Explain_format Class Reference

#include <opt_explain_format.h>

Inheritance diagram for Explain_format:

Collaboration diagram for Explain_format:

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

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)

Detailed Description

Base class for structured and hierarchical EXPLAIN output formatters

Definition at line 528 of file opt_explain_format.h.

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.

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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.

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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.

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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.

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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.

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virtual bool Explain_format::send_headers ( select_result *  result )

inlinevirtual

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.

Definition at line 561 of file opt_explain_format.h.

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

• sql/opt_explain_format.h