the performance of removing resources with externalized literals should be
improved
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Key: CLEREZZA-414
URL: https://issues.apache.org/jira/browse/CLEREZZA-414
Project: Clerezza
Issue Type: Improvement
Reporter: Hasan
Assignee: Reto Bachmann-Gmür
I compared the performance of AbstractDiscobitsHandler.remove() when removing
an InfoDiscoBit in the following cases:
a. with literal externalizer
a1. the infoBit is about 3.5 MB
a2. the infoBit is about 30 KB
b. without literal externalizer
b1. the infoBit is about 3.5 MB
b2. the infoBit is about 30 KB
Using a clerezza instance on my notebook, I obtained an average value for
a1: 15 seconds
a2: 110 ms
b1: 500 ms
b2: 5 ms
I examined the remove method and did some timestamping. The comments in the
code below tell us where most of the times are spent.
public void remove(NonLiteral node) {
MGraph mGraph = getMGraph();
Iterator<Triple> properties = mGraph.filter(node, null, null);
//copying properties to set, as we're modifying underlying graph
Set<Triple> propertiesSet = new HashSet<Triple>();
// this while loop consumes half of the total time needed for the whole remove
operation in case of using literal externalizer
// if literal is NOT externalized, the time consumed by this while loop is
negligible
while (properties.hasNext()) {
propertiesSet.add(properties.next());
}
properties = propertiesSet.iterator();
while (properties.hasNext()) {
Triple triple = properties.next();
UriRef predicate = triple.getPredicate();
if (predicate.equals(DISCOBITS.contains)) {
try {
GraphNode containedNode = new
GraphNode((NonLiteral)triple.getObject(), mGraph);
//The following includes triple
containedNode.deleteNodeContext();
} catch (ClassCastException e) {
throw new RuntimeException("The value
of "+predicate+" is expected not to be a literal");
}
//as some other properties of node could have
been in the context of the object
remove(node);
return;
}
}
// In case of using literal externalizer, the code segment below consumes half
of the total time needed for the whole remove operation
// if literal is NOT externalized, it consumes most of the time needed for the
whole remove operation
GraphNode graphNode = new GraphNode(node, mGraph);
graphNode.deleteNodeContext();
}
It seems that using literal externalizer is pretty expensive.
We need to find a more efficient solution to deal with large literals
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