Db2 Version 11.5 has GAed -- Come See What's New from Availability & Recovery

Db2 11.5 is here and with it comes a bunch of new features and changed behaviors in the area of Availability & Recovery that should make your every day tasks easier.  Check out the list:

New features

  • Advanced log space management
    • Tech Preview (not for production use)
    • Reduce transaction log full
  • Reduced logging
    • Reduced undo logging on by default in 11.5 GA
      • Required log space cut in half
    • Reduced redo logging available only in Warehouse installations
      • Up to 95% less logging

Changed default behavior (ON)

  • For databases configured with a mirrored log path a potential performance improvement can be achieved by writing log data to both files asynchronously in parallel
  • Rollback performance improvements using buffered I/O when reading transaction log file data
  • HADR Reads on Standby – the availability of the standby database to perform SQL queries is significantly enhanced through the avoidance of the replay-only window

New registry variable

    • Controls whether standby will keep log files when the corresponding log files on primary are not archived
    • Set to FALSE on standby, standby will delete log files when the corresponding log files on primary are not archived

Changes to database configuration parameters

  • rec_hist_rentn
    • Current setting 366 days
    • Changed to 90 days for new databases
  • logprimary / logsecond
    • Increased each from 256 to 4096
      • logprimary + logsecond <= 8192
    • Recoverable databases only
    • Be aware: Db2 instance can only have open 65536 concurrent files
    • Maximum theoretical size is:
      • Circular: 256 log files * 64GB = 16TB
      • Recoverable: 8192 log files * 64GB = 512TB

Changes to database manager configuration parameters

  • HADR now respects SSL_CIPHERSPECS
    • Specifies the cipher suites that the server allows for incoming connection requests when using SSL protocol
    • Additionally, will now also specify the cipher suites used to communicate between primary and standby


  • Deprecated APIs
    • db2ReadLogNoConn
    • db2ReadLogNoConnInit
    • db2ReadLogNoConnTerm
  • Upgrade
    • Support from 10.5 and 11.1
      • FYI: 10.5 end of support date April 30, 2020

For a full list of What's New and What's Changed in 11.5 please see the Knowledge Center.

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