[
https://issues.apache.org/jira/browse/SLING-7969?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16749911#comment-16749911
]
Timothee Maret commented on SLING-7969:
---------------------------------------
Thanks [~volteanu]! Indeed, it seems the Johzon library is taking a bold
approach to memory management. This may have changed with JOHNZON-125. I'll
provide a patch to leverage and test it.
Other than that, maybe we can entirely avoid the JsonReaderFactory which seems
to come from [that
change|https://github.com/apache/sling-org-apache-sling-discovery-commons/commit/709c0c23ec5721f33d792082b737cd2809c7c9b0#diff-7f4a97d3aa096f752d678f3f90c374d3R45]
supposedly to parse commented JSON. [~egli] do we expect commented JSON in the
{{DiscoveryLiteDescriptor}} ?
> Memory leak in DiscoveryLiteDescriptor
> --------------------------------------
>
> Key: SLING-7969
> URL: https://issues.apache.org/jira/browse/SLING-7969
> Project: Sling
> Issue Type: Bug
> Components: Discovery
> Affects Versions: Discovery Commons 1.0.20
> Reporter: Timothee Maret
> Assignee: Timothee Maret
> Priority: Major
> Labels: discovery
>
> As identified in [~volteanu]'s adaptTo
> [presentation|https://adapt.to/2018/en/schedule/sling-memory-deep-dive.html],
> it seems that Sling Discovery on Oak is consuming 42MB of RAM on a standard
> instance.
> Sling discovery deals with transient states (the views, leases, etc.) and is
> not caching significant amount of data. The 42MB figure for the discovery
> feature seems like a symptom of a memory leak.
> [~volteanu] shared in his presentation that the 42MB worth of RAM was mainly
> consumed by a Json Factory reference. There is one static JsonReaderFactory
> in the discovery commons module, in the
> [DiscoveryLiteDescriptor|https://github.com/apache/sling-org-apache-sling-discovery-commons/blob/master/src/main/java/org/apache/sling/discovery/commons/providers/spi/base/DiscoveryLiteDescriptor.java].
> Looking at the code, it seems that each invocation of the
> [getDescriptorFrom|https://github.com/apache/sling-org-apache-sling-discovery-commons/blob/master/src/main/java/org/apache/sling/discovery/commons/providers/spi/base/DiscoveryLiteDescriptor.java#L51]
> method creates a JSON reader but never close it. This may may leave
> resources behind as hinted by the description of the
> [close|https://docs.oracle.com/javaee/7/api/javax/json/JsonReader.html#close--]
> method in the API. AFAIK, the
> [getDescriptorFrom|https://github.com/apache/sling-org-apache-sling-discovery-commons/blob/master/src/main/java/org/apache/sling/discovery/commons/providers/spi/base/DiscoveryLiteDescriptor.java#L51]
> is invoked periodically on a relatively high frequency (< seconds) which may
> be the trigger for the leak on all instances.
> This is only a supposition for now, it should be investigated further, simply
> by running a patched version of \{{org.apache.sling.discovery.commons}} that
> make sure each JSON reader is properly closed.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
