15.11 InnoDB Disk I/O and File Space Management .............................................................. 3171 15.11.1 InnoDB Disk I/O ............................................................................................... 3172 15.11.2 File Space Management ................................................................................... 3172 15.11.3 InnoDB Checkpoints ......................................................................................... 3174 15.11.4 Defragmenting a Table ..................................................................................... 3174 15.11.5 Reclaiming Disk Space with TRUNCATE TABLE ............................................... 3175 15.12 InnoDB and Online DDL .............................................................................................. 3175 15.12.1 Online DDL Operations ..................................................................................... 3176 15.12.2 Online DDL Performance and Concurrency ........................................................ 3190 15.12.3 Online DDL Space Requirements ...................................................................... 3194 15.12.4 Simplifying DDL Statements with Online DDL .................................................... 3194 15.12.5 Online DDL Failure Conditions .......................................................................... 3195 15.12.6 Online DDL Limitations ..................................................................................... 3195 15.13 InnoDB Data-at-Rest Encryption .................................................................................. 3196 15.14 InnoDB Startup Options and System Variables ............................................................. 3205 15.15 InnoDB INFORMATION_SCHEMA Tables .................................................................... 3298 15.15.1 InnoDB INFORMATION_SCHEMA Tables about Compression ........................... 3298 15.15.2 InnoDB INFORMATION_SCHEMA Transaction and Locking Information ............. 3300 15.15.3 InnoDB INFORMATION_SCHEMA Schema Object Tables ................................. 3307 15.15.4 InnoDB INFORMATION_SCHEMA FULLTEXT Index Tables .............................. 3313 15.15.5 InnoDB INFORMATION_SCHEMA Buffer Pool Tables ........................................ 3316 15.15.6 InnoDB INFORMATION_SCHEMA Metrics Table ............................................... 3321 15.15.7 InnoDB INFORMATION_SCHEMA Temporary Table Info Table .......................... 3329 15.15.8 Retrieving InnoDB Tablespace Metadata from INFORMATION_SCHEMA.FILES .. 3330 15.16 InnoDB Integration with MySQL Performance Schema .................................................. 3332 15.16.1 Monitoring ALTER TABLE Progress for InnoDB Tables Using Performance Schema ........................................................................................................................ 3334 15.16.2 Monitoring InnoDB Mutex Waits Using Performance Schema .............................. 3335 15.17 InnoDB Monitors ......................................................................................................... 3339 15.17.1 InnoDB Monitor Types ...................................................................................... 3339 15.17.2 Enabling InnoDB Monitors ................................................................................ 3340 15.17.3 InnoDB Standard Monitor and Lock Monitor Output ............................................ 3341 15.18 InnoDB Backup and Recovery ..................................................................................... 3346 15.18.1 InnoDB Backup ................................................................................................ 3346 15.18.2 InnoDB Recovery ............................................................................................. 3347 15.19 InnoDB and MySQL Replication ................................................................................... 3350 15.20 InnoDB memcached Plugin .......................................................................................... 3352 15.20.1 Benefits of the InnoDB memcached Plugin ........................................................ 3352 15.20.2 InnoDB memcached Architecture ...................................................................... 3353 15.20.3 Setting Up the InnoDB memcached Plugin ........................................................ 3357 15.20.4 InnoDB memcached Multiple get and Range Query Support ............................... 3363 15.20.5 Security Considerations for the InnoDB memcached Plugin ................................ 3365 15.20.6 Writing Applications for the InnoDB memcached Plugin ...................................... 3367 15.20.7 The InnoDB memcached Plugin and Replication ................................................ 3379 15.20.8 InnoDB memcached Plugin Internals ................................................................. 3383 15.20.9 Troubleshooting the InnoDB memcached Plugin ................................................ 3388 15.21 InnoDB Troubleshooting .............................................................................................. 3390 15.21.1 Troubleshooting InnoDB I/O Problems ............................................................... 3390 15.21.2 Forcing InnoDB Recovery ................................................................................. 3391 15.21.3 Troubleshooting InnoDB Data Dictionary Operations .......................................... 3393 15.21.4 InnoDB Error Handling ...................................................................................... 3394 15.22 InnoDB Limits ............................................................................................................. 3394 15.23 InnoDB Restrictions and Limitations ............................................................................. 3396 16 Alternative Storage Engines ..................................................................................................... 3397 xvii MySQL 8.0 Reference Manual