RSK-1562 Multiple values

Metrics.md

@@ -2,27 +2,69 @@
 
 ## Introduction
 
-The server keeps a list of the last 50 blocks in the mainchain. Using that list, it generates data
+The server keeps a list of the last blocks in the mainchain. Using that list, it generates data
 that it sends to the client to be rendered.
 
+The list of blocks (the blockchain) is kept by `lib/history.js`, a fragment:
+
+
+```js
+var MAX_HISTORY = 2000;
+
+var MAX_PEER_PROPAGATION = 40;
+var MIN_PROPAGATION_RANGE = 0;
+var MAX_PROPAGATION_RANGE = 10000;
+
+var MAX_UNCLES = 1000;
+var MAX_UNCLES_PER_BIN = 25;
+var MAX_BINS = 40;
+
+var History = function History(data)
+{
+	this._items = [];
+	this._callback = null;
+}
+
+```
+
+The callback function, if defined, is called when the data is changed, ie, a new block arrived to be
+processed.
+
 ## Multiple Values
 
 ### Block Time
 
+A list of times to produce a new block, ordered by ascending height.
+
 ### Difficulty
 
+A list of block difficulty, ordered by ascending height.
+
 ### Block Propagation
 
+A list of times (delta 0.5 seconds), counting the number of blocks that propagate in that interval.
+Each block has many propagation times, one per reached node. 
+
 ### Last Blocks Miners
 
+A list of miners ids, that mined the blocks in the current history.
+
 ### Uncle Count
 
+Count of uncles, in the current block history. Each count is the sum of uncle counts in 25 blocks.
+
 ### Transactions
 
+Number of transactions in the last blocks in current history.
+
 ### Gas Spending
 
+Gas amount spent in each executed block.
+
 ### Gas Limit
 
+Gas limit per block in history.
+
 ## Single Values
 
 ### Best Block