Rocket UniVerse Transaction Logging and Recovery Version 11.2 November 2013 UNV-112-TRAN-1 Notices Edition Publication date: November 2013 Book number: UNV-112-TRAN-1 Product version: Rocket UniVerse V11.2 Copyright © Rocket Software, Inc. or its affiliates 1985-2014. All Rights Reserved. Trademarks Rocket is a registered trademark of Rocket Software, Inc. For a list of Rocket registered trademarks go to: www.rocketsoftware.com/about/legal. All other products or services mentioned in this document may be covered by the trademarks, service marks, or product names of their respective owners. Examples This information might contain examples of data and reports. The examples include the names of individuals, companies, brands, and products. All of these names are fictitious and any similarity to the names and addresses used by an actual business enterprise is entirely coincidental. License agreement This software and the associated documentation are proprietary and confidential to Rocket Software, Inc., are furnished under license, and may be used and copied only in accordance with the terms of such license. Note: This product may contain encryption technology. Many countries prohibit or restrict the use, import, or export of encryption technologies, and current use, import, and export regulations should be followed when exporting this product. Contact information Website: www.rocketsoftware.com Rocket Software, Inc. Headquarters 77 4th Avenue, Suite 100 Waltham, MA 02451-1468 USA Tel: +1 781 577 4321 Fax: +1 617 630 7100 2 Contacting Global Technical Support If you have current support and maintenance agreements with Rocket Software, you can access the Rocket Customer Portal to report and track a problem, to submit an enhancement request or question, or to find answers in the U2 Knowledgebase. The Rocket Customer Portal is the primary method of obtaining support. To log in to the Rocket Customer Portal, go to: www.rocketsoftware.com/support If you do not already have a Rocket Customer Portal account, you can request one by clicking Need an account? on the Rocket Customer Portal login page. Alternatively, you can contact Global Technical Support by email or by telephone: Email: [email protected] Telephone: North America +1 800 729 3553 United Kingdom/France +44 (0) 800 773 771 or +44 (0) 20 8867 3691 Europe/Africa +44 (0) 20 8867 3692 Australia +1 800 707 703 or +61 (0) 29412 5450 New Zealand +0800 505 515 3 Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Table of Contents Table of Contents Chapter 1 Chapter 1: Introduction Transactions . 1-3 Data transactions . 1-3 Warmstart transactions . 1-3 Transaction Logging tools. 1-4 When to use Transaction Logging . 1-5 Media failure . 1-5 System failure . 1-5 Scope of Transaction Logging . 1-6 Transaction Logging and performance . 1-7 Chapter 2 Chapter 2: Transactions What is a transaction? . 2-3 UniVerse BASIC transaction statements . 2-4 File and record locking. 2-5 Reads and locks . 2-6 Releasing locks . 2-6 Restrictions while a transaction Is active. 2-7 Sequential file I/O. 2-8 Transaction commit failures . 2-9 Chapter 3 Chapter 3: Transaction Logging How Transaction Logging works . 3-4 Data transactions and warmstart transactions . 3-4 Logging file updates . 3-4 Transaction Logging modes . 3-5 Flushing log buffer contents to disk. 3-7 Logging directly to log files on a raw device. 3-8 The log daemon . 3-9 Restoring file integrity . 3-9 C:\Users\awaite\Documents\U2Doc\UniVerse\11.2\Source\translog\TranslogTOC.doc (bookTOC.template) March 25, 2014 12:42 pm Protecting the structural integrity of files . 3-11 Warmstart Transaction Logging and recovery . 3-11 System requirements . 3-12 Warmstart transactions . 3-13 How warmstart recovery works . 3-13 Warmstart restrictions . 3-15 Structural integrity of underlying system files . 3-16 Transaction Logging states . 3-17 Logging uninitialized or inactive. 3-18 Initializing and warmstart states . 3-18 Logging enabled, disabled, or suspended . 3-18 Logging full . 3-20 Logging crashed . 3-21 How file updates are treated . 3-22 Log file states . 3-23 Available . 3-23 Current . 3-23 NeedsSync . 3-23 Full . 3-24 Released . 3-24 Activity cycle of disk log files . 3-25 Example . 3-25 Activity cycle of the tape log file . 3-28 The UV_LOGS file . 3-29 The UV.TRANS file . 3-32 Managing the UV.TRANS file . 3-33 Chapter 4 Chapter 4: The Transaction Logging window The Transaction Logging window . 4-4 Chapter 5 Chapter 5: Setting up Transaction Logging Setting up Transaction Logging to disk or raw device . 5-4 Configuring the Transaction Logging system . 5-4 Adding and dropping log files . 5-7 Configuring the frequency of log buffer writes to disk . 5-9 Setting up Transaction Logging to tape. 5-11 Activating the Transaction Logging system . 5-14 Changing TXMODE manually . 5-15 Activating UniVerse files for recovery. 5-16 Activating files . 5-17 Table of Contents 5 Deactivating files. 5-18 Making distributed files recoverable . 5-19 Making secondary indexes recoverable . 5-19 Commands affecting recoverable files . 5-21 Enabling the Transaction Logging system . 5-22 Suspending Transaction Logging . 5-22 Shutting down Transaction Logging . 5-22 Chapter 6 Chapter 6: Managing Transaction Logging Configuring the Transaction Logging buffer . 6-3 Calculating the volume of logged data . 6-4 Determining the size and number of log files. 6-5 Backing up your UniVerse files . 6-6 Backing up log files from disk to tape . 6-7 Backing up and releasing log files on disk or raw device . 6-7 Releasing log files on disk. 6-9 Purging log files on disk . 6-9 Releasing full tape devices . 6-11 Switching the location of log files. 6-12 Recovering application integrity . 6-13 Rolling forward file updates from fog files. 6-13 Recovering accidentally deleted files . 6-26 Managing stale transactions . 6-27 Recovering from a UniVerse file backup failure . 6-28 Managing Transaction Logging files . 6-31 The UV.TRANS file . 6-31 The UV_LOGS file . 6-31 Log directory . 6-32 Information files . 6-33 Restarting Transaction Logging . 6-35 Restarting after disabling Transaction Logging . 6-35 Restarting Transaction Logging from the beginning. 6-35 Chapter 7 Chapter 7: Modifying applications Determining which files to make recoverable . 7-3 Program changes to consider . 7-4 Input/verification . 7-4 Locking/reading . 7-4 Updating . 7-4 6 UniVerse Transaction Logging and Recovery Chapter 8 Chapter 8: UniVerse commands Activating recoverable files . 8-3 Enabling and disabling Transaction Logging. 8-4 Creating log files . 8-5 Managing log files . 8-6 Prohibited UniVerse commands. 8-7 Table of Contents 7 1Administering UniData on Windows NT or Windows 2000 0 Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Chapter Chapter 1: Introduction 1 Transactions . 1-3 Data transactions. 1-3 Warmstart transactions. 1-3 Transaction Logging tools. 1-4 When to use Transaction Logging . 1-5 Media failure . 1-5 System failure . 1-5 Scope of Transaction Logging. 1-6 Transaction Logging and performance . 1-7 C:\Users\awaite\Documents\U2Doc\UniVerse\11.2\Source\translog\Ch1TOC.fm March 25, 2014 12:42 pm Administering UniData on Windows NT or Windows 2000 C:\Users\awaite\Documents\U2Doc\ UniVerse\11.2\Source\translog\Ch1 This chapter introduces transaction logging and recovery. The transaction logging system is a subsystem of UniVerse. It provides security against permanent data loss caused by events such as media or system failure. By restoring a backup copy of your files, then running roll-forward recovery (that is, applying logged updates from log files on disk or tape to your restored files), you can reinstate your files to a usable condition. Transaction logging preserves the application integrity of your UniVerse files by ensuring that any group of logically related updates to specified files is applied either in its entirety or not at all. Warmstart recovery restores the structural integrity of files after sudden system failure. You use UniAdmin to administer the UniVerse transaction logging system on both UNIX and Windows servers. UniAdmin is fully documented in Using UniAdmin. 1-2 C:\Users\awaite\Documents\U2Doc\UniVerse\11.2\Source\translog\Ch1 3/25/14 Transactions To enable you to get your files back to a state of application-defined integrity, the transaction logging system uses transactions. UniVerse distinguishes two kinds of transaction: Data transactions Warmstart transactions Data transactions A data transaction is a group of logically related file updates. The updates are intended to be processed as a single entity against the files. For example, a banking transaction that transfers funds from one account to another involves two logically related updates: a withdrawal and a deposit. To maintain a state of application integrity, both the deposit and the withdrawal must occur, or neither. A set of related files moves from one state of transactional integrity to another by the complete processing of one or more transactions. Events that disrupt normal system operation can cause incomplete processing, resulting in loss of transactional integrity. You can always restore the transactional integrity of your files by using roll-forward recovery, because only completed transactions from the log file are applied to copies of your data files restored from backup. When events terminate individual user processes in a controlled manner, transaction logging detects and reacts to the interruption of a transaction commit. Messages are sent and file operations are suspended pending restoration of transactional integrity. Warmstart transactions Warmstart transactions log information about file-restructuring operations on specified files. When UniVerse is restarted after a system failure, these file- restructuring updates are applied to corrupted or damaged files, then all committed data transactions are applied, guaranteeing the integrity of the database.