Summary:
We occasionally get write stalls (>1s Write() calls) on HDD under read load. The following timers explain almost all of the stalls:
 - perf_context.db_mutex_lock_nanos
 - perf_context.db_condition_wait_nanos
 - iostats_context.open_time
 - iostats_context.allocate_time
 - iostats_context.write_time
 - iostats_context.range_sync_time
 - iostats_context.logger_time

In my experiments each of these occasionally takes >1s on write path under some workload. There are rare cases when Write() takes long but none of these takes long.

Test Plan: Added code to our application to write the listed timings to log for slow writes. They usually add up to almost exactly the time Write() call took.

Reviewers: rven, yhchiang, sdong

Reviewed By: sdong

Subscribers: march, dhruba, tnovak

Differential Revision: https://reviews.facebook.net/D39177

Summary: So iOS size_t is 32-bit, so we need to static_cast<size_t> any uint64_t :(

Test Plan: TARGET_OS=IOS make static_lib

Reviewers: dhruba, ljin, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28743

Summary: Compiling for iOS has by default turned on -Wmissing-prototypes, which causes rocksdb to fail compiling. This diff turns on -Wmissing-prototypes in our compile options and cleans up all functions with missing prototypes.

Test Plan: compiles

Reviewers: dhruba, haobo, ljin, sdong

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17649

Summary:
Add appropriate LICENSE and Copyright message.

Test Plan:
make check

Reviewers:

CC:

Task ID: #

Blame Rev:

Summary: Migrate names of properties from 'leveldb' prefix to 'rocksdb' prefix.

Test Plan: make check

Reviewers: emayanke, haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13311

Summary:
Change namespace from leveldb to rocksdb. This allows a single
application to link in open-source leveldb code as well as
rocksdb code into the same process.

Test Plan: compile rocksdb

Reviewers: emayanke

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13287

Summary:
There is an existing field Options.max_bytes_for_level_multiplier that
sets the multiplier for the size of each level in the database.

This patch introduces the ability to set different multipliers
for every level in the database. The size of a level is determined
by using both max_bytes_for_level_multiplier as well as the
per-level fanout.

size of level[i] = size of level[i-1] * max_bytes_for_level_multiplier
                   * fanout[i-1]

The default value of fanout is 1, so that it is backward compatible.

Test Plan: make check

Reviewers: haobo, emayanke

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D10863