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MDEV-34041 Display additional information for materialized subqueries in EXPLAIN/ANALYZE FORMAT=JSON

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This commits adds the "materialization" block to the output of
EXPLAIN/ANALYZE FORMAT=JSON when materialized subqueries are involved
into processing. In the case of ANALYZE additional runtime information
is displayed, such as:
  - chosen strategy of materialization
  - number of partial match/index lookup loops
  - sizes of partial match buffers
This commit is contained in:
Oleg Smirnov
2024-05-04 19:50:55 +07:00
parent a5e4c34991
commit aae3233c4f
14 changed files with 2024 additions and 615 deletions
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31
sql/sql_explain.h
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@ -86,6 +86,7 @@ class Explain_node : public Sql_alloc
public:
Explain_node(MEM_ROOT *root) :
cache_tracker(NULL),
subq_materialization(NULL),
connection_type(EXPLAIN_NODE_OTHER),
children(root)
{}
@ -115,6 +116,12 @@ public:
*/
Expression_cache_tracker* cache_tracker;
/**
If not NULL, this node is a SELECT (or UNION) in a materialized
IN-subquery.
*/
Explain_subq_materialization* subq_materialization;
/*
How this node is connected to its parent.
(NOTE: EXPLAIN_NODE_NON_MERGED_SJ is set very late currently)
@ -143,6 +150,8 @@ public:
void print_explain_json_for_children(Explain_query *query,
Json_writer *writer, bool is_analyze);
bool print_explain_json_cache(Json_writer *writer, bool is_analyze);
bool print_explain_json_subq_materialization(Json_writer *writer,
bool is_analyze);
virtual ~Explain_node() = default;
};
@ -1003,4 +1012,26 @@ public:
};
/*
EXPLAIN data structure for subquery materialization.
All decisions are made at execution time so here we just store the tracker
that has all the info.
*/
class Explain_subq_materialization : public Sql_alloc
{
public:
Explain_subq_materialization(MEM_ROOT *mem_root)
: tracker(mem_root)
{}
Subq_materialization_tracker *get_tracker() { return &tracker; }
void print_explain_json(Json_writer *writer, bool is_analyze);
private:
Subq_materialization_tracker tracker;
};
#endif //SQL_EXPLAIN_INCLUDED