Re: Archiver Appliance cannot archive structured PV data

[Sky Brewer via Tech-talk <tech-talk at aps.anl.gov>]

Hi Huihui,

The archiver does support custom structures but they must follow the format https://github.com/epics-docs/epics-docs/pull/182/changes 

You’ll note here the timestamp, the timestamp is what looks to be the problem in the error log. 

Hope that helps.

Sky

Sent from Outlook for Mac

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of 吕慧慧 via Tech-talk <tech-talk at aps.anl.gov>
Date: Wednesday, 1 July 2026 at 04:39
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Archiver Appliance cannot archive structured PV data

Hi all,

I have implemented a structured PVA data in an EPICS V7 IOC. The db is as follows:

record(longin, "DEV1:RED:SHOT_ID_TEST") {
    field(DTYP, "PSC Reg")
    field(INP , "@$(NAME) 526 2")
    field(SCAN, "I/O Intr")
    field(TSE , "-2")
    info(Q:group, {
        "DEV1:RED:WAVE_TEST_PVA": {
            "COUNT": {
                +channel:"VAL"
            }
        }
    })
}

record(waveform, "DEV1:RED:WAVE_TEST_C1") {
    field(DTYP, "PSC Block I16 In")
    field(INP , "@$(NAME) 8193")
    field(SCAN, "I/O Intr")
    field(FTVL, "DOUBLE")
    field(NELM, "20000000")
    info(Q:group,{
        "DEV1:RED:WAVE_TEST_PVA": {
            "VALUE": {
                +channel:"VAL"
            }
        }
    })
}

When I try to archive this PV using the pva://pvname prefix in Archiver Appliance, the archiver throws error messages  and cannot establish persistent archiving. 

2026-06-30 15:48:19,766 ERROR [JCA Command Thread 9] pv.EPICS_V4_PV (EPICS_V4_PV.java:241) - Cannot determine the timestamp bitset for PV DEVI:RED:WAVE_TEST_PVA. This means we may not save any data at all for this PV
2026-06-30 15:48:19,767 ERROR [JCA Command Thread 9] pv.EPICS_V4_PV (EPICS_V4_PV.java:442) - exception when reading pv
java.lang.reflect.InvocationTargetException: null
at jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:72) ~[?:?]
at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:502) ~[?:?]
at java.lang.reflect.Constructor.newInstance(Constructor.java:486) ~[?:?]
at org.epics.archiverappliance.engine.pv.EPICS_V4_PV.fromStructure(EPICS_V4_PV.java:278) ~[classes/:?]
at org.epics.archiverappliance.engine.pv.EPICS_V4_PV.subscribe(EPICS_V4_PV.java:438) ~[classes/:?]
at org.epics.archiverappliance.engine.pv.EPICS_V4_PV.handleConnected(EPICS_V4_PV.java:388) ~[classes/:?]
at org.epics.archiverappliance.engine.pv.JCACommandThread.run(JCACommandThread.java:194) [classes/:?]
Caused by: java.lang.NullPointerException: Cannot invoke "org.epics.vtype.PVStructure.getString()" because "timestampPVStructure" is null
at org.epics.archiverappliance.common.TimeUtils.convertFromPVTimestamp(TimeUtils.java:531) ~[classes/:?]
at edu.stanford.slac.archiverappliance.PB.data.PBV4GenericBytes.<init>(PBV4GenericBytes.java:78) ~[classes/:?]
at jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62) ~[?:?]
... 6 more

I would like to ask two questions: 

1. What is the cause of this failure? I have attached the full error logs from AA engine. 

2. Does the current stable version of Archiver Appliance fully support archiving user-defined custom PVA structure PVs?

Thanks a lot for any suggestions.

 Best regards,

Huihui