> What a mess.

The mess with db_get_record() and db_open_record() is even deeper than I thought. There are several anomalies.

Records opened by db_open_record() are later accessed via db_get_record() which requires
that the odb structure and the C structure match exactly.

Of course anybody can modify anything in odb at any time, so there are protections against
modifying the odb structures "from under" db_open_record():

a) db_open_record(MODE_WRITE) makes the odb structure immutable by setting the "exclusive" flag. This works well. In the past 
there were problems with "exclusive mode" getting stuck behind dead clients, but these days it is efficiently cleaned and recovered 
by the odb validation code at the start of all midas programs.

b) db_create_record(), db_reorder_key() and db_delete_key() refuse to function on watched/hotlinked odb structures. One would 
think this is good, but there is a side-effect. If I run "odbedit watch /", all odb delete operations fail (including deletion of temporary 
items in /system/tmp).

c) db_create_key() and db_set_data()/db_set_value() do not have such protections, and they can (and do) add new odb entries and 
change size of existing entries (especially size of strings), and make db_get_record() fail. note that db_get_record() inside 
db_open_record() fails silently and odb hotlinks mysteriously stop working.

One could keep fixing this by adding protections against modification of hotlinked odb structures, but unfortunately, one cannot tell
db_watch() hotlinks from db_open_record() hotlinks. Only the latter ones require protection. db_watch() does not require such 
protections because it does not use db_get_record() internally, it leaves it to the user to sort out any mismatches.

Also it would be nice if "odbedit watch /" did not have the nasty side effect of making all odb unchangable (presently it only makes
things undeletable).

To sort it all out, I am moving in this direction:

1) replace all uses of db_get_record() with db_get_record1() which automatically cures any structure mismatch
2) replace all uses of db_open_record(MODE_READ) with db_watch() in conjunction with db_get_record1(). This is done in mfe.c 
and seems to work ok.
2a) automatic repair of structure mismatch is presently defeated by db_create_record() refusing to work on hotlinked odb entries.
3) with db_get_record() and db_open_record(MODE_READ) removed from use, turn off hotlink protection in item (b) above. This will 
fix problem (2a).
4) maybe replace db_open_record(MODE_WRITE) with explicit db_set_record(). I personally do not like it's "magical" operation, 
when in fact, it is just a short hand for "db_get_key/db_set_record" hidden inside db_send_changed_records().
4a) db_open_record(MODE_WRITE) works well enough right now, no need to touch it.


K.O.

> 2) replace all uses of db_open_record(MODE_READ) with db_watch() in conjunction with db_get_record1().

Done to all in-tree programs, except for mana.c (not using it), sequencer.cxx (cannot test it) and a few places where watching a TID_INT.

Nothing more needs to be done, other than turn off the check for hotlink in db_create_record() & co (removed #define CHECK_OPEN_RECORD in odb.c).

K.O.

$ grep db_open_record src/* | grep MODE_READ
src/lazylogger.cxx:   status = db_open_record(hDB, hKey, &run_state, sizeof(run_state), MODE_READ, NULL, NULL); // watch a TID_INT
src/mana.cxx:   db_open_record(hDB, hkey, NULL, 0, MODE_READ, banks_changed, NULL);
src/mana.cxx:   db_open_record(hDB, hkey, NULL, 0, MODE_READ, banks_changed, NULL);
src/mana.cxx:          db_open_record(hDB, hkey, &out_info, sizeof(out_info), MODE_READ, NULL, NULL);
src/mana.cxx:      db_open_record(hDB, hKey, ar_info, sizeof(AR_INFO), MODE_READ, update_request,
src/midas.c:   status = db_open_record(hDB, hKey, &_requested_transition, sizeof(INT), MODE_READ, NULL, NULL);
src/mlogger.cxx:      status = db_open_record(hDB, hKey, hist_log[index].buffer, size, MODE_READ, log_history, NULL);
src/mlogger.cxx:                     db_open_record(hDB, hVarKey, NULL, varkey.total_size, MODE_READ, log_system_history, (void *) (POINTER_T) index);
src/mlogger.cxx:               db_open_record(hDB, hHistKey, NULL, size, MODE_READ, log_system_history, (void *) (POINTER_T) index);
src/odbedit.cxx:            db_open_record(hDB, hKey, data, size, MODE_READ, key_update, NULL);
src/sequencer.cxx:   status = db_open_record(hDB, hKey, &seq, sizeof(seq), MODE_READ, NULL, NULL);
8s-macbook-pro:midas 8ss$ 

That all makes sense to me. 

Stefan

> > What a mess.
> 
> The mess with db_get_record() and db_open_record() is even deeper than I thought. There are several anomalies.
> 
> Records opened by db_open_record() are later accessed via db_get_record() which requires
> that the odb structure and the C structure match exactly.
> 
> Of course anybody can modify anything in odb at any time, so there are protections against
> modifying the odb structures "from under" db_open_record():
> 
> a) db_open_record(MODE_WRITE) makes the odb structure immutable by setting the "exclusive" flag. This works well. In the past 
> there were problems with "exclusive mode" getting stuck behind dead clients, but these days it is efficiently cleaned and recovered 
> by the odb validation code at the start of all midas programs.
> 
> b) db_create_record(), db_reorder_key() and db_delete_key() refuse to function on watched/hotlinked odb structures. One would 
> think this is good, but there is a side-effect. If I run "odbedit watch /", all odb delete operations fail (including deletion of temporary 
> items in /system/tmp).
> 
> c) db_create_key() and db_set_data()/db_set_value() do not have such protections, and they can (and do) add new odb entries and 
> change size of existing entries (especially size of strings), and make db_get_record() fail. note that db_get_record() inside 
> db_open_record() fails silently and odb hotlinks mysteriously stop working.
> 
> One could keep fixing this by adding protections against modification of hotlinked odb structures, but unfortunately, one cannot tell
> db_watch() hotlinks from db_open_record() hotlinks. Only the latter ones require protection. db_watch() does not require such 
> protections because it does not use db_get_record() internally, it leaves it to the user to sort out any mismatches.
> 
> Also it would be nice if "odbedit watch /" did not have the nasty side effect of making all odb unchangable (presently it only makes
> things undeletable).
> 
> To sort it all out, I am moving in this direction:
> 
> 1) replace all uses of db_get_record() with db_get_record1() which automatically cures any structure mismatch
> 2) replace all uses of db_open_record(MODE_READ) with db_watch() in conjunction with db_get_record1(). This is done in mfe.c 
> and seems to work ok.
> 2a) automatic repair of structure mismatch is presently defeated by db_create_record() refusing to work on hotlinked odb entries.
> 3) with db_get_record() and db_open_record(MODE_READ) removed from use, turn off hotlink protection in item (b) above. This will 
> fix problem (2a).
> 4) maybe replace db_open_record(MODE_WRITE) with explicit db_set_record(). I personally do not like it's "magical" operation, 
> when in fact, it is just a short hand for "db_get_key/db_set_record" hidden inside db_send_changed_records().
> 4a) db_open_record(MODE_WRITE) works well enough right now, no need to touch it.
> 
> 
> K.O.

> Done to all in-tree programs, except for mana.c (not using it), sequencer.cxx (cannot test it) and a few places where watching a TID_INT.
> Nothing more needs to be done, other than turn off the check for hotlink in db_create_record() & co (removed #define CHECK_OPEN_RECORD in odb.c).

Fixed a bug in mfe.c - it was overwriting odb /eq/xxx/common with default values. fixed now.

Running with CHECK_OPEN_RECORD seems to work okey so far. Will test some more before proposing to make it the default.

K.O.

Hello,
Our experiment based on MIDAS 2.x DAQ.
I'm using several identical frontend-%d  with only lam source & event id changed, 
running on 2 computers(~3frontends per one).
Each recieve about 10k Events (Max_SIZE =8*1024, but usually it is less then 
sizeof(DWORD)*400) per 7sec.
With no mlogger running it works just fine, but when I'm starting mlogger (on 3-d 
computer with mserver running)... looking at ethernet stat graph first 2-3 spills 
goes well, with one peak per 7 sec, then it becomes junky and everithing crushed 
(mlogger and frontends).
I tried to increase SYSTEM buffer and restart everything. What I saw was Logger 
writes only half of recieved events from sum of frontends, it stays running for 
awhile ~15minutes. If I push STOP button  before crashing, mlogger continious 
writing data on disk enough priod of time.
I will try to look at disk usage for bad sectors @HDD, but may be there is an easy 
way to fix this problem and i did something wrong. 
structure of frontend has code like
EQ_POLLED , POLL for 500,

frontend_loop{
read big buffer with 10k events;bufferread=true;
}

poll_event{
for (i=0;i<count;i++){
 if (bufferread) lam=1;
 if (!test) return lam;
 }
return 0;
}

read_trigger{
bk_init32();
//fill event with buffer until current word!=0xffffffff
if (currentposition+2 >buffer_size) bufferread=false
}
|
Help needed, please. Suggestions.
Thanks, Alexey.

Hello, once again.
What I found is when I tryed to stop the run, mlogger still working and writing some 
data, that i'm sure is not right, because frontend's are in stopped state
( for ex. every 3*frontend got 50k, mlogger showes 120k . Stop button pushed, but data 
in .mid file collect more then 150k~300k ev)
. And it continue writing until it crashes by the default waiting period 10s.

Hello, 
I'm in deppression.
I removed Everything from computer with mserver and reinstall system and midas.
Then I tried to run tutorial example.
Often run did not stop by pushing STOP button (mlogger stuck it, odbedit stop 
works)
After first START button pushed number of event taken by frontend equals mlogger 
events 
written. Next run (without mlogger restarting) mlogger double the number of 
events taken by 
frontend.(see attachment).Restarting mlogger fix this double counting.
What i've did wrong?

We installed recent mhttpd on a ubuntu machine and discovered a number of problems
with the default mhttpd settings.

We did follow the normal instructions to install and configure an apache https proxy
with a certbot certificate and password protection, this part worked ok. Big thanks
to Lars M. for providing the Ubuntu instructions for apache.

Then we started seeing errors from mhttpd about access to URLs like "manager/html" 
(google "manager/html exploit") that did not go through the proxy.

It turns out that unlike CentOS-7, Ubuntu LTS 18.04 does not run a restrictive firewall
and access to mhttpd ports 8080 and 8443 is not blocked. Then, it turns out that by 
default, the mhttpd access controls are also disabled, and it accepts http requests from 
anywhere/everywhere. Also by default, the mhttpd password is also disabled.

As result, anybody from anywhere can access mhttpd without a password.

One fix for this is to activate the mhttpd access control list by setting ODB 
/Experiment/Security/allowed hosts[0] to "localhost".

K.O.

> It turns out that unlike CentOS-7, Ubuntu LTS 18.04 does not run a restrictive firewall
> and access to mhttpd ports 8080 and 8443 is not blocked
>
> As result, anybody from anywhere can access mhttpd without a password.
> 

elogd can suffer from the same problem, but not as badly, one can connect to elogd and attempt to run 
exploits, but one cannot access elog entries without a password:

a) default configuration is to ask for a password
b) elogd almost immediately redirects to the https URL specified in the URL entry of the config file, which 
normally points to the https proxy, which also immediately asks for a password.

In the absence of firewall protection (as on Ubuntu), 
add "Interface = 127.0.0.1" to the elog config file or run elogd with "-n localhost",
per instructions at https://elog.psi.ch/elog/config.html 

K.O.

Added ss_create_thread support for Linux in system.c
Added pthread library in main make file

Hi,

some minutes ago I published a PR for PostgreSQL support I developed
at INFN-Napoli for Darkside experiment...

I don't know if you receive a notification about this PR and in doubt
I wrote this message...

Thanks in advance,
Gennaro

> some minutes ago I published a PR for PostgreSQL support I developed
> at INFN-Napoli for Darkside experiment...
> 
> I don't know if you receive a notification about this PR and in doubt
> I wrote this message...

Hi, Gennaro, thank you for the very useful contribution. I saw the previous version 
of your pull request and everything looked quite good. But that pull request was 
for an older version of midas and it would not have applied cleanly to the current 
version. I will take a look at your updated pull request. In theory it should only 
add the Postgres class and modify a few other places in history_schema.cxx and have 
no changes to anything else. (if you need those changes, it should be a separate 
pull request).

Also I am curious what benefits and drawbacks of Postgres vs mysql/mariadb you have 
observed for storing and using midas history data.

K.O.

Hi 


> > some minutes ago I published a PR for PostgreSQL support I developed
> > at INFN-Napoli for Darkside experiment...
> > 
> > I don't know if you receive a notification about this PR and in doubt
> > I wrote this message...
> 
> Hi, Gennaro, thank you for the very useful contribution. I saw the previous version 
> of your pull request and everything looked quite good. But that pull request was 
> for an older version of midas and it would not have applied cleanly to the current 
> version. I will take a look at your updated pull request. In theory it should only 
> add the Postgres class and modify a few other places in history_schema.cxx and have 
> no changes to anything else. (if you need those changes, it should be a separate 
> pull request).
> 
> Also I am curious what benefits and drawbacks of Postgres vs mysql/mariadb you have 
> observed for storing and using midas history data.
> 
> K.O.

Hi Konstantin,
thanks for this update |

My main interest for PostgreSQL is usage of TimescaleDB
(https://github.com/timescale/timescaledb) a PostgreSQL extension that
makes possible usage of downsampling functions on time-series...

here at INFN-Napoli we have a large history dataset that we manage
with MIDAS history and MySQL tables. We have a lot of issues 
(wait time, browser hangs, crashes) when we use MIDAS history plot 
pages on large time period because the Javascript web page try to 
download million of records in order to display them on a plot of 
(max) 2000 pixel width...

with native downsampling we can reduce a large dataset keeping the
"shape" of the curve using only the points needed by the plot area;

in TimescaleDB there is "lttb" ( Largest Triangle Three Bucket) a very 
nice and impressive downsampling function that preserve very well the
shape of the series.

If you are interested to see a lttb at work on some data you can open this page:
   https://www.base.is/flot

In next days I will work to add TimescaleDB backend to MIDAS history (it will be
similar to PostgreSQL backend) and we can discuss on how to add these 
downsampling features to history plot web pages, I already developed some
solutions and I will be happy to share them with MIDAS community;

Cheers,
Gennaro

> > some minutes ago I published a PR for PostgreSQL support I developed
> > at INFN-Napoli for Darkside experiment...
> > 
> > I don't know if you receive a notification about this PR and in doubt
> > I wrote this message...
> 
> Hi, Gennaro, thank you for the very useful contribution. I saw the previous version 
> of your pull request and everything looked quite good. But that pull request was 
> for an older version of midas and it would not have applied cleanly to the current 
> version. I will take a look at your updated pull request. In theory it should only 
> add the Postgres class and modify a few other places in history_schema.cxx and have 
> no changes to anything else. (if you need those changes, it should be a separate 
> pull request).
> 
> Also I am curious what benefits and drawbacks of Postgres vs mysql/mariadb you have 
> observed for storing and using midas history data.
> 
> K.O.

Hi,
I have updated the PR with a new one that includes TimescaleDB support and some
changes to mhistory.js to support downsampling queries...

Cheers,
Gennaro

> > some minutes ago I published a PR for PostgreSQL support I developed
> > at INFN-Napoli for Darkside experiment...
> > 
> > I don't know if you receive a notification about this PR and in doubt
> > I wrote this message...
> 
> Hi, Gennaro, thank you for the very useful contribution. I saw the previous version 
> of your pull request and everything looked quite good. But that pull request was 
> for an older version of midas and it would not have applied cleanly to the current 
> version. I will take a look at your updated pull request. In theory it should only 
> add the Postgres class and modify a few other places in history_schema.cxx and have 
> no changes to anything else. (if you need those changes, it should be a separate 
> pull request).
> 
> Also I am curious what benefits and drawbacks of Postgres vs mysql/mariadb you have 
> observed for storing and using midas history data.
> 
> K.O.

Hi,
is there any news regarding this pull request ? 
(https://bitbucket.org/tmidas/midas/pull-requests/30)

If you agree to merge I can resolve conflicts that now 
(after two months) are listed...

Regards,
Gennaro

> 
> Hi,
> I have updated the PR with a new one that includes TimescaleDB support and some
> changes to mhistory.js to support downsampling queries...
> 
> Cheers,
> Gennaro
> 
> > > some minutes ago I published a PR for PostgreSQL support I developed
> > > at INFN-Napoli for Darkside experiment...
> > > 
> > > I don't know if you receive a notification about this PR and in doubt
> > > I wrote this message...
> > 
> > Hi, Gennaro, thank you for the very useful contribution. I saw the previous version 
> > of your pull request and everything looked quite good. But that pull request was 
> > for an older version of midas and it would not have applied cleanly to the current 
> > version. I will take a look at your updated pull request. In theory it should only 
> > add the Postgres class and modify a few other places in history_schema.cxx and have 
> > no changes to anything else. (if you need those changes, it should be a separate 
> > pull request).
> > 
> > Also I am curious what benefits and drawbacks of Postgres vs mysql/mariadb you have 
> > observed for storing and using midas history data.
> > 
> > K.O.

> is there any news regarding this pull request ? 
> (https://bitbucket.org/tmidas/midas/pull-requests/30)

apologies for taking a very long time to review the proposed changes.

the main problem with this pull request remains, it tangles together too many changes to the code and I cannot simply 
say "this is okey", merge and commit it.

example of unrelated change is diff of mlogger.cxx, change of function in: "db_get_value(hDB, 0, "/Logger/Multithread 
transitions" ... )". there is also unrelated changes to whitespace sprinkled around.

can you review your diffs again and try to remove as much unrelated and unnecessary changes as you can?

I could do this for you, and merge my version, but next time you merge base midas, you will have a collision.

unrelated change of function is introduction of something called "downsampling", what is the purpose of this? How is it 
different from requesting binned data? Is it just a kludge to reduce the data size? Before we merge it, can you post a 
description/discussion to this forum here? (as a separate topic, separate from discussion of PostgreSQL merge).

the changes to add PostgreSQL so fat look reasonable:
- CMakeLists, is always painful but if you do same a MySQL, should be okey, we always end up rejigging this several 
times before it works everywhere.
- history.h, ok, minus changes for adding the "downsample" feature
- mlogger.cxx, changes are too tangled with "downsample" feature, cannot review
- SetDownsample() API is defective, should have separate Get() and Set() functions
- history_common.cxx, please do not add downsampling code to history providers that do not/will not support it.
- history_odbc.cxx, please do not change it. it does not support downsampling and never will.
- history.cxx, ditto
- mjsonrpc.cxx, history API is changed, we must know: is new JS compatible with old mhttpd? is old JS compatible with 
new mhttpd? (mixed versions are very common in practice). if there is incompatibility, can you recoded it to be 
compatible?
- history_schema.cxx: bitbucket diff is a dog's breakfast, cannot review. I will have to checkout your branch and diff 
by hand.

changes to mhistory.js appear to be extensive and some explanation is needed for what is changed, what bugs/problems 
are fixed, what new features are added.

to move forward, can you generate a pull requests that only adds pgsql to history_schema.cxx, history_common.cxx and 
mlogger.cxx and does not add any other functions, features and does not change any whistespace?

K.O.


> 
> If you agree to merge I can resolve conflicts that now 
> (after two months) are listed...
> 
> Regards,
> Gennaro
> 
> > 
> > Hi,
> > I have updated the PR with a new one that includes TimescaleDB support and some
> > changes to mhistory.js to support downsampling queries...
> > 
> > Cheers,
> > Gennaro
> > 
> > > > some minutes ago I published a PR for PostgreSQL support I developed
> > > > at INFN-Napoli for Darkside experiment...
> > > > 
> > > > I don't know if you receive a notification about this PR and in doubt
> > > > I wrote this message...
> > > 
> > > Hi, Gennaro, thank you for the very useful contribution. I saw the previous version 
> > > of your pull request and everything looked quite good. But that pull request was 
> > > for an older version of midas and it would not have applied cleanly to the current 
> > > version. I will take a look at your updated pull request. In theory it should only 
> > > add the Postgres class and modify a few other places in history_schema.cxx and have 
> > > no changes to anything else. (if you need those changes, it should be a separate 
> > > pull request).
> > > 
> > > Also I am curious what benefits and drawbacks of Postgres vs mysql/mariadb you have 
> > > observed for storing and using midas history data.
> > > 
> > > K.O.

> > is there any news regarding this pull request ? 
> > (https://bitbucket.org/tmidas/midas/pull-requests/30)
> 
> apologies for taking a very long time to review the proposed changes.
> 

I merged the PgSql bits by hand - the automatic tools make a dog's breakfast from the history_schema.cxx diffs. Ouch.

history_schema.cxx merged pretty much cleanly, but I have one question about CreateSqlColumn() with sql_strict set to "true". Can you say 
more why this is needed? Should this also be made the default for MySQL? The best I can tell the default values are only needed if we write 
to SQL but forget to provide values that should not be NULL? But our code never does this? Or this is for reading from SQL, where NULL values 
are replaced with the default values? I do not have time to look into this right now, I hope you can clarify it for me?

Also notice the fDownsample is set to zero and cannot be changed. I recommend we set it through the MakeMidasHistoryPgsql() factory method.

Please pull, merge, retest, update the pull request, check that there is no unrelated changes (changes in mlogger.cxx is a direct red flag!) 
and we should be able to merge the rest of your stuff pronto.

K.O.

commit e85bb6d37c85f02fc4895cae340ba71ab36de906 (HEAD -> develop, origin/develop, origin/HEAD)
Author: Konstantin Olchanski <olchansk@triumf.ca>
Date:   Fri Jul 21 09:45:08 2023 -0700

    merge PQSQL history in history_schema.cxx

commit f254ebd60a23c6ee2d4870f3b6b5e8e95a8f1f09
Author: Konstantin Olchanski <olchansk@triumf.ca>
Date:   Fri Jul 21 09:19:07 2023 -0700

    add PGSQL Makefile bits

commit aa5a35ba221c6f87ae7a811236881499e3d8dcf7
Author: Konstantin Olchanski <olchansk@triumf.ca>
Date:   Fri Jul 21 08:51:23 2023 -0700

    merge PGSQL support from https://bitbucket.org/gtortone/midas/branch/feature/timescaledb_support except for history_schema.cxx

Hi Konstantin,

thanks a lot for your work on PostgreSQL and TimescaleDB integration...
and sorry for unrelated changes on source code !

I will return on this task at end of this year (maybe October or November) because
I'm working on different tasks... but I will keep in mind your suggestions in order
to provide good source code.

Thanks,
Gennaro


> 
> I merged the PgSql bits by hand - the automatic tools make a dog's breakfast from the history_schema.cxx diffs. Ouch.
> 
> history_schema.cxx merged pretty much cleanly, but I have one question about CreateSqlColumn() with sql_strict set to "true". Can you say 
> more why this is needed? Should this also be made the default for MySQL? The best I can tell the default values are only needed if we write 
> to SQL but forget to provide values that should not be NULL? But our code never does this? Or this is for reading from SQL, where NULL values 
> are replaced with the default values? I do not have time to look into this right now, I hope you can clarify it for me?
> 
> Also notice the fDownsample is set to zero and cannot be changed. I recommend we set it through the MakeMidasHistoryPgsql() factory method.
> 
> Please pull, merge, retest, update the pull request, check that there is no unrelated changes (changes in mlogger.cxx is a direct red flag!) 
> and we should be able to merge the rest of your stuff pronto.
> 
> K.O.
> 
> commit e85bb6d37c85f02fc4895cae340ba71ab36de906 (HEAD -> develop, origin/develop, origin/HEAD)
> Author: Konstantin Olchanski <olchansk@triumf.ca>
> Date:   Fri Jul 21 09:45:08 2023 -0700
> 
>     merge PQSQL history in history_schema.cxx
> 
> commit f254ebd60a23c6ee2d4870f3b6b5e8e95a8f1f09
> Author: Konstantin Olchanski <olchansk@triumf.ca>
> Date:   Fri Jul 21 09:19:07 2023 -0700
> 
>     add PGSQL Makefile bits
> 
> commit aa5a35ba221c6f87ae7a811236881499e3d8dcf7
> Author: Konstantin Olchanski <olchansk@triumf.ca>
> Date:   Fri Jul 21 08:51:23 2023 -0700
> 
>     merge PGSQL support from https://bitbucket.org/gtortone/midas/branch/feature/timescaledb_support except for history_schema.cxx

The compilation of midas was broken by the last modification. The reason is that 

   Pgsql *fPgsql = NULL;

was not protected by 

#ifdef HAVE_PGSQL

So I put all PGSQL code under a big #ifdef and now it compiles again. You might want to double check my modification at

https://bitbucket.org/tmidas/midas/commits/e3c7e73459265e0d7d7a236669d1d1f2d9292a74

Best,
Stefan