Summary:
The change to the public behavior:
* When opening a DB or creating new column family client gets a ColumnFamilyHandle.
* As long as column family handle is alive, client can do whatever he wants with it, even drop it
* Dropped column family can still be read from (using the column family handle)
* Added a new call CloseColumnFamily(). Client has to close all column families that he has opened before deleting the DB
* As soon as column family is closed, any calls to DB using that column family handle will fail (also any outstanding calls)

Internally:
* Ref-counting ColumnFamilyData
* New thread-safety for ColumnFamilySet
* Dropped column families are now completely dropped and their memory cleaned-up

Test Plan: added some tests to column_family_test

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16101

Summary: By discussion with @dhruba, overloading Open makes more sense

Test Plan: compiles!

Reviewers: dhruba

CC: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D16017

Summary: When we open a DB, we should dump only DBOptions and then when we create a new column family, we dump ColumnFamilyOptions for each one.

Test Plan: make check, confirm contents of the LOG

Reviewers: dhruba, haobo, sdong, kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16011

doc: table_stats_collectors -> table_properties_collectors.

Summary:
This diff enables the command line tool `sst_dump` to work for sst files
under plain table format.  Changes include:
  * In tools/sst_dump.cc:
    - add support for plain table format
    - display prefix_extractor information when --show_properties is on
  * In table/format.cc
    - Now the table magic number of a Footer can be later initialized
      via ReadFooterFromFile().
  * In table/meta_bocks:
    - add function ReadTableMagicNumber() that reads the magic number of
      the specified file.

Minor fixes:
 - remove a duplicate #include in table/table_test.cc
 - fix a commentary typo in include/rocksdb/memtablerep.h
 - fix lint errors.

Test Plan:
Runs sst_dump with both block-based and plain-table format files with
different arguments, specifically those with --show-properties and --from.

* sample output:
  https://reviews.facebook.net/P261

Reviewers: kailiu, sdong, xjin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15903

Summary:
Added an option for readrandom benchmark to run with tailing iterator instead of Get. Benefit of tailing iterator is that it doesn't require locking DB mutex on access.

I also have some results when running on my machine. The results highly depend on number of cache shards. With our current benchmark setting of 4 table cache shards and 6 block cache shards, I don't see much improvements of using tailing iterator. In that case, we're probably seeing cache mutex contention.

Here are the results for different number of shards

    cache shards       tailing iterator        get
       6                      1.38M           1.16M
      10                      1.58M           1.15M

As soon as we get rid of cache mutex contention, we're seeing big improvements in using tailing iterator vs. ordinary get.

Test Plan: ran regression test

Reviewers: dhruba, haobo, ljin, kailiu, sding

Reviewed By: haobo

CC: tnovak

Differential Revision: https://reviews.facebook.net/D15867

Summary: Nothing major, just an extra return line and posibility of leaking fb in NewRandomRWFile

Test Plan: make check

Reviewers: kailiu, dhruba

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15993

Summary: To speed up the compilation while allowing us to compile in debug mode.

Test Plan:
make: see -O2 enabled
make dbg: didn't see -O2

Reviewers: igor

Reviewed By: igor

CC: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D15969

Conflicts:
	HISTORY.md
	db/db_impl.cc
	db/db_impl.h
	db/db_iter.cc
	db/db_test.cc
	db/dbformat.h
	db/memtable.cc
	db/memtable_list.cc
	db/memtable_list.h
	db/table_cache.cc
	db/table_cache.h
	db/version_edit.h
	db/version_set.cc
	db/version_set.h
	db/write_batch.cc
	db/write_batch_test.cc
	include/rocksdb/options.h
	util/options.cc

Remove the unnecessary line led from branch merge.

Summary:
This is not column-family related diff. It is in columnfamily branch because the change is significant and we want to push it with next major release (3.0).

It removes the leveldb notion of one thread pool and expands it to two thread pools by default (HIGH and LOW). Flush process is removed from compaction process and all flush threads are executed on HIGH thread pool, since we don't want long-running compactions to influence flush latency.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15987

Fix build in case zlib not found

Summary: Revised thread-safety guarantees and implemented a way to spinlock the object.

Test Plan: make check

Reviewers: dhruba, haobo, sdong, kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15975

Summary:
WriteBatch can have multiple column families in one batch. Every column family has different options. So we have to add a way for write batch to get options for an arbitrary column family.

This required a bit more acrobatics since lots of interfaces had to be changed.

Test Plan: make check

Reviewers: dhruba, haobo, sdong, kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15957

Conflicts:
	HISTORY.md
	db/db_impl.cc
	db/memtable.cc

Summary: Replaced most of occurrences of Options with more specific DBOptions. This brings us very close to supporting different configuration options for each column family.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15933

Summary:
Lots of code expects Options on construction/function call. My original idea was to split Options argument into ColumnFamilyOptions and DBOptions (the latter only if needed). However, this will require huge code changes very deep in the stack.

The better idea is to have ColumnFamilyData hold both ColumnFamilyOptions and Options. ColumnFamilyData::Options would be constructed from DBOptions (same for each column family) and ColumnFamilyOptions (different for each column family)

Now when we construct a class or call any method that requires Options, we can just push him ColumnFamilyData::Options and be sure that it's using column-family-specific settings.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15927

Summary:
Adapting table cache to column families is interesting. We want table cache to be global LRU, so if some column families are use not as often as others, we want them to be evicted from cache. However, current TableCache object also constructs tables on its own. If table is not found in the cache, TableCache automatically creates new table. We want each column family to be able to specify different table factory.

To solve the problem, we still have a single LRU, but we provide the LRUCache object to TableCache on construction. We have one TableCache per column family, but the underyling cache is shared by all TableCache objects.

This allows us to have a global LRU, but still be able to support different table factories for different column families. Also, in the future it will also be able to support different directories for different column families.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15915

crc32c: choose function in static initialization

Before: 4.430 micros/op 225732 ops/sec; 881.8 MB/s (4K per op)
After: 4.125 micros/op 242425 ops/sec; 947.0 MB/s (4K per op)

Summary: InternalStats is a messy thing, keeping both DB data and column family data. However, it's better off living in ColumnFamilyData than in DBImpl. For now, at least.

Test Plan: make check

Reviewers: dhruba, kailiu, haobo, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15879

Summary:
There are three SanitizeOption-s now : one for DBOptions, one for ColumnFamilyOptions and one for Options (which just calls the other two)

I have also reshuffled some options -- table_cache options and info_log should live in DBOptions, for example.

Test Plan: make check doesn't complain

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15873

Summary:
Previous I am too ambitious to hide every detail about table factory
to internal api. However, we cannot pass the compilatoin for external
users since we use table factory as the shared_ptr, which requires
the definition of table factory's destructor.

Test Plan: make check;

Reviewers: sdong, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15861

Summary: user_comparator() is a Column Family property, not DBImpl

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15855

Summary: Support for different column families in Iterator and MultiGet code path.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15849

Summary: RocksDB doesn't compile on 32-bit architecture apparently. This is attempt to fix some of 32-bit errors. They are reported here: https://gist.github.com/paxos/8789697

Test Plan: RocksDB still compiles on 64-bit :)

Reviewers: kailiu

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15825

Conflicts:
	db/db_impl.cc
	db/db_impl.h
	db/db_impl_readonly.cc

Summary:
Use super_version insider NewIterator to avoid Ref() each component
separately under mutex
The new added bench shows NewIterator QPS increases from 515K to 719K
No meaningful improvement for multiget I guess due to its relatively small
cost comparing to 90 keys fetch in the test.

Test Plan: unit test and db_bench

Reviewers: igor, sdong

Reviewed By: igor

CC: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D15609

Summary:
Removed icmp_ from VersionSet (since it's per-column-family, not per-DB-instance)
Unfriended VersionSet and ColumnFamilyData (yay!)
Removed VersionSet::NumberLevels()
Cleaned up DBImpl

Test Plan: make check

Reviewers: dhruba, haobo, kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15819

Summary: In PlainTable, use one single byte to represent 8 bytes of internal bytes, if seqID = 0 and it is value type (which should be common for bottom most files). It is to save 7 bytes for uncompressed cases.

Test Plan: make all check

Reviewers: haobo, dhruba, kailiu

Reviewed By: haobo

CC: igor, leveldb

Differential Revision: https://reviews.facebook.net/D15489

Eliminate stdout message when launching a posix thread.

Summary:
Addressed all the issues in https://reviews.facebook.net/D15447.
Now most table-related modules are hidden from user land.

Test Plan: make check

Reviewers: sdong, haobo, dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15525