Hi there.
I was looking at the performance of code that creates large collections
(CreateManyChildNodesTest, XmlImportTest), and found:
Iterable<NodeDocument> readChildDocs(@Nonnull final String path,
@Nullable String name,
int limit) {
String to = Utils.getKeyUpperLimit(checkNotNull(path));
String from;
if (name != null) {
from = Utils.getIdFromPath(PathUtils.concat(path, name));
} else {
from = Utils.getKeyLowerLimit(path);
}
if (name != null || limit > NUM_CHILDREN_CACHE_LIMIT) {
// do not use cache when there is a lower bound name
// or more than 16k child docs are requested
return store.query(Collection.NODES, from, to, limit);
}
So *if* we use paging, only the first page use the cache.
Paging appears to use maximally 1600 entries at once (DocumentNodeState):
/**
* The number of child nodes to fetch initially.
*/
static final int INITIAL_FETCH_SIZE = 100;
/**
* The maximum number of child nodes to fetch in one call. (1600).
*/
static final int MAX_FETCH_SIZE = INITIAL_FETCH_SIZE << 4;
The maximum number of entries that could be cached however seems to be
bigger:
/**
* Do not cache more than this number of children for a document.
*/
static final int NUM_CHILDREN_CACHE_LIMIT =
Integer.getInteger("oak.documentMK.childrenCacheLimit", 16 * 1024);
Maybe it's just me, but something seems to be weird here:
1) why the different limits that do not seem to be consistent?
2) why disabling caching for all but the first page?
Best regards, Julian
