CREATE TABLE t1 ( uid INTEGER PRIMARY KEY, uname TEXT NOT NULL );
CREATE TABLE
INSERT INTO t1 VALUES ( 101, 'Park Gyu-Ri' );
INSERT 0 1
INSERT INTO t1 VALUES ( 102, 'Han Seung-Yeon' );
INSERT 0 1
INSERT INTO t1 VALUES ( 103, 'Nicole' );
INSERT 0 1
INSERT INTO t1 VALUES ( 104, 'Koo Ha-Ra' );
INSERT 0 1
INSERT INTO t1 VALUES ( 105, 'Kang Ji-Young' );
INSERT 0 1
SELECT pgperf.create_snapshot_pg_statio_user_tables(0);
 create_snapshot_pg_statio_user_tables 
---------------------------------------
 t
(1 row)

SELECT count(*) FROM pgperf.snapshot_pg_statio_user_tables WHERE schemaname <> 'pgperf';
 count 
-------
     1
(1 row)

SELECT pgperf.create_snapshot_pg_statio_user_tables(1);
 create_snapshot_pg_statio_user_tables 
---------------------------------------
 t
(1 row)

SELECT count(*) FROM pgperf.snapshot_pg_statio_user_tables WHERE schemaname <> 'pgperf';
 count 
-------
     2
(1 row)

SELECT pgperf.create_snapshot_pg_statio_user_tables(2);
 create_snapshot_pg_statio_user_tables 
---------------------------------------
 t
(1 row)

SELECT count(*) FROM pgperf.snapshot_pg_statio_user_tables WHERE schemaname <> 'pgperf';
 count 
-------
     3
(1 row)

SELECT pgperf.delete_snapshot_pg_statio_user_tables(1);
 delete_snapshot_pg_statio_user_tables 
---------------------------------------
 t
(1 row)

SELECT count(*) FROM pgperf.snapshot_pg_statio_user_tables WHERE schemaname <> 'pgperf';
 count 
-------
     2
(1 row)

SELECT pgperf.delete_snapshot_pg_statio_user_tables(2);
 delete_snapshot_pg_statio_user_tables 
---------------------------------------
 t
(1 row)

SELECT count(*) FROM pgperf.snapshot_pg_statio_user_tables WHERE schemaname <> 'pgperf';
 count 
-------
     1
(1 row)

SELECT pgperf.delete_snapshot_pg_statio_user_tables(0);
 delete_snapshot_pg_statio_user_tables 
---------------------------------------
 t
(1 row)

SELECT count(*) FROM pgperf.snapshot_pg_statio_user_tables WHERE schemaname <> 'pgperf';
 count 
-------
     0
(1 row)

DROP TABLE t1;
DROP TABLE