Post reply

Buffer Cache Hit Ratio

  • February 10, 2014 at 4:33 am

    #285334

    Hi Experts,

    In one of our servers i got scom alert thatn buffer cache hit ratio is really low. I checked sys.dm_os_performance_counter DMV and most of the times the cntr_value is showing as 7. Please let know is this value good what is the baseline for this column ,what are the min and max values.

  • February 10, 2014 at 4:40 am

    #1687481

    Chapter 4: http://www.red-gate.com/community/books/accidental-dba

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • February 10, 2014 at 6:12 am

    #1687498

    Thanks Gail,

    I was actually going through

    https://www.simple-talk.com/content/article.aspx?article=1426

    Here we have Page Life Expectancy of 17999 and low Buffer Cache Hit ratio

    SQLServer:Buffer Manager Buffer cache hit ratio 15

    SQLServer:Buffer Manager Free list stalls/sec 5202

    SQLServer:Buffer Manager Free pages 223

    SQLServer:Buffer Manager Page life expectancy 17999

  • February 10, 2014 at 5:13 pm

    #1687730

    At best, buffer count hit ratio is just an indication of load. And, as you see with Jonathan's test, it's not even necessarily that. Yeah, a very low number of the hit ratio means that you may be cycling through lots of data in memory, but that doesn't mean your server is under pressure. You need to look at the other counters, wait statistics, queues, to understand what else is happening on the system.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • February 11, 2014 at 1:23 am

    #1687790

    Thanks Grant.

Viewing 5 posts - 1 through 4 (of 4 total)

You must be logged in to reply to this topic. Login to reply