12 Replies Latest reply: Jun 1, 2009 7:55 AM by Tim Haigh
STU9000 Level 1 Level 1 (5 points)
My computer seems to be going reaaaally slow lately, and whenever I check activity monitor there is this program at root level called 'mds' that appears to be hogging my cpu and ram.

What are they, and do I really need them!?

I am also using HP software for my digital camera so the slowness is probably related to that.

MacBook, Mac OS X (10.5.7)
  • 2. Re: What is 'mds' and 'mdworker'?
    STU9000 Level 1 Level 1 (5 points)
    Thanks, but in the meantime until I can work out what is causing this problem, can I just turn this mds off!?
  • 3. Re: What is 'mds' and 'mdworker'?
    hpr3 Level 5 Level 5 (5,710 points)
    You will have to turn Spotlight off which is explained in the post I gave you.
  • 4. Re: What is 'mds' and 'mdworker'?
    STU9000 Level 1 Level 1 (5 points)
    Yeah I read a bit about it, but you know I am kind of getting a bit fed up of spending too much time preforming maintenance on this machine rather than using it for something more useful or interesting. I feel sometime that I might as well have just bought a windows system.

    I have something I need to do, that spotlight thing is just for quick searching and nothing else right?

    ps I am typing this with my wireless keyboard disconnected, waste of time buying that thing, it just causing my MM to malfunction all the time.
  • 5. Re: What is 'mds' and 'mdworker'?
    STU9000 Level 1 Level 1 (5 points)
    I'm pretty sure it's something to do with this terrible software i got with my digital camera, so I have added my entire Picture folder to the list of things I don't want spotlight to index, and hopefully that will help things. I see no advantage in indexing this folder anyway.
  • 6. Re: What is 'mds' and 'mdworker'?
    Pondini Level 8 Level 8 (38,720 points)
    Spotlight is indeed a main user of mds and mdworker, but it's not the only one.

    OSX uses them for various things, as does Time Machine.

    If you're using Time Machine, exclude your backup drive/partition from Spotlight indexing.

    If you're running any anti-virus scanning, some of them use these processes, too. So also exclude your TM drive and anything else you can (such as a photo library) from scanning.

    If these are still a problem, you might be able to figure out what they're working on by selecting Inspect on them via Activity Monitor (in your Applications/Utilities folder), then click the +Open files and ports+ tab (if it appears).
  • 7. Re: What is 'mds' and 'mdworker'?
    V.K. Level 9 Level 9 (56,120 points)
    Pondini wrote:
    Spotlight is indeed a main user of mds and mdworker, but it's not the only one.


    that's wrong AFAIK. I believe both processes are for spotlight only which includes indexing TM backups. I don't believe any AV programs use them directly.
  • 8. Re: What is 'mds' and 'mdworker'?
    Pondini Level 8 Level 8 (38,720 points)
    V.K. wrote:
    Pondini wrote:
    Spotlight is indeed a main user of mds and mdworker, but it's not the only one.


    that's wrong AFAIK. I believe both processes are for spotlight only which includes indexing TM backups. I don't believe any AV programs use them directly.


    from http://developer.apple.com/documentation/Darwin/Reference/ManPages/man8/mds.8.ht ml

    "It serves all clients of the metadata APIs, including Spotlight"

    If there were only two (Spotlight and TM), I suspect it would say that.

    It's my understanding that it's available to any process, including 3rd-party apps, that want to use it to extract metadata from a file, especially since it can determine and use the proper "mdimporter" routine for the file type in question.

    There were a couple of posts a few months ago (which of course I can't find now), reporting mds/mdworker using lots of CPU, even with all disks excluded from Spotlight. Cancelling the anti-virus scanning seems to have fixed it.
  • 9. Re: What is 'mds' and 'mdworker'?
    V.K. Level 9 Level 9 (56,120 points)
    thanks for the link. it looks like you are correct.
  • 10. Re: What is 'mds' and 'mdworker'?
    STU9000 Level 1 Level 1 (5 points)
    I'm not really sure I understand what indexing is, but I'd guess this spotlight is building up a temporary database of files on my computer whenever I turn my computer on for quick keyword searches. I don't normally search for photos using spotlight so I turn that onto privacy mode. I would also hazard a guess that the problem here stems from the fact that I am using third party software digital camera software and it is not communicating with Spotlight as to the whereabouts of the files? No, that is probably not quite right.

    I don't understand why it needs to run every time I start up, should it not already have this information from the previous time it was being used.
  • 11. Re: What is 'mds' and 'mdworker'?
    Pondini Level 8 Level 8 (38,720 points)
    STU9000 wrote:
    I'm not really sure I understand what indexing is, but I'd guess this spotlight is building up a temporary database of files on my computer whenever I turn my computer on for quick keyword searches. I don't normally search for photos using spotlight so I turn that onto privacy mode.


    Spotlight is rather quirky, to put it politely. I've never quite understood the big spike after booting, either, as it does put a hidden index on each drive, and does index files as they're added or changed. It also examines any (non-excluded) disk/partition as soon as it's attached, so perhaps that's at least part of what's going on.

    I would also hazard a guess that the problem here stems from the fact that I am using third party software digital camera software and it is not communicating with Spotlight as to the whereabouts of the files? No, that is probably not quite right.


    It is quite possible for 3rd-party software to be involved, somehow or other, directly or indirectly. The only way to tell for sure would be to turn it off. Even that might not do it, as there could be a separate autostart process doing something, too.

    I don't understand why it needs to run every time I start up, should it not already have this information from the previous time it was being used.


    Ditto.

    One thing you might try is, set up a different user. Do a shutdown and start-up and log in as that other user and see if the problem persists.
  • 12. Re: What is 'mds' and 'mdworker'?
    Tim Haigh Level 7 Level 7 (24,190 points)
    Do you have any bittorrent downloads running when you see this issue?

    If so add your torrent download folder to the privacy section of the spotlight preference panel.