docs: def create_schema(self):
          """Create all necessary tables"""
          execute = self.cursor.execute
          try:
              return execute('SELECT 1 FROM gauged_statistics')
          except self.psycopg2.ProgrammingError:
              pass
          self.db.rollback()
          execute("""CREATE TABLE IF NOT EXISTS gauged_data (
                  namespace integer NOT NULL,
                  "offset" integer NOT NULL,
                  key bigint NOT NULL,
                  data bytea NOT NULL,
                  flags integer NOT NULL,
                  PRIMARY KEY ("offset", namespace, key));
              CREATE TABLE IF NOT EXISTS gauged_keys (
                  id serial PRIMARY KEY,
                  namespace integer NOT NULL,
                  key varchar NOT NULL);
              CREATE UNIQUE INDEX ON gauged_keys (
                  namespace, key);
              CREATE OR REPLACE RULE gauged_ignore_duplicate_keys
                  AS ON INSERT TO gauged_keys WHERE EXISTS (
                  SELECT 1 FROM gauged_keys WHERE key = NEW.key
                      AND namespace = NEW.namespace)
                  DO INSTEAD NOTHING;
              CREATE TABLE IF NOT EXISTS gauged_writer_history (
                  id varchar PRIMARY KEY,
                  timestamp bigint NOT NULL);
              CREATE TABLE IF NOT EXISTS gauged_cache (
                  namespace integer NOT NULL,
                  key bigint NOT NULL,
                  "hash" bytea NOT NULL,
                  length bigint NOT NULL,
                  start bigint NOT NULL,
                  value real,
                  PRIMARY KEY(namespace, hash, length, start));
              CREATE OR REPLACE RULE gauged_ignore_duplicate_cache
                  AS ON INSERT TO gauged_cache WHERE EXISTS (
                  SELECT 1 FROM gauged_cache WHERE namespace = NEW.namespace AND
                  "hash" = NEW.hash AND length = NEW.length
                  AND start = NEW.start)
                  DO INSTEAD NOTHING;
              CREATE TABLE IF NOT EXISTS gauged_statistics (
                  namespace integer NOT NULL,
                  "offset" integer NOT NULL,
                  data_points integer NOT NULL,
                  byte_count integer NOT NULL,
                  PRIMARY KEY (namespace, "offset"));
              CREATE TABLE IF NOT EXISTS gauged_metadata (
                  key varchar PRIMARY KEY,
                  value varchar NOT NULL);
              CREATE OR REPLACE RULE gauged_ignore_duplicate_metadata
                  AS ON INSERT TO gauged_metadata WHERE EXISTS (
                  SELECT 1 FROM gauged_metadata WHERE key = NEW.key)
                  DO INSTEAD NOTHING""")
          self.db.commit()