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https://dev.mysql.com/doc/refman/8.4/en/gone-away.html
You are using a Windows client and the server had dropped the connection (probably because wait_timeout expired) before the command was issued. This section also covers the related Lost connection to server during query error. The most common ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-handling.html
SQL-92 and earlier does not permit queries for which the select list, HAVING condition, or ORDER BY list refer to nonaggregated columns that are not named in the GROUP BY clause. SQL:1999 and later permits such nonaggregates per optional feature ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-distributed-recovery-fault.html
Warning For a remote cloning operation, user-created tablespaces and data on the recipient (the joining member) are dropped before the remote cloning operation begins to transfer the data from the donor. Group Replication's distributed recovery ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-frequently-asked-questions.html
However, if the network drops packets, leading to re-transmissions and higher end-to-end latency, throughput and latency are both negatively affected. What is the maximum number of MySQL servers in a group? A group can consist of maximum 9 servers.
https://dev.mysql.com/doc/refman/8.4/en/index-page-merge-threshold.html
If the “page-full” percentage for an index page falls below the MERGE_THRESHOLD value when a row is deleted or when a row is shortened by an UPDATE operation, InnoDB attempts to merge the index page with a neighboring index page. The default ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-columns-table.html
When a column is dropped, the remaining columns are reordered so that the sequence has no gaps. For related usage information and examples, see Section 17.15.3, “InnoDB INFORMATION_SCHEMA Schema Object Tables”. The INNODB_COLUMNS table has these ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-fields-table.html
When a column is dropped, the remaining columns are reordered so that the sequence has no gaps. The INNODB_FIELDS table provides metadata about the key columns (fields) of InnoDB indexes. For related usage information and examples, see Section ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-compression-usage.html
For general tablespaces, keep in mind that dropping a table does not reduce the size of the general tablespace .ibd file, nor does it return disk space to the operating system. Compressed tables can be created in file-per-table tablespaces or in ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-file-defragmenting.html
Another way to perform a defragmentation operation is to use mysqldump to dump the table to a text file, drop the table, and reload it from the dump file. Random insertions into or deletions from a secondary index can cause the index to become ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-physical-structure.html
If the fill factor of an InnoDB index page drops below the MERGE_THRESHOLD, which is 50% by default if not specified, InnoDB tries to contract the index tree to free the page. With the exception of spatial indexes, InnoDB indexes are B-tree data ...