Minor compaction logging improvements
1) make summary less likely to be truncated
2) format human-readable file sizes in summary
3) log the motivation for each universal compaction
An initial implementation of kCompactionStopStyleSimilarSize for universal compaction
address code review comments on 5e3aeb5f8e
- reduce string copying in Compaction::Summary
- simplify file number checking in UniversalCompactionStopStyleSimilarSize unit test
CleanupIteratorState() only to initialize DeletionState when super version cleanup needed

Summary:
Two changes:
1. DeletionState is only constructed when cleaning up is needed
2. Fix the bug of deletion state construction bug. A change was made in a previous patch: https://reviews.facebook.net/rROCKSDB774ed89c2405ee058086b099cbc8b29e243739cc#71a34e2e However, it somehow got lost when merging

Test Plan: make all check

Reviewers: kailiu, haobo, igor

Reviewed By: igor

CC: igor, dhruba, i.am.jin.lei, yhchiang, leveldb

Differential Revision: https://reviews.facebook.net/D16233
CloseDB in BackupableDBTest to make valgrind happy
MergingIterator assertion

Summary: I wrote a test that triggers assertion in MergingIterator. I have not touched that code ever, so I'm looking for somebody with good understanding of the MergingIterator code to fix this. The solution is probably a one-liner. Let me know if you're willing to take a look.

Test Plan: This test fails with an assertion `use_heap_ == false`

Reviewers: dhruba, haobo, sdong, kailiu

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16521
config max_background_flushes in db_bench

Summary: as title

Test Plan: make release

Reviewers: haobo, sdong, igor

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16437
fix db_bench to use HashSkipList for real

Summary:
For HashSkipList case, DBImpl has sanity check to see if prefix_extractor in
options is the same as the one in memtable factory. If not, it falls
back to SkipList. As result, I was experimenting with SkipList
performance. No wonder it is much worse than LinkedList

Test Plan: ran benchmark

Reviewers: haobo, sdong, igor

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16569
output perf_context in db_bench readrandom

Summary:
Add helper function to print perf context data in db_bench if enabled.
I didn't find any code that actually exports perf context data. Not sure
if I missed anything

Test Plan: ran db_bench

Reviewers: haobo, sdong, igor

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16575
Merge pull request #47 from mlin/kCompactionStopStyleSimilarSize

An initial implementation of kCompactionStopStyleSimilarSize for universal compaction
Allow user to specify log level for info_log

Summary:
Currently, there is no easy way for user to change log level of info log. Add a parameter in options to specify that.
Also make the default level to INFO level. Removing the [INFO] tag if it is INFO level as I don't want to cause performance regression. (add [LOG] means another mem-copy and string formatting).

Test Plan:
make all check
manual check the levels work as expected.

Reviewers: dhruba, yhchiang

Reviewed By: yhchiang

CC: dhruba, igor, i.am.jin.lei, ljin, haobo, leveldb

Differential Revision: https://reviews.facebook.net/D16563
Buffer info logs when picking compactions and write them out after releasing the mutex

Summary: Now while the background thread is picking compactions, it writes out multiple info_logs, especially for universal compaction, which introduces a chance of waiting log writing in mutex, which is bad. To remove this risk, write all those info logs to a buffer and flush it after releasing the mutex.

Test Plan:
make all check
check the log lines while running some tests that trigger compactions.

Reviewers: haobo, igor, dhruba

Reviewed By: dhruba

CC: i.am.jin.lei, dhruba, yhchiang, leveldb, nkg-

Differential Revision: https://reviews.facebook.net/D16515
Make sure GetUniqueID releated tests run on "regular" storage

Summary:
With the use of tmpfs or ramfs, unit tests related to GetUniqueID()
failed because of the failure from ioctl, which doesn't work with these
fancy file systems at all.

I fixed this issue and make sure all related tests run on the "regular"
storage (disk or flash).

Test Plan: TEST_TMPDIR=/dev/shm make check -j32

Reviewers: igor, dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16593
DB Sanity Test

Summary:
@kailiu mentioned on meeting yesterday that we sometimes have trouble opening DB created by old version with the new version. This will be very important to test for column families, since I'm changing disk format for the MANIFEST.

I added a tool that can help us test that. Usage:
./db_sanity_test <path> create
will create a bunch of DBs under <path>
<change RocksDB version>
./db_sanity_test <path> verify
will verify consistency of DBs created under <path>

Test Plan: ran the db_sanity_test

Reviewers: kailiu, dhruba, haobo

Reviewed By: kailiu

CC: leveldb, kailiu, xjin

Differential Revision: https://reviews.facebook.net/D16605