Logical-log I/O

The LIO class of virtual processors performs I/O to the logical-log files.

I/O is performed to logical-log files in the following cases:
  • KAIO is not implemented.
  • The logical-log files are in cooked disk space.

Only when KAIO is implemented and the logical-log files are in raw disk space does the database server use a KAIO thread in the CPU virtual processor to perform I/O to the logical log.

The logical-log files store the data that enables the database server to roll back transactions and recover from system failures. I/O to the logical-log files is the highest priority disk I/O that the database server performs.

If the logical-log files are in a dbspace that is not mirrored, the database server runs only one LIO virtual processor. If the logical-log files are in a dbspace that is mirrored, the database server runs two LIO virtual processors. This class of virtual processors has no parameters associated with it.


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