Add inline bucket support.

This commit adds support for writing small buckets directly inline to their value in
their parent's leaf node. Previously, subbuckets would simply have a bucket header
stored in their parent bucket which pointed to the root page. This required that
every bucket use at least a single page. This has a high overhead for buckets with
only one or two small items.

Inline buckets checks subbuckets to see if they only have a small amount of data
(about 1kb) and no subbuckets. If these conditions are met then the bucket's root
node is written to a fake page which is simply a pointer to the end of the bucket's
header.

Fixes #124.

1 files changed, 2 insertions, 3 deletions

diff --git a/freelist.go b/freelist.go
index ebe2810..6c527fe 100644
--- a/freelist.go
+++ b/freelist.go
@@ -1,6 +1,7 @@
 package bolt
 
 import (
+	"fmt"
 	"sort"
 	"unsafe"
 )
@@ -63,7 +64,7 @@ func (f *freelist) free(txid txid, p *page) {
 	}
 	f.pending[txid] = ids
 
-	// DEBUG ONLY: f.check()
+	f.check() // DEBUG ONLY:
 }
 
 // release moves all page ids for a transaction id (or older) to the freelist.
@@ -114,7 +115,6 @@ func (f *freelist) write(p *page) {
 // check verifies there are no double free pages.
 // This is slow so it should only be used while debugging.
 // If errors are found then a panic invoked.
-/*
 func (f *freelist) check() {
 	var lookup = make(map[pgid]txid)
 	for _, id := range f.ids {
@@ -132,7 +132,6 @@ func (f *freelist) check() {
 		}
 	}
 }
-*/
 
 type reverseSortedPgids []pgid