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gabor@google.com 7263023651 Bugfixes: for Get(), don't hold mutex while writing log.
- Fix bug in Get: when it triggers a compaction, it could sometimes
  mark the compaction with the wrong level (if there was a gap
  in the set of levels examined for the Get).

- Do not hold mutex while writing to the log file or to the
  MANIFEST file.

  Added a new benchmark that runs a writer thread concurrently with
  reader threads.

  Percentiles
  ------------------------------
  micros/op: avg  median 99   99.9  99.99  99.999 max
  ------------------------------------------------------
  before:    42   38     110  225   32000  42000  48000
  after:     24   20     55   65    130    1100   7000

- Fixed race in optimized Get.  It should have been using the
  pinned memtables, not the current memtables.



git-svn-id: https://leveldb.googlecode.com/svn/trunk@50 62dab493-f737-651d-591e-8d6aee1b9529
2011-09-01 19:08:02 +00:00
db Bugfixes: for Get(), don't hold mutex while writing log. 2011-09-01 19:08:02 +00:00
doc Bugfixes for iterator and documentation. 2011-08-16 01:21:01 +00:00
include/leveldb C binding for leveldb, better readseq benchmark for SQLite. 2011-08-05 20:40:49 +00:00
port Adding FreeBSD support, removing Chromium files, adding benchmark. 2011-07-27 01:46:25 +00:00
table Speed up Snappy uncompression, new Logger interface. 2011-07-21 02:40:18 +00:00
util Bugfix for issue 33; reduce lock contention in Get(), parallel benchmarks. 2011-08-22 21:08:51 +00:00
AUTHORS reverting disastrous MOE commit, returning to r21 2011-04-19 23:11:15 +00:00
LICENSE reverting disastrous MOE commit, returning to r21 2011-04-19 23:11:15 +00:00
Makefile C binding for leveldb, better readseq benchmark for SQLite. 2011-08-05 20:40:49 +00:00
NEWS sync with upstream @ 21409451 2011-05-21 02:17:43 +00:00
README @20776309 2011-04-20 22:48:11 +00:00
TODO A number of smaller fixes and performance improvements: 2011-06-22 02:36:45 +00:00
build_detect_platform Adding FreeBSD support, removing Chromium files, adding benchmark. 2011-07-27 01:46:25 +00:00

README

leveldb: A key-value store
Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)

The code under this directory implements a system for maintaining a
persistent key/value store.

See doc/index.html for more explanation.
See doc/impl.html for a brief overview of the implementation.

The public interface is in include/*.h.  Callers should not include or
rely on the details of any other header files in this package.  Those
internal APIs may be changed without warning.

Guide to header files:

include/db.h
    Main interface to the DB: Start here

include/options.h
    Control over the behavior of an entire database, and also
    control over the behavior of individual reads and writes.

include/comparator.h
    Abstraction for user-specified comparison function.  If you want
    just bytewise comparison of keys, you can use the default comparator,
    but clients can write their own comparator implementations if they
    want custom ordering (e.g. to handle different character
    encodings, etc.)

include/iterator.h
    Interface for iterating over data. You can get an iterator
    from a DB object.

include/write_batch.h
    Interface for atomically applying multiple updates to a database.

include/slice.h
    A simple module for maintaining a pointer and a length into some
    other byte array.

include/status.h
    Status is returned from many of the public interfaces and is used
    to report success and various kinds of errors.

include/env.h
    Abstraction of the OS environment.  A posix implementation of
    this interface is in util/env_posix.cc

include/table.h
include/table_builder.h
    Lower-level modules that most clients probably won't use directly