Parsed test spec with 2 sessions

starting permutation: modify vac stats
step modify: 
    insert into smalltbl select max(id)+1 from smalltbl;

step vac: 
    vacuum smalltbl;

step stats: 
    select relpages, reltuples from pg_class
     where oid='smalltbl'::regclass;

relpages|reltuples
--------+---------
       1|       21
(1 row)


starting permutation: modify open fetch1 vac close stats
step modify: 
    insert into smalltbl select max(id)+1 from smalltbl;

step open: 
    begin;
    declare c1 cursor for select 1 as dummy from smalltbl;

step fetch1: 
    fetch next from c1;

dummy
-----
    1
(1 row)

step vac: 
    vacuum smalltbl;

step close: 
    commit;

step stats: 
    select relpages, reltuples from pg_class
     where oid='smalltbl'::regclass;

relpages|reltuples
--------+---------
       1|       20
(1 row)


starting permutation: modify vac stats
step modify: 
    insert into smalltbl select max(id)+1 from smalltbl;

step vac: 
    vacuum smalltbl;

step stats: 
    select relpages, reltuples from pg_class
     where oid='smalltbl'::regclass;

relpages|reltuples
--------+---------
       1|       21
(1 row)