./pg_ctl -D data restart
./psql -d postgres -f test.sql
./psql -d postgres -c "checkpoint"
./pg_ctl -D data restart
./psql -d postgres -c "create extension pg_prewarm;"
./psql -d postgres -c "SELECT pg_prewarm('idx1');"
./psql -d postgres -c "SELECT pg_prewarm('idx2');"
./psql -d postgres -c "SELECT pg_prewarm('idx3');"
./psql -d postgres -c "SELECT pg_prewarm('idx4');"
time ./psql -d postgres -c "vacuum (parallel 4) test"