HOT SPOTS
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Thread: HOT SPOTS

  1. #1
    Join Date
    Jan 2002
    Posts
    65
    Can any one telle me as to what are Hot spots in Oracle?
    Sabitabrata

  2. #2
    Join Date
    Aug 2001
    Location
    Waterloo, On
    Posts
    547
    I think hotspots refer to files with a lot of I/O activity going on. In tuning for performance, you don't want many 'hotspots' so to say, and instead would like the I/O to be distributed more evenly among the various datafiles, tablespaces and disks.

    To detect the 'Hotspots', you can use the V$FILESTAT view and join it with V$DATAFILE.

    Select n.filename, f.phyrds, f.phywrts, f.avgiotim
    from v$datafile n, V$filestat f
    where n.file# = f.file# ;


    Raminder Singh

    Oracle Certified DBA: Oracle 8i, 9i


    Mail me at raminderahluwalia@rediffmail.com.

  3. #3
    Join Date
    Feb 2000
    Location
    Singapore
    Posts
    1,758
    A particular block or datafile on the disk experincing very high amount of I/Os are called hot spots. It happens if the I/Os are not evenly distributed across the available disks.

    Sanjay

  4. #4
    Join Date
    Jan 2002
    Posts
    65
    Thanks all of u
    Sabitabrata

  5. #5
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,447
    there are hot spots in buffer cache as well but the concept is basically the same as datafiles, to check for hot spots in buffer cache you have to check for cache buffer chain latch from v$latch_children then join with x$bh (addr and laddr) and order by touch counts in x$bh

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