From kde-devel  Tue Nov 09 18:42:51 1999
From: David Faure <faure () kde ! org>
Date: Tue, 09 Nov 1999 18:42:51 +0000
To: kde-devel
Subject: QMap bug ? (Re: kioslaves don't die?)
X-MARC-Message: https://marc.info/?l=kde-devel&m=94217296212466


> At Die, 09 Nov 1999 David Faure wrote:
> > > At Die, 09 Nov 1999 David Faure wrote:
> > > > > Boy. I need some coffee.  What I meant to say here is that KIOJob re-uses the
> > > > > slaves for efficeincy and as such keeps io-slaves around using a least
> > > > > recently used LRU in memory cache.  But AFAIK this is only in 
> > > > > memory and nothing is supposed to be written out to file.  Am I wrong 
> > > > > here David ?
> > > > No this is right (we don't pollute /tmp anymore !),
> > > > but it doesn't explain the 100 kioslaves problem.
> > > > 
> > > 
> > > Hi
> > > 
> > > probably I found to cause of the problem : QMap - which is used to store the
> > > running kioslaves - seems to hold one entry per key only. (protocol in that
> > > case) I added lots of debugging stuff in kio_job.cpp to find that out.
> > This
> > > really explains why processes get "forgotten". Anything we 
> > > could do against it?
> > 
> > Huh ??
> > A QMap can contain several entries per keys. I don't think that's the real
> > bug, otherwise a lot of stuff would be broken in KDE !!
> > 
> > Well, perhaps you could check QMap's behaviour with a 4-lines test
> > program... Just to make sure :)
> > 
> 4-line test? Hmm. I don't manage it that short. But - what is 
> wrong with this 30-liner?
> 
> ------------SNIP----------------
> #include <qmap.h>
> #include <stdlib.h>
> #include <stdio.h>
> 
> int main (void)
> {
>   char keyname[64];
>   int i;
> 
>   QMap < QString, int > mymap;
>   for (i=0;i<5;++i)
>     {
>       int r;
>       r = rand ();
> #ifdef VARIABLE_KEY
>       sprintf (keyname, "key%d", rand ());
> #else
>       strcpy (keyname, "key");
> #endif
>       mymap.insert (keyname, r);
>       printf ("New member:  key %s , random %d\n", keyname, r);
>       QMap < QString, int >::Iterator it = mymap.begin ();
>       while (it != mymap.end ())
> 	{
> 	  printf ("Key: %s   Content : %d\n", it.key ().data (), (*it));
> 	  ++it;
> 	}
>     }
> }
> ---------------SNIP----------------------
> 
> 
> With VARIABLE_KEYS undefined I get :
> 
> New member:  key key , random 1804289383
> Key: key   Content : 1804289383
> New member:  key key , random 846930886
> Key: key   Content : 846930886
> New member:  key key , random 1681692777
> Key: key   Content : 1681692777
> New member:  key key , random 1714636915
> Key: key   Content : 1714636915
> New member:  key key , random 1957747793
> Key: key   Content : 1957747793
> 
> With VARIABLE_KEYS defined I get :
> 
> New member:  key key846930886 , random 1804289383
> Key: key846930886   Content : 1804289383
> New member:  key key1714636915 , random 1681692777
> Key: key1714636915   Content : 1681692777
> Key: key846930886   Content : 1804289383
> New member:  key key424238335 , random 1957747793
> Key: key1714636915   Content : 1681692777
> Key: key424238335   Content : 1957747793
> Key: key846930886   Content : 1804289383
> New member:  key key1649760492 , random 719885386
> Key: key1649760492   Content : 719885386
> Key: key1714636915   Content : 1681692777
> Key: key424238335   Content : 1957747793
> Key: key846930886   Content : 1804289383
> New member:  key key1189641421 , random 596516649
> Key: key1189641421   Content : 596516649
> Key: key1649760492   Content : 719885386
> Key: key1714636915   Content : 1681692777
> Key: key424238335   Content : 1957747793
> Key: key846930886   Content : 1804289383
> 
> 
> 
> Can you test it on your machine too?

Just did. Same behaviour here !
(Using Qt CVS from 30-Oct-1999)

But .. reading qmap.h ... insert() calls insertSingle() so this
would be expected.

insertMulti() exists but only in QMapPrivate ??!??
Torben ?

-- 
David FAURE
david@mandrakesoft.com, faure@kde.org
http://home.clara.net/faure/
KDE, Making The Future of Computing Available Today