RE: Archiver Appliance: How to extract a PV current value using a SQL query

[Abdalla Ahmad via Tech-talk <tech-talk at aps.anl.gov>]

Hi Oscar

The archiver uses the MySQL database for storing information and meta-data for PVs, it does not store actual PV data in the mysql database, instead it stores data in Protocol buffers formatted files in the different types of storage. To interact with the archiver, whether to fetch data or querying status, you can send HTTP requests to the server, see the examples here:

https://slacmshankar.github.io/epicsarchiver_docs/userguide.html
https://slacmshankar.github.io/epicsarchiver_docs/details.html

Also, check the other github pages in the above URL, there are more information on data structures, types of requests, and other useful information to help you interact with your archiver installation.

Best Regards,
Abdalla.

-----Original Message-----
From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Oscar Ibañez via Tech-talk
Sent: Monday, December 5, 2022 1:24 PM
To: tech-talk at aps.anl.gov
Subject: Archiver Appliance: How to extract a PV current value using a SQL query

Hi everybody,

First of all, sorry if this question is very silly. My experience with this technology is very limited and, often, I feel lost.

My question is about the archiver appliance. I have been capable of running it using MySQL, as well as archiving one PV. I have also been capable of investigating inside the database I created, so I could find the the tables entitled "ArchivePVRequests", "PVTypeInfo" and so on. 
However, I can't find where is the table used to save the PVs. I understand that there are three different types of storage (short, medium and long term) using specific folders but, is there any table where the PVs values are also saved?

The reason behind this question is because I need to extract the current value of a PV using SQL. The idea is to have a different piece of software querying the MySQL database and selecting the current values that I am interested in. My objective is to use that information inside that external software for other purposes.

Best,
Óscar