node-oracledb/examples/connectionpool.js

117 lines
4.2 KiB
JavaScript

/* Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved. */
/******************************************************************************
*
* You may not use the identified files except in compliance with the Apache
* License, Version 2.0 (the "License.")
*
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0.
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
* See the License for the specific language governing permissions and
* limitations under the License.
*
* NAME
* connectionpool.js
*
* DESCRIPTION
* Shows connection pool usage. Connection pools are recommended
* for applications that use a lot of connections for short periods.
*
* Other connection pool examples are in sessionfixup.js and webappawait.js.
* For a standalone connection example, see connect.js
*
* In some networks forced pool termination may hang unless you have
* 'disable_oob=on' in sqlnet.ora, see
* https://oracle.github.io/node-oracledb/doc/api.html#tnsadmin
*
* This example uses Node 8's async/await syntax.
*
*****************************************************************************/
const oracledb = require('oracledb');
const dbConfig = require('./dbconfig.js');
async function init() {
try {
// Create a connection pool which will later be accessed via the
// pool cache as the 'default' pool.
await oracledb.createPool({
user: dbConfig.user,
password: dbConfig.password,
connectString: dbConfig.connectString
// edition: 'ORA$BASE', // used for Edition Based Redefintion
// events: true, // whether to handle Oracle Database FAN and RLB events or support CQN
// externalAuth: false, // whether connections should be established using External Authentication
// homogeneous: true, // all connections in the pool have the same credentials
// poolAlias: 'default', // set an alias to allow access to the pool via a name.
// poolIncrement: 1, // only grow the pool by one connection at a time
// poolMax: 4, // maximum size of the pool. Increase UV_THREADPOOL_SIZE if you increase poolMax
// poolMin: 0, // start with no connections; let the pool shrink completely
// poolPingInterval: 60, // check aliveness of connection if idle in the pool for 60 seconds
// poolTimeout: 60, // terminate connections that are idle in the pool for 60 seconds
// queueTimeout: 60000, // terminate getConnection() calls in the queue longer than 60000 milliseconds
// sessionCallback: myFunction, // function invoked for brand new connections or by a connection tag mismatch
// stmtCacheSize: 30 // number of statements that are cached in the statement cache of each connection
});
console.log('Connection pool started');
// Now the pool is running, it can be used
await dostuff();
} catch (err) {
console.error('init() error: ' + err.message);
} finally {
await closePoolAndExit();
}
}
async function dostuff() {
let connection;
try {
// Get a connection from the default pool
connection = await oracledb.getConnection();
const sql = `SELECT sysdate FROM dual WHERE :b = 1`;
const binds = [1];
const options = { outFormat: oracledb.OUT_FORMAT_OBJECT };
const result = await connection.execute(sql, binds, options);
console.log(result);
} catch (err) {
console.error(err);
} finally {
if (connection) {
try {
// Put the connection back in the pool
await connection.close();
} catch (err) {
console.error(err);
}
}
}
}
async function closePoolAndExit() {
console.log('\nTerminating');
try {
// Get the pool from the pool cache and close it when no
// connections are in use, or force it closed after 10 seconds
// If this hangs, you may need DISABLE_OOB=ON in a sqlnet.ora file
await oracledb.getPool().close(10);
console.log('Pool closed');
process.exit(0);
} catch(err) {
console.error(err.message);
process.exit(1);
}
}
process
.once('SIGTERM', closePoolAndExit)
.once('SIGINT', closePoolAndExit);
init();