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EXPLAIN FORMAT=JSON: Add support for non-merged semi-joins

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This commit is contained in:
Sergei Petrunia
2014-11-29 01:08:18 +03:00
parent 2ac3b39e68
commit 0b5d989c89
7 changed files with 117 additions and 7 deletions
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19
sql/sql_explain.h
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@@ -77,12 +77,14 @@ const int FAKE_SELECT_LEX_ID= (int)UINT_MAX;
class Explain_query;
class Json_writer;
/*
A node can be either a SELECT, or a UNION.
*/
class Explain_node : public Sql_alloc
{
public:
/* A type specifying what kind of node this is */
enum explain_node_type
{
EXPLAIN_UNION,
@@ -91,16 +93,24 @@ public:
EXPLAIN_DELETE,
EXPLAIN_INSERT
};
/* How this node is connected */
enum explain_connection_type {
EXPLAIN_NODE_OTHER,
EXPLAIN_NODE_DERIVED, /* Materialized derived table */
EXPLAIN_NODE_NON_MERGED_SJ /* aka JTBM semi-join */
};
Explain_node() : is_derived_table(false) {}
Explain_node() : connection_type(EXPLAIN_NODE_OTHER) {}
virtual enum explain_node_type get_type()= 0;
virtual int get_select_id()= 0;
/*
TRUE means this is a derived table. FALSE means otherwise.
How this node is connected to its parent.
(NOTE: EXPLAIN_NODE_NON_MERGED_SJ is set very late currently)
*/
bool is_derived_table;
enum explain_connection_type connection_type;
/*
A node may have children nodes. When a node's explain structure is
@@ -502,6 +512,7 @@ class Explain_table_access : public Sql_alloc
public:
Explain_table_access() :
derived_select_number(0),
non_merged_sjm_number(0),
where_cond(NULL),
cache_cond(NULL),
pushed_index_cond(NULL)
@@ -525,6 +536,8 @@ public:
find the query plan for the derived table
*/
int derived_select_number;
/* TODO: join with the previous member. */
int non_merged_sjm_number;
enum join_type type;