Summary: as title
Test Plan:
make all check
ran db_bench and saw seek stats at the end
Reviewers: yhchiang, igor, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D21651
Summary:
Contains the following changes:
- Implementation of cuckoo_table_factory
- Adding cuckoo table into AdaptiveTableFactory
- Adding cuckoo_table_db_test, similar to lines of plain_table_db_test
- Minor fixes to Reader: When a key is found in the table, return the key found instead of the search key.
- Minor fixes to Builder: Add table properties that are required by Version::UpdateTemporaryStats() during Get operation. Don't define curr_node as a reference variable as the memory locations may get reassigned during tree.push_back operation, leading to invalid memory access.
Test Plan:
cuckoo_table_reader_test --enable_perf
cuckoo_table_builder_test
cuckoo_table_db_test
make check all
make valgrind_check
make asan_check
Reviewers: sdong, igor, yhchiang, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D21219
* 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
Summary:
Contains:
- Implementation of TableReader based on Cuckoo Hashing
- Unittests for CuckooTableReader
- Performance test for TableReader
Test Plan:
make cuckoo_table_reader_test
./cuckoo_table_reader_test
make valgrind_check
make asan_check
Reviewers: yhchiang, sdong, igor, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D20511
Summary:
This diff is adding spatial index support to RocksDB.
When creating the DB user specifies a list of spatial indexes. Spatial indexes can cover different areas and have different resolution (i.e. number of tiles). This is useful for supporting different zoom levels.
Each element inserted into SpatialDB has:
* a bounding box, which determines how will the element be indexed
* string blob, which will usually be WKB representation of the polygon (http://en.wikipedia.org/wiki/Well-known_text)
* feature set, which is a map of key-value pairs, where value can be int, double, bool, null or a string. FeatureSet will be a set of tags associated with geo elements (for example, 'road': 'highway' and similar)
* a list of indexes to insert the element in. For example, small river element will be inserted in index for high zoom level, while country border will be inserted in all indexes (including the index for low zoom level).
Each query is executed on single spatial index. Query guarantees that it will return all elements intersecting the specified bounding box, but it might also return some extra non-intersecting elements.
Test Plan: Added bunch of unit tests in spatial_db_test
Reviewers: dhruba, yinwang
Reviewed By: yinwang
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D20361
Summary:
Add the missing ROCKSDB_JAR variable in Makefile, which is mistakenly
removed in https://reviews.facebook.net/D20289.
Test Plan:
export ROCKSDB_JAR=
make rocksdbjava
Summary:
Add a function GetOptions(), where based on four parameters users give: read/write amplification threshold, memory budget for mem tables and target DB size, it picks up a compaction style and parameters for them. Background threads are not touched yet.
One limit of this algorithm: since compression rate and key/value size are hard to predict, it's hard to predict level 0 file size from write buffer size. Simply make 1:1 ratio here.
Sample results: https://reviews.facebook.net/P477
Test Plan: Will add some a unit test where some sample scenarios are given and see they pick the results that make sense
Reviewers: yhchiang, dhruba, haobo, igor, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18741
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
Summary:
Add -Wsign-compare to WARNING_FLAGS in Makefile as not all g++ compiler
include -Wsign-compare in -Wall when compiling '.h' file.
Test Plan: make -j32
Reviewers: ljin, igor, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D20169
Summary:
This is a rough sketch of our new document API. Would like to get some thoughts and comments about the high-level architecture and API.
I didn't optimize for performance at all. Leaving some low-hanging fruit so that we can be happy when we fix them! :)
Currently, bunch of features are not supported at all. Indexes can be only specified when creating database. There is no query planner whatsoever. This will all be added in due time.
Test Plan: Added a simple unit test
Reviewers: haobo, yhchiang, dhruba, sdong, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18747
Summary:
A generic rate limiter that can be shared by threads and rocksdb
instances. Will use this to smooth out write traffic generated by
compaction and flush. This will help us get better p99 behavior on flash
storage.
Test Plan:
unit test output
==== Test RateLimiterTest.Rate
request size [1 - 1023], limit 10 KB/sec, actual rate: 10.374969 KB/sec, elapsed 2002265
request size [1 - 2047], limit 20 KB/sec, actual rate: 20.771242 KB/sec, elapsed 2002139
request size [1 - 4095], limit 40 KB/sec, actual rate: 41.285299 KB/sec, elapsed 2202424
request size [1 - 8191], limit 80 KB/sec, actual rate: 81.371605 KB/sec, elapsed 2402558
request size [1 - 16383], limit 160 KB/sec, actual rate: 162.541268 KB/sec, elapsed 3303500
Reviewers: yhchiang, igor, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19359
Summary:
After evaluating options for JSON storage, I decided to implement our own. The reason is that we'll be able to optimize it better and we get to reduce unnecessary dependencies (which is what we'd get with folly).
I also plan to write a serializer/deserializer for JSONDocument with our own binary format similar to BSON. That way we'll store binary JSON format in RocksDB instead of the plain-text JSON. This means less storage and faster deserialization.
There are still some inefficiencies left here. I plan to optimize them after we develop a functioning DocumentDB. That way we can move and iterate faster.
Test Plan: added a unit test
Reviewers: dhruba, haobo, sdong, ljin, yhchiang
Reviewed By: haobo
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18831
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
Summary:
db_test includes Benchmark for LogAndApply. This diff removes it from db_test and puts it into a separate log_and_apply bench. I just wanted to play around with our new benchmark framework and figure out how it works.
I would also like to show you how great it is! I believe right set of microbenchmarks can speed up our productivity a lot and help catch early regressions.
Test Plan: no
Reviewers: dhruba, haobo, sdong, ljin, yhchiang
Reviewed By: yhchiang
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18261
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
Summary:
The file tree structure in Version is prebuilt and the range of each file is known.
On the Get() code path, we do binary search in FindFile() by comparing
target key with each file's largest key and also check the range for each L0 file.
With some pre-calculated knowledge, each key comparision that has been done can serve
as a hint to narrow down further searches:
(1) If a key falls within a L0 file's range, we can safely skip the next
file if its range does not overlap with the current one.
(2) If a key falls within a file's range in level L0 - Ln-1, we should only
need to binary search in the next level for files that overlap with the current one.
(1) will be able to skip some files depending one the key distribution.
(2) can greatly reduce the range of binary search, especially for bottom
levels, given that one file most likely only overlaps with N files from
the level below (where N is max_bytes_for_level_multiplier). So on level
L, we will only look at ~N files instead of N^L files.
Some inital results: measured with 500M key DB, when write is light (10k/s = 1.2M/s), this
improves QPS ~7% on top of blocked bloom. When write is heavier (80k/s =
9.6M/s), it gives us ~13% improvement.
Test Plan: make all check
Reviewers: haobo, igor, dhruba, sdong, yhchiang
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17205
Summary:
Add a skeleton binding and test for BackupableDB which shows that BackupableDB
and RocksDB can share the same JNI calls.
Test Plan:
make rocksdbjava
make jtest
Reviewers: haobo, ankgup87, sdong, dhruba
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17793
Summary:
We don't really need sync_point.o if we're compiling with NDEBUG.
This diff depends on D17823
Test Plan: compiles
Reviewers: haobo, ljin, sdong
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17829
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
Summary:
This is first step of my effort to reduce size of librocksdb.a for use in mobile.
ldb object files are huge and are ment to be used as a command line tool. I moved them to `tools/` directory and include them only when compiling `ldb`
This diff reduced librocksdb.a from 42MB to 39MB on my mac (not stripped).
Test Plan: ran ldb
Reviewers: dhruba, haobo, sdong, ljin, yhchiang
Reviewed By: yhchiang
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17823
Summary:
* Add a benchmark for java binding for rocksdb. The java benchmark
is a complete rewrite based on the c++ db/db_bench.cc and the
DbBenchmark in dain's java leveldb.
* Support multithreading.
* 'readseq' is currently not supported as it requires RocksDB Iterator.
* usage:
--benchmarks
Comma-separated list of operations to run in the specified order
Actual benchmarks:
fillseq -- write N values in sequential key order in async mode
fillrandom -- write N values in random key order in async mode
fillbatch -- write N/1000 batch where each batch has 1000 values
in random key order in sync mode
fillsync -- write N/100 values in random key order in sync mode
fill100K -- write N/1000 100K values in random order in async mode
readseq -- read N times sequentially
readrandom -- read N times in random order
readhot -- read N times in random order from 1% section of DB
Meta Operations:
delete -- delete DB
DEFAULT: [fillseq, readrandom, fillrandom]
--compression_ratio
Arrange to generate values that shrink to this fraction of
their original size after compression
DEFAULT: 0.5
--use_existing_db
If true, do not destroy the existing database. If you set this
flag and also specify a benchmark that wants a fresh database, that benchmark will fail.
DEFAULT: false
--num
Number of key/values to place in database.
DEFAULT: 1000000
--threads
Number of concurrent threads to run.
DEFAULT: 1
--reads
Number of read operations to do. If negative, do --nums reads.
--key_size
The size of each key in bytes.
DEFAULT: 16
--value_size
The size of each value in bytes.
DEFAULT: 100
--write_buffer_size
Number of bytes to buffer in memtable before compacting
(initialized to default value by 'main'.)
DEFAULT: 4194304
--cache_size
Number of bytes to use as a cache of uncompressed data.
Negative means use default settings.
DEFAULT: -1
--seed
Seed base for random number generators.
DEFAULT: 0
--db
Use the db with the following name.
DEFAULT: /tmp/rocksdbjni-bench
* Add RocksDB.write().
Test Plan: make jbench
Reviewers: haobo, sdong, dhruba, ankgup87
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17433
Summary: This will allow us to disable them completely for iOS or for better performance
Test Plan: will run make all check
Reviewers: igor, haobo, dhruba
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17511
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
Summary:
* Add java api for rocksdb::WriteBatch and rocksdb::WriteOptions, which are necessary components
for running benchmark.
* Add java test for org.rocksdb.WriteBatch and org.rocksdb.WriteOptions.
* Add remove() to org.rocksdb.RocksDB, and add put() and remove() to RocksDB which take
org.rocksdb.WriteOptions.
Test Plan: make jtest
Reviewers: haobo, sdong, dhruba
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17373
Summary:
* [java] Add a java api for rocksdb::Options, currently only supports create_if_missing.
* [java] Add a test for RocksDBException in RocksDBSample.
Test Plan: make jtest
Reviewers: haobo, sdong
Reviewed By: haobo
CC: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D17385
Summary:
This patch stores gps locations in rocksdb.
Each object is uniquely identified by an id. Each object has
a gps (latitude, longitude) associated with it. The geodb
supports looking up an object either by its gps location
or by its id. There is a method to retrieve all objects
within a circular radius centered at a specified gps location.
Test Plan: Simple unit-test attached.
Reviewers: leveldb, haobo
Reviewed By: haobo
CC: leveldb, tecbot, haobo
Differential Revision: https://reviews.facebook.net/D15567
Summary:
This diff contains a simple jni library for rocksdb which supports open, get,
put and closeusing default options (including Options, ReadOptions, and
WriteOptions.) In the usual case, Java developers can use the c++ rocksdb
library in the way similar to the following:
RocksDB db = RocksDB.open(path_to_db);
...
db.put("hello".getBytes(), "world".getBytes();
byte[] value = db.get("hello".getBytes());
...
db.close();
Specifically, this diff has the following major classes:
* RocksDB: a Java wrapper class which forwards the operations
from the java side to c++ rocksdb library.
* RocksDBException: ncapsulates the error of an operation.
This exception type is used to describe an internal error from
the c++ rocksdb library.
This diff also include a simple java sample code calling c++ rocksdb library.
To build the rocksdb jni library, simply run make jni, and make jtest will try to
build and run the sample code.
Note that if the rocksdb is not built with the default glibc that Java uses,
java will try to load the wrong glibc during the run time. As a result,
the sample code might not work properly during the run time.
Test Plan:
* make jni
* make jtest
Reviewers: haobo, dhruba, sdong, igor, ljin
Reviewed By: dhruba
CC: leveldb, xjin
Differential Revision: https://reviews.facebook.net/D17109
Summary:
@kailiu mentioned on meeting yesterday that we sometimes have trouble opening DB created by old version with the new version. This will be very important to test for column families, since I'm changing disk format for the MANIFEST.
I added a tool that can help us test that. Usage:
./db_sanity_test <path> create
will create a bunch of DBs under <path>
<change RocksDB version>
./db_sanity_test <path> verify
will verify consistency of DBs created under <path>
Test Plan: ran the db_sanity_test
Reviewers: kailiu, dhruba, haobo
Reviewed By: kailiu
CC: leveldb, kailiu, xjin
Differential Revision: https://reviews.facebook.net/D16605
Summary:
this is the key component extracted from diff: https://reviews.facebook.net/D14271
I separate it to a dedicated patch to make the review easier.
Test Plan: added a unit test and passed it.
Reviewers: haobo, sdong, dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D16245
Summary:
This is not a generic thread local implementation in the sense that it
only takes pointer. But it does support multiple instances per thread
and lets user plugin function to perform cleanup when thread exits or an
instance gets destroyed.
Test Plan: unit test for now
Reviewers: haobo, igor, sdong, dhruba
Reviewed By: igor
CC: leveldb, kailiu
Differential Revision: https://reviews.facebook.net/D16131
Summary: A simple benchmark that simulates WAL append. It can be used to test different platform/file system's performance on WAL.
Test Plan: run it.
Reviewers: haobo, kailiu
Reviewed By: haobo
CC: igor, dhruba, i.am.jin.lei, yhchiang, leveldb, nkg-
Differential Revision: https://reviews.facebook.net/D16239
Summary:
Add a test to verify HashLinkList and HashSkipList (mainly for the former one) returns the correct results when inserting the same bucket in the different orders.
Some other changes:
(1) add the test to test list
(2) fix compile error
(3) add header
Test Plan: ./prefix_test
Reviewers: haobo, kailiu
Reviewed By: haobo
CC: igor, yhchiang, i.am.jin.lei, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D16143
Summary: Fix table_reader_bench after some interface changes. Add it to make to avoid future breaking
Test Plan: make table_reader_bench and run it with different options.
Reviewers: kailiu, haobo
Reviewed By: haobo
CC: igor, leveldb
Differential Revision: https://reviews.facebook.net/D16107
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
Summary:
In new third-party release tool, `LIBNAME=<customized_library> make`
will not really change the LIBNAME.
However it's very odd that the same approach works with old third-party
release tools. I checked previous rocksdb version and both librocksdb.a
and librocksdb_debug.a were correctly generated and copied to the
right place.
Test Plan:
`LIBNAME=hello make -j32` generates hello.a
`make -j32` generates librocksdb.a
Reviewers: igor, sdong, haobo, dhruba
Reviewed By: igor
CC: leveldb
Differential Revision: https://reviews.facebook.net/D15555
Summary:
Previous we made `make release` also compile shared library. However it takes a long time to complete.
To make our development process more efficient. I added a new make target shared_lib.
User can of course run `make <library_name>` for direct compilation. However the <library_name> changed under certain condition. Thus we need `make shared_lib` to get rid of the memorization from users' side.
Test Plan: make shared_lib
Reviewers: igor, sdong, haobo, dhruba
Reviewed By: igor
CC: leveldb
Differential Revision: https://reviews.facebook.net/D15309
Compiling the shared libraries took a long time. Thus to speed up the development speed, it still makes sense to be separated from regular compilation.
Summary:
Added a script that reformat only the affected lines in a given diff.
I planned to make that file as pre-commit hook but looks it's a little bit more difficult than I thought. Since I don't want to spend too much time on this task right now, I eventually added a "make command" to achieve this with a few additional key strokes.
Also make the clang-format solely inherited from Google's style -- there are still debates on some of the style issues, but we can address them later once we reach a consensus.
Test Plan: Did some ugly format change and ran "make format", all affected lines are formatted as expected.
Reviewers: igor, sdong, haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D15147
Summary:
Per request, some users need to use dynamic rocksdb library instead of static one.
However currently the dynamic libraries have to be manually compiled by default, which is inconvenient. I made dymamic libraries to be compiled by default.
Test Plan: make clean; make; make clean;
Reviewers: haobo, sdong, dhruba, igor
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D15117
Summary:
This diff provides basic implementations of CreateColumnFamily(), DropColumnFamily() and ListColumnFamilies(). It builds on top of https://reviews.facebook.net/D14733
It also includes a bug fix for DBImplReadOnly, where Get implementation would be redirected to DBImpl instead of DBImplReadOnly.
Test Plan: Added unit test
Reviewers: dhruba, haobo, kailiu
CC: leveldb
Differential Revision: https://reviews.facebook.net/D15021
Summary:
A vector that leverages pre-allocated stack-based array to achieve better
performance for array with small amount of items.
Test Plan:
Added tests for both correctness and performance
Here is the performance benchmark between vector and autovector
Please note that in the test "Creation and Insertion Test", the test case were designed with the motivation described below:
* no element inserted: internal array of std::vector may not really get
initialize.
* one element inserted: internal array of std::vector must have
initialized.
* kSize elements inserted. This shows the most time we'll spend if we
keep everything in stack.
* 2 * kSize elements inserted. The internal vector of
autovector must have been initialized.
Note: kSize is the capacity of autovector
=====================================================
Creation and Insertion Test
=====================================================
created 100000 vectors:
each was inserted with 0 elements
total time elapsed: 128000 (ns)
created 100000 autovectors:
each was inserted with 0 elements
total time elapsed: 3641000 (ns)
created 100000 VectorWithReserveSizes:
each was inserted with 0 elements
total time elapsed: 9896000 (ns)
-----------------------------------
created 100000 vectors:
each was inserted with 1 elements
total time elapsed: 11089000 (ns)
created 100000 autovectors:
each was inserted with 1 elements
total time elapsed: 5008000 (ns)
created 100000 VectorWithReserveSizes:
each was inserted with 1 elements
total time elapsed: 24271000 (ns)
-----------------------------------
created 100000 vectors:
each was inserted with 4 elements
total time elapsed: 39369000 (ns)
created 100000 autovectors:
each was inserted with 4 elements
total time elapsed: 10121000 (ns)
created 100000 VectorWithReserveSizes:
each was inserted with 4 elements
total time elapsed: 28473000 (ns)
-----------------------------------
created 100000 vectors:
each was inserted with 8 elements
total time elapsed: 75013000 (ns)
created 100000 autovectors:
each was inserted with 8 elements
total time elapsed: 18237000 (ns)
created 100000 VectorWithReserveSizes:
each was inserted with 8 elements
total time elapsed: 42464000 (ns)
-----------------------------------
created 100000 vectors:
each was inserted with 16 elements
total time elapsed: 102319000 (ns)
created 100000 autovectors:
each was inserted with 16 elements
total time elapsed: 76724000 (ns)
created 100000 VectorWithReserveSizes:
each was inserted with 16 elements
total time elapsed: 68285000 (ns)
-----------------------------------
=====================================================
Sequence Access Test
=====================================================
performed 100000 sequence access against vector
size: 4
total time elapsed: 198000 (ns)
performed 100000 sequence access against autovector
size: 4
total time elapsed: 306000 (ns)
-----------------------------------
performed 100000 sequence access against vector
size: 8
total time elapsed: 565000 (ns)
performed 100000 sequence access against autovector
size: 8
total time elapsed: 512000 (ns)
-----------------------------------
performed 100000 sequence access against vector
size: 16
total time elapsed: 1076000 (ns)
performed 100000 sequence access against autovector
size: 16
total time elapsed: 1070000 (ns)
-----------------------------------
Reviewers: dhruba, haobo, sdong, chip
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14655
Summary:
db_test should be the first to execute because it finds the most bugs.
Also, when third parties report issues, we don't want ldb error message, we prefer to have db_test error message. For example, see thread: https://github.com/facebook/rocksdb/issues/25
Test Plan: make check
Reviewers: dhruba, haobo, kailiu
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14715
Summary: as title
Test Plan: dynamic_bloom_test
Reviewers: dhruba, sdong, kailiu
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14385
Summary:
In this diff I present you BackupableDB v1. You can easily use it to backup your DB and it will do incremental snapshots for you.
Let's first describe how you would use BackupableDB. It's inheriting StackableDB interface so you can easily construct it with your DB object -- it will add a method RollTheSnapshot() to the DB object. When you call RollTheSnapshot(), current snapshot of the DB will be stored in the backup dir. To restore, you can just call RestoreDBFromBackup() on a BackupableDB (which is a static method) and it will restore all files from the backup dir. In the next version, it will even support automatic backuping every X minutes.
There are multiple things you can configure:
1. backup_env and db_env can be different, which is awesome because then you can easily backup to HDFS or wherever you feel like.
2. sync - if true, it *guarantees* backup consistency on machine reboot
3. number of snapshots to keep - this will keep last N snapshots around if you want, for some reason, be able to restore from an earlier snapshot. All the backuping is done in incremental fashion - if we already have 00010.sst, we will not copy it again. *IMPORTANT* -- This is based on assumption that 00010.sst never changes - two files named 00010.sst from the same DB will always be exactly the same. Is this true? I always copy manifest, current and log files.
4. You can decide if you want to flush the memtables before you backup, or you're fine with backing up the log files -- either way, you get a complete and consistent view of the database at a time of backup.
5. More things you can find in BackupableDBOptions
Here is the directory structure I use:
backup_dir/CURRENT_SNAPSHOT - just 4 bytes holding the latest snapshot
0, 1, 2, ... - files containing serialized version of each snapshot - containing a list of files
files/*.sst - sst files shared between snapshots - if one snapshot references 00010.sst and another one needs to backup it from the DB, it will just reference the same file
files/ 0/, 1/, 2/, ... - snapshot directories containing private snapshot files - current, manifest and log files
All the files are ref counted and deleted immediatelly when they get out of scope.
Some other stuff in this diff:
1. Added GetEnv() method to the DB. Discussed with @haobo and we agreed that it seems right thing to do.
2. Fixed StackableDB interface. The way it was set up before, I was not able to implement BackupableDB.
Test Plan:
I have a unittest, but please don't look at this yet. I just hacked it up to help me with debugging. I will write a lot of good tests and update the diff.
Also, `make asan_check`
Reviewers: dhruba, haobo, emayanke
Reviewed By: dhruba
CC: leveldb, haobo
Differential Revision: https://reviews.facebook.net/D14295
