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https://issues.apache.org/jira/browse/OAK-1130?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13809152#comment-13809152
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Thomas Mueller commented on OAK-1130:
-------------------------------------
Proposed patch. Changes in the AbstractRoot: use ImmutableTree instead of
mutable. Changes in AstElement: cache the used last tree.
{code}
Index: src/main/java/org/apache/jackrabbit/oak/core/AbstractRoot.java
===================================================================
--- src/main/java/org/apache/jackrabbit/oak/core/AbstractRoot.java
(revision 1537076)
+++ src/main/java/org/apache/jackrabbit/oak/core/AbstractRoot.java
(working copy)
@@ -329,7 +329,11 @@
@Override
protected ExecutionContext getExecutionContext() {
NodeState rootState = AbstractRoot.this.getRootState();
- return new ExecutionContext(rootState, rootTree,
getIndexProvider(rootState));
+ Context c =
securityProvider.getConfiguration(AuthorizationConfiguration.class).getContext();
+ PermissionProvider pp = permissionProvider.get();
+ SecureNodeState s = new SecureNodeState(rootState, pp, c);
+ ImmutableTree t = new ImmutableTree(s);
+ return new ExecutionContext(rootState, t,
getIndexProvider(rootState));
}
private QueryIndexProvider getIndexProvider(NodeState rootState) {
Index: src/main/java/org/apache/jackrabbit/oak/query/ast/AstElement.java
===================================================================
--- src/main/java/org/apache/jackrabbit/oak/query/ast/AstElement.java
(revision 1537076)
+++ src/main/java/org/apache/jackrabbit/oak/query/ast/AstElement.java
(working copy)
@@ -30,6 +30,8 @@
abstract class AstElement {
protected QueryImpl query;
+ private Tree lastTree;
+ private String lastPath;
abstract boolean accept(AstVisitor v);
@@ -123,7 +125,11 @@
}
protected Tree getTree(String path) {
- return query.getTree(path);
+ if (lastPath == null || !path.equals(lastPath)) {
+ lastTree = query.getTree(path);
+ lastPath = path;
+ }
+ return lastTree;
}
}
{code}
> Performance issues with MutableTree
> -----------------------------------
>
> Key: OAK-1130
> URL: https://issues.apache.org/jira/browse/OAK-1130
> Project: Jackrabbit Oak
> Issue Type: Bug
> Components: core, query
> Reporter: Thomas Mueller
>
> Benchmarks show that simple queries are slower in Oak than in Jackrabbit 2.x.
> The profiling data shows that most time is spent in the MemoryNodeBuilder
> (see below), called from MutableTree, even thought the query engine
> internally doesn't need mutable trees.
> It would be nice if creating a tree is faster (MemoryNodeBuilder, MutableTree
> and related). Many components would benefit from that. Unfortunately, the
> code is quite complex (meaning, I don't understand it).
> I found two alternatives to speed up queries:
> * Not use MutableTree within the query engine, but instead use ImmutableTree.
> This gave a small performance boost (maybe 15%)
> * Cache trees in the query engine, to avoid creating the same tree multiple
> times. This gave a speedup of about 50% (twice as fast) for some tests.
> Package summary and top stack trace as reported by the profiler.
> {code}
> summary:
> 65%: org.apache.jackrabbit.oak.plugins.memory
> 9%: org.apache.jackrabbit.oak.plugins.segment
> 4%: org.apache.jackrabbit.oak.jcr.session.operation
> 3%: org.apache.jackrabbit.oak.query
> 2%: com.google.common.collect
> 2%: org.apache.jackrabbit.oak.namepath
> 341/3234 (10%):
> org.apache.jackrabbit.oak.plugins.memory.MemoryNodeBuilder$ConnectedHead.getCurrentNodeState(MemoryNodeBuilder.java:601)
> org.apache.jackrabbit.oak.plugins.memory.MemoryNodeBuilder$UnconnectedHead.update(MemoryNodeBuilder.java:535)
> org.apache.jackrabbit.oak.plugins.memory.MemoryNodeBuilder.head(MemoryNodeBuilder.java:152)
> org.apache.jackrabbit.oak.plugins.memory.MemoryNodeBuilder.exists(MemoryNodeBuilder.java:254)
> org.apache.jackrabbit.oak.core.SecureNodeBuilder.getChildNode(SecureNodeBuilder.java:299)
> org.apache.jackrabbit.oak.core.MutableTree.<init>(MutableTree.java:76)
> org.apache.jackrabbit.oak.core.MutableTree.createChild(MutableTree.java:86)
> org.apache.jackrabbit.oak.core.MutableTree.getChild(MutableTree.java:222)
> org.apache.jackrabbit.oak.util.TreeUtil.getTree(TreeUtil.java:169)
> org.apache.jackrabbit.oak.query.QueryImpl.getTree(QueryImpl.java:604)
> org.apache.jackrabbit.oak.query.ast.AstElement.getTree(AstElement.java:126)
> org.apache.jackrabbit.oak.query.ast.SelectorImpl.currentTree(SelectorImpl.java:351)
> {code}
> Some benchmark results for the oak-run SimpleSearchTest with combination of
> changes (patch will follow). Just "N", meaning number of iterations within 10
> seconds (higher is better), using Oak-Tar:
> * old (mutable tree, no cache): 36
> * immutable tree only: 42
> * cache only: 65
> * cache+immutable: 76
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