= TransactionManager Configuration
:index-group: Unrevised
:jbake-date: 2018-12-05
:jbake-type: page
:jbake-status: published


A TransactionManager can be declared via xml in the
`<tomee-home>/conf/tomee.xml` file or in a `WEB-INF/resources.xml` file
using a declaration like the following. All properties in the element
body are optional.

[source,xml]
----
<TransactionManager id="myTransactionManager" type="TransactionManager">
    adler32Checksum = true
    bufferSizeKb = 32
    checksumEnabled = true
    defaultTransactionTimeout = 10 minutes
    flushSleepTime = 50 Milliseconds
    logFileDir = txlog
    logFileExt = log
    logFileName = howl
    maxBlocksPerFile = -1
    maxBuffers = 0
    maxLogFiles = 2
    minBuffers = 4
    threadsWaitingForceThreshold = -1
    txRecovery = false
</TransactionManager>
----

Alternatively, a TransactionManager can be declared via properties in
the `<tomee-home>/conf/system.properties` file or via Java
VirtualMachine `-D` properties. The properties can also be used when
embedding TomEE via the `javax.ejb.embeddable.EJBContainer` API or
`InitialContext`

[source,properties]
----
myTransactionManager = new://TransactionManager?type=TransactionManager
myTransactionManager.adler32Checksum = true
myTransactionManager.bufferSizeKb = 32
myTransactionManager.checksumEnabled = true
myTransactionManager.defaultTransactionTimeout = 10 minutes
myTransactionManager.flushSleepTime = 50 Milliseconds
myTransactionManager.logFileDir = txlog
myTransactionManager.logFileExt = log
myTransactionManager.logFileName = howl
myTransactionManager.maxBlocksPerFile = -1
myTransactionManager.maxBuffers = 0
myTransactionManager.maxLogFiles = 2
myTransactionManager.minBuffers = 4
myTransactionManager.threadsWaitingForceThreshold = -1
myTransactionManager.txRecovery = false
----

Properties and xml can be mixed. Properties will override the xml
allowing for easy configuration change without the need for $\{} style
variable substitution. Properties are not case sensitive. If a property
is specified that is not supported by the declared TransactionManager a
warning will be logged. If a TransactionManager is needed by the
application and one is not declared, TomEE will create one dynamically
using default settings. Multiple TransactionManager declarations are
allowed. # Supported Properties

Property

Type

Default

Description

adler32Checksum

boolean

true

Requires TxRecovery

bufferSizeKb

int

32

Requires TxRecovery

checksumEnabled

boolean

true

Requires TxRecovery

defaultTransactionTimeout

time

10 minutes

flushSleepTime

time

50 Milliseconds

Requires TxRecovery

logFileDir

String

txlog

Requires TxRecovery

logFileExt

String

log

Requires TxRecovery

logFileName

String

howl

Requires TxRecovery

maxBlocksPerFile

int

-1

Requires TxRecovery

maxBuffers

int

0

Requires TxRecovery

maxLogFiles

int

2

Requires TxRecovery

minBuffers

int

4

Requires TxRecovery

threadsWaitingForceThreshold

int

-1

Requires TxRecovery

txRecovery

boolean

false

When set to true, Howl logging is enabled