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MySQL 9.0.0
Source Code Documentation
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An iterator much like IndexRangeScanIterator, but it scans in the reverse order. More...
#include <reverse_index_range_scan.h>
Public Member Functions | |
ReverseIndexRangeScanIterator (THD *thd, TABLE *table, ha_rows *examined_rows, double expected_rows, int index, MEM_ROOT *return_mem_root, uint mrr_flags, Bounds_checked_array< QUICK_RANGE * > ranges, bool using_extended_key_parts) | |
~ReverseIndexRangeScanIterator () override | |
int | Read () override |
Read a single row. More... | |
bool | Init () override |
Initialize or reinitialize the iterator. More... | |
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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... | |
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RowIterator (THD *thd) | |
virtual | ~RowIterator ()=default |
RowIterator (const RowIterator &)=delete | |
RowIterator (RowIterator &&)=default | |
virtual const IteratorProfiler * | GetProfiler () const |
Get profiling data for this iterator (for 'EXPLAIN ANALYZE'). More... | |
virtual void | SetOverrideProfiler ([[maybe_unused]] const IteratorProfiler *profiler) |
virtual RowIterator * | real_iterator () |
If this iterator is wrapping a different iterator (e.g. More... | |
virtual const RowIterator * | real_iterator () const |
Private Member Functions | |
bool | range_reads_after_key (QUICK_RANGE *range) |
int | cmp_prev (QUICK_RANGE *range) |
Static Private Member Functions | |
static range_seq_t | quick_range_rev_seq_init (void *init_param, uint, uint) |
Private Attributes | |
const uint | m_index |
ha_rows | m_expected_rows |
ha_rows * | m_examined_rows |
MEM_ROOT * | mem_root |
bool | inited = false |
MY_BITMAP | column_bitmap |
uint | m_mrr_flags |
Bounds_checked_array< QUICK_RANGE * > | ranges |
QUICK_RANGE_SEQ_CTX | qr_traversal_ctx |
QUICK_RANGE * | last_range |
int | current_range_idx |
KEY_PART_INFO * | key_part_info |
bool | m_using_extended_key_parts {false} |
Additional Inherited Members | |
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int | HandleError (int error) |
void | PrintError (int error) |
TABLE * | table () const |
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THD * | thd () const |
An iterator much like IndexRangeScanIterator, but it scans in the reverse order.
This makes it at times more complicated, but since it doesn't support being a part of a ROR scan, it is also less complicated in many ways.
One could argue that this and IndexRangeScanIterator should be factored into a common base class with separate _ASC and _DESC classes, but they don't actually duplicate that much code.
ReverseIndexRangeScanIterator::ReverseIndexRangeScanIterator | ( | THD * | thd, |
TABLE * | table, | ||
ha_rows * | examined_rows, | ||
double | expected_rows, | ||
int | index, | ||
MEM_ROOT * | return_mem_root, | ||
uint | mrr_flags, | ||
Bounds_checked_array< QUICK_RANGE * > | ranges, | ||
bool | using_extended_key_parts | ||
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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 Index_lookup) and allow you to read the records anew.
Implements RowIterator.
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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].
0 | OK |
-1 | End of records |
1 | Error |
Implements RowIterator.
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