opt_explain_json_namespace::message_ctx Class Reference

Inheritance diagram for opt_explain_json_namespace::message_ctx:

Collaboration diagram for opt_explain_json_namespace::message_ctx:

Public Member Functions
	message_ctx (context *parent_arg)
virtual bool	format_body (Opt_trace_context *json, Opt_trace_object *obj)
virtual size_t	id (bool hide)
virtual bool	cacheable ()
virtual bool	dependent ()
virtual qep_row *	entry ()
virtual bool	format_derived (Opt_trace_context *json)
	Helper function to format output for derived subquery if any.
virtual bool	format_where (Opt_trace_context *json)
	Helper function to format output for associated WHERE subqueries if any.
virtual bool	find_and_set_derived (context *subquery)
virtual bool	add_where_subquery (subquery_ctx *ctx, SELECT_LEX_UNIT *subquery)
Public Member Functions inherited from opt_explain_json_namespace::joinable_ctx
	joinable_ctx (Explain_context_enum type_arg, const char *name_arg, context *parent_arg)
Public Member Functions inherited from opt_explain_json_namespace::context
	context (Explain_context_enum type_arg, const char *name_arg, context *parent_arg)
virtual bool	format (Opt_trace_context *json)
bool	is_query_block () const
virtual void	set_child (context *child)
virtual void	set_union_result (union_result_ctx *ctx)
	associate CTX_UNION_RESULT node with CTX_UNION node
virtual bool	add_subquery (subquery_list_enum subquery_type, subquery_ctx *ctx)
virtual bool	format_nested_loop (Opt_trace_context *json)
virtual bool	add_join_tab (joinable_ctx *ctx)
virtual void	set_sort (sort_ctx *ctx)
virtual bool	add_query_spec (context *ctx)
virtual bool	format_unit (Opt_trace_context *json)
	Helper function to format output for HAVING, ORDER/GROUP BY subqueries.
Public Member Functions inherited from Explain_context
	Explain_context (Explain_context_enum type_arg)
Public Member Functions inherited from opt_explain_json_namespace::table_with_where_and_derived
	table_with_where_and_derived (Explain_context_enum type_arg, const char *name_arg, context *parent_arg)
Public Member Functions inherited from opt_explain_json_namespace::table_base_ctx
	table_base_ctx (Explain_context_enum type_arg, const char *name_arg, context *parent_arg)

Additional Inherited Members
Static Public Member Functions inherited from Sql_alloc
static void *	operator new (size_t size) throw ()
static void *	operator new[] (size_t size) throw ()
static void *	operator new[] (size_t size, MEM_ROOT *mem_root) throw ()
static void *	operator new (size_t size, MEM_ROOT *mem_root) throw ()
static void	operator delete (void *ptr, size_t size)
static void	operator delete (void *ptr, MEM_ROOT *mem_root)
static void	operator delete[] (void *ptr, MEM_ROOT *mem_root)
static void	operator delete[] (void *ptr, size_t size)
Public Attributes inherited from opt_explain_json_namespace::context
context *	parent
	link to parent node or NULL
Protected Attributes inherited from opt_explain_json_namespace::context
const char *	name
Protected Attributes inherited from opt_explain_json_namespace::table_with_where_and_derived
List< subquery_ctx >	where_subqueries
	associated WHERE clause subqueries

Detailed Description

Node class for CTX_MESSAGE

This class is designed to represent fake tables with some messages in the "extra" column ("Impossible where" etc). We do EXPLAIN of these fake tables to replace explanation of: 1) usual actual JOIN_TABs of the whole JOIN or 2) a modifying TABLE of single-table UPDATE/DELETE/etc. So, message_ctx always represent a single half-empty fake table in a "query_block" node with optional subqueries.

Definition at line 797 of file opt_explain_json.cc.

Member Function Documentation

virtual bool opt_explain_json_namespace::message_ctx::add_where_subquery ( subquery_ctx *  ctx, SELECT_LEX_UNIT *  subquery  )

inlinevirtual

Associate WHERE subqueries of given context and unit with this object

Parameters

ctx	Context of WHERE subquery
subquery	For CTX_JOIN_TAB: match given unit with a previously collected by the register_where_subquery function.

Reimplemented from opt_explain_json_namespace::context.

Definition at line 832 of file opt_explain_json.cc.

virtual bool opt_explain_json_namespace::message_ctx::find_and_set_derived ( context *  subquery )

inlinevirtual

Try to associate a derived subquery node with this or underlying node

Parameters

subquery

Derived subquery node

Return values

true	Success
false	Can't associate: this node or its child nodes are not derived from the subquery

Reimplemented from opt_explain_json_namespace::context.

Definition at line 820 of file opt_explain_json.cc.

virtual bool opt_explain_json_namespace::message_ctx::format_body ( Opt_trace_context *  json, Opt_trace_object *  obj  )

inlinevirtual

Format JSON object body

Parameters

json	Formatter
obj	Object of this body

Return values

false	Ok
true	Error

Implements opt_explain_json_namespace::context.

Definition at line 808 of file opt_explain_json.cc.

virtual size_t opt_explain_json_namespace::message_ctx::id ( bool  hide )

inlinevirtual

Analogue of the "id" column in the traditional EXPLAIN output

Parameters

hide	if true, ban the output of K_SELECT_ID JSON property in the underlying table_with_where_and_derived_ctx objects

Returns

"Select number" that is associated with this node

Reimplemented from opt_explain_json_namespace::table_with_where_and_derived.

Definition at line 810 of file opt_explain_json.cc.

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The documentation for this class was generated from the following file:

• sql/opt_explain_json.cc