Flush the logical-log buffer

A number of events can cause the logical-log buffer to flush.

The database server uses the shared-memory logical-log buffer as temporary storage for records that describe modifications to database server pages. From the logical-log buffer, these records of changes are written to the current logical-log file on disk and eventually to the logical-log backup media. For a description of logical logging, see Logical log.

Five events cause the current logical-log buffer to flush:
  • The current logical-log buffer becomes full.
  • A transaction is prepared or committed in a database with unbuffered logging.
  • A nonlogging database session terminates.
  • A checkpoint occurs.
  • A page is modified that does not require a before-image in the physical log.

The following topics explain each of these events in detail.

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