pg2

Description

A PostgreSQL driver for node.js that focuses on performance.

Requirements

• node.js -- v6.3.0 or newer

Install

npm install pg2

Examples

• Buffered SELECT query:

var Client = require('pg2');

var c = new Client({
  host: '127.0.0.1',
  user: 'foo',
  password: 'bar',
  db: 'test'
});

c.query('SELECT i FROM generate_series(1, 10) AS i', (err, rows) => {
  if (err)
    throw err;
  console.dir(rows);
});

c.end();

• Streamed SELECT query:

var Client = require('pg2');

var c = new Client({
  host: '127.0.0.1',
  user: 'foo',
  password: 'bar',
  db: 'test'
});

c.query('SELECT i FROM generate_series(1, 10) AS i');
 .on('data', (result) => {
  result.on('data', (row) => {
    console.dir(row);
  });
});

c.end();

• Using arrays (faster) instead of objects for rows:

var Client = require('pg2');

var c = new Client({
  host: '127.0.0.1',
  user: 'foo',
  password: 'bar',
  db: 'test'
});

c.query('SELECT i FROM generate_series(1, 10) AS i', { arrays: true }, (err, rows) => {
  if (err)
    throw err;
  console.dir(rows);
});

c.end();

• Using positional parameters in a query:

var Client = require('pg2');

var c = new Client({
  host: '127.0.0.1',
  user: 'foo',
  password: 'bar',
  db: 'test'
});

c.query('SELECT i FROM generate_series($1::numeric, $2::numeric) AS i',
        [1, 10],
        (err, rows) => {
  if (err)
    throw err;
  console.dir(rows);
});

c.end();

API

require('pg2') returns a Client object

Client properties

• connected - boolean - true if the Client instance is currently connected to the server.

• backendParams - object - Once authenticated, this value will contain any backend status values. If no such values have been received, the value of this property will be null.

• key - object - Once authenticated, this object will contain two properties (pid and key) which is used to uniquely identify this connection on the server.

• status - integer - Indicates the backend transaction status. Valid values:

  • 73 - Not in a transactional block
  • 84 - In a transactional block
  • 69 - In a failed transactional block (queries will be rejected until block is ended)

Client events

• ready() - A connection to the server has been established and authentication was successful.

• error(< Error >err) - An error occurred at the connection level.

• close() - The connection has been closed.

Client methods

• (constructor)([< object >config]) - Creates and returns a new Client instance. Valid config options include:

  • user - string - Username for authentication. Default: (OS username of current logged in user)

  • password - string - Password for authentication. Default: ''

  • host - string - Hostname or IP address of the server. Default: 'localhost'

  • port - integer - Port number of the server. Default: 5432

  • db - string - A database to automatically select after authentication. Default: ''

  • keepalive - mixed - If true, this enables TCP keepalive probes using the OS default initial delay value. If a number, this both enables TCP keepalive probes and sets the initial delay value to the given value. Default: true

  • streamType - string - Set to 'normal' to use node's full-featured streams instead of simpler streams. The main difference is that the simpler streams do not implement .read() support. Default: 'simple'

• query(< string >query[, < array >values][, < object >options][, < function >callback]) - mixed - Enqueues the given query. If callback is not supplied, a ResultStream instance is returned. values can be an array of values that correspond to positional placeholders inside query. Valid options are:

  • arrays - boolean - When true, arrays are used to store row values instead of an object keyed on column names. (Note: using arrays performs better) Default: false

  • hwm - integer - This is the highWaterMark to use for RowStream instances emitted by a ResultStream instance. This only applies when streaming rows. Default: (node's default) 16

• connect([< function >callback]) - (void) - Explicitly attempts to connect to the server. Note that calling query() will implicitly attempt a connection if one is not already made. If not connected, callback is added as a one-time 'ready' event listener.

• end() - (void) - Closes the connection once all queries in the queue have been executed.

• destroy() - (void) - Closes the connection immediately, even if there are other queries still in the queue. Any/all queries still in the queue are properly notified.

ResultStream is an object stream that emits RowStream instances. In the case of multiple statements/queries passed to query() (separated by ;), there will be one RowStream instance for each statement/query.

RowStream is an object stream that emits rows.

TODO (in no particular order)

• Allow passing back of data type OIDs for columns sent by the server

• client.abort() that implicitly opens a new, temporary connection to kill the currently running query

• COPY data support (both in and out)