When the query has window functions, an outer node named "windowing" is added: query_block: { select_id: 1, windowing: { windows: [ ... list of all windows' details ... ], nested_loop: [ ... ]. More...

Inheritance diagram for opt_explain_json_namespace::window_ctx:

[legend]

Public Member Functions
	window_ctx (context *parent_arg)

Public Member Functions inherited from opt_explain_json_namespace::join_ctx
	join_ctx (enum_parsing_context type_arg, const char name_arg, context parent_arg)

bool	add_join_tab (joinable_ctx *ctx) override
	Add a CTX_QEP_TAB node to a CTX_JOIN node. More...

void	set_sort (sort_ctx *ctx) override
	Set nested ORDER BY/GROUP BY/DISTINCT node to `ctx`. More...

void	set_window (window_ctx *ctx) override
	Set nested WINDOW node to `ctx`. More...

qep_row *	entry () override

bool	find_and_set_derived (context *subquery) override
	Associate a CTX_DERIVED node with its CTX_QEP_TAB node. More...

bool	add_subquery (subquery_list_enum subquery_type, subquery_ctx *ctx) override
	Append a subquery node to the specified list of the unit node. More...

bool	format_nested_loop (Opt_trace_context *json) override
	Format nested loop join subtree (if any) to JSON formatter. More...

size_t	id (bool hide) override
	Analogue of the "id" column in the traditional EXPLAIN output. More...

bool	cacheable () override

bool	dependent () override

int	add_where_subquery (subquery_ctx ctx, Query_expression subquery) override
	Associate WHERE subqueries of given context and unit with this object. More...

Public Member Functions inherited from opt_explain_json_namespace::unit_ctx
	unit_ctx (enum_parsing_context type_arg, const char name_arg, context parent_arg)

bool	has_no_subqueries () const
	Helper function to distinguish subquery-less nodes. More...

bool	format_query_expression (Opt_trace_context *json) override
	Helper function to format output for HAVING, ORDER/GROUP BY subqueries. More...

Public Member Functions inherited from opt_explain_json_namespace::context
	context (enum_parsing_context type_arg, const char name_arg, context parent_arg)

virtual	~context ()=default

virtual bool	format (Opt_trace_context *json)
	Pass the node with its child nodes to a JSON formatter. More...

bool	is_query_block () const

virtual enum_mod_type	get_mod_type ()

virtual void	set_child (context *)
	Associate a child node with this node. More...

virtual void	set_setop_result (setop_result_ctx *)
	associate CTX_UNION_RESULT node with CTX_UNION node More...

virtual bool	add_query_spec (context *ctx)
	Add a query specification node to the CTX_UNION node. More...

virtual bool	format_derived (Opt_trace_context *)
	Helper function to format output for derived subquery if any. More...

virtual bool	format_where (Opt_trace_context *)
	Helper function to format output for associated WHERE subqueries if any. More...

Public Member Functions inherited from Explain_context
	Explain_context (enum_parsing_context type_arg)

Public Member Functions inherited from qep_row
	qep_row ()

virtual	~qep_row ()=default

void	cleanup ()

virtual void	register_where_subquery (Query_expression *subquery)
	Remember a subquery's unit. More...

void	format_extra (Opt_trace_object *obj)

Protected Member Functions
const char *	get_cost_tag () override

Protected Member Functions inherited from opt_explain_json_namespace::join_ctx
bool	format_body_inner (Opt_trace_context json, Opt_trace_object obj)

Private Member Functions
bool	format_body (Opt_trace_context json, Opt_trace_object obj) override
	Format JSON object body. More...

Additional Inherited Members
Public Attributes inherited from opt_explain_json_namespace::context
context *	parent
	link to parent node or NULL More...

Public Attributes inherited from Explain_context
enum_parsing_context	type
	type tag More...

Public Attributes inherited from qep_row
column< uint >	col_id
	"id" column: seq. number of SELECT within the query More...

column< enum_explain_type >	col_select_type
	"select_type" column More...

mem_root_str	col_table_name
	"table" to which the row of output refers More...

List< const char >	col_partitions
	"partitions" column More...

mem_root_str	col_join_type
	"type" column, see join_type_str array More...

List< const char >	col_possible_keys
	"possible_keys": comma-separated list More...

mem_root_str	col_key
	"key" column: index that is actually decided to use More...

mem_root_str	col_key_len
	"key_length" column: length of the "key" above More...

List< const char >	col_ref
	"ref":columns/constants which are compared to "key" More...

column< float >	col_filtered
	"filtered": % of rows filtered by condition More...

List< extra >	col_extra
	"extra" column (traditional) or property list More...

mem_root_str	col_message
	replaces "Extra" column if not empty More...

mem_root_str	col_attached_condition
	former "Using where" More...

column< ulonglong >	col_rows
	"rows": estimated number of examined table rows per single scan More...

column< ulonglong >	col_prefix_rows
	"rows": estimated number of examined table rows per query More...

column< double >	col_read_cost
	Time to read the table. More...

column< double >	col_prefix_cost
	Cost of the partial join including this table. More...

column< double >	col_cond_cost
	Cost of evaluating conditions on this table per query. More...

mem_root_str	col_data_size_query
	Size of data expected to be read per query. More...

List< const char >	col_used_columns
	List of used columns. More...

List< const char >	col_partial_update_columns
	List of columns that can be updated using partial update. More...

uint	query_block_id
	query block id for materialized subqueries More...

List< opt_explain_json_namespace::context >	derived_from
	List of "derived" subquery trees. More...

List< const char >	col_key_parts
	used parts of the key More...

bool	is_dependent

bool	is_cacheable

bool	using_temporary

enum_mod_type	mod_type

bool	is_materialized_from_subquery

uint	derived_clone_id
	If a clone of a materialized derived table, this is the ID of the first underlying query block of the first materialized derived table. More...

List< Window > *	m_windows
	Windows to describe in this node. More...

Protected Attributes inherited from opt_explain_json_namespace::join_ctx
List< joinable_ctx >	join_tabs
	hosted JOIN_TAB nodes More...

sort_ctx *	sort

window_ctx *	window

Protected Attributes inherited from opt_explain_json_namespace::context
const char *	name

Detailed Description

When the query has window functions, an outer node named "windowing" is added: query_block: { select_id: 1, windowing: { windows: [ ... list of all windows' details ... ], nested_loop: [ ... ].

Due to this "outer-node" layout, the implementation of window_ctx is similar to that of sort_ctx. Except that while it makes sense to describe to the user the "subqueries included in ORDER BY", it doesn't for "subqueries included in the window function's arguments" (the window function belongs to the SELECT list or ORDER BY: so does the subquery, simply), so there is no window_with_subqueries_ctx.

Constructor & Destructor Documentation

◆ window_ctx()

opt_explain_json_namespace::window_ctx::window_ctx ( context * parent_arg )

inline

Member Function Documentation

◆ format_body()

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

inlineoverrideprivatevirtual

Format JSON object body.

Parameters

json	Formatter
obj	Object of this body

Return values

false	Ok
true	Error

Reimplemented from opt_explain_json_namespace::join_ctx.

◆ get_cost_tag()

const char * opt_explain_json_namespace::window_ctx::get_cost_tag ( )

inlineoverrideprotectedvirtual

Reimplemented from opt_explain_json_namespace::join_ctx.

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

sql/opt_explain_json.cc

Public Member Functions

Protected Member Functions