Explain_format Class Reference

#include <opt_explain_format.h>

Inheritance diagram for Explain_format:

List of all members.

Public Member Functions
virtual bool	is_hierarchical () const =0
virtual bool	send_headers (select_result *result)
virtual bool	begin_context (Explain_context_enum context, SELECT_LEX_UNIT *subquery=0, const Explain_format_flags *flags=NULL)=0
virtual bool	end_context (Explain_context_enum context)=0
virtual bool	flush_entry ()=0
virtual qep_row *	entry ()=0
Public Attributes
select_result *	output
	output resulting data there

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Detailed Description

Base class for structured and hierarchical EXPLAIN output formatters

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Member Function Documentation

virtual bool Explain_format::begin_context	(	Explain_context_enum	context,
		SELECT_LEX_UNIT *	subquery = 0,
		const Explain_format_flags *	flags = NULL
	)		[pure virtual]

Enter a specified context

Parameters:

context	context type
subquery	for CTX_WHERE: unit of the subquery

Implemented in Explain_format_JSON, and Explain_format_traditional.

virtual bool Explain_format::end_context

(

Explain_context_enum

context

)

[pure virtual]

Leave the current context

Parameters:

context

current context type (for validation/debugging)

Implemented in Explain_format_JSON, and Explain_format_traditional.

virtual qep_row* Explain_format::entry

(

)

[pure virtual]

Get a pointer to the current TABLE/JOIN_TAB property set

Implemented in Explain_format_JSON, and Explain_format_traditional.

virtual bool Explain_format::flush_entry

(

)

[pure virtual]

Flush TABLE/JOIN_TAB property set

For traditional EXPLAIN: output a single EXPLAIN row.

Implemented in Explain_format_JSON, and Explain_format_traditional.

virtual bool Explain_format::is_hierarchical

(

)

const [pure virtual]

A hierarchical text or a plain table

Return values:

true	Formatter produces hierarchical text
false	Traditional explain

Implemented in Explain_format_JSON, and Explain_format_traditional.

virtual bool Explain_format::send_headers

(

select_result *

result

)

[inline, virtual]

Send EXPLAIN header item(s) to output stream

Note:

: This function caches the output result set pointer for further use.

Parameters:

result

output result set

Return values:

false	OK
true	Error

Reimplemented in Explain_format_JSON, and Explain_format_traditional.

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

• opt_explain_format.h