opt_explain_json_namespace::join_tab_ctx Class Reference

Inheritance diagram for opt_explain_json_namespace::join_tab_ctx:

List of all members.

Public Member Functions
	join_tab_ctx (Explain_context_enum type_arg, 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 void	register_where_subquery (SELECT_LEX_UNIT *subquery)
virtual bool	add_where_subquery (subquery_ctx *ctx, SELECT_LEX_UNIT *subquery)
virtual bool	find_and_set_derived (context *subquery)

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Detailed Description

Node class for the CTX_JOIN_TAB context

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Member Function Documentation

virtual bool opt_explain_json_namespace::join_tab_ctx::add_where_subquery	(	subquery_ctx *	ctx,
		SELECT_LEX_UNIT *	subquery
	)		[inline, virtual]

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.

virtual bool opt_explain_json_namespace::join_tab_ctx::find_and_set_derived

(

context *

subquery

)

[inline, virtual]

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.

virtual bool opt_explain_json_namespace::join_tab_ctx::format_body	(	Opt_trace_context *	json,
		Opt_trace_object *	obj
	)		[inline, virtual]

Format JSON object body

Parameters:

json	Formatter
obj	Object of this body

Return values:

false	Ok
true	Error

Implements opt_explain_json_namespace::context.

virtual size_t opt_explain_json_namespace::join_tab_ctx::id

(

bool

hide

)

[inline, virtual]

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.

virtual void opt_explain_json_namespace::join_tab_ctx::register_where_subquery

(

SELECT_LEX_UNIT *

subquery

)

[inline, virtual]

Remember a subquery's unit

JOIN_TAB inside a JOIN, a table in a join-less query (single-table UPDATE/DELETE) or a table that's optimized out may have a WHERE condition. We create the Explain_context of such a JOIN_TAB or table when the Explain_context objects of its in-WHERE subqueries don't exist. This function collects unit pointers of WHERE subqueries that are associated with the current JOIN_TAB or table. Then we can match these units with units of newly-created Explain_context objects of WHERE subqueries.

Parameters:

subquery

WHERE clause subquery's unit

Reimplemented from qep_row.

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

• opt_explain_json.cc