[docs] : rephrase + added example to query logging section (#7032)

wiki/content/deploy/log-format.md

@@ -8,7 +8,9 @@ title = "Log Format"
 
 Dgraph's log format comes from the glog library and is [formatted](https://github.com/golang/glog/blob/23def4e6c14b4da8ac2ed8007337bc5eb5007998/glog.go#L523-L533) as follows:
 
-	`Lmmdd hh:mm:ss.uuuuuu threadid file:line] msg...`
+```
+Lmmdd hh:mm:ss.uuuuuu threadid file:line] msg...
+```
 
 Where the fields are defined as follows:
 
@@ -23,6 +25,31 @@ Where the fields are defined as follows:
 	msg              The user-supplied message
 ```
 
-## Query Logging
+## Increase Logging
+
+To increase logging, you have set `-v=3` which will enable verbose logging for everything. You can set this flag on both Zero and Alpha nodes.
+
+Alternatively, you can set `--vmodule=server=3` for only the Alpha node which would only enable query/mutation logging.
+
+{{% notice "note" %}}
+This requires a restart of the node itself.
+
+Avoid keeping logging verbose for a long time. Revert back to default setting if not needed.
+{{% /notice %}}
 
-To enable query logging, you must set `-v=3` which will enable verbose logging for everything. Alternatively, you can set `--vmodule=server=3` for only the dgraph/server.go file which would only enable query/mutation logging.
+When enabling query logging with the `--vmodule=server=3` flag this prints the queries/mutation that Dgraph Cluster receives from Ratel, Client etc. In this case Alpha log will print something similar to:
+
+```
+I1201 13:06:26.686466   10905 server.go:908] Got a query: query:"{\n  query(func: allofterms(name@en, \"Marc Caro\")) {\n  uid\n  name@en\n  director.film\n  }\n}"  
+```
+As you can see, we got the query that Alpha received, to read it in the original DQL format just replace every `\n` with a new line, any `\t` with a tab character and `\"` with `"`:
+
+```
+{
+  query(func: allofterms(name@en, "Marc Caro")) {
+  uid
+  name@en
+  director.film
+  }
+}
+```