grove / exmeso Goto Github PK
View Code? Open in Web Editor NEWExternal Merge Sort in Java
License: Apache License 2.0
External Merge Sort in Java
License: Apache License 2.0
When and an input file is small enough to fit in a single chunk, distinct option doesn't remove duplicated items.
The reason seems because ExternalMergeSort#mergeSortedChunksNoPartialMerge(List sortedChunks) doesn't honor config.distinct as you see below.
if (sortedChunks.size() == 1) {
File sortedChunk = sortedChunks.get(0);
return new ChunkFile<T>(sortedChunk, serializer, comparator, config.cleanup);
} else {
List<ChunkFile<T>> cfs = new ArrayList<ChunkFile<T>>(sortedChunks.size());
for (File file : sortedChunks) {
cfs.add(new ChunkFile<T>(file, serializer, comparator, config.cleanup));
}
return new MergeSortedIterator<T,ChunkFile<T>>(cfs, comparator, config.distinct);
}
It works fine if you eliminate the above optimizing if-true section.
The sample code to sort json file gets org.codehaus.jackson.map.RuntimeJsonMappingException as you see in exception.txt.
The reason is a bug of org.codehaus.jackson.map.MappingIterator.java, you cannot invoke hasNext() two times or more when it hits END_ARRAY token, ']'.
Because codehaus is no more maintained, it's better to migrate to its successor: com.fasterxml.jackson.
You can see a sample migration in JacksonSerializer.zip.
The differences from the original code are shown in
JacksonSerializer.java.pdf.
When multiple ChunkFile
s contain values that compare equal, I would expect the mergeSortedChunks
method to respect the order of the files in the sortedChunks
parameter. Instead the MergeSortedIterator
uses a PriorityQueue
which does not guarantee a stable ordering.
A declarative, efficient, and flexible JavaScript library for building user interfaces.
๐ Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
An Open Source Machine Learning Framework for Everyone
The Web framework for perfectionists with deadlines.
A PHP framework for web artisans
Bring data to life with SVG, Canvas and HTML. ๐๐๐
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
Some thing interesting about web. New door for the world.
A server is a program made to process requests and deliver data to clients.
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Some thing interesting about visualization, use data art
Some thing interesting about game, make everyone happy.
We are working to build community through open source technology. NB: members must have two-factor auth.
Open source projects and samples from Microsoft.
Google โค๏ธ Open Source for everyone.
Alibaba Open Source for everyone
Data-Driven Documents codes.
China tencent open source team.