Generic Lucene Index Removal
- Applies to:
- Experience Manager as a Cloud Service
- Topics:
- Operations
CREATED FOR:
- Admin
Adobe intends to remove the “generic Lucene” index (/oak:index/lucene-*) from Adobe Experience Manager as a Cloud Service. This index has been deprecated since AEM 6.5. In this document the impact of this decision is described, along with detailed descriptions how to examine if an AEM instance is affected. It also contains ways to change queries so they continue to function without the generic Lucene index.
Background
In AEM, full text queries are those using the following functions:
jcr:contains()in JCR XPATHCONTAINSin JCR-SQL2
Such queries cannot return results without using an index. Unlike a query containing only path or property restrictions, a query containing a full text restriction for which no index can be found (and thus a traversal is performed) will always return zero results.
The generic Lucene index (/oak:index/lucene-*) has existed since AEM 6.0 / Oak 1.0 to provide a full text search across most of the repository hierarchy, although some paths, such as /jcr:system and /var have always been excluded from this. However this index has largely been superseded by indexes on more specific node types (for example, damAssetLucene-* for the dam:Asset node type), which support both full text and property searches.
In AEM 6.5 the generic Lucene index was marked as deprecated, indicating that it would be removed in future versions. Since then, a WARN has been logged when the index has been used as illustrated by the following log snippet:
org.apache.jackrabbit.oak.plugins.index.lucene.LucenePropertyIndex This index is deprecated: /oak:index/lucene-2; it is used for query Filter(query=select [jcr:path], [jcr:score], * from [nt:base] as a where contains(*, 'search term') and isdescendantnode(a, '/content/mysite') /* xpath: /jcr:root/content/mysite//*[jcr:contains(.,"search term")] */ fullText="search" "term", path=/content/mysite//*). Change the query or the index definitions.
In recent AEM versions, the generic Lucene index has been used to support a very small number of features. These are being reworked to use other indexes or otherwise modified to remove the dependency on this index.
For example, reference lookup queries, such as in the following example, should now use the index at /oak:index/pathreference, which indexes only String property values which match a regular expression that looks for JCR paths.
//*[jcr:contains(., '"/content/dam/mysite"')]
To support larger customer data volumes, Adobe no longer creates the generic Lucene index on new AEM as a Cloud Service environments. Also, Adobe removes the index from existing repositories. See the timeline at the end of this document for more details.
Adobe has already adjusted the index costings via the costPerEntry and costPerExecution properties to ensure that other indexes such as /oak:index/pathreference are used in preference wherever possible.
Customer applications which use queries which still depend on this index should be updated immediately to use other existing indexes, which can be customized if necessary. Alternatively new custom indexes can be added to the customer application. Full instructions for index management in AEM as a Cloud Service can be found in the indexing documentation.
Are You Affected?
The generic Lucene index is currently used as a fallback if no other full text index can service a query. When this deprecated index is used, a message similar to the following is logged at the WARN level:
org.apache.jackrabbit.oak.plugins.index.lucene.LucenePropertyIndex This index is deprecated: /oak:index/lucene-2; it is used for query Filter(query=select [jcr:path], [jcr:score], * from [nt:base] as a where contains(*, 'test') /* xpath: //*[jcr:contains(.,"test")] */ fullText="test", path=*). Change the query or the index definitions.
In some circumstances, Oak might attempt to use another full text index (such as /oak:index/pathreference) to support the full text query, but if the query string does not match the regular expression on the index definition, a message is logged at WARN level and the query will likely not return results.
org.apache.jackrabbit.oak.query.QueryImpl Potentially improper use of index /oak:index/pathReference with queryFilterRegex (["']|^)/ to search for value "test"
Once the generic Lucene index has been removed, a message as shown below is logged at WARN level if a full text query is not able to locate any suitable index definition:
org.apache.jackrabbit.oak.query.QueryImpl Fulltext query without index for filter Filter(query=select [jcr:path], [jcr:score], * from [nt:base] as a where contains(*, 'test') /* xpath: //*[jcr:contains(.,"test")] */ fullText="test", path=*); no results are returned
IMPORTANTPotential Dependencies on Generic Lucene Indexes
There are several areas where your applications and AEM installations may be dependent on generic Lucene indexes both on author and publish instances.
Publish Instance
Custom Application Queries
The most common source of queries using the generic Lucene index on a publish instance are custom application queries.
In the simplest cases these might be queries with no node type specified thus implying nt:base or nt:base specified explicitly, such as:
/jcr:root/content/mysite//*[jcr:contains(., 'search term')]
/jcr:root/content/mysite//element(*, nt:base)[jcr:contains(., 'search term')]
For example, the queries can be modified to return results matching pages or any of the aggregates beneath the cq:Page node. The query could thus become:
/jcr:root/content/mysite//element(*, cq:Page)[jcr:contains(., 'search term')]
In other cases, a query might specify a node type but contain a full text restriction that cannot be handled by another full text index, such as:
/jcr:root/content/dam//element(*, dam:Asset)[jcr:contains(jcr:content/metadata/@cq:tags, 'NewsTopics:cateogries/domestic'))]
In this case the query has the dam:Asset node type, but contains a full text restriction on the relative jcr:content/metadata/@cq:tags property.
This property is not marked as analyzed in the damAssetLucene index, which is the full text index most commonly used for queries against the dam:Asset node type. Therefore this index cannot be used for this query.
As such, the query falls back on the generic full text index where all the included properties are marked as analysed by the wildcard match at /oak:index/lucene-2/indexRules/nt:base/properties/prop.
IMPORTANTjcr:content/metadata/@cq:tags property as analyzed in a custom version of the damAssetLucene index results in this query being handled by this index, and no WARN is logged.Author Instance
In addition to queries in customer application servlets, OSGi components, and rendering scripts there can be several author-specific usages of the generic Lucene index.
Reference Search
Historically the generic Lucene index has been used to support reference search or searching for content which contains references to another content path. Such queries should already have updated to use the new /oak:index/pathreference index.
Path Field Picker Search
AEM includes a custom dialog component with the Sling resource type granite/ui/components/coral/foundation/form/pathfield, which provides a browser/picker for selecting another AEM path. The default path field picker, which is used when no custom pickerSrc property is defined in the content structure, renders a search bar in the pop-up dialog box.
The node types against which to search can be specified using the nodeTypes property.
At present, if no nodeTypes property is present, the underlying search query will use the nt:base node type, and thus is likely to use the generic Lucene index, typically logging WARN messages similar to the following.
20.01.2022 18:56:06.412 *WARN* [127.0.0.1 [1642704966377] POST /mnt/overlay/granite/ui/content/coral/foundation/form/pathfield/picker.result.single.html HTTP/1.1] org.apache.jackrabbit.oak.plugins.index.lucene.LucenePropertyIndex This index is deprecated: /oak:index/lucene-2; it is used for query Filter(query=select [jcr:path], [jcr:score], * from [nt:base] as a where contains(*, 'test') and isdescendantnode(a, '/content') /* xpath: /jcr:root/content//element(*, nt:base)[(jcr:contains(., 'test'))] order by @jcr:score descending */ fullText="test", path=/content//*). Change the query or the index definitions.
Prior to removal of the generic Lucene index, the pathfield component will be updated so that the search box is hidden for components using the default picker, which do not provide a nodeTypes property.
IMPORTANTnodeTypes property should be provided listing the node types against which they would like to query. These can be specified as a comma-separated list of node types in a String property. If no search is required, no action is required from the customer.
NOTEdam/cfm/models/editor/components/contentreference.- At present these perform queries without node types specified, resulting in a WARN being logged due to usage of the generic Lucene index.
- Instances of these components will soon automatically default to using
cq:Pageanddam:Assetnode types without further customer action. - The
nodeTypesproperty can be added to override these default node types.
Timeline for Generic Lucene Removal
Adobe will take a two-phase approach to remove the generic Lucene index.
- Phase 1 (planned start 31 January 2022): No longer create
/oak:index/lucene-*on new AEM as a Cloud Service environments. - Phase 2 (planned start 31 March 2022): Remove
/oak:index/lucene-*index from existing AEM as a Cloud Service environments.
Adobe will monitor the log messages noted above and will attempt to contact customers who remain dependant on the generic Lucene index.
As a short term mitigation, Adobe adds custom index definitions directly to customer systems to prevent functional or performance issues as a result of the removal of the generic Lucene index as necessary.
In such cases, the customer is provided with the updated index definition and is advised that they include it in future releases of their application via Cloud Manager.