Compression changes.

Change compaction to attempt compaction any time it looks likely we can
recover the last 10% of the file, and, for now, to only attempt to
recover that last 10% of the file.

Don't rewrite a block if there isn't a useful available block in the
first 90% of the file.  (Previously, compacting the whole file in one
pass could end up re-writing blocks to available blocks at the end of
the file which isn't useful, and, in some cases, even extending the
file.

The reason we're only compacting the last 10% of the file is that we
will need to checkpoint periodically otherwise re-written blocks, which
should be the new, available blocks for compaction, won't be considered
because they're still in use.  Doing that automatically will be the next
set of changes.

Change compaction to use first-fit allocation instead of best-fit so
we're always copying to the beginning of the file if at all possible.
Add WT_SESSION::create "block_allocation" configuration string, allows
applications to configure first-fit.  Change test/format to use the
first-fit algorithm 20% of the time.

Remove the WT_SESSION.compact "trigger" configuration string, it's no
longer used.

Rename WT_SESSION::create "allocation_size" configuration string to
"block_allocation_size" to match "block_allocation" and
"block_compressor" configuration strings.

Inline the block extension search functions, they get called a lot.

Add "compact" verbose debugging string.

Fix a bug where a spinlock could be left held by compaction.

1 files changed, 2 insertions, 1 deletions

diff --git a/test/suite/test_bug004.py b/test/suite/test_bug004.py
index 8bd2bcaf012..ab2453524a5 100644
--- a/test/suite/test_bug004.py
+++ b/test/suite/test_bug004.py
@@ -39,7 +39,8 @@ class test_bug004(wttest.WiredTigerTestCase):
     uri = 'file:test_ovfl_key'
 
     # Use a small page size because we want to create overflow items
-    config = 'allocation_size=512,leaf_page_max=512,value_format=S,key_format=S'
+    config = 'block_allocation_size=512,' +\
+        'leaf_page_max=512,value_format=S,key_format=S'
 
     nentries = 30