v0:
set enable_hashjoin=off;
set enable_mergejoin=off;
explain (ANALYZE,VERBOSE,COSTS,SETTINGS,BUFFERS,TIMING,MEMORY,IO)
select count(*)
from t_name_2 n2, t_name_1 n1
where n1.name = 'B'
  and n2.name = 'B' collate "case_insensitive";
                                                                       QUERY PLAN                                                                        
---------------------------------------------------------------------------------------------------------------------------------------------------------
 Aggregate  (cost=680.98..680.99 rows=1 width=8) (actual time=248.817..248.824 rows=1.00 loops=1)
   Output: count(*)
   Buffers: shared read=136
   ->  Nested Loop  (cost=0.29..653.23 rows=11100 width=0) (actual time=2.344..236.425 rows=22200.00 loops=1)
         Buffers: shared read=136
         ->  Index Only Scan using idx_t_name_1 on public.t_name_1 n1  (cost=0.29..6.23 rows=111 width=0) (actual time=1.227..1.477 rows=111.00 loops=1)
               Output: n1.name
               Index Cond: (n1.name = 'B'::text)
               Heap Fetches: 0
               Index Searches: 1
               Buffers: shared read=3
         ->  Materialize  (cost=0.00..508.50 rows=100 width=0) (actual time=0.010..1.993 rows=200.00 loops=111)
               Storage: Memory  Maximum Storage: 24kB
               Buffers: shared read=133
               ->  Seq Scan on public.t_name_2 n2  (cost=0.00..508.00 rows=100 width=0) (actual time=1.076..212.332 rows=200.00 loops=1)
                     Filter: (n2.name = 'B'::text COLLATE case_insensitive)
                     Rows Removed by Filter: 29800
                     Prefetch: avg=7.69 max=16 capacity=94
                     I/O: count=12 waits=1 size=11.08 in-progress=1.00
                     Buffers: shared read=133
 Settings: enable_hashjoin = 'off', enable_mergejoin = 'off'
 Planning:
   Buffers: shared hit=61 read=32
   Memory: used=30kB  allocated=64kB
 Planning Time: 28.829 ms
 Execution Time: 249.304 ms
(26 rows)

xman1=#




set enable_hashjoin=off;
set enable_mergejoin=off;
set enable_material=off;
explain (ANALYZE,VERBOSE,COSTS,SETTINGS,BUFFERS,TIMING,MEMORY,IO)
select count(*)
from t_name_2 n2, t_name_1 n1
where n1.name = 'B'
  and n2.name = 'B' collate "case_insensitive";