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Sanjay Ghemawat 85584d497e Added bloom filter support.
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.
2012-04-17 08:36:46 -07:00
db Added bloom filter support. 2012-04-17 08:36:46 -07:00
doc Added bloom filter support. 2012-04-17 08:36:46 -07:00
helpers/memenv A number of fixes: 2011-10-31 17:22:06 +00:00
include/leveldb Added bloom filter support. 2012-04-17 08:36:46 -07:00
port Added bloom filter support. 2012-04-17 08:36:46 -07:00
table Added bloom filter support. 2012-04-17 08:36:46 -07:00
util Added bloom filter support. 2012-04-17 08:36:46 -07:00
.gitignore Added bloom filter support. 2012-04-17 08:36:46 -07:00
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 Added bloom filter support. 2012-04-17 08:36:46 -07:00
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 Added bloom filter support. 2012-04-17 08:36:46 -07:00

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