diff options
| author | Keith Bostic <keith@wiredtiger.com> | 2015-05-03 11:51:21 -0400 |
|---|---|---|
| committer | Keith Bostic <keith@wiredtiger.com> | 2015-05-03 11:51:21 -0400 |
| commit | 1025b9fa76089d5d622feabbae339171f56f3702 (patch) | |
| tree | f1c34827b01337027306dcf6ad0d95e2cf854c83 /src/docs/upgrading.dox | |
| parent | 4119c22f29e3b8d9e73ca114f1ace52f48c77c58 (diff) | |
| download | mongo-1025b9fa76089d5d622feabbae339171f56f3702.tar.gz | |
Add LZ4 raw support based on the new LZ4_compress_destSize API, making
it the default (LZ4 block mode is now lz4-noraw, to match zlib).
This implementation mostly works, but...
It's not backward compatible because we're storing more information in
the destination buffer than before (two 4B values instead of a one 8B
value). The 2.5.3 release is the only release that had LZ4 support, so
I don't expect this to be a problem. We could be backward compatible,
but not without a fair amount of pain.
This code sizes decompression buffers incorrectly. The WiredTiger btree
code sizes the decompression buffer based on the final in-memory size
of the data, which isn't correct for data compressed with LZ4's raw
compression function which may have compressed more data than the final
in-memory size.
Diffstat (limited to 'src/docs/upgrading.dox')
| -rw-r--r-- | src/docs/upgrading.dox | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/docs/upgrading.dox b/src/docs/upgrading.dox index 77d290b48c0..1eaef7eea3b 100644 --- a/src/docs/upgrading.dox +++ b/src/docs/upgrading.dox @@ -2,6 +2,7 @@ @section version_254 Upgrading to Version 2.5.4 <dl> + <dt>File handle closing</dt> <dd> In WiredTiger, a separate thread of control periodically reviews open @@ -15,6 +16,13 @@ triggered, can be configured using the \c file_manager configuration values to the ::wiredtiger_open call. </dd> +<dt>LZ4 compression</dt> +<dd> +The LZ4 compression support has been updated in this release in non-backward +compatible ways; tables and files compressed using LZ4 compression should be +dumped and re-loaded into a new database. +</dd> + </dl><hr> @section version_253 Upgrading to Version 2.5.3 <dl> |