Dynamically add a logical-log file to prevent transaction blocking

The DYNAMIC_LOGS configuration parameter determines when the database server dynamically adds a logical-log file to prevent transaction blocking.

When you use the default value of 2 for DYNAMIC_LOGS, the database server dynamically adds a new log file and sets off an alarm if the next active log file contains the beginning of the oldest open transaction.

The database server checks the logical-log space at these points:
  • After switching to a new log file
  • At the beginning of the transaction-cleanup phase of logical recovery

If the DYNAMIC_LOGS parameter is set to 1 and the next active log file contains records from an open transaction, the database server prompts you to add a log file manually and sets off an alarm. After you add the log file, the database server resumes processing the transaction.

If the DYNAMIC_LOGS parameter is set to 0 and the logical log runs out of space during a long transaction rollback, the database server can hang. (The long transaction prevents the first logical-log file from becoming free and available for reuse.) To fix the problem and complete the long transaction, set DYNAMIC_LOGS to 2 and restart the database server.


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