MySQL  8.0.27
Source Code Documentation
TableScanIterator Class Referencefinal

Scan a table from beginning to end. More...

#include <basic_row_iterators.h>

Inheritance diagram for TableScanIterator:
TableRowIterator RowIterator

Public Member Functions

 TableScanIterator (THD *thd, TABLE *table, double expected_rows, ha_rows *examined_rows)
 
 ~TableScanIterator () override
 
bool Init () override
 Initialize or reinitialize the iterator. More...
 
int Read () override
 Read a single row. More...
 
- Public Member Functions inherited from TableRowIterator
 TableRowIterator (THD *thd, TABLE *table)
 
void UnlockRow () override
 The default implementation of unlock-row method of RowIterator, used in all access methods except EQRefIterator. More...
 
void SetNullRowFlag (bool is_null_row) override
 Mark the current row buffer as containing a NULL row or not, so that if you read from it and the flag is true, you'll get only NULLs no matter what is actually in the buffer (typically some old leftover row). More...
 
void StartPSIBatchMode () override
 Start performance schema batch mode, if supported (otherwise ignored). More...
 
void EndPSIBatchModeIfStarted () override
 Ends performance schema batch mode, if started. More...
 
- Public Member Functions inherited from RowIterator
 RowIterator (THD *thd)
 
virtual ~RowIterator ()=default
 
virtual std::string TimingString () const
 
virtual RowIteratorreal_iterator ()
 If this iterator is wrapping a different iterator (e.g. More...
 
virtual const RowIteratorreal_iterator () const
 

Private Attributes

uchar *const m_record
 
const double m_expected_rows
 
ha_rows *const m_examined_rows
 

Additional Inherited Members

- Protected Member Functions inherited from TableRowIterator
int HandleError (int error)
 
void PrintError (int error)
 
TABLEtable () const
 
- Protected Member Functions inherited from RowIterator
THDthd () const
 

Detailed Description

Scan a table from beginning to end.

This is the most basic access method of a table using rnd_init, ha_rnd_next and rnd_end. No indexes are used.

Constructor & Destructor Documentation

◆ TableScanIterator()

TableScanIterator::TableScanIterator ( THD thd,
TABLE table,
double  expected_rows,
ha_rows examined_rows 
)

◆ ~TableScanIterator()

TableScanIterator::~TableScanIterator ( )
override

Member Function Documentation

◆ Init()

bool TableScanIterator::Init ( )
overridevirtual

Initialize or reinitialize the iterator.

You must always call Init() before trying a Read() (but Init() does not imply Read()).

You can call Init() multiple times; subsequent calls will rewind the iterator (or reposition it, depending on whether the iterator takes in e.g. a TABLE_REF) and allow you to read the records anew.

Implements RowIterator.

◆ Read()

int TableScanIterator::Read ( )
overridevirtual

Read a single row.

The row data is not actually returned from the function; it is put in the table's (or tables', in case of a join) record buffer, ie., table->records[0].

Return values
0OK
-1End of records
1Error

Implements RowIterator.

Member Data Documentation

◆ m_examined_rows

ha_rows* const TableScanIterator::m_examined_rows
private

◆ m_expected_rows

const double TableScanIterator::m_expected_rows
private

◆ m_record

uchar* const TableScanIterator::m_record
private

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