SessionPool

class

Class used to manage connections to Spanner.

You don't need to use this class directly, connections will be handled for you.

Constructor

SessionPool

new SessionPool(database, options)

Parameter

database

Database

The DB instance.

options

Optional

SessionPoolOptions

Configuration options.
Extends
EventEmitter

Properties

available

number

Total number of available sessions.

borrowed

number

Total number of borrowed sessions.

isFull

boolean

Flag to determine if Pool is full.

reads

number

Total number of read sessions.

size

number

Total size of pool.

writes

number

Total number of write sessions.

Methods

formatTrace

static

formatTrace(trace) returns string

Formats stack trace objects into Node-like stack trace.

Parameter

trace

Array of object

The trace object.
Returns

string 

_fill

_fill() returns Promise

Fills the pool with the minimum number of sessions.

Returns

Promise 

_getLeaks

_getLeaks() returns Array of string

Returns stack traces for sessions that have not been released.

Returns

Array of string 

_isValidSession

_isValidSession(session) returns boolean

Checks to see whether or not session is expired.

Parameter

session

Session

The session to check.
Returns

boolean 

close

close(callback)

Closes and the pool.

Parameter

callback

function()

The callback function.
Fires
SessionPool#event:close

getReadSession

getReadSession(callback, err, session)

Retrieve a read session.

Parameter

callback

function()

The callback function.

err

Error

Error, if any.

Value may be null.

session

Session

The read session.

getWriteSession

getWriteSession(callback, err, session, transaction)

Retrieve a read/write session.

Parameter

callback

function()

The callback function.

err

Error

Error, if any.

Value may be null.

session

Session

The read/write session.

transaction

Transaction

The transaction object.

open

open() returns Promise

Opens the pool, filling it to the configured number of read and write sessions.

Fires
SessionPool#event:open
Returns

Promise 

release

release(session)

Releases session back into the pool. If the session is a write session it will also prepare a new transaction before releasing it.

Parameter

session

Session

The session to release.
Fires
SessionPool#event:available
SessionPool#event:error
Throws

Error 

For unknown sessions.