94793 - DNS: cancel while resolving does not allow new request immediately

Status: VERIFIED DUPLICATE of bug 70213

(Core :: Networking, defect, P4)

Description

[André Dahlqvist]

[CVS build from 2001-08-10-03]

If I try to go to the above site, who's DNS is currently down, mozilla will
search for it until it times out. If I interrupt the resolving of that URL and
then try to go to another URL mozilla will take a really long time to resolve
that URL as well (but it does resolve eventually). It almost seams as if it is
still stuck resolving the first URL for a while.

bbaetz said this on IRC:

<bbaetz> dns resolving is done in a queue, on a seprate thread
<bbaetz> if it takes a long time, then no subsequent requests will start
<bbaetz> so file it on networking: cache, then

Steps to reproduce:

1) Try to load site which has a DNS that is down.
2) Interrupt the resolving before mozilla gives up.
3) Try going to another site.

Result: The resolving of the second site will take much longer than normal.
Expected result: The resolving should go quickly.

Note that this does *not* happen if I let mozilla try to resolve the first site
until it times out.

Comment 1

[gordon]

Yes. The DNS lookups are performed on another thread using a synchronous API. 
There is no means to cancel the lookup.  The thread just has to wait until the
lookup fails, which means it will take that much longer before it can get on
with processing the next lookup.  We either need the OS to provide an async
gethostbyname API, or we need to use multiple processes (and deal with the
complexities of inter-process communication) to call the sync API.

Comment 2

[Bill Lipa]

The same problem occurs in Windows using 0.9.3.  Windows does have an asynch DNS
call, WSAAsyncGetHostByName.

See:
http://tcfreenet.org/people/parity/nslookup.htm

This is quite annoying because it usually means you have to restart the browser
(or wait a very long time) if you mistype an URL.

Comment 3

[gordon]

We're already using WSAAsyncGetHostByName on Windows.  This bug pertains to the
Unix implementation.

Comment 4

[Asa Dotzler [:asa]]

Bugs targeted at mozilla1.0 without the mozilla1.0 keyword moved to mozilla1.0.1 
(you can query for this string to delete spam or retrieve the list of bugs I've 
moved)

Comment 5

[Andreas Kunz]

Is this a duplicate of bug 70213 ?

Comment 6

[Dan Mosedale (:dmosedale, :dmose)]

*** This bug has been marked as a duplicate of 70213 ***

Comment 7

[benc]

VERIFED/dupe