Update code and data

ch04/build_stats.psql

@@ -0,0 +1,19 @@
+\a
+\t
+\cd /tmp
+\g create_script.sql
+DROP TABLE IF EXISTS table_stats;
+SELECT
+'CREATE TABLE table_stats (
+table_name varchar(255), count bigint);';
+SELECT format(''INSERT INTO TABLE staging.table_stats(
+table_name, count
+)
+VALUES (%1$I.%2$I,
+(SELECT COUNT(1)
+FROM %1$I.%2$I
+) )', table_schema, table_name)
+FROM information_schema.tables
+WHERE table_schema = 'pg_catalog';
+\o
+\i create_script.sql