Manage active and prepared transactions using scripting


 

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In normal circumstances, transactions should run and complete (commit or roll back) automatically, without the need for intervention. However, in some circumstances, we might have to resolve a transaction manually. For example, we might want to roll back a transaction that is stuck polling a resource manager that you know will not become available again in the desired time frame.

If we choose to complete a transaction on an appserver, it is recorded as having completed in the transaction service logs for that server, so it is not eligible for recovery during server start up. If we complete a transaction, you are responsible for cleaning up any in-doubt transactions on the resource managers affected.

The TransactionService Managed Bean (MBean), see API documentation - Application programming interfaces (package: Public MBean Interfaces, class: TransactionService), is used to list transactions in various states by invoking one of the following methods:

listOfTransactions: Lists all non-completed transactions. Under no circumstances should you attempt to alter the state of active transactions (using commit or rollback for example)
listManualTransactions: Lists transactions awaiting admin completion. We can choose to commit or rollback transactions in this state
listRetryTransactions: Lists transactions with some resources being retried. We can choose to finish (stop retrying) transactions in this state
listHeuristicTransactions: Lists transactions that have completed heuristically. We can choose to clear the transaction from the list
listImportedPreparedTransactions: Lists transactions that have been imported and prepared but not yet committed. We can choose to commit or rollback transactions in this state

Each entry in the returned list contains the following attributes:

The TransactionService MBean (see API documentation - Application programming interfaces (package: Public MBean Interfaces, class: TransactionService)) can also be used to gather more information about the properties of the transaction service, by obtaining the following attributes:

transactionLogDirectory The directory into which the log file(s) used for transaction service are placed
totalTranLifetimeTimeout The total lifetime of the transaction (in seconds) before the container rolls it back. This value applies to Container Managed Transaction (CMT) beans only
asyncResponseTimeout The total lifetime of the transaction (in seconds) before the container rolls it back
enableFileLocking Enables the use of file locks when opening the transaction service recovery log
enableProtocolSecurity Causes transaction service protocol messages to be sent securely
maximumTransactionTimeout The maximum transaction timeout allowed for imported transactions. This value applies to Container Managed Transaction (CMT) beans, Bean Managed Transaction (BMT) beans, and imported transactions
clientInactivityTimeout The number of seconds a transaction can remain inactive before it is rolled back
heuristicRetryLimit The maximum number of times to retry transaction completion
heuristicRetryWait The number of seconds to wait between retrying transaction completion
httpProxyPrefix The HTTP prefix for WS-Transaction port SOAP addresses
httpsProxyPrefix The HTTPS prefix for WS-Transaction port SOAP addresses
propogatedOrBMTTranLifetimeTimeout The number of seconds a transaction can remain inactive before it is rolled back
LPSHeuristicCompletion The transaction completion action to be taken when the outcome is unknown

The Transaction MBean (see API documentation - Application programming interfaces (package: Public MBean Interfaces, class: Transaction)) can be used to commit, rollback, finish or remove from the list of heuristically completed transactions depending on the transaction's state, by invoking one of the following methods:

  • commit: Heuristically commits the transaction

  • rollback: Heuristically rolls back the transaction

  • finish: Stops retrying resources for the transaction

  • removeHeuristic: Clears the transaction from the list

    • The Transaction MBean can also be used to gather more information about a transaction, by invoking the following methods:

    The following script is an example of how to use the TransactionService MBean and Transaction MBean. The script should be run only against an appserver, and not against the deployment manager or node agent.

     

    Example

    Working with manual transactions: example jacl script. 

    # get the TransactionService MBean 
set servicembean [$AdminControl queryNames type=TransactionService,*]

# get the Transaction MBean 
set mbean [$AdminControl queryNames type=Transaction,*]
set input 0 
while {$input >= 0} {
    # invoke the listManualTransactions method
    set tranManualList [$AdminControl invoke $servicembean listManualTransactions]

    if {[llength $tranManualList] > 0} {
        puts "----Manual Transaction details---------------"
        set index 0
        foreach tran $tranManualList {
            puts "   Index= $index tran= $tran"
            incr index
        }
        puts "----End of Manual Transactions ---------------"
        puts "Select index of transaction to commit/rollback:"
        set input [gets stdin]
        if {$input < 0} {
            puts "No index selected, exiting."
        } else {
            set tran [lindex $tranManualList $input]
            set commaPos [expr [string first "," $tran ]-1]
            set localTID [string range $tran 0 $commaPos]
            puts "Enter c to commit or r to rollback Transaction $localTID"
            set input [gets stdin]
            if {$input=="c"} {
                puts "Committing transaction=$localTID"
                $AdminControl invoke $mbean commit $localTID
            }
            if {$input=="r"} {
                puts "Rolling back transaction=$localTID"
                $AdminControl invoke $mbean rollback $localTID
            }
        }
    } else {
        puts "No Manual transactions found, exiting"
        set input -1
    }
    puts " "

}

    Working with manual transactions: example Jython script. 

     
import sys def wsadminToList(inStr):
    outList=[]
    if (len(inStr)>0 and inStr[0]=='[' and inStr[-1]==']'):
        tmpList = inStr[1:-1].split(" ")
    else:
        tmpList = inStr.split("\n")  #split for Windows or Linux
    for item in tmpList:
        item = item.rstrip();    #remove any Windows "\r"
        if (len(item)>0):
            outList.append(item)
    return outList
#endDef
 servicembean = AdminControl.queryNames("type=TransactionService,*" ) 
 mbean = AdminControl.queryNames("type=Transaction,*" ) 
 input = 0
 while (input >= 0):
    tranList = wsadminToList(AdminControl.invoke(servicembean, "listManualTransactions" ))

    tranLength = len(tranList) 
    if (tranLength > 0):
        print "----Manual Transaction details---------------"
        index = 0
        for tran in tranList:
            print "   Index=" , index , " tran=" , tran
            index = index+1
        #endFor 
        print "----End of Manual Transactions ---------------"
        print "Select index of transaction to commit/rollback:"
        input = sys.stdin.readline().strip()
        if (input == ""):
            print "No index selected, exiting."
            input = -1
        else:
            tran = tranList[int(input)]
            commaPos = (tran.find(",") -1)
            localTID = tran[0:commaPos+1]
            print "Enter c to commit or r to rollback transaction ", localTID
            input = sys.stdin.readline().strip()
            if (input == "c"):
                print "Committing transaction=", localTID
                AdminControl.invoke(mbean, "commit", localTID )
            #endIf 
            elif (input == "r"):
                print "Rolling back transaction=", localTID
                AdminControl.invoke(mbean, "rollback", localTID )
            #endIf 
            else:
                input = -1
            #endelse
        #endElse 
    else:
        print "No transactions found, exiting"
        input = -1
    #endElse 
    print " "

#endWhile

     

    Related tasks


    Manage active and prepared transactions
    Use the transaction service