Chen Luo created ASTERIXDB-2541:
-----------------------------------
Summary: Introduce GreedyScheduler
Key: ASTERIXDB-2541
URL: https://issues.apache.org/jira/browse/ASTERIXDB-2541
Project: Apache AsterixDB
Issue Type: Improvement
Components: STO - Storage
Reporter: Chen Luo
Assignee: Chen Luo
Our currently AsynchronousScheduler tries to schedule all merge operations at
the same without any control. This is not optimal in terms of minimizing the
number of disk components, which directly impacts query performance.
Here we introduce GreedyScheduler to minimize the number of disk components
over time. It keeps tracks of all merge operations of an LSM index, and only
activates the merge operation with the smallest number of remaining I/Os. It
can be proven that if the number of components is the same for all merge
operations, then this GreedyScheduler is strictly optimal. Otherwise, this will
still be a good heuristic.
In order for GreedyScheduler to work, we need the following two changes:
* Keep track of the number of scanned pages of index cursors so that we will
know how many pages left;
* Introduce a mechanism to activate/deactivate merge operations
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
