db-16 : jta transactions in the rdbms, what's going on down there? deb walz principal software...

DB-16: JTA Transactions in the RDBMS, What's Going on Down There?

Deb WalzPrincipal Software Engineer

2 © 2005 Progress Software Corporation DB-16 JTA Transactions in the RDBMS, What's going on Down There?

JTA Transactions in the RDBMS

JTA Overview Changes to database engine Planning for JTA support Monitoring JTA Transactions


D I S C L A I M E R

Under Development

This talk includes information about potential future products and/or product enhancements.

What I am going to say reflects our current thinking, but the information contained herein is preliminary and subject to change. Any future products we ultimately deliver may be materially different from what is described here.

D I S C L A I M E R


What is JTA?

Java™ Transaction API Part of Sun’s Java 2 Platform, Enterprise

Edition (J2EE) Reference Architecture Supports SQL Two-Phase Commit (2PC)

through JDBC


J2EE Architecture

Application Client

Container

J2SE

Application Client

JM

S

JA

AS

JA

XP

JD

BC

Applet

Container

J2SE

AppletWeb Container

J2SE

JM

S

JA

AS

JA

XP

JT

A

Co

nn

ecto

r

JD

BC

Java Mail

JAF

JSP Servlet

HTTP SSL

HTTP SSL EJB Container

J2SE

EJB

JM

S

JA

AS

JA

XP

JT

A

Co

nn

ecto

r

JD

BC

Java Mail

JAF

Database


JTA Architecture

JTA UserTransaction

ApplicationServer

Application ResourceManager

TransactionManager

EJB

JTA XAResource

JTA TransactionManager

JDBC, JMS


Prepare Phase

Two-Phase Commit Protocol

Transaction

ManagerOracle

OpenEdge

OpenEdgePrepare to Commit

Ready to Commit

Resolution Phase

Transaction

ManagerOracle

OpenEdge

OpenEdgeCommit

Complete


JTA XAResource Methods

start (xid, …) end (xid, …) prepare (xid) commit (xid, …) rollback (xid) recover(…)


JDBC Code Snippets - 1

xaRes.start(xid, TMNOFLAGS);

. . .

xaRes.end(xid, TMSUCCESS);

xaRes.prepare(xid);

xaRes.commit(xid, false);



xaRes.start(xid1, TMNOFLAGS);

...

xaRes.end(xid1, TMSUSPEND);

...

xaRes.start(xid1, TMRESUME);

...

xaRes.end(xid1, TMSUCCESS);



xaRes.start(xid1);

...

xaRes.end(xid1);

... xaRes.start(xid1,TMJOIN);

...

xaRes.end(xid1);

Connection #1

Connection #2



...

xaRes.start(xid2);

...

xaRes.prepare(xid1);

...

xaRes.end(xid2);


Where Do I Learn More about JTA?

http://java.sun.com/j2ee/index.jsp http://java.sun.com/products/jta/ http://www.datadirect.com/developer/jdbc/topics/jta/index.ssp


Database Changes

New type of transaction Data structure changes Crash Recovery changes Lock Manager changes


Controlled by external transaction manager

May be associated with more than one database connection

Once prepared, they withstand shutdown Peaceably co-exist with traditional

transactions

JTA Transactions


TransactionList

UserList

Data Structures – Traditional Transactions

TransactionTableEntry

Transaction Id

State

User Id

Time Started

Flags


Data Structures – JTA Transactions

Transaction Id

State

User Id

Time Started

Pointer to JTA

Flags

JTA XID

State

Transaction Id

User Id

Locks

JTA Entry

JTA (XID)List

Active

Idle

Trad’l

TransactionList

UserList

TransactionTableEntry


Crash Recovery Changes

New Lock Application Phase Presence of Lock Table New BI Notes Effect on database utilities


Crash Recovery - Review

Redo Phase Undo Phase

– Physical Undo

– Logical Undo


Crash Recovery – New Lock Application Phase

No Outstanding Prepared JTA Transactions

Thu Mar 24 17:15:52 2005Multi-user session begin. (333)Begin Physical Redo Phase at 0 . (5326)Physical Redo Phase completed … (7161)Begin JTA Lock ApplicationEnd JTA Lock Application …


Thu Mar 24 18:21:22 2005Multi-user session begin. (333)Begin Physical Redo Phase … (5326)Physical Redo Phase Completed … (7161)Begin JTA Lock ApplicationEnd JTA Lock ApplicationBegin Physical Undo 2 Transactions … (7163)Physical Undo 1 Live JTA Transactions detectedPhysical Undo Phase Completed … (5331)Begin Logical Undo Phase, 1 incomplete transactions

are being backed out. (7162)Logical Undo Phase begin … (11231)Logical Undo: 1 Live JTA Transaction detectedLogical Undo Phase Completed … (12095)Logical Undo: 1 Live JTA Transactions active

New Lock Acquisition Phase – after database crash


Crash Recovery – New BI Notes

RL_TBGN

RL_CXINS

RL_RMCR

RL_TEND

Traditional Transaction

RL_TBGN

RL_CXINS

RL_RMCR

RL_RCOMM

RL_TEND

4GL 2PC Transaction

RL_GTBGN

RL_XID

RL_TBLLK

RL_CXINS

RL_RMCR

RL_GEND

RL_GPREP

RL_GTEND

JTA Transaction


Crash Recovery – Effect on Database Utilities

Redo Phase: JTA Transaction: <xid> in state: Prepared (12572)

Redo Phase: JTA Transactions must access crash recovery through a multi-user process (12573)

The database contains limbo transactions. (2043)See list on the log file .lg. Use PROUTIL <db> -C

2phase recover. (2042)** The server exited with error code 20. (800)


Lock Manager Changes

Locks are owned by transaction Locks are restored during crash recovery Locks may be present on start up

– If JTA Transactions in prepared state


Lock Manager Data Structures

JTA XID

State

Transaction Id

User Id

Locks

JTA EntryJTA (XID)List

Lock Entries …


Planning for JTA Support

Enabling JTA Support Space allocation Startup Parameters


Enabling JTA Support

proutil <dbname> –C enablejta – Disables after-imaging (if enabled)

proutil <dbname> -C disablejta


Space Allocation

More notes implies more BI and AI space needed


Startup Parameters

-maxxids -L -bithreshold Standard performance tuning

– -bibufs

– -B


Usr Name Chn # Recid Tbl Lock Flags 5 deb REC 6 3712 5 SHR L 6 carol REC 7 3713 5 SHR L 7 rich REC 8 3714 5 SHR L 8 george REC 9 3715 5 SHR L

Lock Table Display

Usr Name Chn # Recid Tbl Lock Flags Trans JTA 5 deb REC 6 3712 5 SHR 123 Yes - - REC 7 3713 5 SHR 142 Yes 7 rich REC 8 3714 5 SHR No 8 george REC 9 3715 5 SHR L 214 No

With JTA Support:

Pre-JTA:

Usr Name Chn # Recid Tbl Lock Flags Trans JTA 5 deb REC 6 3712 5 SHR 123 Yes - - REC 7 3713 5 SHR 142 Yes 7 rich REC 8 3714 5 SHR No 8 george REC 9 3715 5 SHR L 214 No

With JTA Support:Usr Name Chn # Recid Tbl Lock Flags Trans JTA 5 deb REC 6 3712 5 SHR 123 Yes - - REC 7 3713 5 SHR 142 Yes 7 rich REC 8 3714 5 SHR No 8 george REC 9 3715 5 SHR L 214 No

With JTA Support:


Shared Resources Display

Current size of locking table (-L): 8192 Locking table entries in use: 691 Locking table high water mark: 692 Max clients per server (-Ma): 5 Max JTA transactions (-maxxids): 200 Delay of before-image flush (-Mf): 3


Active Transactions Display

Usr Name Login Time Tx start Tx Id Tx State 5 dwalz <T1> <T2> 178 Active JTA - - <T3> <T4> 183 Idle JTA

Active JTA Idle JTA Prepared JTA Rollback Only JTA


Resolve JTA Transactions

1. Commit a JTA Transaction

2. Rollback a JTA Transaction

3. Quit


In Summary

JTA Overview Database Changes

– New transaction type

– Crash Recovery Changes

– Lock Manager Changes Planning for JTA Monitoring Enhancements



Questions?


Thank you for your time!

db-16 : jta transactions in the rdbms, what's going on down there? deb walz principal software...

Documents

jta lock application

database engineplanning

database connection

physical redo phase

database utilities

rdbmsjta overviewchanges

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