Fix the valgrind error in newly added unittests for table stats

Summary:

Previous the newly added test called NewBloomFilter without releasing it at the end of the test, which resulted in memory leak and was detected by valgrind.

Test Plan:

Ran valgrind test.
Rephrasing the comment

Summary: Per @haobo's request, rephrasing the comment for allocate

Test Plan: It's a comment!

Reviewers: haobo, kailiu

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13575
Disallow transaction log iterator to skip sequences

Summary:
This is expected to solve the "gaps in transaction log iterator" problem.
* After a lot of observations on the gaps on the sigmafio machines I found that it is due to a race between log reader and writer always.
* So when we drop the wormhole subscription and refresh the iterator, the gaps are not there.
* It is NOT due to some boundary or corner case left unattended in the iterator logic because I checked many instances of the gaps against their log files with ldb. The log files are NOT corrupted also.
* The solution is to not allow the iterator to read incompletely written sequences and detect gaps inside itself and invalidate it which will cause the application to refresh the iterator normally and seek to the required sequence properly.
* Thus, the iterator can at least guarantee that it will not give any gaps.

Test Plan:
* db_test based log iterator tests
* db_repl_stress
* testing on sigmafio setup to see gaps go away

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13593
Dbid feature

Summary:
Create a new type of file on startup if it doesn't already exist called DBID.
This will store a unique number generated from boost library's uuid header file.
The use-case is to identify the case of a db losing all its data and coming back up either empty or from an image(backup/live replica's recovery)
the key point to note is that DBID is not stored in a backup or db snapshot
It's preferable to use Boost for uuid because:
1) A non-standard way of generating uuid is not good
2) /proc/sys/kernel/random/uuid generates a uuid but only on linux environments and the solution would not be clean
3) c++ doesn't have any direct way to get a uuid
4) Boost is a very good library that was already having linkage in rocksdb from third-party
Note: I had to update the TOOLCHAIN_REV in build files to get latest verison of boost from third-party as the older version had a bug.
I had to put Wno-uninitialized in Makefile because boost-1.51 has an unitialized variable and rocksdb would not comiple otherwise. Latet open-source for boost is 1.54 but is not there in third-party. I have notified the concerned people in fbcode about it.
@kailiu : While releasing to third-party, an additional dependency will need to be created for boost in TARGETS file. I can help identify.

Test Plan:
Expand db_test to test 2 cases
1) Restarting db with Id file present - verify that no change to Id
2)Restarting db with Id file deleted - verify that a different Id is there after reopen
Also run make all check

Reviewers: dhruba, haobo, kailiu, sdong

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13587
Update the latest rocksdb version
Enable blobs to be fragmented

Summary:
I have implemented a FreeList version that supports fragmented blob chunks. Each block gets allocated and freed in FIFO order. Since the idea for the blocks to be big, we will not take a big hit of non-sequential IO. Free list is also faster, taking only O(k) size in both free and allocate instead of O(N) as before.

See more info on the task: https://our.intern.facebook.com/intern/tasks/?t=2990558

Also, I'm taking Slice instead of const char * and size in Put function.

Test Plan: unittests

Reviewers: haobo, kailiu, dhruba, emayanke

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13569
Improve the comment for the shared library in Make file
Hardcoding temp file name for Identity file to 000000.dbtmp just like it's done for CURRENT file

Summary: as per Dhruba's suggestion

Test Plan: make all check; Seen the Id getting generated properly in db_repl_stress

Reviewers: dhruba, kailiu

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13635
[RocksDB] Add perf_context.wal_write_time to track time spent on writing the recovery log.

Summary: as title

Test Plan: make check; ./perf_context_test

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13629
Implement max_size in BlobStore

Summary:
I added max_size option in blobstore. Since we now know the maximum number of buckets we'll ever use, we can allocate an array of buckets and access its elements without use of any locks! Common case Get doesn't lock anything now.

Benchmarks on 16KB block size show no impact on speed, though.

Test Plan: unittests + benchmark

Reviewers: dhruba, haobo, kailiu

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13641
BlobStore Benchmark

Summary:
Finally, arc diff works again! This has been sitting in my repo for a while.

I would like some comments on my BlobStore benchmark. We don't have to check this in.

Also, I don't do any fsync in the BlobStore, so this is all extremely fast. I'm not sure what durability guarantees we need from the BlobStore.

Test Plan: Nope

Reviewers: dhruba, haobo, kailiu, emayanke

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13527
Conversion of db_bench, db_stress and db_repl_stress to use gflags

Summary: Converted db_stress, db_repl_stress and db_bench to use gflags

Test Plan: I tested by printing out all the flags from old and new versions. Tried defaults, + various combinations with "interesting flags". Also, tested by running db_crashtest.py and db_crashtest2.py.

Reviewers: emayanke, dhruba, haobo, kailiu, sdong

Reviewed By: emayanke

CC: leveldb, xjin

Differential Revision: https://reviews.facebook.net/D13581
Fix the log number bug when updating MANIFEST file

Summary:
Crash may occur during the flushes of more than two mem tables.

As the info log suggested, even when both were successfully flushed,
the recovery process still pick up one of the memtable's log for recovery.

This diff fix the problem by setting the correct "log number" in MANIFEST.

Test Plan: make test; deployed to leaf4 and make sure it doesn't result in crashes of this type.

Reviewers: haobo, dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13659
Unify DeleteFile and DeleteWalFiles

Summary:
This is to simplify rocksdb public APIs and improve the code quality.
Created an additional parameter to ParseFileName for log sub type and improved the code for deleting a wal file.
Wrote exhaustive unit-tests in delete_file_test
Unification of other redundant APIs can be taken up in a separate diff

Test Plan: Expanded delete_file test

Reviewers: dhruba, haobo, kailiu, sdong

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13647
Fix the gcc warning for unused variable

Summary: Fix the unused variable warning for `first` when running `make release`

Test Plan:
make
make check

Reviewers: dhruba, igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13695
fix the error message in debug mode

Summary:

my fix patch introduced a new error in debug mode.

Test Plan:

`make` and `make release`
Fix a bug that index block's restart_block_interval is not 1

Summary:

This bug may affect the seek performance.

Test Plan:

make
make check

Also gdb into some index block builder to make sure the restart_block_interval is `1`.
If a Put fails, fail all other puts

Summary:
When a Put fails, it can leave database in a messy state. We don't want to pretend that everything is OK when it may not be. We fail every write following the failed one.

I added checks for corruption to DBImpl::Write(). Is there anywhere else I need to add them?

Test Plan: Corruption unit test.

Reviewers: dhruba, haobo, kailiu

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13671
Fix a valgrind warning

Summary:
A latest valgrind test found a recently added unit test has memory leak,
which is because DB is not closed at the end of the test.

Test Plan: re-run the valgrind locally and make sure there's no memory leakage any more.

Reviewers: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13725
Support user-defined table stats collector

Summary:
1. Added a new option that support user-defined table stats collection.
2. Added a deleted key stats collector in `utilities`

Test Plan:
Added a unit test for newly added code.
Also ran make check to make sure other tests are not broken.

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13491