Added support for views

CHANGELOG.md

@@ -1,6 +1,6 @@
 ## 0.3.3 [unreleased]
 
-- Added support for materialized views
+- Added support for views and materialized views
 - Better handle case when multiple indexes are found for a query
 - Added `--min-cost-savings-pct` option
 

lib/dexter/indexer.rb

@@ -38,11 +38,28 @@ def process_queries(queries)
         no_schema_tables[group] = t2.sort_by { |t| [search_path_index[t.split(".")[0]] || 1000000, t] }[0]
       end
 
+      # add tables from views
+      view_tables = database_view_tables
+      view_tables.each do |v, vt|
+        view_tables[v] = vt.map { |t| no_schema_tables[t] || t }
+      end
+
+      # fully resolve tables
+      # make sure no views in result
+      view_tables.each do |v, vt|
+        view_tables[v] = vt.flat_map { |t| view_tables[t] || [t] }.uniq
+      end
+
       # filter queries from other databases and system tables
       queries.each do |query|
         # add schema to table if needed
         query.tables = query.tables.map { |t| no_schema_tables[t] || t }
 
+        # substitute view tables
+        new_tables = query.tables.flat_map { |t| view_tables[t] || [t] }.uniq
+        query.tables_from_views = new_tables - query.tables
+        query.tables = new_tables
+
         # check for missing tables
         query.missing_tables = !query.tables.all? { |t| tables.include?(t) }
       end
@@ -167,6 +184,7 @@ def create_hypothetical_indexes(queries, tables)
 
       # filter tables for performance
       tables = Set.new(explainable_queries.flat_map(&:tables))
+      tables_from_views = Set.new(explainable_queries.flat_map(&:tables_from_views))
 
       if tables.any?
         # since every set of multi-column indexes are expensive
@@ -183,7 +201,8 @@ def create_hypothetical_indexes(queries, tables)
         end
 
         # create hypothetical indexes
-        columns_by_table = columns(tables).select { |c| possible_columns.include?(c[:column]) }.group_by { |c| c[:table] }
+        # use all columns in tables from views
+        columns_by_table = columns(tables).select { |c| possible_columns.include?(c[:column]) || tables_from_views.include?(c[:table]) }.group_by { |c| c[:table] }
 
         # create single column indexes
         create_hypothetical_indexes_helper(columns_by_table, 1, candidates)
@@ -531,6 +550,25 @@ def materialized_views
       result.map { |r| r["table_name"] }
     end
 
+    def database_view_tables
+      result = execute <<-SQL
+        SELECT
+          schemaname || '.' || viewname AS table_name,
+          definition
+        FROM
+          pg_views
+        WHERE
+          schemaname NOT IN ('information_schema', 'pg_catalog')
+      SQL
+
+      view_tables = {}
+      result.each do |row|
+        view_tables[row["table_name"]] = PgQuery.parse(row["definition"]).tables
+      end
+
+      view_tables
+    end
+
     def stat_statements
       result = execute <<-SQL
         SELECT

lib/dexter/query.rb

@@ -2,7 +2,7 @@ module Dexter
   class Query
     attr_reader :statement, :fingerprint, :plans
     attr_writer :tables
-    attr_accessor :missing_tables, :new_cost, :total_time, :calls, :indexes, :suggest_index, :pass1_indexes, :pass2_indexes, :pass3_indexes, :candidate_tables
+    attr_accessor :missing_tables, :new_cost, :total_time, :calls, :indexes, :suggest_index, :pass1_indexes, :pass2_indexes, :pass3_indexes, :candidate_tables, :tables_from_views
 
     def initialize(statement, fingerprint = nil)
       @statement = statement
@@ -11,6 +11,7 @@ def initialize(statement, fingerprint = nil)
       end
       @fingerprint = fingerprint
       @plans = []
+      @tables_from_views = []
     end
 
     def tables

test/dexter_test.rb

@@ -22,8 +22,7 @@ def test_delete
   end
 
   def test_view
-    # can't do views yet
-    assert_no_index "SELECT * FROM posts_view WHERE id = 1"
+    assert_index "SELECT * FROM posts_view WHERE view_id = 1", "public.posts (id)"
   end
 
   def test_materialized_view

test/test_helper.rb

@@ -18,7 +18,7 @@
   hstore hstore
 );
 INSERT INTO posts (SELECT n AS id, n % 1000 AS blog_id, n % 10 AS user_id FROM generate_series(1, 100000) n);
-CREATE VIEW posts_view AS SELECT * FROM posts;
+CREATE VIEW posts_view AS SELECT id AS view_id FROM posts;
 CREATE MATERIALIZED VIEW posts_materialized AS SELECT * FROM posts;
 ANALYZE posts;