Add migration for counter_cache table update

priv/repo/migrations/20200508092434_update_counter_cache_table.exs

@@ -0,0 +1,144 @@
+defmodule Pleroma.Repo.Migrations.UpdateCounterCacheTable do
+  use Ecto.Migration
+
+  @function_name "update_status_visibility_counter_cache"
+  @trigger_name "status_visibility_counter_cache_trigger"
+
+  def up do
+    execute("drop trigger if exists #{@trigger_name} on activities")
+    execute("drop function if exists #{@function_name}()")
+    drop_if_exists(unique_index(:counter_cache, [:name]))
+    drop_if_exists(table(:counter_cache))
+
+    create_if_not_exists table(:counter_cache) do
+      add(:instance, :string, null: false)
+      add(:direct, :bigint, null: false, default: 0)
+      add(:private, :bigint, null: false, default: 0)
+      add(:unlisted, :bigint, null: false, default: 0)
+      add(:public, :bigint, null: false, default: 0)
+    end
+
+    create_if_not_exists(unique_index(:counter_cache, [:instance]))
+
+    """
+    CREATE OR REPLACE FUNCTION #{@function_name}()
+    RETURNS TRIGGER AS
+    $$
+      DECLARE
+        token_id smallint;
+        hostname character varying(255);
+        visibility_new character varying(64);
+        visibility_old character varying(64);
+        actor character varying(255);
+      BEGIN
+      SELECT "tokid" INTO "token_id" FROM ts_token_type('default') WHERE "alias" = 'host';
+      IF TG_OP = 'DELETE' THEN
+        actor := OLD.actor;
+      ELSE
+        actor := NEW.actor;
+      END IF;
+      SELECT "token" INTO "hostname" FROM ts_parse('default', actor) WHERE "tokid" = token_id;
+      IF hostname IS NULL THEN
+        hostname := split_part(actor, '/', 3);
+      END IF;
+      IF TG_OP = 'INSERT' THEN
+        visibility_new := activity_visibility(NEW.actor, NEW.recipients, NEW.data);
+        IF NEW.data->>'type' = 'Create' THEN
+          EXECUTE format('INSERT INTO "counter_cache" ("instance", %1$I) VALUES ($1, 1)
+                          ON CONFLICT ("instance") DO
+                          UPDATE SET %1$I = "counter_cache".%1$I + 1', visibility_new)
+                          USING hostname;
+        END IF;
+        RETURN NEW;
+      ELSIF TG_OP = 'UPDATE' THEN
+        visibility_new := activity_visibility(NEW.actor, NEW.recipients, NEW.data);
+        visibility_old := activity_visibility(OLD.actor, OLD.recipients, OLD.data);
+        IF (NEW.data->>'type' = 'Create') and (OLD.data->>'type' = 'Create') and visibility_new != visibility_old THEN
+          EXECUTE format('UPDATE "counter_cache" SET
+                          %1$I = greatest("counter_cache".%1$I - 1, 0),
+                          %2$I = "counter_cache".%2$I + 1
+                          WHERE "instance" = $1', visibility_old, visibility_new)
+                          USING hostname;
+        END IF;
+        RETURN NEW;
+      ELSIF TG_OP = 'DELETE' THEN
+        IF OLD.data->>'type' = 'Create' THEN
+          visibility_old := activity_visibility(OLD.actor, OLD.recipients, OLD.data);
+          EXECUTE format('UPDATE "counter_cache" SET
+                          %1$I = greatest("counter_cache".%1$I - 1, 0)
+                          WHERE "instance" = $1', visibility_old)
+                          USING hostname;
+        END IF;
+        RETURN OLD;
+      END IF;
+      END;
+    $$
+    LANGUAGE 'plpgsql';
+    """
+    |> execute()
+
+    execute("DROP TRIGGER IF EXISTS #{@trigger_name} ON activities")
+
+    """
+    CREATE TRIGGER #{@trigger_name}
+    BEFORE
+      INSERT
+      OR UPDATE of recipients, data
+      OR DELETE
+    ON activities
+    FOR EACH ROW
+      EXECUTE PROCEDURE #{@function_name}();
+    """
+    |> execute()
+  end
+
+  def down do
+    execute("DROP TRIGGER IF EXISTS #{@trigger_name} ON activities")
+    execute("DROP FUNCTION IF EXISTS #{@function_name}()")
+    drop_if_exists(unique_index(:counter_cache, [:instance]))
+    drop_if_exists(table(:counter_cache))
+
+    create_if_not_exists table(:counter_cache) do
+      add(:name, :string, null: false)
+      add(:count, :bigint, null: false, default: 0)
+    end
+
+    create_if_not_exists(unique_index(:counter_cache, [:name]))
+
+    """
+    CREATE OR REPLACE FUNCTION #{@function_name}()
+    RETURNS TRIGGER AS
+    $$
+      DECLARE
+      BEGIN
+      IF TG_OP = 'INSERT' THEN
+          IF NEW.data->>'type' = 'Create' THEN
+            EXECUTE 'INSERT INTO counter_cache (name, count) VALUES (''status_visibility_' || activity_visibility(NEW.actor, NEW.recipients, NEW.data) || ''', 1) ON CONFLICT (name) DO UPDATE SET count = counter_cache.count + 1';
+          END IF;
+          RETURN NEW;
+      ELSIF TG_OP = 'UPDATE' THEN
+          IF (NEW.data->>'type' = 'Create') and (OLD.data->>'type' = 'Create') and activity_visibility(NEW.actor, NEW.recipients, NEW.data) != activity_visibility(OLD.actor, OLD.recipients, OLD.data) THEN
+             EXECUTE 'INSERT INTO counter_cache (name, count) VALUES (''status_visibility_' || activity_visibility(NEW.actor, NEW.recipients, NEW.data) || ''', 1) ON CONFLICT (name) DO UPDATE SET count = counter_cache.count + 1';
+             EXECUTE 'update counter_cache SET count = counter_cache.count - 1 where count > 0 and name = ''status_visibility_' || activity_visibility(OLD.actor, OLD.recipients, OLD.data) || ''';';
+          END IF;
+          RETURN NEW;
+      ELSIF TG_OP = 'DELETE' THEN
+          IF OLD.data->>'type' = 'Create' THEN
+            EXECUTE 'update counter_cache SET count = counter_cache.count - 1 where count > 0 and name = ''status_visibility_' || activity_visibility(OLD.actor, OLD.recipients, OLD.data) || ''';';
+          END IF;
+          RETURN OLD;
+      END IF;
+      END;
+    $$
+    LANGUAGE 'plpgsql';
+    """
+    |> execute()
+
+    """
+    CREATE TRIGGER #{@trigger_name} BEFORE INSERT OR UPDATE of recipients, data OR DELETE ON activities
+    FOR EACH ROW
+    EXECUTE PROCEDURE #{@function_name}();
+    """
+    |> execute()
+  end
+end