Summary:
...and fix all the errors :)

Jim suggested turning on -Wshadow because it helped him fix number of critical bugs in fbcode. I think it's a good idea to be -Wshadow clean.

Test Plan: compiles

Reviewers: yhchiang, rven, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27711

Summary: D24513 introduced a bug that a variable is not initialized. It also causes valgrind issue.

Test Plan: Run tests used to fail valgrind and make sure it passes

Reviewers: yhchiang, ljin, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D25569

Summary: It is useful to print out number of keys in DB Stats

Test Plan:
./db_bench --benchmarks fillrandom --num 1000000 -threads 16 -batch_size=16

and watch the outputs in LOG files

Reviewers: MarkCallaghan, ljin, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D24513

Summary: Added one new counter for GetProperty

Test Plan: Not sure if needs a test case. compiles

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D25023

Summary:
Add two stats to compaction summary:
1. Total input records from previous level
2. Total number of records dropped after compaction

Test Plan: See outputs of printing when runnning locally

Reviewers: ljin, igor, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D24411

Summary:
Add property 'rocksdb.is-file-deletions-enable'
	 which equals disable_delete_obsole_file_

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D22119

Summary:
Add a DB Property "rocksdb.estimate-table-readers-mem" to return estimated memory usage by all loaded table readers, other than allocated from block cache.

Refactor the property codes to allow getting property from a version, with DB mutex not acquired.

Test Plan: Add several checks of this new property in existing codes for various cases.

Reviewers: yhchiang, ljin

Reviewed By: ljin

Subscribers: xjin, igor, leveldb

Differential Revision: https://reviews.facebook.net/D20733

Summary: We have quite some properties that are integers and we are adding more. Add a function to directly return them as an integer, instead of a string

Test Plan: Add several unit test checks

Reviewers: yhchiang, igor, dhruba, haobo, ljin

Reviewed By: ljin

Subscribers: yoshinorim, leveldb

Differential Revision: https://reviews.facebook.net/D20637

Summary: Add a DB property of estimated number of live keys, by adding number of entries of all mem tables and all files, subtracted by all deletions in all files.

Test Plan: Add the case in unit tests

Reviewers: hobbymanyp, ljin

Reviewed By: ljin

Subscribers: MarkCallaghan, yoshinorim, leveldb, igor, dhruba

Differential Revision: https://reviews.facebook.net/D20631

Summary:
It has one-to-one relationship with CFD. Take a pointer to CFD on
constructor to avoid passing cfd through member functions.

Test Plan: make

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20565

Summary:
also make it aware of column family
output from db_bench

```
** Compaction Stats [default] **
Level Files Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) RW-Amp W-Amp Rd(MB/s) Wr(MB/s)  Rn(cnt) Rnp1(cnt) Wnp1(cnt) Wnew(cnt)  Comp(sec) Comp(cnt) Avg(sec) Stall(sec) Stall(cnt) Avg(ms)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  L0    14      956   0.9      0.0     0.0      0.0       2.7      2.7    0.0   0.0      0.0    111.6        0         0         0         0         24        40    0.612      75.20     492387    0.15
  L1    21     2001   2.0      5.7     2.0      3.7       5.3      1.6    5.4   2.6     71.2     65.7       31        43        55        12         82         2   41.242      43.72      41183    1.06
  L2   217    18974   1.9     16.5     2.0     14.4      15.1      0.7   15.6   7.4     70.1     64.3       17       182       185         3        241        16   15.052       0.00          0    0.00
  L3  1641   188245   1.8      9.1     1.1      8.0       8.5      0.5   15.4   7.4     61.3     57.2        9        75        76         1        152         9   16.887       0.00          0    0.00
  L4  4447   449025   0.4     13.4     4.8      8.6       9.1      0.5    4.7   1.9     77.8     52.7       38        79       100        21        176        38    4.639       0.00          0    0.00
 Sum  6340   659201   0.0     44.7    10.0     34.7      40.6      6.0   32.0  15.2     67.7     61.6       95       379       416        37        676       105    6.439     118.91     533570    0.22
 Int     0        0   0.0      1.2     0.4      0.8       1.3      0.5    5.2   2.7     59.1     65.6        3         7         9         2         20        10    2.003       0.00          0    0.00
Stalls(secs): 75.197 level0_slowdown, 0.000 level0_numfiles, 0.000 memtable_compaction, 43.717 leveln_slowdown
Stalls(count): 492387 level0_slowdown, 0 level0_numfiles, 0 memtable_compaction, 41183 leveln_slowdown

** DB Stats **
Uptime(secs): 202.1 total, 13.5 interval
Cumulative writes: 6291456 writes, 6291456 batches, 1.0 writes per batch, 4.90 ingest GB
Cumulative WAL: 6291456 writes, 6291456 syncs, 1.00 writes per sync, 4.90 GB written
Interval writes: 1048576 writes, 1048576 batches, 1.0 writes per batch, 836.0 ingest MB
Interval WAL: 1048576 writes, 1048576 syncs, 1.00 writes per sync, 0.82 MB written

Test Plan: ran it

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19917

Summary: as title

Test Plan:
sampe output:
Level Files Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) Write(BG) Wnew(GB) RW-Amp W-Amp Rd(MB/s) Wr(MB/s)  Rn(cnt) Rnp1(cnt) Wnp1(cnt) Wnew(cnt)  Comp(sec) Comp(cnt) Avg(sec) Stall(sec) Stall(cnt) Avg(ms)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  L0    15     1024   1.0      0.0     0.0      0.0       8.2      8.2    0.0   0.0      0.0    111.4        0         0         1         1         75       123    0.612     295.94    1939238    0.15
  L1    23     2118   2.1     20.9     8.3     12.7      20.0      7.3    5.0   2.4     73.2     69.9      124       141       208        67        293         8   36.582      17.05      16100    1.06
  L2   162    15333   1.5     47.0     7.1     40.0      42.6      2.6   12.7   6.0     67.9     61.5       62       457       482        25        709        55   12.898       0.00          0    0.00
  L3   985   108065   1.1     37.8     4.0     33.9      36.9      3.0   18.8   9.3     60.1     58.5       41       338       363        25        645        31   20.812       0.00          0    0.00
  L4  2788   356033   0.3      0.0     0.0      0.0       0.0      0.0    0.0   0.0      0.0      0.0        0         0         0         0          0         0    0.000       0.00          0    0.00
 Sum  3973   482572   0.0    105.8    19.3     86.5     107.7     21.2   11.1   5.6     62.9     64.0      227       936      1054       118       1723       217    7.938     312.99    1955338    0.16

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19707

Summary: stall count is wrong

Test Plan: make release

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19539

Summary: In this patch, two new DB properties are defined: rocksdb.num-immutable-mem-table and rocksdb.num-entries-imm-mem-tables, from where number of entries in mem tables can be exposed to users

Test Plan:
Cover the codes in db_test
make all check

Reviewers: haobo, ljin, igor

Reviewed By: igor

CC: nkg-, igor, yhchiang, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D18207

Summary: as title

Test Plan: db_test

Reviewers: sdong

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17217

Summary: Add a property to calculate number of background errors encountered to help users build their monitoring

Test Plan: Add a unit test. make all check

Reviewers: haobo, igor, dhruba

Reviewed By: igor

CC: ljin, nkg-, yhchiang, leveldb

Differential Revision: https://reviews.facebook.net/D16959

Summary: To partly address the request @nkg- raised, add three easy-to-add properties to compactions and flushes.

Test Plan: run unit tests and add a new unit test to cover new properties.

Reviewers: haobo, dhruba

Reviewed By: dhruba

CC: nkg-, leveldb

Differential Revision: https://reviews.facebook.net/D13677

Summary: Compaction picker and internal key comparator are different for each column family (not global), so they should live in ColumnFamilyData

Test Plan: make check

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15801

Summary:
In DBImpl we keep track of some statistics internally and expose them via GetProperty(). This diff encapsulates all the internal statistics into a class InternalStatisics. Most of it is copy/paste.

Apart from cleaning up db_impl.cc, this diff is also necessary for Column families, since every column family should have its own CompactionStats, MakeRoomForWrite-stall stats, etc. It's much easier to keep track of it in every column family if it's nicely encapsulated in its own class.

Test Plan: make check

Reviewers: dhruba, kailiu, haobo, sdong, emayanke

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15273