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MySQL 26.7.0
Source Code Documentation
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MySQL 26.7.0
Source Code Documentation
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Describes the state of the capacity in sufficient detail that InnoDB knows if it should rush with page cleaning and checkpointing. More...
#include <log0handler_interface.h>
Public Member Functions | |
| Lsn | soft_logical_capacity () const |
| The so called Soft Logical Capacity, which is the lower bound on the length of the lsn range this Handler can provide to the InnoDB, including the margin needed for wait_for_space(). More... | |
Public Attributes | |
| Lsn | max_history_length |
| The estimated lower bound on the maximum difference between peek_first_unassigned_lsn() and oldest still not removed lsn, which the Handler could keep. More... | |
| Lsn | margin_length |
| The length of the lsn range reserved by wait_for_space(). More... | |
Describes the state of the capacity in sufficient detail that InnoDB knows if it should rush with page cleaning and checkpointing.
It depicts a hypothetical state at the border between has_space() returning true and false, by providing how much of the redo log history could be retained in this state, and how much of space is reserved for the margin needed by wait_for_space().
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The so called Soft Logical Capacity, which is the lower bound on the length of the lsn range this Handler can provide to the InnoDB, including the margin needed for wait_for_space().
"Soft" is in contrast to "Hard" limit which might be a little larger, but not exposed to InnoDB, and is the real limit which can't be exceeded for technical reasons, even if the contract of reconfigure(..) and wait_for_space(..) is not followed by InnoDB. "Logical" is in contrast to "Physical" which is the actual number of bytes taken on disc by the data structures.
Always equal to max_history_length + margin_length.
| Lsn ib::redo::Handler_interface::Capacity_estimate::margin_length |
The length of the lsn range reserved by wait_for_space().
| Lsn ib::redo::Handler_interface::Capacity_estimate::max_history_length |
The estimated lower bound on the maximum difference between peek_first_unassigned_lsn() and oldest still not removed lsn, which the Handler could keep.
1.9.2