Discrepancy in the costs of prepared operators depending on the architecture of the system

[Xen-On-core]

For reproduce that, you can use follow script

CREATE TABLE t1 AS SELECT a FROM generate_series(0, 999) a;
CREATE INDEX ON t1(a);

-- seqscan
SET enable_seqscan = on;
SET enable_indexscan = off;
SET enable_bitmapscan = off;
PREPARE p1 AS SELECT * FROM t1 WHERE a < 999;
EXPLAIN EXECUTE p1;
DEALLOCATE p1;

-- indexscan
SET enable_seqscan = off;
SET enable_indexscan = on;
SET enable_bitmapscan = off;
PREPARE p1 AS SELECT * FROM t1 WHERE a < 999;
EXPLAIN EXECUTE p1;
DEALLOCATE p1;

-- bitmapscan
SET enable_seqscan = off;
SET enable_indexscan = off;
SET enable_bitmapscan = on;
PREPARE p1 AS SELECT * FROM t1 WHERE a < 999;
EXPLAIN EXECUTE p1;
DEALLOCATE p1;

DROP TABLE t1;

• In x64 system output looks like this

                   QUERY PLAN                      
  -----------------------------------------------------
  Seq Scan on t1  (cost=0.00..17.50 rows=333 width=4)
  Filter: (a < 999)
  (2 rows)
  
                              QUERY PLAN                                 
  ---------------------------------------------------------------------------
  Index Only Scan using t1_a_idx on t1  (cost=0.28..34.10 rows=333 width=4)
  Index Cond: (a < 999)
  (2 rows)
  
                              QUERY PLAN                                
  --------------------------------------------------------------------------
  Bitmap Heap Scan on t1  (cost=10.86..20.02 rows=333 width=4)
  Recheck Cond: (a < 999)
  ->  Bitmap Index Scan on t1_a_idx  (cost=0.00..10.77 rows=333 width=0)
       Index Cond: (a < 999)
  (4 rows)

• But in x32 looks like this

                   QUERY PLAN                      
  -----------------------------------------------------
  Seq Scan on t1  (cost=0.00..16.50 rows=333 width=4)
  Filter: (a < 999)
  (2 rows)
  
                              QUERY PLAN                                 
  ---------------------------------------------------------------------------
  Index Only Scan using t1_a_idx on t1  (cost=0.28..30.10 rows=333 width=4)
  Index Cond: (a < 999)
  (2 rows)
  
                              QUERY PLAN                                
  --------------------------------------------------------------------------
  Bitmap Heap Scan on t1  (cost=10.86..19.02 rows=333 width=4)
  Recheck Cond: (a < 999)
  ->  Bitmap Index Scan on t1_a_idx  (cost=0.00..10.77 rows=333 width=0)
       Index Cond: (a < 999)
  (4 rows)

I'm not sure if this is the right. Is this the expected behavior?

[michaelpq]

In what is that related to this extension?

[Xen-On-core]

@michaelpq, sorry, I didn't notice that you have already fixed this problem.

[michaelpq]

My mistake as well, I guess. I did not see any references to the regression tests in your initial report.