Add freelist cache.

This commit adds a cache to the freelist which combines the available free pages and pending free pages in
a single map. This was added to improve performance where freelist.isFree() was consuming 70% of CPU time
for large freelists.

1 files changed, 1 insertions, 1 deletions

diff --git a/tx.go b/tx.go
index d8ffc08..5eada65 100644
--- a/tx.go
+++ b/tx.go
@@ -496,7 +496,7 @@ func (tx *Tx) Page(id int) (*PageInfo, error) {
 	}
 
 	// Determine the type (or if it's free).
-	if tx.db.freelist.isFree(pgid(id)) {
+	if tx.db.freelist.freed(pgid(id)) {
 		info.Type = "free"
 	} else {
 		info.Type = p.typ()