The following error has been reported to me by T2K colleagues:

When using  "odbedit -c "msg my_message", the following behavior 
has been observed depending on the length "n" of the message. 

1)  n < 100        All is well
2)  100 <= n < 245 Log not written but exit code = 0
3)  245 <= n < 280 Error: "Experiment not defined" and exit code = 1
4)  280 <= n       Error: "Cannot connect to remote host" and exit code = 1

Also, when logging from compiled C code - when messages reach some magic length
the MIDAS client sending them segfaults.

Please fix

> The following error has been reported to me by T2K colleagues:
> 
> When using  "odbedit -c "msg my_message", the following behavior 
> has been observed depending on the length "n" of the message. 
> 
> 1)  n < 100        All is well
> 2)  100 <= n < 245 Log not written but exit code = 0
> 3)  245 <= n < 280 Error: "Experiment not defined" and exit code = 1
> 4)  280 <= n       Error: "Cannot connect to remote host" and exit code = 1
> 
> Also, when logging from compiled C code - when messages reach some magic length
> the MIDAS client sending them segfaults.
> 
> Please fix

Uhhh, who wants this long messages? You should consider to split this into several 
smaller messages. Anyhow, having the above behavior is not good, so I fixed it in 
SVN revision 4422. I increased the maximum length to 1000 characters. Above that, 
the message gets truncated. If you need even more, we can make it a #define.

The second problem you describe (logging from compiled C code) I could not 
reproduce, so maybe it was related to the first one. Please try again and report 
if it persists.

There is an obvious "unwanted feature" in this version of the mhttpd. It writes the
"plot time" into the gif (mhttpd, if-statement starting in line 8853). 

Please check this obvious things more carefully in the future before submitting code. ;-)

> mhttpd and mlogger have been updated with potentially troublesome changes.
> Before using these latest versions, please make a backup of your ODB. This is
> svn revisions 4434 (mhttpd.c) and 4435 (mlogger.c).
> 
> These new features are now available:
> - a "feature complete" implementation of "history in an SQL database". We use
> this new code to write history data from the T2K test setup in the TRIUMF M11
> beam line to a MySQL database (mlogger) and to make history plots directly from
> this database (mhttpd). We still write normal midas history files and we have a
> utility to import midas .hst files into an SQL database (utils/mh2sql). The code
> is functional, but incomplete. For best SQL database data layout, you should
> enable the "per variable history" (but backup your ODB before you do this!). All
> are welcome to try it, kick the tires, report any problems. Documentation TBW.
> - experimental implementation of "ODBRpc" added to the midas javascript library
> (ODBSet, ODBGet & co). This permits buttons on midas "custom" web pages to
> invoke RPC calls directly into user frontend programs, for example to turn
> things on or off. Documentation TBW.
> - the mlogger/mhttpd implementation of /History/Tags has proved troublesome and
> we are moving away from it. The SQL database history implementation already does
> not use it. During the present transition period:
> - mlogger and mhttpd will now work without /History/Tags. This implementation
> reads history tags directly from the history files themselves. Two downsides to
> this: it is slower and tags become non-persistent: if some frontends have not
> been running for a while, their variables may vanish from the history panel
> editor. To run in this mode, set "/History/DisableTags" to "y". Existing
> /History/Tags will be automatically deleted.
> - for the above 2 reasons, I still recommend using /History/Tags, but the format
> of the tags is now changed to simplify management and reduce odb size. mlogger
> will automatically convert the tags to this new format (this is why you should
> make a backup of your ODB).
> - using old mlogger with new mhttpd is okey: new mhttpd understands both formats
> of /History/Tags.
> - using old mhttpd with new mlogger is okey: please set ODB
> "/History/CreateOldTags" to "y" (type TID_BOOL/"boolean") before starting mlogger.
> 
> K.O.

When using "/bin/bash" shell, if I exit odbedit (and other midas programs) using ctrl-C, the terminal 
enters a funny state, "echo" is turned off (I cannot see what I type), "delete" key does not work (echoes 
^H instead).

This problem does not happen if I exit using the "exit" command or if I use the "/bin/tcsh" shell.

When this happens, the terminal can be restored to close to normal state using "stty sane", and "stty 
erase ^H".

The terminal is set into this funny state by system.c::getchar() and normal settings are never restored 
unless the midas program calls getchar(1) at the end. If the program does not finish normally, original 
terminal settings are never restored and the terminal is left in a funny state.

It is not clear why the problem does not happen with /bin/tcsh - perhaps they restore sane terminal 
settings automatically for us.
K.O.

We have seen on several daq systems this problem: we start a run and observe that the number of 
events written by mlogger to the output file is double the number of events actually collected. Upon 
inspection of the output file, we see that every event is written twice. Restarting the run usually fixes 
this problem.

We now traced this to an error in mlogger.c. If we start a run and the run transition fails in some 
frontend,  mlogger does not disconnect from the SYSTEM buffer (it does not know the transition failed 
and the run did not really start). The SYSTEM buffer connection and the associated event request 
remain active. Then we start the next run and mlogger connects to the SYSTEM buffer again, creates a 
second (third, etc) event request. Eventually mlogger reaches the maximum permitted number of event 
requests and no more runs can be started unless mlogger is restarted.

If at some point a run actually starts successfully, there are multiple event requests present from 
mlogger and theoretically, each event should be written to the output file many times. This was a 
puzzle until we got a good laugh from looking at mlogger.c::receive_event() callback - in retrospect it 
is obvious why events are only written in duplicate.

Then, after the run is ended, mlogger disconnects from the SYSTEM buffer, all multiple event requests 
are automatically deleted and the problem is not present during the next run.

I am not yet sure how to best fix this, but I see that other midas programs (i.e. mevb) suffer form the 
same problem - multiple connections to the event buffer - in presence of failed run starts. I think we 
have seen "event duplication" from mevb, as well.

K.O.

> We have seen on several daq systems this problem: we start a run and observe that the number of 
> events written by mlogger to the output file is double the number of events actually collected. Upon 
> inspection of the output file, we see that every event is written twice. Restarting the run usually fixes 
> this problem.

mlogger.c fixed svn rev 4497. (from tr_start(), call tr_stop() if somehow it was not called already by end-run transition).

K.O.

> When using "/bin/bash" shell, if I exit odbedit (and other midas programs) using ctrl-C, the terminal 
> enters a funny state, "echo" is turned off (I cannot see what I type), "delete" key does not work (echoes 
> ^H instead).
> 
> This problem does not happen if I exit using the "exit" command or if I use the "/bin/tcsh" shell.
> 
> When this happens, the terminal can be restored to close to normal state using "stty sane", and "stty 
> erase ^H".
> 
> The terminal is set into this funny state by system.c::getchar() and normal settings are never restored 
> unless the midas program calls getchar(1) at the end. If the program does not finish normally, original 
> terminal settings are never restored and the terminal is left in a funny state.
> 
> It is not clear why the problem does not happen with /bin/tcsh - perhaps they restore sane terminal 
> settings automatically for us.
> K.O.

Who uses bash ??? And who keeps baning on Ctrl-C, when there is a nice "exit" command ;-)

Well, I implemented a simple CTRL-C handler in odbedit (Rev. 4503) which resets the terminal before exiting. 
Give it a try. Of course this cannot catch a hard kill (-9), but CTRL-C works now correctly under bash at 
least.

Hi

Not sure how the rest of you specify mhttpd to work with multiple experiments on
one machine, but it would seem not the same as me ;-)

when executing mhttpd with 

mhttpd -e "experimentname" -p "experimentport" -D 

that experiment name is not transfered to transitions as cm_transition never
specifies the experiment in the call to "transition STOP" etc.
the only flag it sends is a -d for debug if selected.

The result is that the stop and start button of the webinterface does not work,
and transitions sit endlessly doing nothing but consuming all the processor,
odbedit works fine though.

Does everyone else use an apache reverse proxy and or explicit experiment choice
in the url ?

As an aside in mhttpd.c in the reply to -? it states 2 -h options the second
should be a -e. line 13378.


Thanks
Sean

> Not sure how the rest of you specify mhttpd to work with multiple experiments on
> one machine, but it would seem not the same as me ;-)

Please note that there has been a change concerning multiple experiments inside 
mhttpd. From revision 4346 on, mhttpd can only connect to one single experiment, 
and the experiment name in the URL (aka ?exp=name) is not supported any more. So if 
you have several experiments, you start several instances of mhttpd now on 
different ports.

> that experiment name is not transfered to transitions as cm_transition never
> specifies the experiment in the call to "transition STOP" etc.
> the only flag it sends is a -d for debug if selected.

When connecting to an experiment, any midas client uses the ODB from that 
experiment so lives in that "namespace". So one client can never call any client 
from another experiment. So your problem must be something else. Of course there is 
not parameter "experiment" passed to cm_transition() since the experiment is 
implicitly defined by the ODB mhttpd is attached to.

> The result is that the stop and start button of the webinterface does not work,
> and transitions sit endlessly doing nothing but consuming all the processor,
> odbedit works fine though.

I guess you have to do some debugging there. Note that "detached" transitions have 
been implemented recently by Konstantin, so maybe your problem is related to that. 
In this case Konstantin should check what's wrong.

> Does everyone else use an apache reverse proxy and or explicit experiment choice
> in the url ?

I use a

ProxyPass /megon/ http://megon.psi.ch/

on our public web server to make an online machine accessible from outside the 
firewall, but just with a single experiment.

> As an aside in mhttpd.c in the reply to -? it states 2 -h options the second
> should be a -e. line 13378.

Fixed in revision 4504.

Hi

> > Not sure how the rest of you specify mhttpd to work with multiple experiments on
> > one machine, but it would seem not the same as me ;-)
> 
> Please note that there has been a change concerning multiple experiments inside 
> mhttpd. From revision 4346 on, mhttpd can only connect to one single experiment, 
> and the experiment name in the URL (aka ?exp=name) is not supported any more. So if 
> you have several experiments, you start several instances of mhttpd now on 
> different ports.

That i do with : 
mhttpd -p xx -e experiment_name -D

> 
> > that experiment name is not transfered to transitions as cm_transition never
> > specifies the experiment in the call to "transition STOP" etc.
> > the only flag it sends is a -d for debug if selected.
> 
> When connecting to an experiment, any midas client uses the ODB from that 
> experiment so lives in that "namespace". So one client can never call any client 
> from another experiment. So your problem must be something else. Of course there is 
> not parameter "experiment" passed to cm_transition() since the experiment is 
> implicitly defined by the ODB mhttpd is attached to.

Will have to look else where.

> 
> > The result is that the stop and start button of the webinterface does not work,
> > and transitions sit endlessly doing nothing but consuming all the processor,
> > odbedit works fine though.
> 
> I guess you have to do some debugging there. Note that "detached" transitions have 
> been implemented recently by Konstantin, so maybe your problem is related to that. 
> In this case Konstantin should check what's wrong.

cm_transition does a "system(str)" on line 3243 inside the "if(async_flag == DETACH)" of
line 3219, how does an external program know about the state of the originating mhttpd
process ? Surely that str which executes "mtransition ......." should get a -e
specifying the experiment explicitly ? probably a -h as well to be thorough.
The only other way that mtransition.cxx will be able to pull in the experimentname is
from the environment variable in its call to cm_get_environment(....) on its startup.


Ok after some testing .... 
If i start the mhttpd with the environment variable MIDAS_EXPT_NAME set then its happy
as mtransition inherits the environment of mhttpd so cm_get_environment(...) of
mtransition picks up the experiment. Similarly if i insert "-e experimentname" into the
string "str" that is passed in system(str) of line 3243. Then start and stop buttons work. 

Konstantin any comments.

I suppose i can live with starting mhttpd with the environment set before running, but
that kind of negates the command line argument to mhttpd. 

Thanks for the help

Sean

> I guess you have to do some debugging there. Note that "detached" transitions have 
> been implemented recently by Konstantin, so maybe your problem is related to that. 
> In this case Konstantin should check what's wrong.

Yes, I think there is a problem - cm_transition() starts the mtransition helper without the "-h expt" switch, so 
mtransition can only connect to the "default" experiment. Will fix. K.O.

> > We have seen on several daq systems this problem: we start a run and observe that the number of 
> > events written by mlogger to the output file is double the number of events actually collected. Upon 
> > inspection of the output file, we see that every event is written twice. Restarting the run usually fixes 
> > this problem.
> 
> mlogger.c fixed svn rev 4497. (from tr_start(), call tr_stop() if somehow it was not called already by end-run transition).

There is a new problem: after an unsuccessful run start, the next run start bombs with the error "output file runNNN.mid already exists". One way around this is to 
manually remove the useless data file, another is to bump up the run number. Better solution is to automatically erase the output file created by unsuccessful run 
starts.

K.O.

> > I guess you have to do some debugging there. Note that "detached" transitions have 
> > been implemented recently by Konstantin, so maybe your problem is related to that. 
> > In this case Konstantin should check what's wrong.
> 
> Yes, I think there is a problem - cm_transition() starts the mtransition helper without the "-h expt" switch, so 
> mtransition can only connect to the "default" experiment. Will fix. K.O.

Fixed midas.c svn rev 4506: in cm_transition(), always pass "-e expt" to mtransition, if connected remotely, pass the
"-h host:port".

svn rev 4506
K.O.

> > > We have seen on several daq systems this problem: we start a run and observe that the number of 
> > > events written by mlogger to the output file is double the number of events actually collected. Upon 
> > > inspection of the output file, we see that every event is written twice. Restarting the run usually fixes 
> > > this problem.
> > 
> > mlogger.c fixed svn rev 4497. (from tr_start(), call tr_stop() if somehow it was not called already by end-run transition).
> 
> There is a new problem: after an unsuccessful run start, the next run start bombs with the error "output file runNNN.mid already exists". One way around this is to 
> manually remove the useless data file, another is to bump up the run number. Better solution is to automatically erase the output file created by unsuccessful run 
> starts.

Stefan suggested implementing a new transition, TR_STARTABORT, issued if TR_START fails. mlogger can use it to cleanup open files, etc, similar to TR_STOP.

This is now implemented. In mlogger, TR_STARTABORT is similar to TR_STOP, but deletes open output files and does not save end-of-run information into databases, etc. mfe.c does not handle this trnasition yet, but I 
plan to add it - to fix the observed situations where the run failed to start, but some equipment does not know about it and continues to generate events and send data.

svn rev 4514
K.O.

> Stefan suggested implementing a new transition, TR_STARTABORT, issued if TR_START fails. mlogger can use it to cleanup open files, etc, similar to TR_STOP.
> 
> This is now implemented. In mlogger, TR_STARTABORT is similar to TR_STOP, but deletes open output files and does not save end-of-run information into databases, etc. mfe.c does not handle this trnasition yet, but I 
> plan to add it - to fix the observed situations where the run failed to start, but some equipment does not know about it and continues to generate events and send data.
> 
> svn rev 4514
> K.O.

There is one problem with the TR_STARTABORT: If you combine old and new clients they will crash, since the old clients don't know anything about TR_STARTABORT. The way to prevent this is to increase the Midas version from 
2.0.0 to 2.1.0. Then you will get a warning if you mix clients. Please test this and commit the change if it works.

> > Stefan suggested implementing a new transition, TR_STARTABORT, issued if TR_START fails. mlogger can use it to cleanup open files, etc, similar to TR_STOP.
> > 
> > This is now implemented. In mlogger, TR_STARTABORT is similar to TR_STOP, but deletes open output files and does not save end-of-run information into databases, etc. mfe.c does not handle this trnasition yet, but I 
> > plan to add it - to fix the observed situations where the run failed to start, but some equipment does not know about it and continues to generate events and send data.
> > 
> > svn rev 4514
> > K.O.
> 
> There is one problem with the TR_STARTABORT: If you combine old and new clients they will crash, since the old clients don't know anything about TR_STARTABORT. The way to prevent this is to increase the Midas version from 
> 2.0.0 to 2.1.0. Then you will get a warning if you mix clients. Please test this and commit the change if it works.

Are you sure? Only clients that register themselves to receive the TR_STARTABORT transition (via cm_register_transition()) will receive this transition.

As of now, the only client that registers and receives this transition is mlogger.

I also confirm that old clients that know nothing about TR_STARTABORT are *not* sent this transition. (this is tested).

K.O.

> Are you sure? Only clients that register themselves to receive the TR_STARTABORT transition (via cm_register_transition()) will receive this transition.
> 
> As of now, the only client that registers and receives this transition is mlogger.
> 
> I also confirm that old clients that know nothing about TR_STARTABORT are *not* sent this transition. (this is tested).

Ok, then we are fine.

I tried to use odbedit to set the "/System/Prompt" to "%h:%e:%s %p> " and got a
problem: pressing "Return" doesn't work any more. But "[%h:%e:%s]%p> " works fine.
Please see the attachment.

> I tried to use odbedit to set the "/System/Prompt" to "%h:%e:%s %p> " and got a
> problem: pressing "Return" doesn't work any more. But "[%h:%e:%s]%p> " works fine.
> Please see the attachment.

I fixed that problem in SVN revision 4556. It occurred when the prompt does start with a 
'%' which nobody tried before...

Another problem while using odbedit.
I tried the batch mode of "odbedit". I created a key as "/A_Str" by mistake and 
wanted to delete it. Then "odbedit" failed to accept the "Return" key. Please see 
the screen-shot attached. :-(