lob::ReadContext Struct Reference

The context information for reading a single BLOB. More...

#include <lob0lob.h>

Public Member Functions
	ReadContext (const page_size_t &page_size, const byte *data, ulint prefix_len, byte *buf, ulint len, bool is_sdi)
	Constructor. More...
void	read_blobref ()
	Read the space_id, page_no and offset information from the BLOB reference object and update the member variables. More...
bool	is_valid_blob () const
	Check if the BLOB reference is valid. More...
dict_index_t *	index ()
bool	is_sdi () const
	Is it a space dictionary index (SDI)? More...
bool	assert_read_uncommitted () const
	Assert that current trx is using isolation level read uncommitted. More...

Public Attributes
const page_size_t &	m_page_size
	The page size information. More...
const byte *	m_data
	The 'internally' stored part of the field containing also the reference to the external part; must be protected by a lock or a page latch. More...
ulint	m_local_len
	Length (in bytes) of BLOB prefix stored inline in clustered index record. More...
const ref_t	m_blobref
	The blob reference of the blob that is being read. More...
byte *	m_buf
	Buffer into which data is read. More...
ulint	m_len
	Length of the buffer m_buf. More...
space_id_t	m_space_id
	The identifier of the space in which blob is available. More...
page_no_t	m_page_no
	The page number obtained from the blob reference. More...
ulint	m_offset
	The offset information obtained from the blob reference. More...
dict_index_t *	m_index
ulint	m_lob_version
const bool	m_is_sdi
	Is it a tablespace dictionary index (SDI)? More...
trx_t *	m_trx = nullptr
	The transaction that is reading. More...

Detailed Description

The context information for reading a single BLOB.

Constructor & Destructor Documentation

ReadContext()

lob::ReadContext::ReadContext ( const page_size_t &  page_size, const byte *  data, ulint  prefix_len, byte *  buf, ulint  len, bool  is_sdi  )

inline

Constructor.

Parameters

[in]	page_size	page size information.
[in]	data	'internally' stored part of the field containing also the reference to the external part; must be protected by a lock or a page latch.
[in]	prefix_len	length of BLOB data stored inline in the clustered index record, including the blob reference.
[out]	buf	the output buffer.
[in]	len	the output buffer length.
[in]	is_sdi	true for SDI Indexes.

Member Function Documentation

assert_read_uncommitted()

bool lob::ReadContext::assert_read_uncommitted

(

)

const

Assert that current trx is using isolation level read uncommitted.

Returns

true if transaction is using read uncommitted, false otherwise.

index()

dict_index_t * lob::ReadContext::index ( )

inline

is_sdi()

bool lob::ReadContext::is_sdi ( ) const

inline

Is it a space dictionary index (SDI)?

Returns

true if SDI, false otherwise.

is_valid_blob()

bool lob::ReadContext::is_valid_blob ( ) const

inline

Check if the BLOB reference is valid.

For this particular check, if the length of the BLOB is greater than 0, it is considered valid.

Returns

true if valid.

read_blobref()

void lob::ReadContext::read_blobref ( )

inline

Read the space_id, page_no and offset information from the BLOB reference object and update the member variables.

Member Data Documentation

m_blobref

const ref_t lob::ReadContext::m_blobref

The blob reference of the blob that is being read.

m_buf

byte* lob::ReadContext::m_buf

Buffer into which data is read.

m_data

const byte* lob::ReadContext::m_data

The 'internally' stored part of the field containing also the reference to the external part; must be protected by a lock or a page latch.

m_index

dict_index_t* lob::ReadContext::m_index

m_is_sdi

const bool lob::ReadContext::m_is_sdi

Is it a tablespace dictionary index (SDI)?

m_len

ulint lob::ReadContext::m_len

Length of the buffer m_buf.

m_lob_version

ulint lob::ReadContext::m_lob_version

m_local_len

ulint lob::ReadContext::m_local_len

Length (in bytes) of BLOB prefix stored inline in clustered index record.

m_offset

ulint lob::ReadContext::m_offset

The offset information obtained from the blob reference.

m_page_no

page_no_t lob::ReadContext::m_page_no

The page number obtained from the blob reference.

m_page_size

const page_size_t& lob::ReadContext::m_page_size

The page size information.

m_space_id

space_id_t lob::ReadContext::m_space_id

The identifier of the space in which blob is available.

m_trx

trx_t* lob::ReadContext::m_trx = nullptr

The transaction that is reading.

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The documentation for this struct was generated from the following files:

• storage/innobase/include/lob0lob.h
• storage/innobase/lob/lob0lob.cc