Add performance counters.

This commit adds performance counters for each transaction which are rolled
up to the database level on each commit/rollback. Counters are meant to be
a very fast way to track what is going on in the database. A few timers are
also added in areas where the time.Now() overhead is not noticible.

The DB.Stat() function is now deprecated since the `bolt` CLI now performs
similar functions.

Fixes #108.

1 files changed, 3 insertions, 0 deletions

diff --git a/node.go b/node.go
index 0a4c7af..709c0ca 100644
--- a/node.go
+++ b/node.go
@@ -233,6 +233,9 @@ func (n *node) rebalance() {
 	}
 	n.unbalanced = false
 
+	// Update statistics.
+	n.tx.stats.Rebalance++
+
 	// Ignore if node is above threshold (25%) and has enough keys.
 	var threshold = n.tx.db.pageSize / 4
 	if n.size() > threshold && len(n.inodes) > n.minKeys() {