MySQL 9.0.0
Source Code Documentation
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Fetch the record IDs from a memory buffer, but the records themselves from the table on disk. More...
#include <basic_row_iterators.h>
Public Member Functions | |
SortBufferIndirectIterator (THD *thd, Mem_root_array< TABLE * > tables, Sort_result *sort_result, bool ignore_not_found_rows, bool has_null_flags, ha_rows *examined_rows) | |
~SortBufferIndirectIterator () override | |
bool | Init () override |
Initialize or reinitialize the iterator. More... | |
int | Read () override |
Read a single row. More... | |
void | SetNullRowFlag (bool) 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 | UnlockRow () override |
Public Member Functions inherited from RowIterator | |
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 void | StartPSIBatchMode () |
Start performance schema batch mode, if supported (otherwise ignored). More... | |
virtual void | EndPSIBatchModeIfStarted () |
Ends performance schema batch mode, if started. More... | |
virtual RowIterator * | real_iterator () |
If this iterator is wrapping a different iterator (e.g. More... | |
virtual const RowIterator * | real_iterator () const |
Private Attributes | |
Sort_result *const | m_sort_result |
Mem_root_array< TABLE * > | m_tables |
uint | m_sum_ref_length |
ha_rows *const | m_examined_rows |
uchar * | m_cache_pos = nullptr |
uchar * | m_cache_end = nullptr |
bool | m_ignore_not_found_rows |
bool | m_has_null_flags |
Additional Inherited Members | |
Protected Member Functions inherited from RowIterator | |
THD * | thd () const |
Fetch the record IDs from a memory buffer, but the records themselves from the table on disk.
Used when the above (comment on SortBufferIterator) is not true, UPDATE, DELETE and so forth and SELECT's involving large BLOBs. It is also used for the result of Unique, which returns row IDs in the same format as filesort. In this case the record data is fetched from the handler using the saved reference using the rnd_pos handler call.
SortBufferIndirectIterator::SortBufferIndirectIterator | ( | THD * | thd, |
Mem_root_array< TABLE * > | tables, | ||
Sort_result * | sort_result, | ||
bool | ignore_not_found_rows, | ||
bool | has_null_flags, | ||
ha_rows * | examined_rows | ||
) |
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override |
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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 Index_lookup) and allow you to read the records anew.
Implements RowIterator.
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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].
0 | OK |
-1 | End of records |
1 | Error |
Implements RowIterator.
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inlineoverridevirtual |
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).
This is used for outer joins, when an iterator hasn't produced any rows and we need to produce a NULL-complemented row. Init() or Read() won't necessarily reset this flag, so if you ever set is to true, make sure to also set it to false when needed.
Note that this can be called without Init() having been called first. For example, NestedLoopIterator can hit EOF immediately on the outer iterator, which means the inner iterator doesn't get an Init() call, but will still forward SetNullRowFlag to both inner and outer iterators.
TODO: We shouldn't need this. See the comments on AggregateIterator for a bit more discussion on abstracting out a row interface.
Implements RowIterator.
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inlineoverridevirtual |
Implements RowIterator.
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