[jira] [Closed] (OAK-12411) Avoid allocation and cache hash code in Template.hashCode()

["Julian Reschke (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/OAK-12411?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Julian Reschke closed OAK-12411.
--------------------------------

> Avoid allocation and cache hash code in Template.hashCode()
> -----------------------------------------------------------
>
>                 Key: OAK-12411
>                 URL: https://issues.apache.org/jira/browse/OAK-12411
>             Project: Jackrabbit Oak
>          Issue Type: Improvement
>          Components: segment-tar
>            Reporter: Nuno Santos
>            Priority: Major
>             Fix For: 2.8.0
>
>
> {{Template.hashCode()}} currently recomputes its hash on every call via {{Objects.hash(primaryType, mixinTypes, Arrays.asList(properties), getTemplateType(), childName)}}, which allocates a varargs {{Object[]}} and a {{List}} wrapper around {{properties}} on every invocation.
> {{Template}} is immutable once constructed, so the hash code can be computed once and cached, following the same lazy-caching pattern as {{java.lang.String#hashCode()}}:
> * A field initialized to {{0}} means "not yet computed".
> * A benign race across threads just recomputes the same value; no synchronization needed.
> This removes the per-call allocation, which matters because {{Template.equals()}}/{{hashCode()}} are used for template deduplication during node writes — one of the hotter paths in {{DefaultSegmentWriter}}.
> No behavioral change intended; the {{equals()}}/{{hashCode()}} contract is preserved.



--
This message was sent by Atlassian Jira
(v8.20.10#820010)