Improved InnoDB I/O Scalability Improved InnoDB I/O Scalability¶
Because InnoDB is a complex storage engine it must be configured properly in order to perform at its best. Some points are not configurable in standard InnoDB. The goal of this feature is to provide a more exhaustive set of options for XtraDB.
Version Specific Information¶
8.0.12-1- the feature was ported from Percona Server for MySQL 5.7.
System Variables¶
-
variable
innodb_flush_method¶ Command Line: Yes Config File: Yes Scope: Global Dyn: No Variable Type: Enumeration Default Value: fdatasyncAllowed Values: fdatasync,O_DSYNC,O_DIRECT,O_DIRECT_NO_FSYNC
See innodb_flush_method in the MySQL 8.0 Reference Manual).
This variable affects the parallel doublewrite buffer as follows
| Value | Usage |
|---|---|
| fdatasync | Use fsync() to flush parallel doublewrite files. |
| O_SYNC | Use O_SYNC to open and flush parallel doublewrite files; Do not use
the fsync() system call to flush the parallel doublewrite file. |
| O_DIRECT | Use O_DIRECT to open the data files and the fsync() system call to flush
parallel doublewrite files. |
| O_DIRECT_NO_FSYNC | Use O_DIRECT to open the data files but don’t use fsync() system
call to flush doublewrite files. |
Status Variables¶
The following information has been added to SHOW ENGINE INNODB STATUS to confirm the checkpointing activity:
The max checkpoint age
The current checkpoint age target
The current age of the oldest page modification which has not been flushed to disk yet.
The current age of the last checkpoint
...
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LOG
---
Log sequence number 0 1059494372
Log flushed up to 0 1059494372
Last checkpoint at 0 1055251010
Max checkpoint age 162361775
Checkpoint age target 104630090
Modified age 4092465
Checkpoint age 4243362
0 pending log writes, 0 pending chkp writes
...
