[ADMIN] Adding indexes for database.

install/gargamelle/psqlIndexes.sql

+--                       ____ 
+--                      / ___|
+--                     | |  _ 
+--                     | |_| |
+--                      \____|arganTexT
+----------------------------------------------------------------------
+--                  Gargantext optimization of Database             --
+----------------------------------------------------------------------
+
+--> Manual optimization with indexes according to usages
+-- Weakness and Strengths of indexes:
+    --> it can slow down the insertion(s)
+    --> it can speed up  the selection(s)
+
+--> Conventions for this document:
+    --> indexes commented already have been created 
+    --> indexes not commented have not been created yet
+
+----------------------------------------------------------------------
+-- Retrieve Nodes
+----------------------------------------------------------------------
+create INDEX on nodes (user_id, typename, parent_id) ;
+create INDEX on nodes_hyperdata (node_id, key);
+create INDEX on ngrams (id, n) ;
+create INDEX on ngrams (n) ;
+create INDEX on nodes_ngrams (node_id, ngram_id) ;
+create INDEX on nodes_ngrams (node_id) ;
+create INDEX on nodes_ngrams (ngram_id) ;
+create INDEX on nodes_ngrams_ngrams (node_id, ngram1_id, ngram2_id) ;
+
+create INDEX on nodes_ngrams_ngrams (node_id) ;
+create INDEX on nodes_ngrams_ngrams (ngram1_id) ;
+create INDEX on nodes_ngrams_ngrams (ngram2_id) ;
+
+----------------------------------------------------------------------
+DELETE optimization of Nodes -- todo on dev
+create INDEX on nodes_nodes_ngrams (node1_id);
+create INDEX on nodes_nodes_ngrams (node2_id);
+
+create INDEX on nodes_nodes (node1_id, node2_id);
+
+-- Maybe needed soon:
+-- create INDEX on nodes_nodes_ngrams (node1_id, node2_id);
+----------------------------------------------------------------------
+Analytics
+
+create INDEX on nodes_hyperdata (node_id,value_utc);  -- remove ?
+create INDEX on nodes_hyperdata (node_id,key,value_utc);
+create INDEX on nodes_hyperdata (node_id,key,value_int);
+create INDEX on nodes_hyperdata (node_id,key,value_flt);
+create INDEX on nodes_hyperdata (node_id,key,value_str);
+
+----------------------------------------------------------------------
+----------------------------------------------------------------------
+
+create index on nodes using GIN (hyperdata);
+----------------------------------------------------------------------