-- oid check
SET enable_seqscan=on;
SELECT count(*) FROM moneytmp WHERE oid <  ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   372
(1 row)

SELECT count(*) FROM moneytmp WHERE oid <= ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   373
(1 row)

SELECT count(*) FROM moneytmp WHERE oid  = ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
     1
(1 row)

SELECT count(*) FROM moneytmp WHERE oid >= ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   228
(1 row)

SELECT count(*) FROM moneytmp WHERE oid >  ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   227
(1 row)

CREATE INDEX oididx ON moneytmp USING gist ( oid );
SET enable_seqscan=off;
SELECT count(*) FROM moneytmp WHERE oid <  ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   372
(1 row)

SELECT count(*) FROM moneytmp WHERE oid <= ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   373
(1 row)

SELECT count(*) FROM moneytmp WHERE oid  = ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
     1
(1 row)

SELECT count(*) FROM moneytmp WHERE oid >= ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   228
(1 row)

SELECT count(*) FROM moneytmp WHERE oid >  ( SELECT oid FROM moneytmp WHERE a  = '22649.64' );
 count 
-------
   227
(1 row)