Documentation

Database Pruning for Faster Upgrades

The more data you have the longer your data upgrade takes. Unneeded site data is a common occurrence. Pruning the database of unneeded data improves upgrade process performance.

For example, sites may store many unused versions of Web Content articles or Documents and Media files. If you’re done revising them and don’t need the intermediate revisions, you can safely remove them. This saves space and upgrade time.

Here are the database pruning topics:

  • Removing Duplicate Web Content Structure Field Names

  • Finding and Remove Unused Objects

  • Testing with a Copy of the Pruned Database

Removing Duplicate Web Content Structure Field Names

If you’ve used Web Content Management extensively, you might have structures without unique field names. Find and remove duplicate field names before upgrading. If you upgraded to Liferay Portal 6.2 previously and skipped doing this, you’ll encounter this error:

19:29:35,298 ERROR [main][VerifyProcessTrackerOSGiCommands:221] com.liferay.portal.verify.VerifyException: com.liferay.dynamic.data.mapping.validator.DDMFormValidationException$MustNotDuplicateFieldName: The field name page cannot be defined more than once
com.liferay.portal.verify.VerifyException: com.liferay.dynamic.data.mapping.validator.DDMFormValidationException$MustNotDuplicateFieldName: The field name page cannot be defined more than once

If this error occurs, roll back to your previous backup of Liferay Portal 6.2 and find and remove the duplicate field names.

Removing Unused Objects

Your database may have data leftover from obsolete features or unused objects.

  1. Use the Data Cleanup screen to remove data from obsolete modules.

  2. Identify other unused objects in the UI or by using using SELECT queries with your database, and remove the objects either via the UI, the API through the script console, or a portlet you create.

Warning

You should only use Liferay’s UI or API to manipulate data because they account for relationships between objects in Liferay DXP. Never use SQL directly on your database to remove records. Your SQL may miss object relationships, orphaning objects and causing performance problems.

Next are some common places to check for unused objects.

Objects From the Large/Populated Tables

Table rows are mapped to objects in Liferay DXP. Large tables with many records might contain many unused objects. The greater the table size and the records per table, the longer upgrading takes.

Finding and removing unused objects associated with such tables reduces upgrade times. Importing data from your Liferay backup can provide valuable table information. Database engines show this information in different ways. For example, your database import log might look like this:

Processing object type SCHEMA\_EXPORT/TABLE/TABLE\_DATA

imported "LIFERAY"."JOURNALARTICLE" 13.33 GB 126687 rows

imported "LIFERAY"."RESOURCEPERMISSION" 160.9 MB 1907698 rows

imported "LIFERAY"."PORTLETPREFERENCES" 78.13 MB 432285 rows

imported "LIFERAY"."LAYOUT" 52.05 MB 124507 rows

imported "LIFERAY"."ASSETENTRY" 29.11 MB 198809 rows

imported "LIFERAY"."MBMESSAGE" 24.80 MB 126185 rows

imported "LIFERAY"."PORTALPREFERENCES" 4.091 MB 62202 rows

imported "LIFERAY"."USER\_" 17.32 MB 62214 rows

...

Several items stand out in the example database import:

  • The JOURNALARTICLE table makes up 98% of the database size.

  • There are many RESOURCEPERMISSION records.

  • There are many PORTLETPREFERENCES records.

Search for unused objects associated with the tables that stand out and use Liferay’s API (e.g., using the script console) to delete unneeded objects.

Common Object Types Worth Checking

Some specific object types should be checked for unused objects. Here are some reasons for checking them:

  • Removing them frees related unused objects for removal

  • They might be version objects that aren’t worth keeping

Check these object types:

  • Sites: Remove sites you don’t need. When you remove a site, this removes its related objects, including:

    • Layouts

    • Portlet preferences

    • File entries (document library objects)

    • Asset Entries

    • Tags

    • Vocabularies and categories

    • Expando fields and their values

    • ResourcePermission objects

    • All other objects unique to the site

  • Instances: Unused instances are rare, but since they are the highest object in the hierarchy, removing their objects can optimize upgrades considerably. Removing instances removes these objects associated with them:

    • Sites (and all their related content)

    • Users

    • Roles

    • Organizations

    • Global ResourcePermission objects

  • Intermediate web content versions: Liferay DXP generates a new web content version after any modification (including translations). Consider removing versions you don’t need. This may free up significant space, especially if the removed versions have objects such as image files specific to those versions. For more details, see Example: Removing Intermediate Journal Article Versions.

  • Document versions: As with Journal Articles, if you don’t need intermediate document versions, delete them. This saves space both in the database and on the file system.

  • Layouts: Layouts are site pages, and they affect upgrade performance because they relate to other entities such as portlet preferences, permissions, assets, ratings, and more. Remove unneeded layouts.

  • Roles: Remove any Roles you don’t need. Deleting them also deletes related ResourceBlockPermission and ResourcePermission objects.

  • Users: Remove Users that are inactive and no longer needed.

  • Vocabularies: Remove any unused vocabularies. Note that removing a vocabulary also removes its categories.

  • Orphaned data: Check for unused objects that are not connected to anything. Here are some examples:

    • DLFileEntries with no file system data.

    • ResourcePermission objects associated to a Role, Layout, User, portlet instance, etc. that no longer exists.

    • PortletPreference objects associated with a portlet or layout that no longer exists. This is common in environments with many embedded portlets. These portlet instances have a different lifecycle and aren’t deleted when the portlet is removed from a template.

To see an example of removing intermediate object versions, read Example: Removing Intermediate Journal Article Versions.

Next, test your instance with its pruned database.

Testing with a Copy of the Pruned Database

Find and resolve any issues related to the objects you removed. This is an important step, in case objects were mistakenly removed, or if this affects other content. You can always restart pruning a new copy of your production database if you can’t resolve an issue.