Connection Pooling is fully supported by offical hana client, please use Node.js Connection Pooling instead
HANA Database Connection pool for Node.js, inspired by (and copied some ideas from): Generic Pool.
This module supports hana-client and node-hdb. If both exist, the hana-client will be chosen.
- Install
- Getting started
- Creating a pool
- Getting a connection
- Returning a connection
- Destroying a connection
- Clearing the pool
- Receiving events from pool
- Getting status overview of pool
- Running tests
- License
npm install hdb-poolThis is an example how to use this module:
// import the module
const Pool = require('hdb-pool');
// HANA connection info
const dbParams = {
hostName: 'hana-server-name',
port: '30015',
userName: 'user-name',
password: 'user-password'
};
// pool options
const options = {
min: 2,
max: 15,
};
// create the pool
const pool = Pool.createPool(dbParams, options);
// execute some sample sql via the pool
pool.getConnection()
.then(conn => {
conn.exec('select current_timestamp from dummy', (err, rows) => {
//return the connection back to pool
pool.release(client);
if (err) {
// error handling
} else {
// handle the result: rows
}
});
})
.catch(err => {
// error handling
});The pool constructor takes two arguments:
dbParams: a dictionary containing the HANA DB connection information.options: a dictionary containing the configuration for thePool
const Pool = require('hdb-pool');
const pool = Pool.createPool(dbParams, options);A dictionary with following properties:
hostName: host name of HANA server.port: port number.userName: user name.password: password.
An optional dictionary with the any of the following properties:
max: maximum number of resources to create at any given time. (default=50)min: minimum number of resources to keep in pool at any given time. (default=3)maxWaitingRequests: maximum number of waiting requests allowed. (default=0, no limit)requestTimeout: max milliseconds arequestwill wait for a resource before timing out. (default=5000)checkInterval: how often to run resource timeout checks. (default=0, disabled)idleTimeout: the time of a connection staying idle in the pool that eligible for eviction. (default=30000)debug: a flag for emitting those debug message. (default=false, disabled)
pool.getConnection()
.then(conn => {...})
.catch(err => {...});Getting a HANA connection from the pool, the getConnecction does not have any argument.
It returns a Promise. The promise will be resolved with a connection if the connection is available in the pool. And the promise will be rejected with an error if the pool is unable to give a connection(eg: timeout).
pool.release(connection)
.then(() => {...})
.catch(err => {...});Returning a connection to the pool, the release takes one required argument:
connection: a 'borrowed' connection.
This function returns a Promise. This promise will resolve once the connection is accepted by the pool, or reject if the pool is unable to accept the connection for any reason (e.g connection is not a resource that came from the pool). If you do not care the outcome it is safe to ignore this promise.
pool.destroy(connection)
.then(() => {...})
.catch(err => {...});Removing the connection from the pool and destroy the connection itself as well. The function takes one required argument:
connection: a "borrowed" connection.
This function returns a Promise. This promise will resolve once the connection is accepted by the pool, If you do not care the outcome it is safe to ignore this promise.
pool.clear()
.then(() => {...})
.catch(err => {...});This function clears the pool, removing/destroying all the connections and all the pending requests from the pool.
Pool.eventEmitter.on('poolDebug', myEventHandler);
Pool.eventEmitter.on('poolError', myEventHandlerError);
Pool.eventEmitter.on('connectionCreateError', myEventHandlerCreateError);
Pool.eventEmitter.on('connectionValidationError', myEventHandlerValidateError);
Pool.eventEmitter.on('requestTimeout', myEventHandlerValidateError);Pool supports 5 different types of events:
poolDebug: debug information of the pool, needs to be enabled by options.debug first.poolError: error information of the pool.connectionCreateError: connection creation error.connectionValidationError: connection validation error.requestTimeout: request timeout.
const overview = pool.getPoolStatusOverview();This function will show current status of the pool.
npm install
npm test
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