IBM 000-8697 ユーザーズマニュアル

Data Consistency, Recovery, and Migration

OnLine logs dbspace data operations in six steps, illustrated in

.

Following is an overview of steps in logging dbspace data:

Read the data page from disk to shared-memory page buffer.

Copy the unchanged page to the physical log buffer.

Write the new data into the page buffer; create a logical log record of
the transaction, if needed.

Flush physical log buffer to the physical log on disk.

Flush logical log buffer to a logical log file on disk.

Flush the page buffer and write it back to disk.