How to restore free space shown in INFORMATION_SCHEMA.TABLES.DATA_FREE?
We have a version 5.7.38 MySQL database running on AWS for a long time and the free storage space has been quite constant until recently - the free storage space has suddenly dropped 30%. INFORMATION_SCHEMA.TABLES shows us that DATA_FREE of many of the tables have grown significantly, e.g.,
TABLE_SCHEMA | TABLE_NAME | ENGINE | DATA_LENGTH | DATA_FREE (bytes) | DATA_FREE (bytes, 14 days ago)
information_schema | COLUMNS | InnoDB | 6,384.00 | 339,738,624.00 | 8,388,608.00
information_schema | OPTIMIZER_TRACE | InnoDB | 16,384.00 | 339,738,624.00 | 8,388,608.00
information_schema | PARAMETERS | InnoDB | 16,384.00 | 339,738,624.00 | 8,388,608.00
information_schema | PARTITIONS | InnoDB | 16,384.00 | 339,738,624.00 | 8,388,608.00
information_schema | PLUGINS | InnoDB | 16,384.00 | 339,738,624.00 | 8,388,608.00
information_schema | PROCESSLIST | InnoDB | 16,384.00 | 339,738,624.00 | 8,388,608.00
Questions:
#1 The database is dynamic but not only recently so we are puzzled about the growth. Would anyone know what could be the triggers?
#2 Is there a way to trim free space?
#3 Am I looking at the right place for the loss of free storage space? Where else should I look at?
Thanks!