I tested Michael's patch and it fixes the problem when I run the ADSimDetector test.
(base) J:\epics\devel\asyn\iocBoot\ioctestAsynPortDriver>python monitor_test_ad.py
2022-06-27 15:50:43.877772: Adding BIGARRAY callback function
2022-06-27 15:50:43.878761: Sleeping for 5 seconds
2022-06-27 15:50:45.787905: pv_callback counter=1, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=99
2022-06-27 15:50:48.880187: Starting acquisition
2022-06-27 15:50:48.901216: Waiting for acquisition to complete
2022-06-27 15:50:50.290341: pv_callback counter=2, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=100
2022-06-27 15:50:51.699526: pv_callback counter=3, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=112
2022-06-27 15:50:52.709903: pv_callback counter=4, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=126
2022-06-27 15:50:53.127619: pv_callback counter=5, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=136
2022-06-27 15:50:53.545305: pv_callback counter=6, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=140
2022-06-27 15:50:53.956352: pv_callback counter=7, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=144
2022-06-27 15:50:54.371361: pv_callback counter=8, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=148
2022-06-27 15:50:55.201308: pv_callback counter=9, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=152
2022-06-27 15:50:55.626239: pv_callback counter=10, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=161
2022-06-27 15:50:56.240083: pv_callback counter=11, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=165
2022-06-27 15:50:56.654982: pv_callback counter=12, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=171
2022-06-27 15:50:57.071780: pv_callback counter=13, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=175
2022-06-27 15:50:57.495975: pv_callback counter=14, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=179
2022-06-27 15:50:57.909298: pv_callback counter=15, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=183
2022-06-27 15:50:58.536483: pv_callback counter=16, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=188
2022-06-27 15:50:59.158556: pv_callback counter=17, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=194
2022-06-27 15:50:59.574255: pv_callback counter=18, pvName=13SIM1:image1:ArrayData, size=20000000, value=[0]=199
2022-06-27 15:50:59.576321: Acquisition complete
2022-06-27 15:50:59.576321: Sleeping for 60 seconds
2022-06-27 15:51:59.579580: Exiting
There are no callbacks after acquisition is complete.
Mark
-----Original Message-----
From: Core-talk <core-talk-bounces at aps.anl.gov> On Behalf Of Michael Davidsaver via Core-talk
Sent: Monday, June 27, 2022 9:51 AM
To: Zimoch Dirk (PSI) <dirk.zimoch at psi.ch>
Cc: core-talk at aps.anl.gov
Subject: Re: Problem with huge waveforms in EPICS 7
On 6/27/22 06:56, Zimoch Dirk (PSI) via Core-talk wrote:
> On Mon, 2022-06-27 at 15:12 +0200, Zimoch Dirk wrote:
>> The problem appears between commit 4ab98081 and 56f05d72. (The two
>> commits in between do not produce stable code.)
>>
>
> Ben did some code refactoring of db_field_log which changed array handling.
>
> In particular in dbEvent.c the following snipped disappeared from
> db_queue_event_log()
>
> /*
> * if we have an event on the queue and both the last
> * event on the queue and the current event are emtpy
> * (i.e. of type dbfl_type_rec), simply ignore duplicate
> * events (saving empty events serves no purpose)
> */
> if (pevent->npend > 0u &&
> (*pevent->pLastLog)->type == dbfl_type_rec &&
> pLog->type == dbfl_type_rec) {
> db_delete_field_log(pLog);
> UNLOCKEVQUE (ev_que);
> return;
> }
>
> I have added a debug printf in this code and see that it triggers
> whenever a frame is dropped. That is about 3 out of 4 frames in my test case.
>
> It is not trivial to put back the code because dbfl_type_rec disappeared from enum dbfl_type too.
I think the (untested) equivalent would now be:
> diff --git a/modules/database/src/ioc/db/dbEvent.c
> b/modules/database/src/ioc/db/dbEvent.c
> index 0164f55b9..480784d1e 100644
> --- a/modules/database/src/ioc/db/dbEvent.c
> +++ b/modules/database/src/ioc/db/dbEvent.c
> @@ -789,6 +789,18 @@ static void db_queue_event_log (evSubscrip
> *pevent, db_field_log *pLog)
>
> LOCKEVQUE (ev_que);
>
> + /* if we have an event on the queue and both the last
> + * event on the queue and the current event are empty,
> + * simply ignore duplicate events.
> + */
> + if (pevent->npend > 0u
> + && !dbfl_has_copy(*pevent->pLastLog)
> + && !dbfl_has_copy(pLog)) {
> + db_delete_field_log(pLog);
> + UNLOCKEVQUE (ev_que);
> + return;
> + }
> +
> /*
> * add to task local event que
> */