Re: Squid, events, and file descriptors

On 26/06/2008, Henrik Nordstrom <henrik_at_henriknordstrom.net> wrote:
> On tor, 2008-06-26 at 11:08 +0100, Bradley Kite wrote:
> > I am just rolling out your patch, I will send over the mgr:idns output
> > when I have the next failure. In the mean time here is the other
> > output you requested. The number of callbacks is just 1 - I would
> > expect it to be equal to the number of requests queued?
>
>
> It should be one only.
>
> Was a bit worried that it had been forgotten somehow. Your mgr:idns
> output looks very much like the queue is not being run at all..
>

Hi Henrik,

I have another failure, this time with the extra DNS debug output.

I have just reliased that our load balancer, which also load-balances
DNS lookups, was not properly configured to support TCP (only UDP DNS
lookups). I think this might be triggering the bug. I will fix this
issue and let you know if this fixes it. However, its not the case
that making an HTTP request which requires a TCP DNS lookup causes
this problem, as in most cases squid handles this situation
gracefully. But still, it might help in reproducing the problem.

# squidclient mgr:events | grep idns
idnsCheckQueue 0.055396 seconds 1 N/A

# squidclient mgr:idns

Internal DNS Statistics:

The Queue:
                       DELAY SINCE
  ID SIZE SENDS FIRST SEND LAST SEND PRO NAME
------ ---- ----- ---------- --------- --- ------------------
0x1ddd 33 18795 4625.516 183.604 TCP ads.lookery.com
0x26ce 42 1 223.976 223.976 UDP www.lister.newham.sch.uk
0x1939 32 1 448.168 448.168 UDP nb.myspace.com
0x757c 48 1 448.188 448.188 UDP mail.moreland.islington.sch.uk
0xe8f8 32 1 774.415 774.415 UDP login.live.com
0xa703 39 1 774.632 774.632 UDP my.screenname.aol.com
0xf2dc 33 1 774.639 774.639 UDP www.jocsdoc.com
0xd274 36 1 914.552 914.552 UDP www.taggedmail.com
0x8f14 33 1 914.556 914.556 UDP x59.iloveim.com
0x0ad0 36 1 1154.667 1154.667 UDP www.realgame.co.uk
0xd7e9 28 1 1154.679 1154.679 UDP h.live.com
0x1ce4 40 1 1388.933 1388.933 UDP www.sharedteaching.com
0x84a6 30 1 1529.649 1529.649 UDP uk.yahoo.com
0xf184 38 1 1529.649 1529.649 UDP www.schoolzone.co.uk
0xeadd 30 1 1529.649 1529.649 UDP im1music.net
0xf3b3 42 1 1529.649 1529.649 UDP www.google-analytics.com
0x148b 33 1 1529.649 1529.649 UDP www.youtube.com
0x285c 34 1 1618.308 1618.308 UDP www.siteflow.com
0xf0f9 37 1 1618.314 1618.314 UDP ad.linkexchange.com
0x3af2 35 1 1618.323 1618.323 UDP www.wimbledon.org
0x48b7 38 1 1637.662 1637.662 UDP imp.tradedoubler.com
0x35c0 35 1 2198.505 2198.505 UDP kona3.kontera.com
0x07c7 40 1 2198.518 2198.518 UDP afe2.specificclick.net
0x2f71 32 1 2198.526 2198.526 UDP ads.adviva.net
0x931c 33 1 2198.550 2198.550 UDP eur.i1.yimg.com
0xffe3 43 1 2297.117 2297.117 UDP ehg-autotrader.hitbox.com
0xee20 48 1 2363.631 2363.631 UDP www.download.windowsupdate.com
0x8021 52 1 2363.642 2363.642 UDP content.yieldmanager.edgesuite.net
0x98b1 40 1 2363.678 2363.678 UDP thumbs1.ebaystatic.com
0x8850 31 1 2363.732 2363.732 UDP www.mdx.ac.uk
0xc33d 39 1 2437.109 2437.109 UDP edit.europe.yahoo.com
0x8197 38 1 2558.818 2558.818 UDP www.kathe-werbung.de
0x8e26 37 1 2558.841 2558.841 UDP media.fastclick.net
0x1cde 50 1 2558.841 2558.841 UDP redir.metaservices.microsoft.com
0x3d87 40 1 2558.841 2558.841 UDP www.lancerregister.com
0x5f90 45 1 2605.982 2605.982 UDP by123w.bay123.mail.live.com
0xa814 38 1 3029.761 3029.761 UDP web23.mathletics.com
0x10ab 39 1 3120.154 3120.154 UDP ecx.images-amazon.com
0xd15e 30 1 3391.349 3391.349 UDP www.yell.com
0x9dac 42 1 3391.349 3391.349 UDP www.1staudiovisual.co.uk
0xa6cf 37 1 3391.351 3391.351 UDP ts4.images.live.com
0x593f 45 1 3409.253 3409.253 UDP by106w.bay106.mail.live.com
0x9cc9 34 1 3409.264 3409.264 UDP www.facebook.com
0xb9bc 34 1 3409.325 3409.325 UDP go.microsoft.com
0xdb7f 49 1 3568.263 3568.263 UDP images-na.ssl-images-amazon.com
0x71d8 32 1 3568.372 3568.372 UDP mt1.google.com
0x1577 38 1 3568.372 3568.372 UDP dosic.en.alibaba.com
0xe1e4 45 1 3651.021 3651.021 UDP bl148w.blu148.mail.live.com
0x22e0 29 1 3651.021 3651.021 UDP fronter.com
0xda74 40 1 3693.320 3693.320 UDP www.capitalradio.co.uk
0x948a 36 1 3876.280 3876.280 UDP us.music1.yimg.com
0x8948 42 1 3935.261 3935.261 UDP www.unlocked-mobiles.com
0x7066 39 1 3962.139 3962.139 UDP www.soccermanager.com
0x2413 39 1 4017.456 4017.456 UDP static.jackpotjoy.com
0x853d 32 1 4022.252 4022.252 UDP images.hi5.com
0x363f 34 1 4033.988 4033.988 UDP a.hotcourses.com
0xd0e2 29 1 4034.021 4034.021 UDP joechip.net
0x8b30 35 1 4034.026 4034.026 UDP img0.gmodules.com
0xc40c 38 1 4034.030 4034.030 UDP www.simpsoncrazy.com
0xcdd2 29 1 4034.049 4034.049 UDP dw.cnet.com
0xd243 33 1 4034.064 4034.064 UDP www.seemp.co.uk
0xb78a 39 1 4034.083 4034.083 UDP delb.opt.fimserve.com
0x43db 41 1 4034.138 4034.138 UDP www.citysearchworld.com
0xa982 35 1 4054.133 4054.133 UDP owa1.brunel.ac.uk
0xb2d9 45 1 4268.671 4268.671 UDP co101w.col101.mail.live.com
0x3efe 35 1 4304.614 4304.614 UDP www.skysports.com
0x4ca4 43 1 4334.632 4334.632 UDP www.travelsupermarket.com
0xd8a1 33 1 4334.639 4334.639 UDP www.edupics.com
0xfac2 36 1 4334.645 4334.645 UDP ads.newgrounds.com
0x0c40 36 1 4334.646 4334.646 UDP find.myrecipes.com
0xda70 39 1 4364.141 4364.141 UDP www.thehairstyler.com
0xa3d6 43 1 4364.170 4364.170 UDP motifcdn2.doubleclick.net
0xb73e 39 1 4364.199 4364.199 UDP weather.yahooapis.com
0x9acc 29 1 4364.199 4364.199 UDP i4.bebo.com
0x4165 34 1 4383.954 4383.954 UDP about.dtmpub.com
0xe3bc 42 1 4413.154 4413.154 UDP uni2.cox.streamaudio.com
0x8ad0 38 1 4413.154 4413.154 UDP wmlive-acl.bbc.co.uk
0x5d90 36 1 4661.727 4661.727 UDP www.dickshovel.com
0x0373 29 1 4680.145 4680.145 UDP www.cdc.gov
0xa66a 42 1 4684.446 4684.446 UDP ad.globalinteractive.com
0x57e1 32 2577 5264.299 4719.385 UDP flash.7k7k.com
0xf7cb 34 1 4743.423 4743.423 UDP pix01.revsci.net
0x3413 37 1 4755.790 4755.790 UDP media.scanscout.com
0x2132 51 1 4755.841 4755.841 UDP www.buytickets.virgintrains.co.uk
0xc30c 41 1 4755.916 4755.916 UDP search.autotrader.co.uk
0xc0a5 35 1 4988.864 4988.864 UDP deco-01.slide.com
0xdbf1 47 1 4988.890 4988.890 UDP a583.ac-images.myspacecdn.com
0x313f 47 1 5049.700 5049.700 UDP tpmcafe.talkingpointsmemo.com
0x5885 35 1 5731.396 5731.396 UDP www.britannia.com
0xa948 41 1 5731.401 5731.401 UDP farm3.static.flickr.com
0xbbee 47 1 5731.442 5731.442 UDP a644.ac-images.myspacecdn.com
0x4506 38 1 5731.482 5731.482 UDP www.cartoonstock.com
0xe4f7 24 1 6230.619 6230.619 UDP server
0x8b28 39 1 6681.668 6681.668 UDP www.wordreference.com
0xf923 40 1 6681.753 6681.753 UDP analytics.worldnow.com
0xd01e 40 1 7039.806 7039.806 UDP presence.msg.yahoo.com
0x2da7 39 1172 7266.445 7074.876 UDP video.freeproxies.org

Nameservers:
IP ADDRESS # QUERIES # REPLIES
--------------- --------- ---------
82.198.234.9 550040 549797

Rcode Matrix:
RCODE ATTEMPT1 ATTEMPT2 ATTEMPT3
    0 514665 25 2
    1 0 0 0
    2 580 555 553
    3 8701 0 0
    4 0 0 0
    5 0 0 0

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Received on Fri Jun 27 2008 - 13:10:28 MDT