Create view in Citus

view.sql

CREATE OR REPLACE FUNCTION public.create_shard_view(table_shardid bigint, view_name regclass, query_format text)
 RETURNS bigint
 LANGUAGE plpgsql
AS $function$
DECLARE
  view_shardid bigint := master_get_new_shardid();
  table_name regclass;
  placement record;
BEGIN
  SELECT logicalrelid INTO table_name FROM pg_dist_shard WHERE shardid = table_shardid;

  INSERT INTO pg_dist_shard
  SELECT view_name, view_shardid, 'r', NULL, shardminvalue, shardmaxvalue
  FROM pg_dist_shard
  WHERE shardid = table_shardid;

  INSERT INTO pg_dist_shard_placement
  SELECT view_shardid, shardstate, 0, nodename, nodeport
  FROM pg_dist_shard_placement
  WHERE shardid = table_shardid;

  PERFORM dblink_exec(format('host=%s port=%s', nodename, nodeport),
                      format('CREATE VIEW %I AS %s', view_name||'_'||view_shardid,
                      format(query_format, table_name||'_'||table_shardid)))
  FROM pg_dist_shard_placement WHERE shardid = view_shardid;

  RETURN view_shardid;
END;
$function$;

CREATE OR REPLACE FUNCTION public.create_view_shards(view_name regclass, table_name regclass, query_format text)
 RETURNS void
 LANGUAGE plpgsql
AS $function$
BEGIN
  IF EXISTS (SELECT 1 FROM pg_dist_shard WHERE logicalrelid = view_name) THEN
    RAISE EXCEPTION '% already has shards', view_name;
  END IF;

  PERFORM create_shard_view(shardid, view_name, query_format)
  FROM pg_dist_shard
  WHERE logicalrelid = table_name;
END;
$function$;