[LUCENE-4946] Refactor SorterTemplate

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 4.4
• Lucene Fields: New
• Assignee: Adrien Grand
• Reporter: Adrien Grand
• Created: 21/Apr/13 20:46
• Updated: 28/Aug/22 13:44
• Resolved: 03/May/13 15:54

Description

When working on TimSort (LUCENE-4839), I was a little frustrated of not being able to add galloping support because it would have required to add new primitive operations in addition to compare and swap.

I started working on a prototype that uses inheritance to allow some sorting algorithms to rely on additional primitive operations. You can have a look at https://github.com/jpountz/sorts/tree/master/src/java/net/jpountz/sorts (but beware it is a prototype and still misses proper documentation and good tests).

I think it would offer several advantages:

• no more need to implement setPivot and comparePivot when using in-place merge sort or insertion sort,
• the ability to use faster stable sorting algorithms at the cost of some memory overhead (our in-place merge sort is very slow),
• the ability to implement properly algorithms that are useful on specific datasets but require different primitive operations (such as TimSort for partially-sorted data).

If you are interested in comparing these implementations with Arrays.sort, there is a Benchmark class in src/examples.

What do you think?

Issue Links

• relates to: LUCENE-5140 Slowdown of the span queries caused by LUCENE-4946