Small tweaks and bugfixes for Issue 18 and 19.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/include/leveldb/options.h b/include/leveldb/options.h
index a94651f..a0afbf2 100644
--- a/include/leveldb/options.h
+++ b/include/leveldb/options.h
@@ -75,6 +75,8 @@ struct Options {
   // Larger values increase performance, especially during bulk loads.
   // Up to two write buffers may be held in memory at the same time,
   // so you may wish to adjust this parameter to control memory usage.
+  // Also, a larger write buffer will result in a longer recovery time
+  // the next time the database is opened.
   //
   // Default: 4MB
   size_t write_buffer_size;