after migration, having distinct slow load on one sub site

  • This WordPress instance was recently migrated from shared hosting to a VPS, and everything appears to be working properly now and is very fast, with two funny exceptions:

    1. When I click on the “My Sites” dropdown at the top of the page and then select one of the subsites, the meat of the page takes almost exactly 60 seconds to load. This appears to happen with only one of the subsites.

    2. When I am in that same subsite and click the “upload an image” icon for a post (new or existing), the popup containing the upload dialog takes almost exactly 60 seconds to load.

    I don’t think this is a coincidence. This is not repeatable every time, perhaps because of something that’s being cached; however, when it does happen, I can see a mysql sleep process take almost exactly 60 seconds too, terminating when the process in either exception #1 or #2 finishes loading.

    I have also separately migrated this WordPress instance to another shared hosting account at a third hosting provider, and I don’t see this problem.

    I have tried disabling all plugins, changing all wait/timeout settings I could find in PHP and MySQL, especially any 60-second ones, and that did nothing to fix the speed problem for these functions. I have attempted to place debug scaffolding in the code to see where there slowdown occurs; but since it loads quickly on subsequent clicks, it’s difficult to pinpoint.

    Any ideas on what this could be?

Viewing 6 replies - 1 through 6 (of 6 total)
  • Moderator Ipstenu (Mika Epstein)

    (@ipstenu)

    ?????? Advisor and Activist

    Is that subsite running a special theme?

    How much RAM does MySQL have access to on the vps? Is the vps also set to the Apache default threads? (cuz they suck ?? )

    Thread Starter fatherfrost

    (@fatherfrost)

    Andrea_r and Ipstenu, thanks for the responses. The VPS offers 4 MB per process and a total of 1.6 GB to the database (shared with the rest of the VPS). Here are the main ones:
    query-cache-size = 4M
    table_cache = 256
    tmp_table_size = 64M

    When this happens, memory doesn’t seem to be an issue. WRT your comment about Apache default threads, I would presume that if those were a problem for this then it would be impacting much more than these two functions. Does that sound reasonable?

    With regard to special themes, this site is using a fairly standard theme, “the source”, and remember this exact code base works just fine on two different shared hosting accounts. Also, this slowness is happening just in the admin panel when uploading images or switching to this subsite, so I don’t think themes would be a factor there? (I’m not an expert on how the themes work, though, so I could be wrong.)

    Any other suggestions? thanks!

    Moderator Ipstenu (Mika Epstein)

    (@ipstenu)

    ?????? Advisor and Activist

    Themes contain functions.php. Functions.php can affect your admin end (that’s where many themes put CPT code for example). So yes, a theme can totally bollux your admin end.

    deactivate all the plugins on this subsite. switch to the default theme. What happens?

    Thread Starter fatherfrost

    (@fatherfrost)

    Thanks for the continued help! I have deactivated all themes and plugins several times and still run into the same slowness.

    In digging a little deeper, I see that this one subsite (where I’m experiencing the slowness during the uploads and slowness when connecting to the admin panel) has approximately 186,000 image files in the month-subdirectories (01-12) of “wp-content/blogs.dir/9/files/2011/”. (“9” just happens to be the ID of the subsite in question.)

    Could this be the cause of the slowdown, especially if my hosting company is perhaps using SAN storage or has some other filesystem bottleneck? How could I confirm this without destroying the site? Thanks again for the help.

Viewing 6 replies - 1 through 6 (of 6 total)
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