GitHub user robertwb opened a pull request: https://github.com/apache/incubator-beam/pull/741
Top improvements Be sure to do all of the following to help us incorporate your contribution quickly and easily: - [ ] Make sure the PR title is formatted like: `[BEAM-<Jira issue #>] Description of pull request` - [ ] Make sure tests pass via `mvn clean verify`. (Even better, enable Travis-CI on your fork and ensure the whole test matrix passes). - [ ] Replace `<Jira issue #>` in the title with the actual Jira issue number, if there is one. - [ ] If this contribution is large, please file an Apache [Individual Contributor License Agreement](https://www.apache.org/licenses/icla.txt). --- You can merge this pull request into a Git repository by running: $ git pull https://github.com/robertwb/incubator-beam top Alternatively you can review and apply these changes as the patch at: https://github.com/apache/incubator-beam/pull/741.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #741 ---- commit 9151fcf861704c550c21f411a9047f955f179ec4 Author: Robert Bradshaw <rober...@gmail.com> Date: 2016-07-27T17:09:49Z Better top implementation. When selecting the top k of n, it is common that k << n. Using a heap is O(n log k) while select algorithms can achieve O(n + k log k). This also avoids the ugliness that heapq does not take the comparator as an argument, resulting in _HeapItem classes that were cumbersome and expensive to serialize. commit e38d6f60f18bf6ad61f2d387c67efa2012af2e14 Author: Robert Bradshaw <rober...@gmail.com> Date: 2016-07-27T19:23:02Z Allow Top operations to take key argument rather than compare, and order by the natural ordering if neither is specified. ---- --- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastruct...@apache.org or file a JIRA ticket with INFRA. ---