Issue - (#3): README file update.

README.md

@@ -1,12 +1,19 @@
-pg_stat_monitor - Statists collector for [PostgreSQL][1].
+pg_stat_monitor - Statistics collector for [PostgreSQL][1].
 
-The pg_stat_monitor is statistics collector tool based on PostgreSQL's pg_stat_statement.
+The pg_stat_monitor is statistics collector tool based on PostgreSQL's pg_stat_statement. PostgreSQL’s “pg_stat_statment” provides the basic statistics which is sometimes not enough. The major flaw in this that it accumulates all the queries and its statistics and does not provide aggregate statistics, in that case, the user needs to calculate the aggregate which is quite expensive.
+
+Pg_stat_monitor is build on top of pg_stat_statment, so it provides all the pg_stat_statment plus its own feature set. 
+
 #### Supported PostgreSQL Versions.
+Pg_stat_monitor should work on the latest version of PostgreSQL but only tested with these versions of PostgreSQL.
+
     *   PostgreSQL Version 11
     *   PostgreSQL Version 12
-    *   Percona Dsitribution for PostgreSQL
+    *   Percona Distribution for PostgreSQL
+
 #### Installation
-There are two ways to install the pg_stat_monitor. The first is by downloading the pg_stat_monitor source code and compiling it. The second option is to download the deb or rpm packages.
+There are two ways to install pg_stat_monitor. The first is by downloading the pg_stat_monitor source code and compiling it. The second is to download the deb or rpm packages.
+
 ##### Download and compile
 The latest release of pg_stat_monitor can be downloaded from this GitHub page:
 
@@ -18,13 +25,32 @@ or it can be downloaded using the git:
 
 After downloading the code, set the path for the [PostgreSQL][1] binary:
 
+###### Compile
     cd pg_stat_monitor
     make USE_PGXS=1
     make USE_PGXS=1 install
 
+###### Enable Extension
+    postgres=# alter system set shared_preload_libraries=pg_stat_monitor;
+    ALTER SYSTEM
+
+    sudo systemctl restart postgresql-11
+
+    postgres=# create extension pg_stat_monitor;
+    CREATE EXTENSION
+
+
 #### Usage
 There are four views, and complete statistics can be accessed using these views.
 
+  Pg_stat_monitor
+  Pg_stat_agg_database
+  Pg_stat_agg_user
+  pg_stat_agg_hots
+
+##### pg_stat_monitor
+This is the main view which stores per query-based statistics, similar to pg_stat_statment with some additional columns.
+
     \d pg_stat_monitor;
                           View "public.pg_stat_monitor"
            Column        |       Type       | Collation | Nullable | Default 
@@ -61,6 +87,19 @@ There are four views, and complete statistics can be accessed using these views.
     cpu_user_time       | double precision |           |          | 
     cpu_sys_time        | double precision |           |          | 
 
+
+These are new column added to have more detail about the query.
+
+    host: Client IP or Hostname
+    hist_calls: Hourly based 24 hours calls of query histogram
+    hist_min_time: Hourly based 24 hours min time of query histogram
+    Hist_max_time: Hourly based 24 hours max time of query histogram
+    hist_mean_time: Hourly based 24 hours mean time of query histogram
+    slow_query: Slowest query with actual parameters.
+    cpu_user_time: CPU user time for that query.
+    cpu_sys_time: CPU System time for that query.
+
+
     regression=# \d pg_stat_agg_database 
                          View "public.pg_stat_agg_database"
          Column     |           Type           | Collation | Nullable | Default 
@@ -131,7 +170,7 @@ There are four views, and complete statistics can be accessed using these views.
      slow_query     | text                     |           |          |    
 
 Examples
-1 - Here in this query we are getting the exact value of f1 which is '05:06:07-07' in case of slow query.
+1 - In this query we are getting the exact value of f1 which is '05:06:07-07' in the case of slow queries.
 
     # select userid, queryid, query, slow_query, max_time, total_calls from pg_stat_agg_user; 
     -[ RECORD 1 ]----------------------------------------------------------------------------------------
@@ -142,7 +181,7 @@ Examples
     max_time    | 1.237875
     total_calls | 8
 
-2 - Collect all the statistics based on user.
+2 - Collect all statistics based on the user.
 
     # select usename, query, max_time, total_calls from pg_stat_agg_user au, pg_user u where au.userid = u.usesysid; 
      usename |                          query                          | max_time | total_calls 
@@ -154,11 +193,11 @@ Examples
 
 
 #### Limitation
-There are some limitations and Todo's. 
+There are some limitations and Todos. 
 
 #### Licence
 Copyright (c) 2006 - 2019, Percona LLC.
-See [`LICENSE`][2] for full detail
+See [`LICENSE`][2] for full details.
 
 [1]: https://www.postgresql.org/
 [2]: https://github.com/Percona-Lab/pg_stat_monitor/blob/master/LICENSE