implement pool.getConnection with wait

vbuehringer

I resolved the problem with events ( waiting on a event, if no available connection, and event.emit after release )

but the pool should be implemented with waiting and not error, if no connection is available

in a pure request driven api without sessions could be much more concurrent requests than connections

available

the waiting should be implemented with a configurable timeout (milliseconds) if the connections are

not available for a longer period, mostly caused by  long running db-calls

(the http-request also times out )

perhaps there should be a combination of:

- get connection

- execute

- commit

- release con.

in one function

this would simplify the handling ( one callback instead of four )

( in case of error: rollback and release )

multiple sql-statements can be combined in a procedure  on the server

and this sequence is sufficient for most rest-apis

Christopher Jones-Oracle

Implementing a configurable timeout is on our list to evaluate for feasibility.  The current choice of returning an error seemed more flexible and useful than blocking until a connection is available. It allows apps to control how to retry instead of forcing every app to "hang" for an unknown amount of time.

Your 4 statement sequence can already be dropped to 3 by making use of isAutoCommit mode https://github.com/oracle/node-oracledb/blob/master/doc/api.md#propdbisautocommit

I like hearing how you use Node.js and PL/SQL. If there is sufficient demand for a one-call-does-everything function, we would evaluate it.  However, we want to keep the API small and flexible.

danmcghan-Oracle

Hi vbuehringer,

I wrote a blog post that touches on this topic. https://jsao.io/2015/03/making-a-wrapper-module-for-the-node-js-driver-for-oracle-database/

There's a simpleExecute method that you could customize to meet your needs. Also, it shouldn't be too hard to update the getConnection method to simulate waiting.

Regards,

Dan

danmcghan-Oracle

Hi vbuehringer,

I'm not sure if you still need a fix for the original issue, but I just added support for connection request queueing at the pool level to orawrap. It limits the number of active connections in a pool to the poolMax setting. I'd love it if you could give it a test and/or provide some feedback.

Regards,

Dan