node-pool-oracle.js

var genericPool = require('generic-pool');
// This is the 'nearinfinity' driver: `npm install oracle`
var oracle = require('oracle');
conf = {
	"hostName": "localhost",
	"port": 1521,
	"user": "oracle",
	"password": "oracle",
	"database": "xe",
}
var query = "SELECT systimestamp FROM dual";

var pool = genericPool.Pool({
	name: 'testpool',
	log: true,
	max: 20,
	create: function(callback) {
		var settings = {
			hostname: conf.hostName,
			port: conf.port,
			database: conf.database,
			user: conf.user,
			password: conf.password
		}
		new oracle.connect(settings, function(err, connection) {
			callback(err, connection);
		});
	},
	destroy: function(connection) {
		connection.close();
	}
});

var acquireAndQuery = function() {
	pool.acquire(function(err, connection) {
		if (err) {
			console.log(err, "Error acquiring from pool.");
			return;
		}
		connection.execute(query, [], function(err, results) {
			if (err) {
				console.log(err, "Error executing query.");

				// Simply releasing this connection back to the pool means a potentially
				// corrupt connection may get reused.
				pool.release(connection)

				// This solves the issue
				// pool.destroy(connection);

				return;
			}
			pool.release(connection);
			console.log(results);
		});
	});
};

// Continuously make DB calls
setInterval(acquireAndQuery, (3000));
setInterval(acquireAndQuery, (3100));