Author: mreutegg
Date: Thu Jun 19 08:25:22 2014
New Revision: 1603753
URL: http://svn.apache.org/r1603753
Log:
OAK-1861: Limit memory usage of DocumentNodeStore.readChildren()
Merge r1603748 from trunk.
Modified:
jackrabbit/oak/branches/1.0/ (props changed)
jackrabbit/oak/branches/1.0/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStore.java
Propchange: jackrabbit/oak/branches/1.0/
------------------------------------------------------------------------------
Merged /jackrabbit/oak/trunk:r1603748
Modified:
jackrabbit/oak/branches/1.0/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStore.java
URL:
http://svn.apache.org/viewvc/jackrabbit/oak/branches/1.0/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStore.java?rev=1603753&r1=1603752&r2=1603753&view=diff
==============================================================================
---
jackrabbit/oak/branches/1.0/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStore.java
(original)
+++
jackrabbit/oak/branches/1.0/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStore.java
Thu Jun 19 08:25:22 2014
@@ -708,10 +708,20 @@ public final class DocumentNodeStore
return children;
}
- DocumentNodeState.Children readChildren(DocumentNodeState parent, String
name, int limit) {
- // TODO use offset, to avoid O(n^2) and running out of memory
- // to do that, use the *name* of the last entry of the previous batch
of children
- // as the starting point
+ /**
+ * Read the children of the given parent node state starting at the child
+ * node with {@code name}. The given {@code name} is exclusive and will not
+ * appear in the list of children. The returned children are sorted in
+ * ascending order.
+ *
+ * @param parent the parent node.
+ * @param name the name of the lower bound child node (exclusive) or
+ * {@code null} if no lower bound is given.
+ * @param limit the maximum number of child nodes to return.
+ * @return the children of {@code parent}.
+ */
+ DocumentNodeState.Children readChildren(DocumentNodeState parent,
+ String name, int limit) {
String path = parent.getPath();
Revision rev = parent.getLastRevision();
Iterable<NodeDocument> docs;
@@ -721,13 +731,15 @@ public final class DocumentNodeStore
// child nodes than requested.
int rawLimit = (int) Math.min(Integer.MAX_VALUE, ((long) limit) + 1);
for (;;) {
- c.children.clear();
docs = readChildDocs(path, name, rawLimit);
int numReturned = 0;
for (NodeDocument doc : docs) {
numReturned++;
- // filter out deleted children
String p = doc.getPath();
+ // remember name of last returned document for
+ // potential next round of readChildDocs()
+ name = PathUtils.getName(p);
+ // filter out deleted children
DocumentNodeState child = getNode(p, rev);
if (child == null) {
continue;
@@ -748,8 +760,6 @@ public final class DocumentNodeStore
c.hasMore = false;
return c;
}
- // double rawLimit for next round
- rawLimit = (int) Math.min(((long) rawLimit) * 2,
Integer.MAX_VALUE);
}
}
