Re: bitSets and PVStructure

[Marty Kraimer <mrkraimer@comcast.net>]

On 08/14/2018 12:12 PM, Heinz Junkes wrote:
> I have a question about bitSets.
>
> I use the example program from exampleCPP get.cpp
> with the code fragment
>
>          PvaClientGetDataPtr data = pvaClientGet->getData();
>          BitSetPtr bitSet =  data->getChangedBitSet();
>
> Cardinality is "1" although obviously nothing changes.
> Bit #0 is set “structure”.
>
> Now to my question. Is bitSet set by the server?
>
> And then I don't understand that either (from the documentation).
>
> "Only fields that change are transmitted.
> Only the data for fields that change value between requests are sent.”
That was true for pvaSrv and is still true if you use provider ca 
(except for bug shown below).
qsrv changed the semantics.

I am using the latest from the master branch from github for everything.
In one window I start

> mrk> pwd
> /home/epicsv4/masterCPP/exampleCPP/database/iocBoot/exampleDatabase
> mrk> ../../bin/linux-x86_64/exampleDatabase st.cmd
In another window I start:

> pwd
> /home/epicsv4/masterCPP/exampleCPP/exampleClient
> mrk> bin/linux-x86_64/get -p pva -r "value" DBRdouble
> provider pva channelName PVRdouble request value debug false
> _____get starting__
> Type exit to stop:
> channelGetConnect DBRdouble status Status [type=OK]
>
> channelGetDone DBRdouble status Status [type=OK]
> changed DBRdouble
>  = epics:nt/NTScalar:1.0
>     double value 0
>     alarm_t alarm
>         int severity 3
>         int status 2
>         string message UDF
>     time_t timeStamp
>         long secondsPastEpoch 631152000
>         int nanoseconds 0
>         int userTag 0
>     display_t display
>         double limitLow -10
>         double limitHigh 10
>         string description
>         string format
>         string units volts
>     control_t control
>         double limitLow -9
>         double limitHigh 9
>         double minStep 0
>     valueAlarm_t valueAlarm
>         boolean active false
>         double lowAlarmLimit -8
>         double lowWarningLimit -6
>         double highWarningLimit 6
>         double highAlarmLimit 8
>         int lowAlarmSeverity 0
>         int lowWarningSeverity 0
>         int highWarningSeverity 0
>         int highAlarmSeverity 0
>         double hysteresis 0
>
> bitSet {0}
> Type exit to stop:
>
> channelGetDone DBRdouble status Status [type=OK]
> changed DBRdouble
>  = epics:nt/NTScalar:1.0
>     double value 0
>     alarm_t alarm
>         int severity 3
>         int status 2
>         string message UDF
>     time_t timeStamp
>         long secondsPastEpoch 631152000
>         int nanoseconds 0
>         int userTag 0
>     display_t display
>         double limitLow -10
>         double limitHigh 10
>         string description
>         string format
>         string units volts
>     control_t control
>         double limitLow -9
>         double limitHigh 9
>         double minStep 0
>     valueAlarm_t valueAlarm
>         boolean active false
>         double lowAlarmLimit -8
>         double lowWarningLimit -6
>         double highWarningLimit 6
>         double highAlarmLimit 8
>         int lowAlarmSeverity 0
>         int lowWarningSeverity 0
>         int highWarningSeverity 0
>         int highAlarmSeverity 0
>         double hysteresis 0
>
> bitSet {0}
> Type exit to stop:
But if I use ca I get

> mrk> bin/linux-x86_64/get -p ca -r "value" DBRdouble
> provider ca channelName PVRdouble request value debug false
> _____get starting__
> Type exit to stop:
> channelGetConnect DBRdouble status Status [type=OK]
> CA.Client.Exception...............................................
>     Warning: "Identical process variable names on multiple servers"
>     Context: "Channel: "DBRdouble", Connecting to: 10.0.0.127:5064, 
> Ignored: localhost.localdomain:5064"
>     Source File: ../cac.cpp line 1320
>     Current Time: Tue Aug 14 2018 13:50:08.091716384
> ..................................................................
>
> channelGetDone DBRdouble status Status [type=OK]
> changed DBRdouble
>  = structure
>     double value 0
>
> bitSet {0}
> Type exit to stop:
>
> channelGetDone DBRdouble status Status [type=OK]   FOLLOWING IS 
> WRONG:  BUG IN LATEST ca provider
> changed DBRdouble
> value = 0
> bitSet {1}
> Type exit to stop:
If I use database from release4_6, which uses pvaSrv
> mrk> pwd
> /home/epicsv4/release4_6/exampleCPP/database/iocBoot/exampleDatabase
> mrk> ../../bin/linux-x86_64/exampleDatabase st.cmd
Then I get:

> mrk> pwd
> /home/epicsv4/masterCPP/exampleCPP/exampleClient
> mrk> bin/linux-x86_64/get -p pva -r "value" DBRdouble00
> provider pva channelName PVRdouble request value debug false
> _____get starting__
> Type exit to stop:
> channelGetConnect DBRdouble00 status Status [type=OK]
>
> channelGetDone DBRdouble00 status Status [type=OK]
> changed DBRdouble00
>  = epics:nt/NTScalar:1.0
>     double value 0
>
> bitSet {0}
> Type exit to stop:
>
> channelGetDone DBRdouble00 status Status [type=OK]
> Type exit to stop:
> exit
> mrk>
qsrv changed  the rules.
I maintain that qsrv should follow the old rules.

Marty Kraimer

> in the pvaGet I only request “value”.
>
> The PV I am looking at is a classic V3 PV (ca) and on my server runs pvAccess-Server (qsrv).
>
> ioc:
>
> dbpr CRYAFM:AWG0:DDSA:SetDDSFreq,4
>
> ACKS: NO_ALARM      ACKT: YES           ADEL: 0             ALST: 123456
> AOFF: 0             ASG:                ASLO: 0             ASP: 0x0
> BKLNK: 00 00 00 00 00 00 00 00 00 00 00 00                  BKPT: 00
> DESC: Frequency DDS DDSA:               DISA: 0             DISP: 0
> DISS: NO_ALARM      DISV: 1             DOL:CONSTANT        DPVT: 0x19df880
> DRVH: 0             DRVL: 0             DSET: 0x4fb724      DTYP: asynFloat64
> EGU: Hz             EGUF: 0             EGUL: 0             EOFF: 0
> ESLO: 1             EVNT:               FLNK:CONSTANT 0     HHSV: NO_ALARM
> HIGH: 0             HIHI: 0             HOPR: 0             HSV: NO_ALARM
> HYST: 0             INIT: 0             IVOA: Continue normally
> IVOV: 0             LALM: 123456        LBRK: 0             LCNT: 0
> LINR: NO CONVERSION LLSV: NO_ALARM      LOLO: 0             LOPR: 0
> LOW: 0              LSET: 0x1942808     LSV: NO_ALARM       MDEL: 0
> MLIS: 00 00 00 00 00 00 00 00 00 00 00 00                   MLOK: 01 94 e7 40
> MLST: 123456        NAME: CRYAFM:AWG0:DDSA:SetDDSFreq       NSEV: NO_ALARM
> NSTA: NO_ALARM      OIF: Full           OLDSIMM: NO         OMOD: 0
> OMSL: supervisory   ORAW: 123456        ORBV: 0             OROC: 0
> OUT:INST_IO @asyn(awg0, 0)DDS Frequency OVAL: 123456        PACT: 0
> PBRK: 0x0           PHAS: 0             PINI: NO            PPN: 0x0
> PPNR: 0x0           PREC: 3             PRIO: LOW           PROC: 0
> PUTF: 0             PVAL: 123456        RBV: 0              RDES: 0xcdc5d0
> ROFF: 0             RPRO: 0             RSET: 0x4fbac8      RVAL: 123456
> SCAN: Passive       SDIS:CONSTANT       SDLY: -1            SEVR: NO_ALARM
> SIML:CONSTANT       SIMM: NO            SIMPVT: 0x0         SIMS: NO_ALARM
> SIOL:CONSTANT       SPVT: 0x0           SSCN: <nil>         STAT: NO_ALARM
> TIME: 2018-08-14 08:51:37.697697041     TPRO: 0             TSE: 0
> TSEL:CONSTANT       UDF: 0              UDFS: INVALID       VAL: 123456
>
> humma-kavula:examples junkes$ cainfo CRYAFM:AWG0:DDSA:SetDDSFreq
> CRYAFM:AWG0:DDSA:SetDDSFreq
>      State:            connected
>      Host:             cry-test.rz-berlin.mpg.de:5064
>      Access:           read, write
>      Native data type: DBF_DOUBLE
>      Request type:     DBR_DOUBLE
>      Element count:    1
>
>
> humma-kavula:examples junkes$ pvinfo CRYAFM:AWG0:DDSA:SetDDSFreq
> CHANNEL  : CRYAFM:AWG0:DDSA:SetDDSFreq
> STATE    : CONNECTED
> ADDRESS  : 141.14.128.53:5075
> epics:nt/NTScalar:1.0
>      double value
>      alarm_t alarm
>          int severity
>          int status
>          string message
>      time_t timeStamp
>          long secondsPastEpoch
>          int nanoseconds
>          int userTag
>      display_t display
>          double limitLow
>          double limitHigh
>          string description
>          string format
>          string units
>      control_t control
>          double limitLow
>          double limitHigh
>          double minStep
>      valueAlarm_t valueAlarm
>          boolean active
>          double lowAlarmLimit
>          double lowWarningLimit
>          double highWarningLimit
>          double highAlarmLimit
>          int lowAlarmSeverity
>          int lowWarningSeverity
>          int highWarningSeverity
>          int highAlarmSeverity
>          double hysteresis
>
>
> get, nothing is changing ???
>
> code fragment:
>
>     void get()
>      {
>
>          if(!channelConnected) {
>              cout << channelName << " channel not connected\n";
>              return;
>          }
>          if(!getConnected) {
>              cout << channelName << " channelGet not connected\n";
>              return;
>          }
>          pvaClientGet->get();
>          PvaClientGetDataPtr data = pvaClientGet->getData();
>          BitSetPtr bitSet =  data->getChangedBitSet();
> cout << "bitset Cardinality : " << bitSet->cardinality() << endl;
>          if(bitSet->cardinality()>0) {
>               cout << "changed " << channelName << endl;
>               data->showChanged(cout);
>               cout << "bitSet " << *bitSet << endl;
>          }
>      }
>
>
> output:
>
> channelGetConnect CRYAFM:AWG0:DDSA:SetDDSFreq status Status [type=OK]
> channelGetDone CRYAFM:AWG0:DDSA:SetDDSFreq status Status [type=OK]
> bitset Cardinality : 1
> changed CRYAFM:AWG0:DDSA:SetDDSFreq
>   = epics:nt/NTScalar:1.0
>      double value 123456
>      alarm_t alarm
>          int severity 0
>          int status 0
>          string message NO_ALARM
>      time_t timeStamp
>          long secondsPastEpoch 1534254697
>          int nanoseconds 697697041
>          int userTag 0
>      display_t display
>          double limitLow 0
>          double limitHigh 0
>          string description Frequency DDS DDSA:
>          string format
>          string units Hz
>      control_t control
>          double limitLow 0
>          double limitHigh 0
>          double minStep 0
>      valueAlarm_t valueAlarm
>          boolean active false
>          double lowAlarmLimit nan
>          double lowWarningLimit nan
>          double highWarningLimit nan
>          double highAlarmLimit nan
>          int lowAlarmSeverity 0
>          int lowWarningSeverity 0
>          int highWarningSeverity 0
>          int highAlarmSeverity 0
>          double hysteresis 0
>
> bitSet {0}
>
>
> channelGetDone CRYAFM:AWG0:DDSA:SetDDSFreq status Status [type=OK]
> bitset Cardinality : 1
> changed CRYAFM:AWG0:DDSA:SetDDSFreq
>   = epics:nt/NTScalar:1.0
>      double value 123456
>      alarm_t alarm
>          int severity 0
>          int status 0
>          string message NO_ALARM
>      time_t timeStamp
>          long secondsPastEpoch 1534254697
>          int nanoseconds 697697041
>          int userTag 0
>      display_t display
>          double limitLow 0
>          double limitHigh 0
>          string description Frequency DDS DDSA:
>          string format
>          string units Hz
>      control_t control
>          double limitLow 0
>          double limitHigh 0
>          double minStep 0
>      valueAlarm_t valueAlarm
>          boolean active false
>          double lowAlarmLimit nan
>          double lowWarningLimit nan
>          double highWarningLimit nan
>          double highAlarmLimit nan
>          int lowAlarmSeverity 0
>          int lowWarningSeverity 0
>          int highWarningSeverity 0
>          int highAlarmSeverity 0
>          double hysteresis 0
>
> bitSet {0}
>
>
>
>
> ----------------------------------------------------------------------
> Das FHI verarbeitet, speichert und loescht Daten im Rahmen seiner
> Geschaeftstaetigkeit gemaess der Datenschutz-Grundverordnung (DSGVO)
> [General Data Protection Regulation (GDPR)] der Europaeischen Union.