6699c7ebe6
Slight tweak to the no-overlap optimization: only push to level 2 to reduce the amount of wasted space when the same small key range is being repeatedly overwritten. Fix for Issue 18: Avoid failure on Windows by avoiding deletion of lock file until the end of DestroyDB(). Fix for Issue 19: Disregard sequence numbers when checking for overlap in sstable ranges. This fixes issue 19: when writing the same key over and over again, we would generate a sequence of sstables that were never merged together since their sequence numbers were disjoint. Don't ignore map/unmap error checks. Miscellaneous fixes for small problems Sanjay found while diagnosing issue/9 and issue/16 (corruption_testr failures). - log::Reader reports the record type when it finds an unexpected type. - log::Reader no longer reports an error when it encounters an expected zero record regardless of the setting of the "checksum" flag. - Added a missing forward declaration. - Documented a side-effects of larger write buffer sizes (longer recovery time). git-svn-id: https://leveldb.googlecode.com/svn/trunk@37 62dab493-f737-651d-591e-8d6aee1b9529
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