Flexible approximate counts with fallback strategies.

1 files changed, 18 insertions, 14 deletions

diff --git a/lib/gitlab/database/count.rb b/lib/gitlab/database/count.rb
index 55f0cbd18be..beb5a8d3556 100644
--- a/lib/gitlab/database/count.rb
+++ b/lib/gitlab/database/count.rb
@@ -25,21 +25,17 @@ module Gitlab
       #
       # @param [Array]
       # @return [Hash] of Model -> count mapping
-      def self.approximate_counts(models)
-        counts_by_model = {}
-
-        if Gitlab::Database.postgresql?
-          #counts_by_model = ReltuplesCountStrategy.new(models).count
-          counts_by_model = reltuples_from_recently_updated(models)
-        end
-
-        missing_models = models - counts_by_model.keys
-
-        ExactCountStrategy.new(missing_models).count.each do |model, count|
-          counts_by_model[model] = count
+      def self.approximate_counts(models, strategies = [ReltuplesCountStrategy, ExactCountStrategy])
+        strategies.each_with_object({}) do |strategy, counts_by_model|
+          if strategy.enabled?
+            models_with_missing_counts = models - counts_by_model.keys
+            counts = strategy.new(models_with_missing_counts).count
+
+            counts.each do |model, count|
+              counts_by_model[model] = count
+            end
+          end
         end
-
-        counts_by_model
       end
 
       # Returns a hash of the table names that have recently updated tuples.
@@ -61,6 +57,10 @@ module Gitlab
             data[model] = model.count
           end
         end
+
+        def self.enabled?
+          true
+        end
       end
 
       class ReltuplesCountStrategy
@@ -92,6 +92,10 @@ module Gitlab
           {}
         end
 
+        def self.enabled?
+          Gitlab::Database.postgresql?
+        end
+
         private
 
         def table_names