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https://issues.apache.org/jira/browse/SLING-11229?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17513385#comment-17513385
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Thomas Mueller edited comment on SLING-11229 at 3/28/22, 1:33 PM:
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I agree about the limit. The offset, in my experience, is almost never useful:
it isn't a good solution for pagination. See also
https://jackrabbit.apache.org/oak/docs/query/query-engine.html#Keyset_Pagination
"Note that “offset” with large values (more than a few hundred) should be
avoided, as it can lead to performance and memory issues."
I recommend to simplify this a bit, to:
{noformat}
public static QueryResult query(Session session, String query,
String language, long limit) throws RepositoryException {
{noformat}
This simplification also ensures that the parameters are not passed in the
wrong order by mistake (limit + offset, vs. offset + limit).
was (Author: tmueller):
I agree about the limit. The offset, in my experience, is almost never useful:
it isn't a good solution for pagination. See also
https://jackrabbit.apache.org/oak/docs/query/query-engine.html#Keyset_Pagination
"Note that “offset” with large values (more than a few hundred) should be
avoided, as it can lead to performance and memory issues."
I recommend to simplify this a bit:
{noformat}
public static QueryResult query(Session session, String query,
String language, long limit) throws RepositoryException {
{noformat}
This simplification also ensures that the parameters are not passed in the
wrong order by mistake (limit + offset, vs. offset + limit).
> Add Option to Limit JCR Resource Provider Queries
> -------------------------------------------------
>
> Key: SLING-11229
> URL: https://issues.apache.org/jira/browse/SLING-11229
> Project: Sling
> Issue Type: Improvement
> Components: JCR
> Affects Versions: JCR Resource 3.2.0
> Reporter: Dan Klco
> Assignee: Dan Klco
> Priority: Major
> Fix For: JCR Resource 3.2.2
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> **Problem Statement**
> Currently, the [BasicQueryLanguageProvider
> |https://github.com/apache/sling-org-apache-sling-jcr-resource/blob/18edb8d7e7106c1e1e3333b89bf4d2a49c686e3b/src/main/java/org/apache/sling/jcr/resource/internal/helper/jcr/BasicQueryLanguageProvider.java]
> used by the
> [JCRResourceProvider|https://github.com/apache/sling-org-apache-sling-jcr-resource/blob/8345f4ed4857ed5ca240ac20050b68c84c61646c/src/main/java/org/apache/sling/jcr/resource/internal/helper/jcr/JcrResourceProvider.java]
> for executing queries for methods like findResources executes a query
> without a limit set.
> At the same time, in Apache Jackrabbit Oak, queries will fail if the query
> reads more than a configurable limit of nodes:
> [https://jackrabbit.apache.org/oak/docs/query/query-engine.html#Slow_Queries_and_Read_Limits]
> This means that it's entirely possible to create a well indexed, well crafted
> query in Apache Sling that will still throw an Exception at runtime for
> larger repositories when using
> [ResourceResolver.findResources|https://sling.apache.org/apidocs/sling12/org/apache/sling/api/resource/ResourceResolver.html#findResources-java.lang.String-java.lang.String-]
> or
> [ResourceResolver.queryResources|https://sling.apache.org/apidocs/sling12/org/apache/sling/api/resource/ResourceResolver.html#queryResources-java.lang.String-java.lang.String-]
> if the query returns more than the Oak Read limit number of results.
> **Solution**
> Add an optional setting to the JCR Resource Provider to set a limit on the
> number of returned results from queries. While this would mean that in
> certain cases the queries would return an incomplete set of results, they
> would still nevertheless return results rather than failing.
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