src/test/fsync/output/setup.source

create or replace function dirty_buffers_on_qd() returns setof record as
 '@abs_builddir@/fsync_helper@DLSUFFIX@', 'dirty_buffers'
  LANGUAGE C VOLATILE STRICT NO SQL EXECUTE ON MASTER;
create or replace function dirty_buffers_on_qes() returns setof record as
 '@abs_builddir@/fsync_helper@DLSUFFIX@', 'dirty_buffers'
  LANGUAGE C VOLATILE STRICT NO SQL EXECUTE ON ALL SEGMENTS;