The second permutation was uncommented. We need to fix something.

Author: rzharkov

src/test/isolation/expected/snapfs_set_backend_snapshot_table.out

@@ -23,7 +23,7 @@ step s2_tab_u:
 	update foo set name = name || '_upd_sess_2';
 
 step s1_tab_s: 
-	select * from foo;
+	select * from foo order by id;
 
 id             name           
 
@@ -43,7 +43,7 @@ pg_set_backend_snapshot
 
 
 step s1_tab_s: 
-	select * from foo;
+	select * from foo order by id;
 
 id             name           
 
@@ -64,7 +64,7 @@ step s2_tab_u:
 	update foo set name = name || '_upd_sess_2';
 
 step s1_tab_s: 
-	select * from foo;
+	select * from foo order by id;
 
 id             name           
 
@@ -87,7 +87,7 @@ step s2_tab_u:
 	update foo set name = name || '_upd_sess_2';
 
 step s1_tab_s: 
-	select * from foo;
+	select * from foo order by id;
 
 id             name           
 
@@ -100,3 +100,61 @@ id             name
 
 1              some_text_sess_1_upd_sess_2_upd_sess_2_upd_sess_2
 2              some_text_sess_2_upd_sess_2_upd_sess_2_upd_sess_2
+
+starting permutation: s1_mk_sn s1_tab_i s2_tab_i s1_mk_sn s2_tab_u s1_sb_sn_1 s1_tab_s s2_rm_sn_1 s1_sb_sn_0 s1_tab_s s2_tab_s
+step s1_mk_sn: 
+	select 1 as "make_snapshot" from pg_make_snapshot();
+
+make_snapshot  
+
+1              
+step s1_tab_i: 
+	insert into foo ( name ) values ( 'some_text_sess_1' );
+
+step s2_tab_i: 
+	insert into foo ( name ) values ( 'some_text_sess_2' );
+
+step s1_mk_sn: 
+	select 1 as "make_snapshot" from pg_make_snapshot();
+
+make_snapshot  
+
+1              
+step s2_tab_u: 
+	update foo set name = name || '_upd_sess_2';
+
+step s1_sb_sn_1: 
+	select pg_set_backend_snapshot( ( select recent_snapshot - 1 from pg_control_snapshot() ) );
+
+pg_set_backend_snapshot
+
+               
+step s1_tab_s: 
+	select * from foo order by id;
+
+id             name           
+
+step s2_rm_sn_1: 
+	select pg_remove_snapshot( ( select recent_snapshot - 1 from pg_control_snapshot() ) );
+
+pg_remove_snapshot
+
+               
+step s1_sb_sn_0: 
+	select pg_set_backend_snapshot( 0 );
+
+ERROR:  Snapshot 51 is not valid any more
+step s1_tab_s: 
+	select * from foo order by id;
+
+id             name           
+
+1              some_text_sess_1_upd_sess_2
+2              some_text_sess_2_upd_sess_2
+step s2_tab_s: 
+	select * from foo;
+
+id             name           
+
+1              some_text_sess_1_upd_sess_2
+2              some_text_sess_2_upd_sess_2

src/test/isolation/specs/snapfs_set_backend_snapshot_table.spec

@@ -7,7 +7,7 @@ setup {
 teardown {
 	select pg_set_backend_snapshot( 0 );
 	select pg_remove_snapshot( ( select recent_snapshot from pg_control_snapshot() ) );
-	drop table foo;
+	DROP TABLE IF EXISTS foo;
 }
 
 session "s1"
@@ -32,7 +32,7 @@ step "s1_tab_i" {
 }
 
 step "s1_tab_s" {
-	select * from foo;
+	select * from foo order by id;
 }
 
 session "s2"
@@ -53,4 +53,4 @@ step "s2_rm_sn_1" {
 }
 
 permutation "s1_mk_sn" "s1_tab_i" "s2_tab_i" "s1_mk_sn" "s2_tab_u" "s1_tab_s" "s2_tab_s" "s1_sb_sn_1" "s1_tab_s" "s2_tab_s" "s1_sb_sn_2" "s2_tab_u" "s1_tab_s" "s2_tab_s" "s1_sb_sn_0" "s2_tab_u" "s1_tab_s" "s2_tab_s"
-#permutation "s1_mk_sn" "s1_tab_i" "s2_tab_i" "s1_mk_sn" "s2_tab_u" "s1_sb_sn_1" "s1_tab_s" "s2_rm_sn_1" "s1_sb_sn_0" "s1_tab_s" "s2_tab_s"
+permutation "s1_mk_sn" "s1_tab_i" "s2_tab_i" "s1_mk_sn" "s2_tab_u" "s1_sb_sn_1" "s1_tab_s" "s2_rm_sn_1" "s1_sb_sn_0" "s1_tab_s" "s2_tab_s"