Fix compilation error with gcc 4.7

Summary:
Fix compilation error with gcc 4.7

Test Plan:
make clean
make

Reviewers:

CC:

Task ID: #

Blame Rev:
Make table properties shareable

Summary:
We are going to expose properties of all tables to end users through "some" db interface.
However, current design doesn't naturally fit for this need, which is because:

1. If a table presents in table cache, we cannot simply return the reference to its table properties, because the table may be destroy after compaction (and we don't want to hold the ref of the version).
2. Copy table properties is OK, but it's slow.

Thus in this diff, I change the table reader's interface to return a shared pointer (for const table properties), instead a const refernce.

Test Plan: `make check` passed

Reviewers: haobo, sdong, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15999
Fix incompatible compilation in Linux server
Fix the valgrind error in table test.
Support for LZ4 compression.
Fixed wrong comment GetTableMetaData -> GetLiveFilesMetaData
Switch to c++11

Summary:
Looks like gnu++11 is not very portable (see https://github.com/facebook/rocksdb/issues/80). We don't (yet) depend on any extensions of gnu++11, so I think we should switch back to c++11.

More on this topic here: http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Extensions.html

Test Plan: make check works :)

Reviewers: kailiu, dhruba, haobo

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16053
Merge pull request #74 from alberts/lz4

Support for LZ4 compression.
Quick fix for table_test failure

Summary:
* Fixed the compression state array size bug.
* Temporarily disable running `DoCompressionTest()` against bzip, which will fail the test.

Test Plan: make && ./table_test

Reviewers: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16065
Add LIBRARY back to `make dbg`
Reduce malloc of iterators in Get() code paths

Summary:
This patch optimized Get() code paths by avoiding malloc of iterators. Iterator creation is moved to mem table rep implementations, where a callback is called when any key is found. This is the same practice as what we do in (SST) table readers.

db_bench result for readrandom following a writeseq, with no compression, single thread and tmpfs, we see throughput improved to 144958 from 139027, about 3%.

Test Plan: make all check

Reviewers: dhruba, haobo, igor

Reviewed By: haobo

CC: leveldb, yhchiang

Differential Revision: https://reviews.facebook.net/D14685
Fix a member variables initialization order issue

Summary:
In MacOS, I got issue with `Footer`'s default constructor, which initialized the magic number with some random number instead of 0.
With investigation, I found we forgot to make the kInvalidTableMagicNumber to be static. As a result, kInvalidTableMagicNumber was assgined to `table_magic_number_` before it is initialized (which will be populated with random number).

Test Plan: passed current unit tests; also passed the unit tests for the incoming diff which used the default footer.

Reviewers: yhchiang

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16077
Fix problem 3 for issue #80
enable plain table in db_bench

Summary: as title

Test Plan: ran db_bench to gather stats

Reviewers: haobo, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16059
preload table handle on Recover() when max_open_files == -1

Summary: This covers existing table files before DB open happens and avoids contention on table cache

Test Plan: db_test

Reviewers: haobo, sdong, igor, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16089
IOError cleanup

Summary: Clean up IOErrors so that it only indicates errors talking to device.

Test Plan: make all check

Reviewers: igor, haobo, dhruba, emayanke

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15831
CompactionContext to include is_manual_compaction

Summary: Added a bit more information to compaction context, requested by internal team at FB.

Test Plan: Modified CompactionFilter test to make sure is_manual_compaction is properly set.

Reviewers: haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16095
Support prefix seek in UserCollectedProperties

Summary: We'll need the prefix seek support for property aggregation.

Test Plan: make all check

Reviewers: haobo, sdong, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15963
Merge branch 'master' into columnfamilies

Conflicts:
	db/db_impl.cc
	db/db_impl.h
	db/memtable_list.cc
	db/memtable_list.h
	db/version_set.cc
	db/version_set.h