r16 - 2016-02-15 - 15:13:32 - WilliamChenYou are here: TWiki >  Deployment Web > DeploymentInstallingUpgradingAndMigrating > RationalQualityManagerV406MigrationOnlineOrOffline

new.pngGuidelines for running Rational Quality Manager online migration in a production environment

Authors: WilliamChen
Build basis: IBM Rational Quality Manager 4.0.6 and later

IBM Rational Quality Manager (RQM) V4.0.6 introduced a new online migration feature that you can use to migrate large amounts of quality management (QM) data to 4.0.6 and later versions while the old production server is still online. The online migration is built for large amounts of repository data that have extremely high volume manual test script states and manual execution scripts. In most cases, you do not need to use online migration for production upgrades; the traditional offline migration method is still the most common migration path.

If you use the online migration method to migrate data for large enterprise QM server upgrades, before you begin, read these guidelines.

Determining whether to run an online migration

IBM Rational developers tested online migration against large databases internally. You can use their test results to determine whether online migration is right for you. For more information, see the Rational Quality Manager online migration test matrix.

Backing up the QM database for the production environment

Before you run the online migration commands, back up your production QM database. If issues occur during the online migration, it is difficult to roll back to a clean state. If a rollback is required in a production environment, you might lose some of the data that changed since the last full backup.

If you encounter problems during an online migration, immediately contact IBM Rational Support. Important: Do not try to run any more commands until IBM Support instructs you to.

Repository tools commands

The Repository Tools application now supports these new commands and parameters:

  • -onlineMigrateEstimate: Finds the number of states in the database that need to be migrated.
  • [teamserver.properties=conf/qm/teamserver.properties]: The path to the teamserver.properties file of the server that is currently running.
  • [logFile=repotools-qm_onlineMigrate.log]: The path to the log file.
  • -onlineMigrate: Runs the online migration on a live server.
  • [numStatesPerRun=100]: The number of item states to process for each iteration.
  • [priority=<1-100> (default=50)]: The percentage of time that online migration should run.
  • [noPrompt]: Will not prompt before the migration starts.
  • -onlineMigrateRevert: Reverts the database changes that were made from an online migration.
  • -onlineMigrateStop: Prompts the online migration process to finish the current transaction and exit. If you need to stop online migration to make sure that database locks are not held unnecessarily, use this command.
  • -validateMigration: Validates the QM online migration result.
  • [validateLevel=<1-3> (default=1)]: The detailed level to validate. The default is 1. If the value is 2, the number of states for each manual script are compared. If the value is 3, the number of steps for the current state of the manual script are compared.

For detailed information about repository tools commands, run repotools-qm.bat or repotools-qm.sh.

Issues and workarounds

  • If the tables and statistics are out of date, the online migration might result in poor performance. Make sure that statistics are up to date by checking them against these online migration tables:
    • REPOSITORY.ITEM_STATES
    • REPOSITORY.ITEM_CURRENTS
    • REPOSITORY.ITEM_TYPES
    • LINKS.AUDITABLE_LINK

  • You might encounter this error: ORA-01555: snapshot too old: rollback segment number xx with name "systemValue" too small. The exception occurs on the following query, which calculates the percentage of complete values that involves a table scan against the ITEM_STATES table. Typically, that percentage is large.
    select count(*), {ITEM_TYPE_DBID}
    from {REPOSITORY.ITEM_STATES}
    where {ITEM_TYPE_DBID} in (%s)
    and {KEY_UUID} not like '-%%'
    group by {ITEM_TYPE_DBID}
    To resolve this issue, a database administrator must increase the size of the rollback segment (undo) size or extend the tablespace on the small segment. Then, you can restart the online migration. The migration will start at the point where you left off.

  • You might encounter this error: Failed to add tables to the database. The database has not been modified. This error can occur when you run an online migration without the noPrompt parameter:
    2014-07-27 07:19:47,815 CRJAZ2523I Setting the global server rename state to false and the validation state to false.
    2014-07-27 09:30:43,708 Failed to add tables to the database. The database has not been modified.
    To resolve this issue, add the noPrompt parameter to the online migration command. Then, the addTables command can begin to run as part of the online migration process.

Log files for troubleshooting

If you encounter issues with the online migration, try to provide the following information to the IBM support and development teams:

Full online migration command syntax
You can get this information from the console window when you run any online migration command.
onlineMigrateEstimate.log
By default, this log file resides in the online migration server logs directory. The onlineMigrateEstimate.log file contains the number of states in the QM database that must be migrated.
repotools-qm_onlineMigrate.log
This file contains online migration events and related activities. By default, this file is in the online migration server logs directory.
onlineMigrateStateProcessed.log
This log file is specific to the online migration process and can provide details about the process time and activities. The file also contains timestamps of each state migration. By default, this file is in the online migration server logs directory.

Enabling logging for online migration

You can enable online migration logging to determine what tables might need to be optimized. For example, the CONTENT_STORAGE table is heavily used during the online migration. To verify that other online migration tables statistics are up to date, turn on both log4j.logger.sqlTxLogger and log4j.appender.file.Threshold to debug mode:

  1. Stop the online migration by entering this command: repotools-qm -onlineMigrateStop
  2. Edit install_dir\conf\repotools_log4j.properties.
  3. Add these lines:
        # Turn on debugging of all SQL
        _log4j.logger.sqlTxLogger=DEBUG_
  4. Update this property: _log4j.appender.file.Threshold=DEBUG_
  5. Save and restart the online migration.
  6. After the repotools_onlineMigrate log updates with a time estimate again, which can take some time, let the online migration command run for 30 minutes to capture enough SQL tracing for a full anlaysis.
  7. Stop the migration, as you did earlier in this procedure.
  8. Collect the online migration log or logs (repotools-qm_onlineMigrate) and states processed log or logs (onlineMigrateStatesProcessed) and send them to IBM Support.
  9. Undo the edits that you made in steps 3 and 4.
  10. Restart the online migration.

Q & A

1. How accurate is the estimated completion time from the onlineMigrateEstimate command?

When you run the onlineMigrateEstimate command, the estimated completion time is the best estimate that is based on the available data. Fluctuations are unavoidable because of several unknown variables; for example, the database server load or the complexity of test cases over time. During performance testing, old statistics on the ITEM_STATES and ITEM_CURRENTS tables resulted in long run times. If you have not already done so, ensure that the statistics are up to date on those tables.

The /server/OnlineMigrateSettings.cfg file contains the priority of the process. You can change this file while the online migration is running. To improve efficiency, you can adjust it to a larger value such as '90' during off peak hours.

If you need to migrate large databases that contain a lot of data, the migration runs in the background while the server is online so that the amount of time that the server is offline is minimized and performance is not noticeably affected.

2. How much can I gain by increasing the priority value when running the onlineMigrate command?

The priority is equal to the percentage of time that the online migration runs. You can specify a percentage value between 1 and 100. The primary consideration is how much load the database can handle and how responsive the old server is.

For example, if the priority value is 10, the task for online migration runs 10% of the time and is idle the remaining 90%. If the priority value is 100, the migration process never pauses. You might notice improvement in the estimated completion time. At priority=50, the online migration runs half the time and waits half the time.

Increasing the priority to 90 might make the application somewhat slower, but it is unlikely to be noticeable. Offline migration is identical to online migration running at priority=100. The process is the same except there is no pause between transactions.

You can change /server/OnlineMigrateSettings.cfg to adjust the priority while the online migration is running. This adjustment is dynamic; it does not require you to stop and restart the migration. You can maximize the available system resources during offpeak hours by increasing the priority as close to 100 as possible. This means that online migration runs all the time, and users who need to access QM projects might be affected. Therefore, take a conservative approach to reducing priority during peak times while the online migration is running until the true impact is acceptable for users to continue with their work on the same QM server.

3. What new tables are used by the online migration process?

The following tables are used during online migration. A query or insert is done on the tables.

  • Existing tables:
    • REPOSITORY_CONTENT_STORAGE
    • REPOSITORY_ITEM_STATES
    • REPOSITORY_ITEM_CURRENTS
    • REPOSITORY_ITEM_TYPES
    • LINKS_AUDITABLE_LINK
  • New tables created for migrated data:
    • PLANNING_EXECUTION_ELEMENT2
    • PLNNNGMNLXCTNSCRPTSTPLKPLMNT2H
    • PLANNNG_MNL_XCTN_SCRPT_STP_LKP

When the online migration starts, query the REPOSITORY_ITEM_STATES to get the total counts of how many states you need to migrate. Then, migrate them by time order. Process the oldest one first. Then, cache 50,000 records at a time, process each one ManualScriptSate, read all of its steps, create ones and put the data into the above related tables.

Commit to database no more than (numStatesPerRun=100) states are processed. It is important for the database administrator to keep these table statistics up to date to optimize online migration process.

4. How can I enable logging for online migration?

See the information about onlineMigrateStateProcessed.log in the "Log files for troubleshooting" section of this article.

Related topics: Deployment web home,

External links:

Additional contributors: : JingQian, JamesBognar, PaulEllis, RosaNaranjo, DeniseMcKinnon, LauraHinson

Edit | Attach | Printable | Raw View | Backlinks: Web, All Webs | History: r16 < r15 < r14 < r13 < r12 | More topic actions
 
This site is powered by the TWiki collaboration platformCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Contributions are governed by our Terms of Use. Please read the following disclaimer.
Ideas, requests, problems regarding the Deployment wiki? Create a new task in the RTC Deployment wiki project