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diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 5f4881b2f54..31badd10746 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -117,6 +117,7 @@ enum enum_best_search {
SEARCH_OK= 0,
SEARCH_FOUND_EDGE=1
};
+static table_map get_allowed_nj_tables(JOIN *join, uint idx);
static enum_best_search
best_extension_by_limited_search(JOIN *join,
table_map remaining_tables,
@@ -2136,6 +2137,82 @@ JOIN::optimize_inner()
thd->restore_active_arena(arena, &backup);
}
+ // psergey-new:
+ /*
+ Compute
+ JOIN::allowed_top_level_tables - a bitmap of tables one can put into the
+ join order if the last table in the join prefix is not inside any outer
+ join nest.
+
+ NESTED_JOIN::direct_children_map - a bitmap of tabhes ... if the last
+ table in the join prefix is inside the join nest.
+
+ Note: it looks like a sensible way to do this is a top-down descent on
+ JOIN::join_list, but apparently that list is missing I_S tables.
+ e.g. for SHOW TABLES WHERE col IN (SELECT ...) it will just have a
+ semi-join nest.
+ */
+ {
+ TABLE_LIST *tl;
+ List_iterator<TABLE_LIST> ti(select_lex->leaf_tables);
+ while ((tl= ti++))
+ {
+ table_map map;
+ if (tl->table)
+ map= tl->table->map;
+ else
+ {
+ DBUG_ASSERT(tl->jtbm_subselect);
+ map= table_map(1) << tl->jtbm_table_no;
+ }
+
+ TABLE_LIST *embedding= tl->embedding;
+
+ if (!embedding)
+ {
+ allowed_top_level_tables |= map;
+ continue;
+ }
+
+ // Walk out of any semi-join nests
+ while (embedding && !embedding->on_expr)
+ {
+ // DBUG_ASSERT(embedding->sj_on_expr);
+ // semi-join nest or an INSERT-INTO view...
+ embedding->nested_join->direct_children_map |= map;
+ embedding= embedding->embedding;
+ }
+
+ // Ok we are in the parent nested outer join nest.
+ if (!embedding)
+ {
+ allowed_top_level_tables |= map;
+ continue;
+ }
+ embedding->nested_join->direct_children_map |= map;
+
+ // Walk to grand-parent join nest.
+ embedding= embedding->embedding;
+
+ // Walk out of any semi-join nests
+ while (embedding && !embedding->on_expr)
+ {
+ DBUG_ASSERT(embedding->sj_on_expr);
+ embedding->nested_join->direct_children_map |= map;
+ embedding= embedding->embedding;
+ }
+
+ if (embedding)
+ {
+ DBUG_ASSERT(embedding->on_expr);
+ embedding->nested_join->direct_children_map |= map;
+ }
+ else
+ allowed_top_level_tables |= map;
+ }
+ }
+////
+
if (optimize_constant_subqueries())
DBUG_RETURN(1);
@@ -9939,6 +10016,8 @@ best_extension_by_limited_search(JOIN *join,
if (join->emb_sjm_nest)
allowed_tables= join->emb_sjm_nest->sj_inner_tables & ~join->const_table_map;
+ table_map dbug_allowed_tables= get_allowed_nj_tables(join, idx);
+
for (JOIN_TAB **pos= join->best_ref + idx ; (s= *pos) ; pos++)
{
table_map real_table_bit= s->table->map;
@@ -9953,6 +10032,12 @@ best_extension_by_limited_search(JOIN *join,
POSITION loose_scan_pos;
Json_writer_object trace_one_table(thd);
+ if (!(s->table->map & dbug_allowed_tables))
+ {
+ fprintf(stderr, "booom! %s\n", thd->query());
+ //DBUG_ASSERT(0);
+ }
+
if (unlikely(thd->trace_started()))
{
trace_plan_prefix(join, idx, remaining_tables);
@@ -17393,7 +17478,31 @@ static void restore_prev_nj_state(JOIN_TAB *last)
}
}
-
+static table_map get_allowed_nj_tables(JOIN *join, uint idx)
+{
+ if (idx == join->const_tables)
+ return join->allowed_top_level_tables;
+
+ DBUG_ASSERT(idx > 0);
+ // Then, copy.
+ TABLE_LIST *last_emb= join->positions[idx-1].table->table->pos_in_table_list->embedding;
+
+ for (;last_emb != NULL && last_emb != join->emb_sjm_nest;
+ last_emb= last_emb->embedding)
+ {
+ if (!last_emb->sj_on_expr)
+ {
+ NESTED_JOIN *nest= last_emb->nested_join;
+ if (!nest->is_fully_covered())
+ {
+ // Return tables that are direct members of this join nest
+ return nest->direct_children_map;
+ }
+ }
+ }
+ // Return bitmap of tables not in any join nest;
+ return join->allowed_top_level_tables;
+}
/*
Change access methods not to use join buffering and adjust costs accordingly
diff --git a/sql/sql_select.h b/sql/sql_select.h
index 4a2929207a5..c5f8b4e2622 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -1250,6 +1250,8 @@ class JOIN :public Sql_alloc
table_map outer_join;
/* Bitmap of tables used in the select list items */
table_map select_list_used_tables;
+
+ table_map allowed_top_level_tables;
ha_rows send_records,found_records,join_examined_rows, accepted_rows;
/*
diff --git a/sql/table.h b/sql/table.h
index 8d609fbf1bb..1fddcdcf786 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -3081,6 +3081,7 @@ typedef struct st_nested_join
2. All child join nest nodes are fully covered.
*/
bool is_fully_covered() const { return n_tables == counter; }
+ table_map direct_children_map;
} NESTED_JOIN;
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