optimize stats using "materialized view"

sqlpage/migrations/001_schema.sql

@@ -0,0 +1,30 @@
+CREATE TABLE if not exists instances (
+  -- PK will be rowid
+    domain TEXT UNIQUE
+  , name TEXT
+  , slogan TEXT
+  , description TEXT
+  , languages TEXT
+  , open INT -- BOOLEAN
+  , version TEXT
+  , location TEXT  -- from IP
+  , failure INTEGER
+  , createdAt INTEGER  -- second since epoch
+  , updatedAt INTEGER  -- second since epoch
+)  strict;
+
+create table if not exists stats (
+    insertedAt INTEGER
+  , instance_id INTEGER  -- rowid of instance
+  , users INTEGER
+  , local_groups INTEGER
+  , total_groups INTEGER
+  , local_events INTEGER
+  , total_events INTEGER
+  , local_comments INTEGER
+  , total_comments INTEGER
+  , following INTEGER
+  , followers INTEGER
+  -- PK, would have been (instance_id, date)
+  -- to spare index, we declare no PK
+) strict;

sqlpage/migrations/002_index_stats.sql

@@ -0,0 +1,2 @@
+CREATE INDEX if not exists idx_stats_day ON stats(insertedAt / (3600*24));
+

sqlpage/migrations/003_create_daystats.sql

@@ -0,0 +1,12 @@
+DROP table if exists day_stats;
+
+Create table day_stats as
+SELECT 
+    count(instance_id) as i
+  , sum(users) as u
+  , sum(local_events) as e
+  , sum(local_groups) as g
+  , insertedAt  as x
+  , insertedAt / (3600*24) as j
+FROM stats
+GROUP BY j