbl_a a, tbl_b b WHERE a.pkey = b.pkey;
+SELECT a.pkey FROM tbl_a a, tbl_b b WHERE a.pkey+0 = b.pkey+0 ORDER BY a.pkey; # MDEV-29947
 if ($USE_CHILD_GROUP2)
 {
   if (!$OUTPUT_CHILD_GROUP2)