Commit Graph

101 Commits

Author SHA1 Message Date
Jim Meyering
a42324e370 build: do not relink every single binary just for a timestamp
Summary:
Prior to this change, "make check" would always waste a lot of
time relinking 60+ binaries. With this change, it does that
only when the generated file, util/build_version.cc, changes,
and that happens only when the date changes or when the
current git SHA changes.

This change makes some other improvements: before, there was no
rule to build a deleted util/build_version.cc. If it was somehow
removed, any attempt to link a program would fail.
There is no longer any need for the separate file,
build_tools/build_detect_version.  Its functionality is
now in the Makefile.

* Makefile (DEPFILES): Don't filter-out util/build_version.cc.
No need, and besides, removing that dependency was wrong.
(date, git_sha, gen_build_version): New helper variables.
(util/build_version.cc): New rule, to create this file
and update it only if it would contain new information.
* build_tools/build_detect_platform: Remove file.
* db/db_impl.cc: Now, print only date (not the time).
* util/build_version.h (rocksdb_build_compile_time): Remove
declaration.  No longer used.

Test Plan:
- Run "make check" twice, and note that the second time no linking is performed.
- Remove util/build_version.cc and ensure that any "make"
command regenerates it before doing anything else.
- Run this: strings librocksdb.a|grep _build_.
That prints output including the following:

  rocksdb_build_git_date:2015-02-19
  rocksdb_build_git_sha:2.8.fb-1792-g3cb6cc0

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D33591
2015-02-19 13:11:10 -08:00
Igor Sugak
4d98e29352 rocksdb: Enable scan-build static analysis
Summary:
Added new target ##make analyze## into Makefile. This command runs clang static analyzer and builds the sources as ##make all##. The result report is put into ##$(RocksDbSourceRoot)/can_build_report/##

If the development environment is a Facebook devserver and ##ROCKSDB_NO_FBCODE## is not set, then scan-build is used from fbcode. If it is run not on a Facebook devserver, scan-build should be available in ##$PATH##. I'll add details to wiki how to install scan-build on a non Facebook devserver environment.

Test Plan:
Run the fallowing commands on a Facebook devserver and Mac OS, and ensure no build or test errors.

```
% make all check -j32
% make clean
% USE_CLANG=1 make all -j32
% make analyze
% USE_CLANG=1 make analyze
```

Reviewers: sdong, lgalanis, leveldb, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D32799
2015-02-03 21:43:06 -08:00
Igor Canadi
2fd8f750ab Compile MemEnv with standard RocksDB library
Summary: This was a feature request by osquery. See task t5617758

Test Plan: compiles and memenv_test runs

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32115
2015-01-29 16:33:11 -08:00
Yueh-Hsuan Chiang
c4fb83441c Update the comment for the removal of mac-install-gflags.sh
Summary: Update the comment for the removal of mac-install-gflags.sh

Test Plan: n/a

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D32295
2015-01-27 10:30:35 -08:00
Igor Canadi
58f34edfce Fix valgrind 2015-01-26 13:17:28 -08:00
Igor Canadi
910186c278 Return the build with 4.8.1
Summary: We need this because we build MySQL with 4.8.1.

Test Plan: ROCKSDB_FBCODE_BUILD_WITH_481=1 make check

Reviewers: sdong, yhchiang, rven, yoshinorim

Reviewed By: yoshinorim

Subscribers: jonahcohen, yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32073
2015-01-23 14:51:27 -08:00
Igor Canadi
401d4205ef Add thread sanitizer
Summary: When you compile with COMPILE_WITH_TSAN=1, we will compile the code with -fsanitize=thread. This will resolve bunch of data race issues we might have.

Test Plan: COMPILE_WITH_TSAN=1 m db_test

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32019
2015-01-23 11:22:20 -08:00
Igor Canadi
b068f0a673 Upgrade our compilers
Summary:
Upgrade gcc to 4.9.1 and clang to dev.

With new compilers I succeeded to run thread sanitizer, too. I'll post output (doesn't look good) and fix some things in separate diffs.

Test Plan: compiles with both g++ and clang

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32007
2015-01-23 11:12:37 -08:00
Igor Canadi
155bec4cf2 fallocate also tests FALLOC_FL_KEEP_SIZE 2015-01-15 14:15:43 -08:00
Igor Canadi
a3001b1d3d Remove -mtune=native because it's redundant 2014-12-19 09:06:45 -08:00
Igor Canadi
06eed650a0 Optimize default compile to compilation platform by default
Summary:
This diff changes compile to optimize for native platform by default. This will automatically turn on crc32 optimizations for modern processors, which greatly improves rocksdb's performance.

I also did some more changes to compilation documentation.

Test Plan:
compile with `make`, observe -march=native
compile with `PORTABLE=1 make`, observe no -march=native

Reviewers: sdong, rven, yhchiang, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30225
2014-12-15 11:29:41 +01:00
Igor Canadi
767777c2bd Turn on -Wshorten-64-to-32 and fix all the errors
Summary:
We need to turn on -Wshorten-64-to-32 for mobile. See D1671432 (internal phabricator) for details.

This diff turns on the warning flag and fixes all the errors. There were also some interesting errors that I might call bugs, especially in plain table. Going forward, I think it makes sense to have this flag turned on and be very very careful when converting 64-bit to 32-bit variables.

Test Plan: compiles

Reviewers: ljin, rven, yhchiang, sdong

Reviewed By: yhchiang

Subscribers: bobbaldwin, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28689
2014-11-11 16:47:22 -05:00
Igor Canadi
5c93090530 Turn on -Wshadow
Summary:
Only one more try, I promise.

I talked to Jim and he mentioned that if we include our system includes with -isystem rather than with -I, that signals to the compile that those are system includes and thus no warnings are issued. So I turned our glibc includes into system includes and now we no longer get the warning from there, making us shadow-warning-free!

Test Plan: compiles with both clang and gcc

Reviewers: sdong, yhchiang, rven, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28479
2014-11-07 12:57:08 -08:00
Igor Canadi
30ca3752ba Revamp our build tools
Summary:
This diff is revamping our build tools:
1) Use third-party2 instead of third-party
2) consolidate clang and gcc scripts together, lots of duplication there
3) remove hdfs libs, we never compile rocksdb with them

clang compilation doesn't work yet. It doesn't work in master either. I plan to fix it soon, but I just spent 2 hours trying to make it work and failed. I'll ask experts.

Test Plan: compiles with gcc

Reviewers: ljin, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28047
2014-11-03 14:00:45 -08:00
Lei Jin
8db24f4b35 exclude mock test file from MOCK_SOURCES
Summary: as title

Test Plan: build with mock_env_test.cc

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28107
2014-10-31 15:07:27 -07:00
Igor Canadi
c082853340 Include all the mocks 2014-10-28 17:55:08 -07:00
Igor Canadi
abac3d6476 TableMock + framework for mock classes
Summary:
This diff replaces BlockBasedTable in flush_job_test with TableMock, making it depend on less things and making it closer to an unit test than integration test.

It also introduces a framework to compile mock classes -- Any file named *mock.cc will not be compiled into the build. It will only get compiled into the tests. What way we can mock out most other classes, Version, VersionSet, DBImpl, etc.

Test Plan: flush_job_test

Reviewers: ljin, rven, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27681
2014-10-28 17:52:32 -07:00
Igor Canadi
48842ab316 Deprecate AtomicPointer
Summary: RocksDB already depends on C++11, so we might as well all the goodness that C++11 provides. This means that we don't need AtomicPointer anymore. The less things in port/, the easier it will be to port to other platforms.

Test Plan: make check + careful visual review verifying that NoBarried got memory_order_relaxed, while Acquire/Release methods got memory_order_acquire and memory_order_release

Reviewers: rven, yhchiang, ljin, sdong

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D27543
2014-10-27 14:50:21 -07:00
fyrz
69d4c5123e Cross-platform fix version.sh
version.sh now works also on linux properly.
2014-10-04 11:17:06 +02:00
Igor Canadi
079a612b5e Fix build_tools/version.sh 2014-10-02 14:03:49 -07:00
Igor Canadi
0908ddcea5 Don't keep managing two rocksdb version
Summary:
Before this diff, there are two places with rocksdb versions. After the diff:
1. we only have one source of truth for rocksdb version
2. we have a script that we can use to get the version that we can use in other compilations (java, go, etc).

Test Plan: make

Reviewers: yhchiang, sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D24333
2014-10-02 11:59:22 -07:00
mike@arpaia.co
ee1f3ccb06 Package generation for Ubuntu and CentOS
Summary:
I put together a script to assist in the generation of deb's and
rpm's. I've tested that this works on ubuntu via vagrant. I've included the
Vagrantfile here, but I can remove it if it's not useful. The package.sh
script should work on any ubuntu or centos machine, I just added a bit of
logic in there to allow a base Ubuntu or Centos machine to be able to build
RocksDB from scratch.

Example output on Ubuntu 14.04:

```
root@vagrant-ubuntu-trusty-64:/vagrant# ./tools/package.sh
[+] g++-4.7 is already installed. skipping.
[+] libgflags-dev is already installed. skipping.
[+] ruby-all-dev is already installed. skipping.
[+] fpm is already installed. skipping.
Created package {:path=>"rocksdb_3.5_amd64.deb"}
root@vagrant-ubuntu-trusty-64:/vagrant# dpkg --info rocksdb_3.5_amd64.deb
 new debian package, version 2.0.
 size 17392022 bytes: control archive=1518 bytes.
     275 bytes,    11 lines      control
    2911 bytes,    38 lines      md5sums
 Package: rocksdb
 Version: 3.5
 License: BSD
 Vendor: Facebook
 Architecture: amd64
 Maintainer: rocksdb@fb.com
 Installed-Size: 83358
 Section: default
 Priority: extra
 Homepage: http://rocksdb.org/
 Description: RocksDB is an embeddable persistent key-value store for fast storage.
 ```

 Example output on CentOS 6.5:

 ```
 [root@localhost vagrant]# rpm -qip rocksdb-3.5-1.x86_64.rpm
 Name        : rocksdb                      Relocations: /usr
 Version     : 3.5                               Vendor: Facebook
 Release     : 1                             Build Date: Mon 29 Sep 2014 01:26:11 AM UTC
 Install Date: (not installed)               Build Host: localhost
 Group       : default                       Source RPM: rocksdb-3.5-1.src.rpm
 Size        : 96231106                         License: BSD
 Signature   : (none)
 Packager    : rocksdb@fb.com
 URL         : http://rocksdb.org/
 Summary     : RocksDB is an embeddable persistent key-value store for fast storage.
 Description :
 RocksDB is an embeddable persistent key-value store for fast storage.
 ```

Test Plan:
How this gets used is really up to the RocksDB core team. If you
want to actually get this into mainline, you might have to change `make
install` such that it install the RocksDB shared object file as well, which
would require you to link against gflags (maybe?) and that would require some
potential modifications to the script here (basically add a depends on that
package).

Currently, this will install the headers and a pre-compiled statically linked
object file. If that's what you want out of life, than this requires no
modifications.

Reviewers: ljin, yhchiang, igor

Reviewed By: igor

Differential Revision: https://reviews.facebook.net/D24141
2014-09-29 16:09:46 -07:00
Igor Canadi
3b897cddd7 Enable no-fbcode RocksDB build
Summary: I want to use open source build rather than fbcode one. This enables me to run `ROCKSDB_NO_FBCODE=1 make` and run it with my system g++.

Test Plan:
ROCKSDB_NO_FBCODE=1 make
make

Reviewers: sdong, ljin, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D23613
2014-09-19 09:27:16 -07:00
Igor Canadi
8de151bb99 Add db_bench with lots of column families to regression tests
Summary:
That way we can see when this graph goes up and be happy.

Couple of changes:
1. title
2. fix db_bench to delete column families before deleting the DB. this was asserting when compiled in debug mode
3. don't sync manifest when disableDataSync. We discussed this offline. I can move it to separate diff if you'd like

Test Plan: ran it

Reviewers: sdong, yhchiang, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D22815
2014-09-05 14:20:18 -07:00
miguelportilla
93e6b5e9d9 Changes to support unity build:
* Script for building the unity.cc file via Makefile
* Unity executable Makefile target for testing builds
* Source code changes to fix compilation of unity build
2014-08-11 13:22:47 -04:00
Yueh-Hsuan Chiang
ae7743f226 Fixed some make and linking issues of RocksDBJava
Summary:
Fixed some make and linking issues of RocksDBJava. Specifically:
* Add JAVA_LDFLAGS, which does not include gflags
* rocksdbjava library now uses JAVA_LDFLAGS instead of LDFLAGS
* java/Makefile now includes build_config.mk
* rearrange make rocksdbjava workflow to ensure the library file is correctly
  included in the jar file.

Test Plan:
make rocksdbjava
make jdb_bench
java/jdb_bench.sh

Reviewers: dhruba, swapnilghike, zzbennett, rsumbaly, ankgup87

Reviewed By: ankgup87

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20289
2014-07-21 22:41:54 -07:00
Radheshyam Balasundaram
f0660d5253 Adding NUMA support to db_bench tests
Summary:
Changes:
- Adding numa_aware flag to db_bench.cc
- Using numa.h library to bind memory and cpu of threads to a fixed NUMA node
Result: There seems to be no significant change in the micros/op time with numa_aware enabled. I also tried this with other implementations, including a combination of pthread_setaffinity_np, sched_setaffinity and set_mempolicy methods. It'd be great if someone could point out where I'm going wrong and if we can achieve a better micors/op.

Test Plan:
Ran db_bench tests using following command:
./db_bench --db=/mnt/tmp --num_levels=6 --key_size=20 --prefix_size=20 --keys_per_prefix=0 --value_size=100 --block_size=4096 --cache_size=17179869184 --cache_numshardbits=6 --compression_type=none --compression_ratio=1 --min_level_to_compress=-1 --disable_seek_compaction=1 --hard_rate_limit=2 --write_buffer_size=134217728 --max_write_buffer_number=2 --level0_file_num_compaction_trigger=8 --target_file_size_base=134217728 --max_bytes_for_level_base=1073741824 --disable_wal=0 --wal_dir=/mnt/tmp --sync=0 --disable_data_sync=1 --verify_checksum=1 --delete_obsolete_files_period_micros=314572800 --max_grandparent_overlap_factor=10 --max_background_compactions=4 --max_background_flushes=0 --level0_slowdown_writes_trigger=16 --level0_stop_writes_trigger=24 --statistics=0 --stats_per_interval=0 --stats_interval=1048576 --histogram=0 --use_plain_table=1 --open_files=-1 --mmap_read=1 --mmap_write=0 --memtablerep=prefix_hash --bloom_bits=10 --bloom_locality=1 --perf_level=0 --duration=300 --benchmarks=readwhilewriting --use_existing_db=1 --num=157286400 --threads=24 --writes_per_second=10240 --numa_aware=[False/True]

The tests were run in private devserver with 24 cores and the db was prepopulated using filluniquerandom test. The tests resulted in 0.145 us/op with numa_aware=False and 0.161 us/op with numa_aware=True.

Reviewers: sdong, yhchiang, ljin, igor

Reviewed By: ljin, igor

Subscribers: igor, leveldb

Differential Revision: https://reviews.facebook.net/D19353
2014-07-07 10:53:31 -07:00
nawu
fb54eef744 escaped the special characters and added a dot 2014-06-24 00:14:02 -05:00
nawu
c9ad282e4a added a dot 2014-06-24 00:05:03 -05:00
Igor Canadi
d4a8423334 Remove seek compaction
Summary:
As discussed in our internal group, we don't get much use of seek compaction at the moment, while it's making code more complicated and slower in some cases.

This diff removes seek compaction and (hopefully) all code that was introduced to support seek compaction.

There is one test case that relied on didIO information. I'll try to find another way to implement it.

Test Plan: make check

Reviewers: sdong, haobo, yhchiang, ljin, dhruba

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19161
2014-06-20 10:23:02 +02:00
Lei Jin
578cf84ddf give correct metric name for grep in regression script
Summary: as title

Test Plan: jenkin

Reviewers: igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19005
2014-06-10 16:32:09 -07:00
Lei Jin
c4b3817d7c fix regression test
Summary: as title

Test Plan: push

Reviewers: igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D18999
2014-06-10 11:24:24 -07:00
Lei Jin
e2d3101cf1 collect metrics for in memory workload get/seek
Summary:
collect in-memory workload get/seek metrics so that we can alert on
regression

Test Plan: ran locally

Reviewers: igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D18969
2014-06-10 09:59:16 -07:00
Igor Canadi
457bae6911 Fix regression test
Summary:
388d2054c7
added extra line to db_bench output, breaking regression tests. This diff makes it more robust and fixes the issue

Test Plan: ran it

Reviewers: ljin, sdong

Reviewed By: sdong

Subscribers: sdong, leveldb

Differential Revision: https://reviews.facebook.net/D18897
2014-06-04 09:59:44 -07:00
Mike Orr
c2fda55cfe hdfs cleanup and compile test against CDH 4.4. 2014-05-20 17:22:12 -04:00
Mike Lin
76596b5318 Fix building RocksDB in paths containing spaces -- quote path names in Makefile and build_detect_platform. 2014-05-10 21:01:25 -07:00
Igor Canadi
a1068c91a1 Make RocksDB work with newer gflags
Summary:
Newer gflags switched from `google` namespace to `gflags` namespace. See: https://github.com/facebook/rocksdb/issues/139 and https://github.com/facebook/rocksdb/issues/102

Unfortunately, they don't define any macro with their namespace, so we need to actually try to compile gflags with two different namespace to figure out which one is the correct one.

Test Plan: works in fbcode environemnt. I'll also try in ubutnu with newer gflags

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18537
2014-05-08 17:25:13 -07:00
Igor Canadi
313b2e5da1 Better INSTALL.md and Makefile rules
Summary: We have a lot of problems with gflags. However, when compiling rocksdb static library, we don't need gflags dependency. Reorganize INSTALL.md such that first-time customers don't need any dependency installed to actually build rocksdb static library.

Test Plan: none

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18501
2014-05-07 16:51:30 -07:00
Igor Canadi
9e7d00d9e7 Make rocksdb work with all versions of lz4
Summary:
There are some projects in fbcode that define lz4 dependency on r108. We, however, defined dependency on r117. That produced some interesting issues and our build system was not happy.

This diff makes rocksdb work with both r108 and r117. Hopefully this will fix our problems.

Test Plan: compiled rocksdb with both r108 and r117 lz4

Reviewers: dhruba, sdong, haobo

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18465
2014-05-05 11:35:40 -07:00
Igor Canadi
77edbfd642 link with lz4
Summary: link our fbcode build with lz4

Test Plan: compiles

Reviewers: sdong, haobo, dhruba, yhchiang

Reviewed By: yhchiang

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18447
2014-05-02 13:55:33 -07:00
Igor Canadi
66f88c43a5 Some fixes as preparation for release 2014-04-30 09:03:24 -07:00
Igor Canadi
de825e7307 Create new branch instead of tag in make_new_version 2014-04-29 13:22:34 -04:00
Igor Canadi
8dc34364d2 Rename "benchmark" back to "bench".
Also, make `benchharness.cc` not compiled into rocksdb library.
2014-04-21 13:12:15 -07:00
Pratyush Seth
ff1b5df4c6 Added benchmark functionality on the lines of folly/Benchmark.h
Summary: Added benchmark functionality on the lines of folly/Benchmark.h

Test Plan: Added unit tests

Reviewers: igor, haobo, sdong, ljin, yhchiang, dhruba

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17973
2014-04-21 12:29:55 -07:00
Igor Canadi
588bca2020 RocksDBLite
Summary:
Introducing RocksDBLite! Removes all the non-essential features and reduces the binary size. This effort should help our adoption on mobile.

Binary size when compiling for IOS (`TARGET_OS=IOS m static_lib`) is down to 9MB from 15MB (without stripping)

Test Plan: compiles :)

Reviewers: dhruba, haobo, ljin, sdong, yhchiang

Reviewed By: yhchiang

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17835
2014-04-15 13:39:26 -07:00
Igor Canadi
51023c3911 Make RocksDB compile for iOS
Summary:
I had to make number of changes to the code and Makefile:
* Add `make lib`, that will create static library without debug info. We need this to avoid growing binary too much. Currently it's 14MB.
* Remove cpuinfo() function and use __SSE4_2__ macro. We actually used the macro as part of Fast_CRC32() function.
As a result, I also accidentally fixed this issue: https://www.facebook.com/groups/rocksdb.dev/permalink/549700778461774/?stream_ref=2
* Remove __thread locals in OS_MACOSX

Test Plan: `make lib PLATFORM=IOS`

Reviewers: ljin, haobo, dhruba, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17475
2014-04-04 13:11:44 -07:00
Igor Canadi
8e634d3ea4 Merge pull request #74 from alberts/lz4
Support for LZ4 compression.
2014-02-10 15:46:56 -08:00
Igor Canadi
5833f47114 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
2014-02-10 11:06:25 -08:00
Albert Strasheim
df2f92214a Support for LZ4 compression. 2014-02-08 14:15:51 -08:00
Igor Canadi
1560bb913e Readrandom with tailing iterator
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
2014-02-07 09:47:47 -08:00