MySQL 9.0.0
Source Code Documentation
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An operand (query block) to be materialized by MaterializeIterator. More...
#include <composite_iterators.h>
Public Attributes | |
unique_ptr_destroy_only< RowIterator > | subquery_iterator |
The iterator to read the actual rows from. More... | |
int | select_number |
Used only for optimizer trace. More... | |
JOIN * | join |
The JOIN that this query block represents. More... | |
bool | disable_deduplication_by_hash_field = false |
If true, de-duplication checking via hash key is disabled when materializing this query block (ie., we simply avoid calling check_unique_fields() for each row). More... | |
bool | copy_items |
If set to false, the Field objects in the output row are presumed already to be filled out. More... | |
ulonglong | m_total_operands {0} |
The number of operands (i.e. More... | |
ulonglong | m_operand_idx {0} |
The current operand (i.e. More... | |
uint | m_first_distinct {0} |
Used for EXCEPT computation: the index of the first operand involved in a N-ary except operation which has DISTINCT. More... | |
Temp_table_param * | temp_table_param |
If copy_items is true, used for copying the Field objects into the temporary table row. More... | |
bool | is_recursive_reference = false |
FollowTailIterator * | recursive_reader = nullptr |
double | m_estimated_output_rows {0.0} |
The estimated number of rows produced by this block. More... | |
An operand (query block) to be materialized by MaterializeIterator.
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bool materialize_iterator::Operand::copy_items |
If set to false, the Field objects in the output row are presumed already to be filled out.
This is the case iff there's a windowing iterator earlier in the chain.
bool materialize_iterator::Operand::disable_deduplication_by_hash_field = false |
If true, de-duplication checking via hash key is disabled when materializing this query block (ie., we simply avoid calling check_unique_fields() for each row).
Used when materializing UNION DISTINCT and UNION ALL parts into the same table. We'd like to just use a unique constraint via unique index instead, but there might be other indexes on the destination table that we'd like to keep, and the implementation doesn't allow disabling only one index.
If you use this on a query block, doing_hash_deduplication() must be true.
bool materialize_iterator::Operand::is_recursive_reference = false |
JOIN* materialize_iterator::Operand::join |
The JOIN that this query block represents.
Used for performance schema batch mode: When materializing a query block that consists of a single table, MaterializeIterator needs to set up schema batch mode, since there is no nested loop iterator to do it. (This is similar to what ExecuteIteratorQuery() needs to do at the top level.)
double materialize_iterator::Operand::m_estimated_output_rows {0.0} |
The estimated number of rows produced by this block.
uint materialize_iterator::Operand::m_first_distinct {0} |
Used for EXCEPT computation: the index of the first operand involved in a N-ary except operation which has DISTINCT.
This is significant for calculating whether to set the counter to zero or just decrement it when we see a right side operand.
ulonglong materialize_iterator::Operand::m_operand_idx {0} |
The current operand (i.e.
block) number, starting at zero. We use this for INTERSECT and EXCEPT materialization operand.
ulonglong materialize_iterator::Operand::m_total_operands {0} |
The number of operands (i.e.
blocks) involved in the set operation: used for INTERSECT to determine if a value is present in all operands
FollowTailIterator* materialize_iterator::Operand::recursive_reader = nullptr |
int materialize_iterator::Operand::select_number |
Used only for optimizer trace.
unique_ptr_destroy_only<RowIterator> materialize_iterator::Operand::subquery_iterator |
The iterator to read the actual rows from.
Temp_table_param* materialize_iterator::Operand::temp_table_param |
If copy_items is true, used for copying the Field objects into the temporary table row.
Otherwise unused.