Temporary data and Differential Backup size

  • Thomas Franz

    Hall of Fame

    Points: 3647

    Comments posted to this topic are about the item Temporary data and Differential Backup size

    God is real, unless declared integer.

  • Carlo Romagnano

    SSC-Insane

    Points: 21967

    My results:

    Processed 5128 pages for database 'test', file 'test' on file 1.

    100 percent processed.

    Processed 3 pages for database 'test', file 'test_log' on file 1.

    BACKUP DATABASE WITH DIFFERENTIAL successfully processed 5131 pages in 0.244 seconds (164.266 MB/sec).

  • Neil Burton

    SSC-Insane

    Points: 22205

    I got the same results as Carlos.

    It logically makes sense that because there has been no net change the differential will only be small but the outcome of my test said otherwise.


    On two occasions I have been asked, "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" ... I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.
    —Charles Babbage, Passages from the Life of a Philosopher

    How to post a question to get the most help http://www.sqlservercentral.com/articles/Best+Practices/61537

  • Louis Hillebrand

    SSCarpal Tunnel

    Points: 4200

    My Result when running the entire batch:

    Processed 4 pages for database 'test', file 'test_log' on file 1.

    BACKUP DATABASE WITH DIFFERENTIAL successfully processed 5108 pages in 1.766 seconds (22.594 MB/sec).

    Running the same batch with a WAITFOR DELAY '00:00:05' before the differential backup gives this result:

    Processed 4 pages for database 'test', file 'test_log' on file 3.

    BACKUP DATABASE WITH DIFFERENTIAL successfully processed 92 pages in 0.336 seconds (2.127 MB/sec).

    With a delay of less than 3 seconds more than 5000 pages were processed in the differential backup.

    The correct answer should have been 'It Depends'

    Louis.

     

     

  • Carlo Romagnano

    SSC-Insane

    Points: 21967

    Well done, "WAITFOR DELAY '00:00:05' " makes the difference.

  • Jeff Moden

    SSC Guru

    Points: 996648

    Heh... perhaps the next article should be about the delays of ghost row cleanups. 😀

    --Jeff Moden


    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.
    "Change is inevitable... change for the better is not".
    "If "pre-optimization" is the root of all evil, then what does the resulting no optimization lead to?"

    Helpful Links:
    How to post code problems
    How to Post Performance Problems
    Create a Tally Function (fnTally)

  • Stewart "Arturius" Campbell

    SSC Guru

    Points: 71812

    Interesting question, thanks Thomas

    ____________________________________________
    Space, the final frontier? not any more...
    All limits henceforth are self-imposed.
    “libera tute vulgaris ex”

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