First cut at planner support for bitmap index scans. Lots to do yet,

but the code is basically working.  Along the way, rewrite the entire
approach to processing OR index conditions, and make it work in join
cases for the first time ever.  orindxpath.c is now basically obsolete,
but I left it in for the time being to allow easy comparison testing
against the old implementation.

src/test/regress/expected/alter_table.out

@@ -131,8 +131,10 @@ ALTER INDEX tmp_onek_unique1 RENAME TO onek_unique1;
 -- renaming views
 CREATE VIEW tmp_view (unique1) AS SELECT unique1 FROM tenk1;
 ALTER TABLE tmp_view RENAME TO tmp_view_new;
--- analyze to ensure we get an indexscan here
+-- hack to ensure we get an indexscan here
 ANALYZE tenk1;
+set enable_seqscan to off;
+set enable_bitmapscan to off;
 -- 5 values, sorted 
 SELECT unique1 FROM tenk1 WHERE unique1 < 5;
  unique1 
@@ -144,6 +146,8 @@ SELECT unique1 FROM tenk1 WHERE unique1 < 5;
        4
 (5 rows)
 
+reset enable_seqscan;
+reset enable_bitmapscan;
 DROP VIEW tmp_view_new;
 -- toast-like relation name
 alter table stud_emp rename to pg_toast_stud_emp;

src/test/regress/expected/arrays.out

@@ -367,6 +367,7 @@ insert into arr_tbl values ('{2,3,4}');
 insert into arr_tbl values ('{1,5,3}');
 insert into arr_tbl values ('{1,2,10}');
 set enable_seqscan to off;
+set enable_bitmapscan to off;
 select * from arr_tbl where f1 > '{1,2,3}' and f1 <= '{1,5,3}';
     f1    
 ----------
@@ -376,6 +377,8 @@ select * from arr_tbl where f1 > '{1,2,3}' and f1 <= '{1,5,3}';
 
 -- note: if above select doesn't produce the expected tuple order,
 -- then you didn't get an indexscan plan, and something is busted.
+reset enable_seqscan;
+reset enable_bitmapscan;
 -- test [not] (like|ilike) (any|all) (...)
 select 'foo' like any (array['%a', '%o']); -- t
  ?column? 

src/test/regress/expected/stats.out

@@ -11,6 +11,8 @@ SHOW stats_start_collector;  -- must be on
  on
 (1 row)
 
+-- XXX stopgap until we figure out how bitmap scans should be counted
+SET enable_bitmapscan = off;
 -- save counters
 CREATE TEMP TABLE prevstats AS
 SELECT t.seq_scan, t.seq_tup_read, t.idx_scan, t.idx_tup_fetch,

src/test/regress/sql/alter_table.sql

@@ -171,10 +171,16 @@ ALTER INDEX tmp_onek_unique1 RENAME TO onek_unique1;
 -- renaming views
 CREATE VIEW tmp_view (unique1) AS SELECT unique1 FROM tenk1;
 ALTER TABLE tmp_view RENAME TO tmp_view_new;
--- analyze to ensure we get an indexscan here
+
+-- hack to ensure we get an indexscan here
 ANALYZE tenk1;
+set enable_seqscan to off;
+set enable_bitmapscan to off;
 -- 5 values, sorted 
 SELECT unique1 FROM tenk1 WHERE unique1 < 5;
+reset enable_seqscan;
+reset enable_bitmapscan;
+
 DROP VIEW tmp_view_new;
 -- toast-like relation name
 alter table stud_emp rename to pg_toast_stud_emp;

src/test/regress/sql/arrays.sql

@@ -178,10 +178,14 @@ insert into arr_tbl values ('{1,2,3}');
 insert into arr_tbl values ('{2,3,4}');
 insert into arr_tbl values ('{1,5,3}');
 insert into arr_tbl values ('{1,2,10}');
+
 set enable_seqscan to off;
+set enable_bitmapscan to off;
 select * from arr_tbl where f1 > '{1,2,3}' and f1 <= '{1,5,3}';
 -- note: if above select doesn't produce the expected tuple order,
 -- then you didn't get an indexscan plan, and something is busted.
+reset enable_seqscan;
+reset enable_bitmapscan;
 
 -- test [not] (like|ilike) (any|all) (...)
 select 'foo' like any (array['%a', '%o']); -- t

src/test/regress/sql/stats.sql

@@ -8,6 +8,9 @@
 -- conditio sine qua non
 SHOW stats_start_collector;  -- must be on
 
+-- XXX stopgap until we figure out how bitmap scans should be counted
+SET enable_bitmapscan = off;
+
 -- save counters
 CREATE TEMP TABLE prevstats AS
 SELECT t.seq_scan, t.seq_tup_read, t.idx_scan, t.idx_tup_fetch,