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https://dev.mysql.com/doc/refman/8.4/en/innochecksum.html
In order for the progress indicator to be printed, the log file must be specified using the --log option. If the new checksum is identical to the existing checksum, the new checksum is not written to disk in order to minimize I/O. This tool reads an ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-change-buffer.html
Figure 17.3 Change Buffer Unlike clustered indexes, secondary indexes are usually nonunique, and inserts into secondary indexes happen in a relatively random order. Configuring Change Buffering When INSERT, UPDATE, and DELETE operations are ... The ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-deadlocks.html
A deadlock is a situation in which multiple transactions are unable to proceed because each transaction holds a lock that is needed by another one. Because all transactions involved are waiting for the same resource to become available, none of ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-file-defragmenting.html
Fragmentation means that the physical ordering of the index pages on the disk is not close to the index ordering of the records on the pages, or that there are many unused pages in the 64-page blocks that were allocated to the index. Random ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-buffer-pool-tables.html
INNODB_BUFFER_PAGE_LRU: Holds information about the pages in the InnoDB buffer pool, in particular how they are ordered in the LRU list that determines which pages to evict from the buffer pool when it becomes full. The InnoDB INFORMATION_SCHEMA ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-locking.html
If one session has a shared or exclusive lock on record R in an index, another session cannot insert a new index record in the gap immediately before R in the index order. There is no absolute ordering concept in multidimensional data, so it is not ...Shared and Exclusive Locks Intention Locks Record Locks Gap Locks Next-Key Locks Insert Intention Locks AUTO-INC Locks Predicate Locks for Spatial Indexes Shared and Exclusive Locks InnoDB implements standard row-level locking where there are two types of locks, shared (S) locks and exclusive (X) ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-locks-set.html
A locking read, an UPDATE, or a DELETE generally set record locks on every index record that is scanned in the processing of an SQL statement. It does not matter whether there are WHERE conditions in the statement that would exclude the row. InnoDB ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-parameters.html
innodb_flush_log_at_timeout allows the timeout period between flushes to be increased in order to reduce flushing and avoid impacting performance of binary log group commit. FOR UPDATE statements for multiple tables, so that each transaction ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-physical-structure.html
If index records are inserted in a sequential order (ascending or descending), the resulting index pages are about 15/16 full. If records are inserted in a random order, the pages are from 1/2 to 15/16 full. With the exception of spatial indexes, ...
https://dev.mysql.com/doc/refman/8.4/en/insert-on-duplicate.html
SELECT statements depend on the ordering of rows from the SELECT and this order cannot always be guaranteed, it is possible when logging INSERT ... If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate ...