A general warning: With the recent history changes implemented in the develop branch, starting from a fresh ODB and editing 
any history panel, on gets tons of errors and debug output from mhttpd:

MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Log axis" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
Load from ODB History/Display/Default/Trigger rate: hist plot: 2 variables
timescale: 1h, minimum: 0.000000, maximum: 0.000000, zero_ylow: 0, log_axis: 0, show_run_markers: 1, show_values: 1, 
show_fill: 1
var[0] event [System][Trigger per sec.] formula [], colour [#00AAFF] label [] factor 1.000000 offset 0.000000 voffset 
0.000000 order 10
var[1] event [System][Trigger kB per sec.] formula [], colour [#FF9000] label [] factor 1.000000 offset 0.000000 voffset 
0.000000 order 20



This has to be fixed by the original author. I strongly recommend to make such modifications on a separate branch not to 
break running experiments.

Stefan

We are using the new history formula as a quick way to convert signals from sensors to actual physical values (for example Voltage->Temperature, Voltage->relative humidity 
...), so it is great that the shown voltage is the calculated one.

I would like to add a point to this discussion.
In our collaboration people attach images of history plots to elogs, meeting presentation and/or physical logbooks.
The proposed scaling formula may work fine online using the cursors, but, once an image is created, I do not understand how it is possible to extract the value for a scaled 
variables.
Suppose you see a graph in a presentation with a current increase by some PSU and the current was scaled to be in the same plot of the voltage.
Looking at the delta in the image, how can you judge the current increase without any axis/grid to refer to?

So I support Stefan proposal for a secondary axis, as long as it is clear which value belong to which axis.
Maybe marking the channels in the description or using different line styles/thickness?

Best,
Marco

> A general warning: With the recent history changes implemented in the develop branch, starting from a fresh ODB and editing 
> any history panel, on gets tons of errors and debug output from mhttpd: ...

This is the reason most projects have separate development and production branches.

I recommend everybody to use the released tagged versions of midas for production.

> I strongly recommend to make such modifications on a separate branch not to 
> break running experiments.

Is there something that does not work anymore? Did I break something? The debug messages I am still
tuning.

K.O.


> 
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Log axis" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
> Load from ODB History/Display/Default/Trigger rate: hist plot: 2 variables
> timescale: 1h, minimum: 0.000000, maximum: 0.000000, zero_ylow: 0, log_axis: 0, show_run_markers: 1, show_values: 1, 
> show_fill: 1
> var[0] event [System][Trigger per sec.] formula [], colour [#00AAFF] label [] factor 1.000000 offset 0.000000 voffset 
> 0.000000 order 10
> var[1] event [System][Trigger kB per sec.] formula [], colour [#FF9000] label [] factor 1.000000 offset 0.000000 voffset 
> 0.000000 order 20
> 
> 
> 
> This has to be fixed by the original author. I strongly recommend to make such modifications on a separate branch not to 
> break running experiments.
> 
> Stefan

> I disagree ...

I am happy with disagreement and differences of opinions. Zest of life, driver of progress and improvements, etc.

I am even more happy with solutions to problems. The current problem is that the offset and factor feature
of history plots has been removed without much discussion.

I stress, we have been using this feature to run experiments for the last 20 years.

I do not understand objections to it being restored. If you do not want to use it, do not use it.

K.O.

> with the proposed change to scale the HV current for a "nice" display. If values are scaled, the axis should be 
> scaled in the same way. Otherwise people might read the current from the plot, look at the axis, and again get the wrong 
> value (the factor of 25x you mention). Sure you can hover with the cursor over the graph, and see the right value, but think 
> of taking a screen shot, putting this into a publication, and get complaints from the reviewer.
> 
> The only "correct" way in my opinion is to implement two vertical axis, as can be seen in some papers. One for the HV, and a 
> new TBD right axis for the current values, then indicating for each graph if the left or right vertical axis applies. For 
> the secondary axis we can have autoscaling or fixed scaling, as we have for the primary axis.
> 
> Stefan

> > The only "correct" way in my opinion is to implement two vertical axis, as can be seen in some papers. One for the HV, and a 
> > new TBD right axis for the current values, then indicating for each graph if the left or right vertical axis applies. For 
> > the secondary axis we can have autoscaling or fixed scaling, as we have for the primary axis.

In the past, we have done some useful plots with maybe 10 variables plotted
at the same time with different scaling and positioning on the graph.

Having 2 vertical axis is maybe useful for the specific case of plotting high voltages,
but not in the general case.

Actually, just 2 vertical axis will not work to plot high voltages in ALPHA-g, because
we have anode currents on the scale 0..0.1 uA and cathode currents on the scale 50..60 uA.

K.O.

I will have to post an example of a scaled plot. I figure everybody forgot how they look like.

K.O.


> We are using the new history formula as a quick way to convert signals from sensors to actual physical values (for example Voltage->Temperature, Voltage->relative humidity 
> ...), so it is great that the shown voltage is the calculated one.
> 
> I would like to add a point to this discussion.
> In our collaboration people attach images of history plots to elogs, meeting presentation and/or physical logbooks.
> The proposed scaling formula may work fine online using the cursors, but, once an image is created, I do not understand how it is possible to extract the value for a scaled 
> variables.
> Suppose you see a graph in a presentation with a current increase by some PSU and the current was scaled to be in the same plot of the voltage.
> Looking at the delta in the image, how can you judge the current increase without any axis/grid to refer to?
> 
> So I support Stefan proposal for a secondary axis, as long as it is clear which value belong to which axis.
> Maybe marking the channels in the description or using different line styles/thickness?
> 
> Best,
> Marco

> I am updating the history plots.
> So the idea is to use this computation:
> y_position_on_plot = offset + factor*(formula(history_value) - voffset)

Stefan and myself did some brain storming on zoom. Writing it down the way I remember it.

- we distilled the gist of the problem - the numerical values we show in the plot labels and in hover-over-the-graph
are before formula is applied or after the formula is applied?

- I suggested a universal solution using a double formula: use formula1 for one case;
  use formula2 for the other case;
  use formula1 for "physics calibration", use formula2 for factor and offset for composite plots:
     numeric_value = formula1(history_value)
     plotted_value = formula2(numeric_value)

- we agree that this is way too complicated, difficult to explain and difficult to coherently present in the history editor

- Stefan suggested a simple solution, a checkbox labeled "show raw value" next to each history variable. by default, the 
value after the formula is plotted and displayed. if checked, the raw value (before the formula) is displayed, and the 
value after the formula is plotted. (so this works the same as the factor and offset on the old history plots).

- if "show raw value" is enabled, the numerical values shown will be inconsistent against the labels on the vertical axis. 
Our solution it to turn the axis labels off. (for composite plots, like oscillator frequency in Hz vs oscillator 
temperature in degC, both scaled to see their correlation, the vertical axis is unit-less "arbitrary units", of course)

- to simplify migration of old history plots that use custom factor and offset settings, we think in the direction of 
automatically moving them to the "formula". (factor=2, offset=10 automatically populates formula with "2*x+10", "show raw 
value" checked/enabled). Thus we can avoid implementing factor and offset in the new history code (an unwelcome 
complication).

- I think this covers all the use cases I have seen in the past, so we will move in this direction.

K.O.

Moving in the direction of this proposal. History plot editor is updated according to it. Remaining missing piece is the "show 
raw value" buttons and code behind them.

Changes:

- "show factor and offset" moved to the top of the page, "off" by default
- factor and offset (if not zero) are automatically migrated to the formula field (if it is empty), one needs to save the panel 
for this to take effect.

K.O.


> > I am updating the history plots.
> > So the idea is to use this computation:
> > y_position_on_plot = offset + factor*(formula(history_value) - voffset)
> 
> Stefan and myself did some brain storming on zoom. Writing it down the way I remember it.
> 
> - we distilled the gist of the problem - the numerical values we show in the plot labels and in hover-over-the-graph
> are before formula is applied or after the formula is applied?
> 
> - I suggested a universal solution using a double formula: use formula1 for one case;
>   use formula2 for the other case;
>   use formula1 for "physics calibration", use formula2 for factor and offset for composite plots:
>      numeric_value = formula1(history_value)
>      plotted_value = formula2(numeric_value)
> 
> - we agree that this is way too complicated, difficult to explain and difficult to coherently present in the history editor
> 
> - Stefan suggested a simple solution, a checkbox labeled "show raw value" next to each history variable. by default, the 
> value after the formula is plotted and displayed. if checked, the raw value (before the formula) is displayed, and the 
> value after the formula is plotted. (so this works the same as the factor and offset on the old history plots).
> 
> - if "show raw value" is enabled, the numerical values shown will be inconsistent against the labels on the vertical axis. 
> Our solution it to turn the axis labels off. (for composite plots, like oscillator frequency in Hz vs oscillator 
> temperature in degC, both scaled to see their correlation, the vertical axis is unit-less "arbitrary units", of course)
> 
> - to simplify migration of old history plots that use custom factor and offset settings, we think in the direction of 
> automatically moving them to the "formula". (factor=2, offset=10 automatically populates formula with "2*x+10", "show raw 
> value" checked/enabled). Thus we can avoid implementing factor and offset in the new history code (an unwelcome 
> complication).
> 
> - I think this covers all the use cases I have seen in the past, so we will move in this direction.
> 
> K.O.

> Moving in the direction of this proposal. Remaining missing piece is the "show 
> raw value" buttons and code behind them.

added "show raw value" button, updated on-page instructions.

I think this is the final layout of the history panel editor, conversion
to html+javascript will be done "as is". If you have suggestions to improve
the layout (add/remove/move things around, etc), please shoult out (on the elog
here or by direct email to me).

I am thinking in the direction of changing the control flow of the history editor:

- midas "history" manu button click redirects to
- current history panel selection (with checkbox to open old history plots), click on "new plot" button redirects to
- new page for creating new plots. this will present a list of all history variables, click on variable name creates a new history 
panel containing just this one variable and redirects to it.

In other words, to see the history for any history variable:
- click on "history" menu button
- click on "new"
- click on desired history variable
- see this history plot

From here, click on the "wheel" button to open the existing history panel editor and add any additional variables, change settings, 
etc.

In the history panel editor, I am thinking in the direction of replacing the existing drop-down selection of history variables (now 
very workable for large experiments) with an overlay dialog to show all history variables, with checkboxes to select them, basically 
the same history variable select page as described above. Not sure yet how this will work visually.

K.O.

One addition I would be in favour of is to remove the "Order" and replace it with drag&drop handles, because this is what people are more 
used to today. Only the old guys like us remember the /etc/init.d/xx_yy scheme where one uses an integer number in the file name to 
determine an order. 

See for example: https://jsbin.com/hijetos/edit?js,output

But instead of relying on a foreign library, I would rather implement that myself, since I need the same thing later for the to-be-
implemented ODB editor (next year? next lockdown?)

Stefan

> --- Makefile
> < 	ld -shared -o $@ $^ $(LIBS) -lc
> ---
> > 	$(CXX) -shared -o $@ $^ $(LIBS) -lc

Will do. We also have a long standing request to change shared library name from lidmidas.so to libmidas-shared.so.

Different name for the .so file will permit us to build the shared library by default, but still link all MIDAS executables
with the static libmidas.a.

(there is no benefit from linking MIDAS executables - mlogger, mhttpd, etc - with the shared library,
and there is a significant cost in confusion from version skew between the executables and shared
libraries - I have had enough midnight calls "why did odbedit stop working? Oh, who changed LD_LIBRARY_PATH
and why is it now binding against this obsolete libmidas.so left over from 2 years ago?").

For user applications you can do whatever, but for MIDAS core applications I strongly suggest that they
be linked to the midas static library.

K.O.

> > > 	$(CXX) -shared -o $@ $^ $(LIBS) -lc

Done.
MIDAS shared library renamed from libmidas.so to libmidas-shared.so and always build on Linux (.so) and MacOS (.dylib and .so bundle).

Users who wish to link their applications to the shared library should change their Makefile from "gcc ... -lmidas" to "gcc ... -lmidas-shared".

MIDAS core applications (mhttpd, mlogger, etc) are linked to the static library to permit multiple versions of midas to be used
at the same time (LD_LIBRARY_PATH should point to the shared library for *which* midas?!?), avoid problems with wrong setting
of LD_LIBRARY_PATH and to avoid problems with version skew (which we found unavoidable once a midas daq is used for a year or
more - main reason we gave up on using the midas shared library in the first place).

svn rev 4594
K.O.

> While reviving midas on midtig01 after it was not used for a while ... 
> [local:tigress:S]/>scl -w
> Name                Host                Timeout    Last called
> mhttpd              midtig01.triumf.ca  10000      -2037131082

These clients cannot be deleted. I tried:
1) shutdown from mhttpd "programs" page -> "cannot shutdown client"
2) "sh mhttpd" from odbedit -> 
   [midas.c:5298:cm_shutdown] cannot connect to client mhttpd on host
   midtig01.triumf.ca, port 32853
   Client mhttpd not active
3) in odbedit: "cd /system/clients; rm xxxx"
   refuses to delete the key

Lacking any better ideas, I deleted them via brain surgery on the odb file:
1) stop everything
2) ipcrm the SYSV shared memory segment
3) odbedit -> save xxx.odb
4) xemacs xxx.odb, delete offending odb entries
5) rm .ODB.SHM
6) odbedit -> load xxx.odb
7) voila, bad clients gone, gone, gone.

K.O.

> 1) shutdown from mhttpd "programs" page -> "cannot shutdown client"
> 2) "sh mhttpd" from odbedit -> 
>    [midas.c:5298:cm_shutdown] cannot connect to client mhttpd on host
>    midtig01.triumf.ca, port 32853
>    Client mhttpd not active
> 3) in odbedit: "cd /system/clients; rm xxxx"
>    refuses to delete the key

Have you tried a "cleanup" in ODBEdit?

The "last_activity" is a 32-bit int, filled with milliseconds. So indeed it 
wraps around after about one month. So if a all clients are stopped 
simultaneously the hard way (such that nobody's watchdog can clean any other 
client from the ODB), like with a power off, and you start the thing one 
month later, there might be a problem. I never tried that before. So next 
time to a cleanup. If that does not help, we should change last_activity 
from INT to DWORD. This way it's alway positive and the wraparound does not 
hurt.

> > 1) shutdown from mhttpd "programs" page -> "cannot shutdown client"
> Have you tried a "cleanup" in ODBEdit?

Nope. Will try next time...

> The "last_activity" is a 32-bit int, filled with milliseconds. So indeed it 
> wraps around after about one month.... change last_activity 
> from INT to DWORD. This way it's alway positive and the wraparound does not 
> hurt.

INT == "int", wraparound in 1 month
DWORD == "unsigned int", wraparound in 2 months

should we make it the 64-bit "long long" (or C98's "int64_t")?

K.O.

> INT == "int", wraparound in 1 month
> DWORD == "unsigned int", wraparound in 2 months
> 
> should we make it the 64-bit "long long" (or C98's "int64_t")?

Won't work on all supported compilers. The point is that DWORD wraps around in 
2 months, but the difference of two DWORDs is alywas positive, never negative 
like you had it. We only have to distinguish if the difference of the current 
time (im ms) minus the last_activity of a client is larget than the timeout, 
typically 10 seconds or so. If you have a wraparound on 32-bit DWORD, the 
difference is still ok. Like

current "time" : 0x0000 0100
last_activity:   0xFFFF FF00

then current_time - last_activity = 0x00000100 - 0xFFFFFF00 = 0x00000200 if 
calculated with 32-bit values.

Indeed the ODB command "cleanup" really works. I have used it several
times with the TWIST DAQ and regularly with the BNMR/MUSR setups where
we have these stubborn clients (ie feepics) that do not want to shutdown
cleanly.  
But there is one problem with "cleanup". It has a hardwired timeout of
2 seconds.  This is a problem for tasks like lazylogger which set a timeout
of 60 seconds when moving the tape. So BEWARE, if you issue the "cleanup"
command, it might kill some clients who have setup their timeout to longer
than 2 seconds. 

I have asked Stefan to change this before. He said that, to be effective,
the timeout value used for "cleanup" has to be rather short. 
One possibility, would be to allow for a user entered "cleanup" timeout.
The default could stay at 2 seconds. 




> > Have you tried a "cleanup" in ODBEdit?
> 
> Nope. Will try next time...
> 

> But there is one problem with "cleanup". It has a hardwired timeout of
> 2 seconds.  This is a problem for tasks like lazylogger which set a timeout
> of 60 seconds when moving the tape. So BEWARE, if you issue the "cleanup"
> command, it might kill some clients who have setup their timeout to longer
> than 2 seconds. 
> 
> I have asked Stefan to change this before. He said that, to be effective,
> the timeout value used for "cleanup" has to be rather short. 
> One possibility, would be to allow for a user entered "cleanup" timeout.
> The default could stay at 2 seconds. 

I changed the behaviour of cleanup by adding an extra parameter 
ignore_timeout to cm_cleanup(). Now, in ODBEdit, a "clanup" obeys the 
timeout set by the clients. The problem with that is if the logger crashes 
for example, and it's timeout is set o 5 min., it cannot be clean-up'ed any 
more for the next five minutes, and therefor not be restarted wasting 
precious beam time. That's why I hard-wired originally the "cleanup" timout 
to 2 sec. Now I added a flag "-f" to the ODBEdit cleanup command which works 
in the old fashion with a 2 sec. timeout. So a "cleanup" alone won't kill a 
looger which currently rewinds a tape or so, but a "cleanup -f" does.

I also changed internal timeouts from INT to DWORD, which should fix the 
problem Konstantin reported recently (re-starting an experiment after 
several weeks). New changes are commited, but I only did basic tests. So 
please try the new code and tell me if there is any problem.

- Stefan

the day has arrived when I cannot git push to bitbucket. cloud computing rules!

I have never seen this error before and I do not think we have any hooks installed,
so it must be some bitbucket stuff. their status page says some kind of maintenance
is happening, but the promised error message is "repository is read only" or something 
similar.

I hope this clears out automatically. I am updating all the cmake crud and I have no idea 
which changes I already pushed and which I did not, so no idea if anything will work for 
people who pull from midas until this problem is cleared out.

daq00:mvodb$ git push
X11 forwarding request failed on channel 0
Enumerating objects: 3, done.
Counting objects: 100% (3/3), done.
Delta compression using up to 12 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (2/2), 247 bytes | 247.00 KiB/s, done.
Total 2 (delta 1), reused 0 (delta 0)
remote: null value in column "attempts" violates not-null constraint
remote: DETAIL:  Failing row contains (13586899, 2021-07-10 01:13:28.812076+00, 1970-01-01 
00:00:00+00, 1970-01-01 00:00:00+00, 65975727, null).
To bitbucket.org:tmidas/mvodb.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git@bitbucket.org:tmidas/mvodb.git'
daq00:mvodb$

K.O.

The default el6 (RHEL/SL/CentOS-6) compiler is gcc-4.4.7, it does not support c++11, not even a little bit.

Do this to install newer c++ compilers and build MIDAS with c++11:

ssh root@sl6machine
# yum install centos-release-scl-rh
# yum install devtoolset-8
# yum install cmake3
# scl -l
devtoolset-8
...

$ ssh user@sl6machine
$ scl enable devtoolset-8 bash
$ gcc -v
COLLECT_LTO_WRAPPER=/opt/rh/devtoolset-8/root/usr/libexec/gcc/x86_64-redhat-linux/8/lto-wrapper
gcc version 8.3.1 20190311 (Red Hat 8.3.1-3) (GCC) 
$ cd git/midas
$ make cclean
$ make cmake3
$ ls -l bin/odbedit

K.O.