webMethods

Can you explain what you mean by borrow a connection ? The only thing that you can do with a connection is to use it. So if you invoke a service that uses the connection, essentially you are borrowing it and returning it to the pool afterwards. So some clarity on the use case would be helpful

Are you referring to the connections in Settings -> JDBC pools or webMethods Adapter for JDBC? Please provide a screenshot for the connections you are referring to. Also I agree, I am not sure what you mean by barrowing a connection. If you use JDBC adapter services, it takes a connection from the pools in webMethods Adapter for JDBC, and then it returns it back.

@Rupinder Singh, by "borrowing an [adapter] connection" I actually meant borrowing a connection from a Adaprter Connection Pool, managed by the IS's Connection Manager.

This connection can be a MongoDB Connection or a JDBC Connection - hence I used the more generic term "Adapter Connection", as it could be any kind of connection - depending on the type of check.

The reasoning behind it this is to check whether the expected database components are in place. This might seem to be an overkill (or over-engineering), but such sanity-check is necessary, as we are always "short of hands" to check why things go "not as expected". And access to he underlying database is not something quick, hence anything that eases these kinds of check is welcome.

@Engin Sarlak The "Adapter Connection" I'm referring to are the adapter connnections set up using the IS Admin > Adapters > webMethods Adapter for <whatever adapter in there, it could be JDBC, MongoDB, etc.)>.

I still don't understand. Lets assume you can borrow a connection. What would you specifically do with it. That would help me understand what you mean.

I didn't understand what you mean either. You can write a simple custom query or use select adapter services to check if the table and the connection are still there, and when you run it it will get a connection from the pool and it will return it to the pool after running the query. I am also not sure about what you are trying to detect. What do you expect to go wrong that needs a sanity check? DBs are usually very stable. If your tables are disappearing or something, that means you have some critical permission issues in your DB. I don't think the integration layer is the right place for this task. Are your tables managed by code? Is that what you are looking for? 

I'm not sure if this answers your question, but both MongoDB and JDBC adapter services take an optional input called $connectionName. You can pass in the fully qualified name of the connection you want to test, and it will use that connection for the call. This allows you have a generic test service that maybe takes in a connection name, a collection name and the expected indexes, and checks if the expected indexes are there. 

@Rupinder Singh,the idea is to issue db commands. Perhaps some clarifications here.

On a relational database, we can access some the "object catalog" for checkeing whether the conditions are met (whether the index X is there or not). And such action can be done using a usual SELECT (eg SELECT * FROM USEROBJECTS et all).

However, on MongoDB, the things are not so easy: in order to get the index list, we need to issue commands that aren't available as adapter services. Eg. getting the list of indexes a collection sports would be like (using `mongosh`) `db.collection.getIndexes()`. However, such command is not available as an adapter service (at least not on IS 10.11).

@Engin Sarlak, you're absolutely right. However, these concepts remain true only if you have dependable and good-quality providers, that can watch and respond quickly when things go wrong. 

@Theo Ezell, that _would work_ - but, since "my pain" is actually with MongoDB and there is no adapter service available for running commands like the "db.collection.getIndexes()", this won't work for me...

The JDBC adapter also has the ExecuteService template that allows you to use a JDBC connection in your own java service.

@Theo Ezell thanks for the examples! I tested the MongoDB-related portion, and it works!

And I wonder what are the other commands that I could employ - perhaps some sort of `createIndex`?

If listIndexes works, I would thin createIndexes would too. Here's a reference for you:

Administration Commands - Database Manual v8.0 - MongoDB Docs