Bug 326089

Summary: accessing mail contents lags for minutes and then sending mail does as well
Product: [Applications] kmail2 Reporter: Martin Steigerwald <Martin>
Component: generalAssignee: kdepim bugs <kdepim-bugs>
Status: RESOLVED DUPLICATE    
Severity: normal    
Priority: NOR    
Version: 4.11.2   
Target Milestone: ---   
Platform: Debian unstable   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: strace of kmail going mad with akonadi and mysql

Description Martin Steigerwald 2013-10-16 10:29:00 UTC 
Note: This bug may be Akonadi related, but since without KMail being started Akonadi seems to be idling I report it here first.

Today I upgraded kdepim to 4.11 as well after kdelibs/base stuff and kdepimlibs and akonadi are already updated. Debian Experimental that is.

With kmail 4.11 I get much worse latencies when accessing mails. I get "retrieving folder contents" for minutes before mail is displayed even when without kmail being started Akonadi appears to be idle.

CPU wise I usually get something like this:

  PID SYSCPU USRCPU  VGROW  RGROW  RDDSK   WRDSK ST EXC S  CPU  CMD
 3949  1.40s  3.35s     0K     0K     4K    448K --   - S  48%  mysqld
 6450  0.22s  3.69s     0K     0K     0K      0K --   - R  40%  kmail
 3946  1.27s  2.60s     0K     0K     0K      0K --   - S  39%  akonadiserver

But what on earth is KMail doing here when it *waits* for Akonadi to retrieve the mail?



In strace -fF -p pid-of-kmail I get stuff like this

[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] ioctl(10, FIONREAD, [255])  = 0
[pid  6097] read(10, "* 81 22 (NAME \"Spam\" MIMETYPE (m"..., 255) = 255
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=3, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=5, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15, events=POLLIN}, {fd=22, events=POLLIN}, {fd=24, events=POLLIN}], 10, 20) = 1 ([{fd=10, revents=POLLIN}])
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] ioctl(10, FIONREAD, [251])  = 0
[pid  6097] read(10, "* 82 22 (NAME \"Unsicher\" MIMETYP"..., 251) = 251
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=3, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=5, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15, events=POLLIN}, {fd=22, events=POLLIN}, {fd=24, events=POLLIN}], 10, 19) = 1 ([{fd=10, revents=POLLIN}])
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] ioctl(10, FIONREAD, [347])  = 0
[pid  6097] read(10, "* 22 10 (NAME \"trash\" MIMETYPE ("..., 347) = 347
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=3, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=5, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15, events=POLLIN}, {fd=22, events=POLLIN}, {fd=24, events=POLLIN}], 10, 19) = 1 ([{fd=10, revents=POLLIN}])
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] ioctl(10, FIONREAD, [394])  = 0
[pid  6097] read(10, "* 10 0 (NAME \"Lokale Ordner\" MIM"..., 394) = 394
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=3, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=5, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15, events=POLLIN}, {fd=22, events=POLLIN}, {fd=24, events=POLLIN}], 10, 18) = 1 ([{fd=10, revents=POLLIN}])
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] ioctl(10, FIONREAD, [24])   = 0
[pid  6097] read(10, "1351 OK List completed\r\n", 24) = 24
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=3, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=5, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15, events=POLLIN}, {fd=22, events=POLLIN}, {fd=24, events=POLLIN}], 10, 0) = 1 ([{fd=3, revents=POLLIN}])
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=3, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=5, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15, events=POLLIN}, {fd=22, events=POLLIN}, {fd=24, events=POLLIN}], 10, 0) = 1 ([{fd=3, revents=POLLIN}])
[pid  6097] read(3, "\t\0\0\0\0\0\0\0", 16) = 8
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] sendmsg(5, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\1\1`\0\0\0\335\27\0\0\213\0\0\0\1\1o\0\v\0\0\0/jobtrac"..., 160}, {"\20\0\0\0kmail2-542439653\0\0\0\0\7\0\0\0005484"..., 96}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 256
[pid  6097] sendmsg(5, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\1\1`\0\0\0\336\27\0\0\213\0\0\0\1\1o\0\v\0\0\0/jobtrac"..., 160}, {"\20\0\0\0kmail2-542439653\0\0\0\0\7\0\0\00053c5"..., 96}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 256
[pid  6097] sendmsg(5, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\1\1\21\0\0\0\337\27\0\0\210\0\0\0\1\1o\0\v\0\0\0/jobtrac"..., 152}, {"\7\0\0\000545e230\0\0\0\0\0\0", 17}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 169
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=3, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=5, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15, events=POLLIN}, {fd=22, events=POLLIN}, {fd=24, events=POLLIN}, {fd=10, events=POLLOUT}], 11, 0) = 2 ([{fd=3, revents=POLLIN}, {fd=10, revents=POLLOUT}])
[pid  6097] read(3, "\5\0\0\0\0\0\0\0", 16) = 8
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] sendmsg(5, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\1\1\f\0\0\0\340\27\0\0\207\0\0\0\1\1o\0\v\0\0\0/jobtrac"..., 152}, {"\7\0\0\000545e110\0", 12}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 164
[pid  6097] poll([{fd=7, events=POLLIN|POLLOUT}], 1, 4294967295) = 1 ([{fd=7, revents=POLLOUT}])
[pid  6097] writev(7, [{"+\3\1\0", 4}, {NULL, 0}, {"", 0}], 3) = 4
[pid  6097] poll([{fd=7, events=POLLIN}], 1, 4294967295) = 1 ([{fd=7, revents=POLLIN}])
[pid  6097] recvfrom(7, "\1\1IK\0\0\0\0\32\0\0\5\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 4096, 0, NULL, NULL) = 32
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=7, events=POLLIN|POLLOUT}], 1, 4294967295) = 1 ([{fd=7, revents=POLLOUT}])
[pid  6097] writev(7, [{"&\3\2\0\241\0\0\0", 8}, {NULL, 0}, {"", 0}], 3) = 8
[pid  6097] poll([{fd=7, events=POLLIN}], 1, 4294967295) = 1 ([{fd=7, revents=POLLIN}])
[pid  6097] recvfrom(7, "\1\1JK\0\0\0\0\241\0\0\0h\3\300\1\374\0\256\3\374\0\256\3\4\0\0\0\0\0\0\0", 4096, 0, NULL, NULL) = 32
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] poll([{fd=7, events=POLLIN|POLLOUT}], 1, 4294967295) = 1 ([{fd=7, revents=POLLOUT}])
[pid  6097] writev(7, [{"(\3\4\0\241\0\0\0U\0\340\6\374\0\256\3", 16}, {NULL, 0}, {"", 0}], 3) = 16
[pid  6097] poll([{fd=7, events=POLLIN}], 1, 4294967295) = 1 ([{fd=7, revents=POLLIN}])
[pid  6097] recvfrom(7, "\1\1KK\0\0\0\0\0\0\0\0\374\0O\3\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 4096, 0, NULL, NULL) = 32
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] recvfrom(7, 0x2469ca4, 4096, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  6097] write(3, "\1\0\0\0\0\0\0\0", 8) = 8

So basically KMail seems to be polling something endlessly.


Whats going on there?

Its 1, in words: one, mail I try to access in kmail.


While this activity happens I can still change folders and get updates mail lists quickly, it is just accessing the mail contents that is so slow that KMail is currently unusable for me and I am considering downgrading to 4.10 again.


According to akonadiconsole Akonadi is basically idling during that time which is basically a lie above atop CPU usage information above.


I used up 10 minutes or so in writing this mail and I still get: 

  PID SYSCPU USRCPU  VGROW  RGROW  RDDSK  WRDSK ST EXC S  CPU CMD        1/3
 3949  1.45s  3.44s     0K     0K     4K   480K --   - S  50% mysqld
 3946  1.31s  2.65s     0K     0K     0K     0K --   - S  40% akonadiserver
 6450  0.21s  3.60s   296K   252K     0K     0K --   - S  39% kmail


I am still trying to send this as mail out to kdepim-users and it just *stalls*. This is unusable slow and I think I will have to downgrade.

Reproducible: Always

Steps to Reproduce:
1. have some POP3 accounts with lots of mails.
2. start kmail
3. access a mail
4. access another mail
5. wait
6. wait
7. wait
…
Actual Results:  
Unusable long lags.

Expected Results:  
Snappy response.

martin@merkaba:~> apt-show-versions | egrep "akonadi|kdepim|kmail|kdelibs|libqtgui|crm114|mysql"
akonadi-backend-mysql:all/experimental 1.10.2-1 uptodate
akonadi-backend-sqlite:amd64/sid 1.9.2-2+b1 uptodate
akonadi-server:amd64/experimental 1.10.2-1 uptodate
akonadiconsole:amd64/experimental 4:4.11.2-1 uptodate
crm114:amd64/sid 20100106-3 uptodate
kdelibs-bin:amd64/experimental 4:4.11.2-1 uptodate
kdelibs5-data:all/experimental 4:4.11.2-1 uptodate
kdelibs5-plugins:amd64/experimental 4:4.11.2-1 uptodate
kdepim:all/experimental 4:4.11.2-1 uptodate
kdepim-kresources:amd64/experimental 4:4.11.2-1 uptodate
kdepim-runtime:amd64/experimental 4:4.11.2-2 uptodate
kdepimlibs-kio-plugins:amd64/experimental 4:4.11.2-2 uptodate
kmail:amd64/experimental 4:4.11.2-1 uptodate
libakonadi-calendar4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-contact4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kabc4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kcal4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kde4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kmime4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-notes4:amd64/experimental 4:4.11.2-2 uptodate
libakonadiprotocolinternals1:amd64/experimental 1.10.2-1 uptodate
libdbd-mysql-perl:amd64/sid 4.024-1 uptodate
libkdepim4:amd64/experimental 4:4.11.2-1 uptodate
libkdepimdbusinterfaces4:amd64/experimental 4:4.11.2-1 uptodate
libmysqlclient-dev:amd64/sid 5.5.33+dfsg-1 uptodate
libmysqlclient18:amd64/sid 5.5.33+dfsg-1 uptodate
libqt4-sql-mysql:amd64/sid 4:4.8.5+git121-g2a9ea11+dfsg1-2 uptodate
libqtgui4:amd64/sid 4:4.8.5+git121-g2a9ea11+dfsg1-2 uptodate
mysql-client:all/sid 5.5.33+dfsg-1 uptodate
mysql-client-5.5:amd64/sid 5.5.33+dfsg-1 uptodate
mysql-common:all/sid 5.5.33+dfsg-1 uptodate
mysql-server-core-5.5:amd64/sid 5.5.33+dfsg-1 uptodate
python-mysqldb:amd64/sid 1.2.3-2 uptodate
Comment 1 Martin Steigerwald 2013-10-16 10:32:03 UTC 
merkaba:~> strace -c -fF -p 6450
Process 6450 attached with 4 threads - interrupt to quit
^CProcess 6450 detached
Process 6453 detached
Process 6456 detached
Process 6457 detached
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 69.10    3.770837          48     79331           poll
 12.55    0.684976           4    155855    154100 recvfrom
  7.73    0.421865           6     73673       327 read
  5.57    0.304150           4     72483           ioctl
  3.88    0.211901      105951         2           restart_syscall
  0.57    0.030906           5      5739           write
  0.30    0.016511           9      1911           writev
  0.24    0.012888          10      1272           sendmsg
  0.02    0.001015           9       114           socket
  0.02    0.000995           9       114           close
  0.01    0.000453          38        12           sendto
  0.00    0.000262           9        30           recvmsg
  0.00    0.000107          10        11         5 stat
  0.00    0.000036           6         6           bind
  0.00    0.000025           4         6           getsockname
------ ----------- ----------- --------- --------- ----------------
100.00    5.456927                390559    154432 total

I am now producting a longer strace dump.
Comment 2 Martin Steigerwald 2013-10-16 10:41:15 UTC 
Created attachment 82876 [details]
strace of kmail going mad with akonadi and mysql

I anomized the folder names. Its different folder names during the strace. Basically kmail seems to asks around all folders repeatedly while I just tried to access *one* mail.

file descriptors of this strace.

merkaba:~> cd /proc/$(pidof kmail)
merkaba:/proc/6450> ls -l fd
insgesamt 0
lr-x------ 1 martin martin 64 Okt 16 12:37 0 -> pipe:[11849]
l-wx------ 1 martin martin 64 Okt 16 12:37 1 -> /home/martin/.xsession-errors
lrwx------ 1 martin martin 64 Okt 16 12:37 10 -> socket:[62091]
lr-x------ 1 martin martin 64 Okt 16 12:37 11 -> /var/tmp/kdecache-martin/ksycoca4
lrwx------ 1 martin martin 64 Okt 16 12:37 12 -> anon_inode:[eventfd]
lr-x------ 1 martin martin 64 Okt 16 12:37 13 -> anon_inode:inotify
lrwx------ 1 martin martin 64 Okt 16 12:37 14 -> anon_inode:[eventfd]
lrwx------ 1 martin martin 64 Okt 16 12:37 15 -> socket:[64313]
lrwx------ 1 martin martin 64 Okt 16 12:37 18 -> socket:[65573]
l-wx------ 1 martin martin 64 Okt 16 12:37 2 -> /home/martin/.xsession-errors
lr-x------ 1 martin martin 64 Okt 16 12:37 21 -> /dev/urandom
lrwx------ 1 martin martin 64 Okt 16 12:37 25 -> socket:[66530]
lrwx------ 1 martin martin 64 Okt 16 12:37 3 -> anon_inode:[eventfd]
lr-x------ 1 martin martin 64 Okt 16 12:37 4 -> pipe:[61291]
lrwx------ 1 martin martin 64 Okt 16 12:37 5 -> socket:[65534]
l-wx------ 1 martin martin 64 Okt 16 12:37 6 -> pipe:[61291]
lrwx------ 1 martin martin 64 Okt 16 12:37 7 -> socket:[61292]
lrwx------ 1 martin martin 64 Okt 16 12:37 8 -> socket:[61293]
lrwx------ 1 martin martin 64 Okt 16 12:37 9 -> socket:[62090]

merkaba:~> netstat -anp | grep 61291
merkaba:~#1> netstat -anp | grep 65534
unix  3      [ ]         STREAM     VERBUNDEN     65534    6450/kmail          
merkaba:~> netstat -anp | grep 61292
unix  3      [ ]         STREAM     VERBUNDEN     61292    6450/kmail          
merkaba:~> netstat -anp | grep 61293 
unix  3      [ ]         STREAM     VERBUNDEN     61293    6450/kmail          
merkaba:~> netstat -anp | grep 62090
unix  3      [ ]         STREAM     VERBUNDEN     62090    6450/kmail          
merkaba:~> netstat -anp | grep 65530
merkaba:~#1> netstat -anp | grep 64313
unix  3      [ ]         STREAM     VERBUNDEN     64313    6450/kmail          
merkaba:~> netstat -anp | grep 65573
unix  3      [ ]         STREAM     VERBUNDEN     65573    6450/kmail
Comment 3 Martin Steigerwald 2013-10-16 10:47:59 UTC 
Downgrading to

martin@merkaba:~> apt-show-versions | egrep "akonadi|kdepim|kmail|kdelibs|libqtgui|crm114|mysql"
akonadi-backend-mysql:all/experimental 1.10.2-1 uptodate
akonadi-backend-sqlite:amd64/sid 1.9.2-2+b1 uptodate
akonadi-server:amd64/experimental 1.10.2-1 uptodate
akonadiconsole:amd64/sid 4:4.10.5-2 uptodate
crm114:amd64/sid 20100106-3 uptodate
kdelibs-bin:amd64/experimental 4:4.11.2-1 uptodate
kdelibs5-data:all/experimental 4:4.11.2-1 uptodate
kdelibs5-plugins:amd64/experimental 4:4.11.2-1 uptodate
kdepim:all/sid 4:4.10.5-2 uptodate
kdepim-kresources:amd64/sid 4:4.10.5-2 uptodate
kdepim-runtime:amd64/experimental 4:4.11.2-2 uptodate
kdepim-strigi-plugins:amd64/sid 4:4.10.5-2 uptodate
kdepimlibs-kio-plugins:amd64/experimental 4:4.11.2-2 uptodate
kmail:amd64/sid 4:4.10.5-2 uptodate
libakonadi-calendar4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-contact4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kabc4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kcal4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kde4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-kmime4:amd64/experimental 4:4.11.2-2 uptodate
libakonadi-notes4:amd64/experimental 4:4.11.2-2 uptodate
libakonadiprotocolinternals1:amd64/experimental 1.10.2-1 uptodate
libdbd-mysql-perl:amd64/sid 4.024-1 uptodate
libkdepim4:amd64/sid 4:4.10.5-2 uptodate
libkdepimdbusinterfaces4:amd64/sid 4:4.10.5-2 uptodate
libmysqlclient-dev:amd64/sid 5.5.33+dfsg-1 uptodate
libmysqlclient18:amd64/sid 5.5.33+dfsg-1 uptodate
libqt4-sql-mysql:amd64/sid 4:4.8.5+git121-g2a9ea11+dfsg1-2 uptodate
libqtgui4:amd64/sid 4:4.8.5+git121-g2a9ea11+dfsg1-2 uptodate
mysql-client:all/sid 5.5.33+dfsg-1 uptodate
mysql-client-5.5:amd64/sid 5.5.33+dfsg-1 uptodate
mysql-common:all/sid 5.5.33+dfsg-1 uptodate
mysql-server-core-5.5:amd64/sid 5.5.33+dfsg-1 uptodate
python-mysqldb:amd64/sid 1.2.3-2 uptodate

and restarting Akonadi and kmail *immediately* fixes this issue.
Comment 4 Martin Steigerwald 2013-10-16 10:53:49 UTC 
Some informations about my setup:

- Just POP3 accounts
- Some have a large amount of mail, main account has Linux kernel-ml with 130000 mails in one folder
- ThinkPad T520 Intel Sandybridge i5 with about 2,5 GHz, 8 GB of RAM, 300 GB Intel SSD, thus: The machine is *blazingly* fast.
- BTRFS filesystem

This basically works in KDEPIM 4.10. So I won´t follow any try this on Ext4 comments. Last time I did, it didn´t change a thing.

There is some delay when Akonadi synchronized the kernel-ml folder, but here at lags with Akonadi due to Akonadiconsole just idling.
Comment 5 Martin Steigerwald 2013-10-16 10:58:59 UTC 
Here we have an about 10 minuted install with that CPU usage distribution:

merkaba:~> atopsar -O -b 12:30 -e 13:00

merkaba  3.12.0-rc4-tp520  #34 SMP PREEMPT Mon Oct 7 10:25:01 CEST 2013  x86_64  2013/10/16

-------------------------- analysis date: 2013/10/16 --------------------------

12:31:56    pid command  cpu% |   pid command  cpu% |   pid command  cpu%_top3_
12:41:56   3949 mysqld    37% |  6450 kmail     35% |  3946 akonadis   5%
12:51:56   8202 mysqld    49% |  4076 virtuoso  20% |  8257 akonadi_  14%

For "retrieving folder contents" or more specifically I think "mail contents" KMail is using up too much CPU on this Sandybridge machine.
Comment 6 Martin Steigerwald 2013-10-16 12:27:01 UTC 
The symptoms of Bug #322958 "KMail: duplicate special folder causes endless loop "Emitting defaultFoldersChanged" read very familiar to what I have been seeing. But other than a duplicate "drafs" folder I didn´t see any duplicate folders in ls -a ~/.local/share/local-mail or Akonadiconsole.

I deleted the duplicate "drafts" folder from within Akonadiconsole.
Comment 7 Martin Steigerwald 2013-10-16 12:48:03 UTC 
Well, deleting the duplicate "drafts" folder did the trick, so this is a duplicate of

Bug #322958 "KMail: duplicate special folder causes endless loop "Emitting defaultFoldersChanged"

*** This bug has been marked as a duplicate of bug 322958 ***