(Based on a suggestion by cmumford.)
"open" benchmark on my workstation speeds up significantly since we
can now avoid three fdatasync calls and a compaction per open:
Before: ~80000 microseconds
After: ~130 microseconds
Details:
(1) Added Options::reuse_logs (currently defaults to false) to control
new behavior. The intention is to change the default to true after some
baking.
(2) Added Env::NewAppendableFile() whose default implementation returns
a not-supported error.
(3) VersionSet::Recovery attempts to reuse the MANIFEST from which
it is recovering.
(4) DBImpl recovery attempts to reuse the last log file and memtable.
(5) db_test.cc now tests a new configuration that sets reuse_logs to true.
(6) fault_injection_test also tests a reuse_logs==true config.
(7) Added a new recovery_test.
This test is intended to ensure leveldb properly detects and recovers from
faults - specifically unwritten file data lost as a result of a system reset.
Changes are:
* Update version number to 1.18
* Replace the basic fprintf call with a call to fwrite in order to
work around the apparent compiler optimization/rewrite failure that we are
seeing with the new toolchain/iOS SDKs provided with Xcode6 and iOS8.
* Fix ALL the header guards.
* Createed a README.md with the LevelDB project description.
* A new CONTRIBUTING file.
* Don't implicitly convert uint64_t to size_t or int. Either preserve it as
uint64_t, or explicitly cast. This fixes MSVC warnings about possible value
truncation when compiling this code in Chromium.
* Added a DumpFile() library function that encapsulates the guts of the
"leveldbutil dump" command. This will allow clients to dump
data to their log files instead of stdout. It will also allow clients to
supply their own environment.
* leveldb: Remove unused function 'ConsumeChar'.
* leveldbutil: Remove unused member variables from WriteBatchItemPrinter.
* OpenBSD, NetBSD and DragonflyBSD have _LITTLE_ENDIAN, so define
PLATFORM_IS_LITTLE_ENDIAN like on FreeBSD. This fixes:
* issue #143
* issue #198
* issue #249
* Switch from <cstdatomic> to <atomic>. The former never made it into the
standard and doesn't exist in modern gcc versions at all. The later contains
everything that leveldb was using from the former.
This problem was noticed when porting to Portable Native Client where no memory
barrier is defined. The fact that <cstdatomic> is missing normally goes
unnoticed since memory barriers are defined for most architectures.
* Make Hash() treat its input as unsigned. Before this change LevelDB files
from platforms with different signedness of char were not compatible. This
change fixes: issue #243
* Verify checksums of index/meta/filter blocks when paranoid_checks set.
* Invoke all tools for iOS with xcrun. (This was causing problems with the new
XCode 5.1.1 image on pulse.)
* include <sys/stat.h> only once, and fix the following linter warning:
"Found C system header after C++ system header"
* When encountering a corrupted table file, return Status::Corruption instead of
Status::InvalidArgument.
* Support cygwin as build platform, patch is from https://code.google.com/p/leveldb/issues/detail?id=188
* Fix typo, merge patch from https://code.google.com/p/leveldb/issues/detail?id=159
* Fix typos and comments, and address the following two issues:
* issue #166
* issue #241
* Add missing db synchronize after "fillseq" in the benchmark.
* Removed unused variable in SeekRandom: value (issue #201)
- Cleanup: delete unused IntSetToString
It was added in http://cr/19491949 (and was referenced at the time).
The last reference was removed in http://cr/19507363.
This fixes warning/error with pre-release crosstoolv18:
'std::string leveldb::{anonymous}::IntSetToString(const std::set<long unsigned int>&)' defined but not used [-Werror=unused-function]
- Added arm64 and and armv7s to IOS build as suggested on leveldb mailing list.
- Changed local variable type from int to size_t
This eliminates compiler warning/error and resolves
https://code.google.com/p/leveldb/issues/detail?id=140
- Make Log::Reader not report a corruption when the last record in a
log file is truncated.
- Fix issue 224: variable created but not utilized.
- Remove comment that referenced a removed feature.
- switched from mmap based writing to simpler stdio based writing. Has a
minor impact (0.5 microseconds) on microbenchmarks for asynchronous
writes. Synchronous writes speed up from 30ms to 10ms on linux/ext4.
Should be much more reliable on diverse platforms.
- compaction errors now immediately put the database into a read-only
mode (until it is re-opened). As a downside, a disk going out of
space and then space being created will require a re-open to recover
from, whereas previously that would happen automatically. On the
plus side, many corruption possibilities go away.
- force the DB to enter an error-state so that all future writes fail
when a synchronous log write succeeds but the sync fails.
- repair now regenerates sstables that exhibit problems
- fix issue 218 - Use native memory barriers on OSX
- fix issue 212 - QNX build is broken
- fix build on iOS with xcode 5
- make tests compile and pass on windows
Fix issues 200, 201
Also,
* Fix link to bigtable paper in docs.
* New sstables will have the file extension .ldb. .sst files will
continue to be recognized.
* When building for iOS, use xcrun to execute the compiler. This may
affect issue 177.
Fix issues 77, 87, 182, 190.
Additionally, fix the bug described in
https://groups.google.com/d/msg/leveldb/yL6h1mAOc20/vLU64RylIdMJ
where a large contiguous keyspace of deleted data was not getting
compacted.
Also fix a bug where options.max_open_files was not getting clamped
properly.
Fixes issues
147 - thanks feniksgordonfreeman
153
156
166
Additionally,
* Remove calls to exit(1).
* Fix unused-variable warnings from clang.
* Fix possible overflow error related to num_restart value >= (2^32/4).
* Add leveldbutil to .gitignore.
* Add better log messages when Write is stalled on a compaction.
Details:
* Fix shared library building.
* Reorganize linking commands so flags like --as-needed can be passed.
* C binding exports version numbers.
* Fix small typos in documention.
Highlights
----------
Mmap at most 1000 files on Posix to improve performance for large databases.
Support for more architectures (thanks to Alexander K.)
Building and porting
--------------------
HP/UX support (issue 126)
AtomicPointer for ia64 (issue 123)
Sparc v9 support (issue 124)
Atomic ops for powerpc
Use -fno-builtin-memcmp only when using g++
Simplify IOS build rules (issue 114)
Use CXXFLAGS instead of CFLAGS when invoking C++ compiler (issue 118)
Fix snappy shared library problem (issue 94)
Fix shared library installation path regression
Endian-ness detection tweak for FreeBSD
Bug fixes
---------
Stop ignoring FLAGS_open_files in db_bench
Make bloom test behavior agnostic to endian-ness
Performance
-----------
Limit number of mmapped files to 1000 to improve perf for large dbs
Do not delay for 1 second on shutdown path (issue 125)
Misc
----
Make InMemoryEnv return a no-op logger
C binding now has a wrapper for free (issue 117)
Add thread-safety annotations
Added an in-process lock table (issue 120)
Make RandomAccessFile and SequentialFile non-copyable
various platforms; improve android port speed.
Avoid static initializer by using a new portability interface for
thread-safe lazy initialization. Custom ports will need to be
extended to implement InitOnce/OnceType/LEVELDB_ONCE_INIT.
Fix endian-ness detection (fixes Powerpc builds).
Build related fixes:
- Support platforms that have unversioned shared libraries.
- Fix IOS build rules.
Android improvements
- Speed up atomic pointers
- Share more code with port_posix.
Do not spin in a tight loop attempting compactions if the file system
is inaccessible (e.g., if kerberos tickets have expired or if it is out
of space).
In particular, we add a new FilterPolicy class. An instance
of this class can be supplied in Options when opening a
database. If supplied, the instance is used to generate
summaries of keys (e.g., a bloom filter) which are placed in
sstables. These summaries are consulted by DB::Get() so we
can avoid reading sstable blocks that are guaranteed to not
contain the key we are looking for.
This change provides one implementation of FilterPolicy
based on bloom filters.
Other changes:
- Updated version number to 1.4.
- Some build tweaks.
- C binding for CompactRange.
- A few more benchmarks: deleteseq, deleterandom, readmissing, seekrandom.
- Minor .gitignore update.
(1) Separate out C++ and CC flags (fixes c_test compilation)
(2) Move snappy/perftools detection to script
(3) Fix db_bench_sqlite3 and db_bench_tree_db build rules
- Makefile: Use $(CXX) for compiling C++ files,
don't override the environment's value of $CXX
- build_detect_platform: use $CXX instead of g++.
Based on bug report from Theo Schlossnagle:
http://code.google.com/p/leveldb/issues/detail?id=46
(Sync with uptream at 25807040.)
- Pass system's values of CFLAGS,LDFLAGS.
Don't override OPT if it's already set.
Original patch by Alessio Treglia <alessio@debian.org>:
http://code.google.com/p/leveldb/issues/detail?id=27#c6
- Remove 1 exit time destructor from leveldb.
See http://crbug.com/101600
- Fix problem where sstable building code would pass an
internal key to the user comparator.
(Sync with uptream at 25436817.)
Fix GCC -Wshadow warnings in LevelDB's public header files,
reported by Dustin.
Add in-memory Env implementation (helpers/memenv/*).
This enables users to create LevelDB databases in-memory.
Initialize ShardedLRUCache::last_id_ to zero.
This fixes a Valgrind warning.
(Also delete port/sha1_* which were removed upstream some time ago.)
- Added a C binding for LevelDB.
May be useful as a stable ABI that can be used by
programs that keep leveldb in a shared library,
or for JNI API.
- Replaced SQLite's readseq benchmark to a more efficient version.
SQLite readseq speeds increased by about a factor of 2x
from the previous version. Also updated benchmark page to
reflect readseq speed up.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@46 62dab493-f737-651d-591e-8d6aee1b9529
- LevelDB patch for FreeBSD. This resolves Issue 22.
Contributed by dforsythe (thanks!).
- Removing Chromium-specific files.
They are now going to live in the Chromium repository.
- Adding a benchmark page comparing LevelDB performance
to SQLite and Kyoto Cabinet's TreeDB, along with
code to generate the benchmarks.
Thanks to Kevin Tseng for compiling the benchmarks,
and Scott Hess and Mikio Hirabayashi for their
help and advice.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@40 62dab493-f737-651d-591e-8d6aee1b9529
This revision adds two major changes:
1. build_detect_platform which generates build_config.mk
with platform-dependent flags for the build process
2. /port/atomic_pointer.h with anAtomicPointerimplementation
for platforms without <cstdatomic>
Some of this code is loosely based on patches submitted to the
LevelDB mailing list at https://groups.google.com/forum/#!forum/leveldb
Tip of the hat to Dave Smith and Edouard A, who both sent patches.
The presence of Snappy (http://code.google.com/p/snappy/) and
cstdatomic are now both detected in the build_detect_platform
script (1.) which gets executing during make.
For (2.), instead of broadly importing atomicops_* from Chromium or
the Google performance tools, we chose to just implement AtomicPointer
and the limited atomic load and store operations it needs.
This resulted in much less code and fewer files - everything is
contained in atomic_pointer.h.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@34 62dab493-f737-651d-591e-8d6aee1b9529
- Implemented Get() directly instead of building on top of a full
merging iterator stack. This speeds up the "readrandom" benchmark
by up to 15-30%.
- Fixed an opensource compilation problem.
Added --db=<name> flag to control where the database is placed.
- Automatically compact a file when we have done enough
overlapping seeks to that file.
- Fixed a performance bug where we would read from at least one
file in a level even if none of the files overlapped the key
being read.
- Makefile fix for Mac OSX installations that have XCode 4 without XCode 3.
- Unified the two occurrences of binary search in a file-list
into one routine.
- Found and fixed a bug where we would unnecessarily search the
last file when looking for a key larger than all data in the
level.
- A fix to avoid the need for trivial move compactions and
therefore gets rid of two out of five syncs in "fillseq".
- Removed the MANIFEST file write when switching to a new
memtable/log-file for a 10-20% improvement on fill speed on ext4.
- Adding a SNAPPY setting in the Makefile for folks who have
Snappy installed. Snappy compresses values and speeds up writes.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@32 62dab493-f737-651d-591e-8d6aee1b9529
Minor changes:
* Reformat the bodies of the iterator interface routines in IteratorWrapper to
make them a bit easier to read
* Switched the default in the leveldb makefile to be optimized mode, rather
than debug mode
* Fix build problem in chromium port
git-svn-id: https://leveldb.googlecode.com/svn/trunk@30 62dab493-f737-651d-591e-8d6aee1b9529
* Patch LevelDB to build for OSX and iOS
* Fix race condition in memtable iterator deletion.
* Other small fixes.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@29 62dab493-f737-651d-591e-8d6aee1b9529
* env_chromium.cc should not export symbols.
* Fix MSVC warnings.
* Removed large value support.
* Fix broken reference to documentation file
git-svn-id: https://leveldb.googlecode.com/svn/trunk@24 62dab493-f737-651d-591e-8d6aee1b9529
