Re: archiver appliance and CA -> PVA

[Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>]

On 1/29/25 14:32, Pierrick M Hanlet via Tech-talk wrote:
> Greetings,
> We are working toward going full PVA.  We've also recently upgraded the
> archiver appliance to 2.0.5
> and configured it for PVA.
>
> However, we have a number of PVs for which we've been collecting data
> for several years, and these
> were originally configured with CA.  The IOCs have been restructured
> with PVXS and with CA turned
> off with EPICS_IOC_IGNORE_SERVERS=rsrv.  From the mgmt web page for the
> AA, I see that these
> PVs are not connected.  Furthermore, even explicity archiving them with
> pva:// they still won't
> connect.  Apart from reverting back to CA, what can I do so that they
> connect to the AA with PVA?

As it happens, I was recently asking this question.

All per-PV configuration lives in the associated RDB.
Mostly in the PVTypeInfo table, typeInfoJSON column.
Each of these JSON blobs has a key boolean 'usePVAccess'.

For fun, I tried simply changing this key for a couple of
scalar double PVs.  I was a little concerned that these
might show up as Type Change events, which AA does not
handle.  However, in this case it did not.  So all is well.

I still would caution on simply making a bulk change.
It might be a good idea to eg. make a copy of the
configuration and MTS to start up another instance and
check if everything connects, no type changes occur, and
that you are able to query across the boundary.