tree 5c4c0e1c38767a46ad2f2030455448d58761b066
parent dc3f31c3f9b4b3fb5ca48245beafa9dbc874fa98
author luochen <cluo8@uci.edu> 1569513506 -0700
committer Luo Chen <cluo8@uci.edu> 1569517122 +0000

[ASTERIXDB-2541][STO] Introduce GreedyScheduler

- user model changes: yes.
   Add new option: storage.io.scheduler (async/greedy)
- storage format changes: no.
- interface changes: yes.
  Introduce IIndexCursorStats

Details:
- Introduce GreedyScheduler that always executes the merge
operation with the smallest number of remaining pages to minimize
the number of disk components
- Introduce IIndexCursorStats to collect the statistics of index scans.
This allows GreedyScheduler to know the remaning pages of merge
operations.
- Extend AbstractIoOperation so that GreedyScheduler can pause/resume
merge operations if needed.

Change-Id: I38fe394d1180d4e3f6796064c0e6c6630b6ad303
Reviewed-on: https://asterix-gerrit.ics.uci.edu/3284
Reviewed-by: Murtadha Hubail <mhubail@apache.org>
Contrib: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Michael Blow <mblow@apache.org>