Hello and welcome to our community! Is this your first visit?
Register
Enjoy an ad free experience by logging in. Not a member yet? Register.
Results 1 to 4 of 4
  1. #1
    Senior Coder
    Join Date
    Dec 2005
    Location
    Slovenia
    Posts
    1,963
    Thanks
    120
    Thanked 76 Times in 76 Posts

    use / foce index

    Should that affect result of explain ?

    It does not.
    Neither it affect performance.
    Found a flower or bug and don't know what it is ?
    agrozoo.net galery
    if you don't spot search button at once, there is search form:
    agrozoo.net galery search

  • #2
    Supreme Master coder! Old Pedant's Avatar
    Join Date
    Feb 2009
    Posts
    25,799
    Thanks
    78
    Thanked 4,410 Times in 4,375 Posts
    I'm sorry...I don't understand the question.
    An optimist sees the glass as half full.
    A pessimist sees the glass as half empty.
    A realist drinks it no matter how much there is.

  • #3
    Senior Coder
    Join Date
    Dec 2005
    Location
    Slovenia
    Posts
    1,963
    Thanks
    120
    Thanked 76 Times in 76 Posts
    One of my quryies is slow, so I run explain.

    I get:

    Code:
    possible_keys     key
     
    mykey               NULL
    so the key is not used but it should be. Trying to force it has no effect, nor on result of explain nor speed of query
    Found a flower or bug and don't know what it is ?
    agrozoo.net galery
    if you don't spot search button at once, there is search form:
    agrozoo.net galery search

  • #4
    Supreme Master coder! Old Pedant's Avatar
    Join Date
    Feb 2009
    Posts
    25,799
    Thanks
    78
    Thanked 4,410 Times in 4,375 Posts
    Ahh...I see.

    It's not used because MySQL has decided--for reasons known only to its builders--the it won't be any faster to use it than to not use it.

    I can't judge whether reorganizing the data would improve things, because you showed us no details.

    I fought with MySQL many many times over stuff like this, and often the only solution is to actually make the query more complex so that MySQL can work on smaller pieces and so use the indexes efficiently.
    An optimist sees the glass as half full.
    A pessimist sees the glass as half empty.
    A realist drinks it no matter how much there is.


  •  

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •