Fix bitmap scan crash issue for AO/AOCS table. (#10407)

When ExecReScanBitmapHeapScan get executed, bitmap state (tbmiterator
and tbmres) gets freed in freeBitmapState. So the tbmres is NULL, and we
need to reinit bitmap state to start scan from the beginning and reset AO/AOCS
bitmap pages' flags(baos_gotpage, baos_lossy, baos_cindex and baos_ntuples).

Especially when ExecReScan happens on the bitmap append only scan and
not all the matched tuples in bitmap are consumed, for example, Bitmap
Heap Scan as inner plan of the Nest Loop Semi Join. If tbmres not get init,
and not read all tuples in last bitmap, BitmapAppendOnlyNext will assume the
current bitmap page still has data to return. but bitmap state already freed.

From the code, for Nest Loop Semi Join, when a match find, a new outer slot is
requested, and then `ExecReScanBitmapHeapScan` get called, `node->tbmres` and
`node->tbmiterator` set to NULL. `node->baos_gotpage` still keeps true.
When execute `BitmapAppendOnlyNext`, it skip create new `node->tbmres`.
And jump to access `tbmres->recheck`.
Reviewed-by: NJinbao Chen <jinchen@pivotal.io>
Reviewed-by: NAsim R P <pasim@vmware.com>

src/backend/executor/nodeBitmapHeapscan.c

@@ -676,7 +676,19 @@ BitmapAppendOnlyNext(BitmapHeapScanState *node)
 		if (QueryFinishPending)
 			return NULL;
 
-		if (!node->baos_gotpage)
+		/*
+		* When ExecReScanBitmapHeapScan get executed, bitmap state (tbmiterator and 
+		* tbmres) gets freed in freeBitmapState. So the tbmres is NULL, and we need
+		* to reinit bitmap state to start scan from begining and reset AO/AOCS bitmap
+		* pages' flags(baos_gotpage, baos_lossy, baos_cindex and baos_ntuples). 
+		*
+		* Especially when ExecReScan happens on the bitmap append only scan and not all the
+		* matched tuples in bitmap are consumed, for example, Bitmap Heap Scan as inner plan
+		* of the Nest Loop Semi Join. If tbmres not get init, and not read all tuples
+		* in last bitmap, BitmapAppendOnlyNext will assume the current bitmap page still
+		* has data to return. but bitmap state already freed.
+		*/
+		if (!node->baos_gotpage || tbmres == NULL)
 		{
 			/*
 			 * Obtain the next psuedo-heap-page-info with item bit-map.  Later, we'll
@@ -733,6 +745,9 @@ BitmapAppendOnlyNext(BitmapHeapScanState *node)
 			continue;
 		}
 
+		/* Make sure the bitmap state get initalized */
+		Assert(tbmres);
+
 		if (node->baos_lossy || tbmres->recheck)
 			need_recheck = true;
 

src/test/regress/expected/co_nestloop_idxscan.out

 --
 -- Nested loop join with index scan on CO table, test for MPP-17658
 --
+-- The test should also make sure the AO/AOCO table's bitmap state
+-- get re-init in BitmapHeapScanState if the current scan on AO/AOCO table
+-- not finished, and after ExecReScanBitmapHeapScan get called which will free
+-- current bitmap state.
+-- If the scan read all from AO/AOCO, the bitmap state in BitmapHeapScanState
+-- always get re-init, so this case is not considered.
+-- This is test through Nested Loop Semi Join, since it garentees that if
+-- find a match, a new outer slot is request, which the inner plan may not
+-- read all tuples. The inner plan of the Nested Loop Semi Join is Bitmap
+-- Heap Scan. So for a new outer slot, the inner plan need to rescan from
+-- the begining.
+--
 create schema co_nestloop_idxscan;
 create table co_nestloop_idxscan.foo (id bigint, data text) with (appendonly=true, orientation=column)
 distributed by (id);
@@ -76,6 +88,42 @@ select f.id from co_nestloop_idxscan.foo f, co_nestloop_idxscan.bar b where f.id
 (1 row)
 
 set optimizer_enable_hashjoin = on;
+-- test with Nested Loop Semi Join for AO/AOCS freed bitmap state get re-init.
+-- Make sure each bitmap index scan contains more than 1 matched tuples,
+-- to make sure rescan frees bitmap state in BitmapHeapScanState. Since if only
+-- 1 tuple matched, the bitmap state in BitmapHeapScanState always get re-init
+-- when read all matched tuples.
+insert into co_nestloop_idxscan.foo select i%10, repeat('xxxxxxxxxx', 100000) from generate_series(1,20) i;
+-- Fill enouth tuples on same segment for the outer relation in next loop join
+-- to make sure rescan get called for inner plan.
+insert into co_nestloop_idxscan.bar values (1);
+-- turn off the optimizer since we can not make the orca generate the same plan with planner.
+set optimizer = off;
+-- The outher plan of the Nested Loop Semi Join should be Seq Scan on bar b.
+-- The inner plain should be a Bitmap Heap Scan on foo f.
+-- So the Bitmap Heap Scan will call ExecReScanBitmapHeapScan for new outer slot.
+explain select b.id from co_nestloop_idxscan.bar b where b.id in (select f.id from co_nestloop_idxscan.foo f where f.id in (1, 2, 3, 4, 5, 6));
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
+ Gather Motion 3:1  (slice1; segments: 3)  (cost=10000000048.90..10000000054.01 rows=4 width=8)
+   ->  Nested Loop Semi Join  (cost=10000000048.90..10000000053.95 rows=2 width=8)
+         ->  Seq Scan on bar b  (cost=10000000000.00..10000000001.02 rows=1 width=8)
+               Filter: (id = ANY ('{1,2,3,4,5,6}'::bigint[]))
+         ->  Bitmap Heap Scan on foo f  (cost=48.90..52.92 rows=1 width=8)
+               Recheck Cond: ((id = b.id) AND (id = ANY ('{1,2,3,4,5,6}'::bigint[])))
+               ->  Bitmap Index Scan on foo_id_idx  (cost=0.00..48.90 rows=1 width=0)
+                     Index Cond: ((id = b.id) AND (id = ANY ('{1,2,3,4,5,6}'::bigint[])))
+ Optimizer: Postgres query optimizer
+(9 rows)
+
+select b.id from co_nestloop_idxscan.bar b where b.id in (select f.id from co_nestloop_idxscan.foo f where f.id in (1, 2, 3, 4, 5, 6));
+ id 
+----
+  1
+  1
+(2 rows)
+
+reset optimizer;
 drop schema co_nestloop_idxscan cascade;
 NOTICE:  drop cascades to 2 other objects
 DETAIL:  drop cascades to append only columnar table co_nestloop_idxscan.foo

src/test/regress/expected/co_nestloop_idxscan_optimizer.out

 --
 -- Nested loop join with index scan on CO table, test for MPP-17658
 --
+-- The test should also make sure the AO/AOCO table's bitmap state
+-- get re-init in BitmapHeapScanState if the current scan on AO/AOCO table
+-- not finished, and after ExecReScanBitmapHeapScan get called which will free
+-- current bitmap state.
+-- If the scan read all from AO/AOCO, the bitmap state in BitmapHeapScanState
+-- always get re-init, so this case is not considered.
+-- This is test through Nested Loop Semi Join, since it garentees that if
+-- find a match, a new outer slot is request, which the inner plan may not
+-- read all tuples. The inner plan of the Nested Loop Semi Join is Bitmap
+-- Heap Scan. So for a new outer slot, the inner plan need to rescan from
+-- the begining.
+--
 create schema co_nestloop_idxscan;
 create table co_nestloop_idxscan.foo (id bigint, data text) with (appendonly=true, orientation=column)
 distributed by (id);
@@ -80,6 +92,42 @@ select f.id from co_nestloop_idxscan.foo f, co_nestloop_idxscan.bar b where f.id
 (1 row)
 
 set optimizer_enable_hashjoin = on;
+-- test with Nested Loop Semi Join for AO/AOCS freed bitmap state get re-init.
+-- Make sure each bitmap index scan contains more than 1 matched tuples,
+-- to make sure rescan frees bitmap state in BitmapHeapScanState. Since if only
+-- 1 tuple matched, the bitmap state in BitmapHeapScanState always get re-init
+-- when read all matched tuples.
+insert into co_nestloop_idxscan.foo select i%10, repeat('xxxxxxxxxx', 100000) from generate_series(1,20) i;
+-- Fill enouth tuples on same segment for the outer relation in next loop join
+-- to make sure rescan get called for inner plan.
+insert into co_nestloop_idxscan.bar values (1);
+-- turn off the optimizer since we can not make the orca generate the same plan with planner.
+set optimizer = off;
+-- The outher plan of the Nested Loop Semi Join should be Seq Scan on bar b.
+-- The inner plain should be a Bitmap Heap Scan on foo f.
+-- So the Bitmap Heap Scan will call ExecReScanBitmapHeapScan for new outer slot.
+explain select b.id from co_nestloop_idxscan.bar b where b.id in (select f.id from co_nestloop_idxscan.foo f where f.id in (1, 2, 3, 4, 5, 6));
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
+ Gather Motion 3:1  (slice1; segments: 3)  (cost=10000000048.90..10000000054.01 rows=4 width=8)
+   ->  Nested Loop Semi Join  (cost=10000000048.90..10000000053.95 rows=2 width=8)
+         ->  Seq Scan on bar b  (cost=10000000000.00..10000000001.02 rows=1 width=8)
+               Filter: (id = ANY ('{1,2,3,4,5,6}'::bigint[]))
+         ->  Bitmap Heap Scan on foo f  (cost=48.90..52.92 rows=1 width=8)
+               Recheck Cond: ((id = b.id) AND (id = ANY ('{1,2,3,4,5,6}'::bigint[])))
+               ->  Bitmap Index Scan on foo_id_idx  (cost=0.00..48.90 rows=1 width=0)
+                     Index Cond: ((id = b.id) AND (id = ANY ('{1,2,3,4,5,6}'::bigint[])))
+ Optimizer: Postgres query optimizer
+(9 rows)
+
+select b.id from co_nestloop_idxscan.bar b where b.id in (select f.id from co_nestloop_idxscan.foo f where f.id in (1, 2, 3, 4, 5, 6));
+ id 
+----
+  1
+  1
+(2 rows)
+
+reset optimizer;
 drop schema co_nestloop_idxscan cascade;
 NOTICE:  drop cascades to 2 other objects
 DETAIL:  drop cascades to append only columnar table co_nestloop_idxscan.foo

src/test/regress/sql/co_nestloop_idxscan.sql

 --
 -- Nested loop join with index scan on CO table, test for MPP-17658
 --
-
+-- The test should also make sure the AO/AOCO table's bitmap state
+-- get re-init in BitmapHeapScanState if the current scan on AO/AOCO table
+-- not finished, and after ExecReScanBitmapHeapScan get called which will free
+-- current bitmap state.
+-- If the scan read all from AO/AOCO, the bitmap state in BitmapHeapScanState
+-- always get re-init, so this case is not considered.
+-- This is test through Nested Loop Semi Join, since it garentees that if
+-- find a match, a new outer slot is request, which the inner plan may not
+-- read all tuples. The inner plan of the Nested Loop Semi Join is Bitmap
+-- Heap Scan. So for a new outer slot, the inner plan need to rescan from
+-- the begining.
+--
 
 create schema co_nestloop_idxscan;
 create table co_nestloop_idxscan.foo (id bigint, data text) with (appendonly=true, orientation=column)
@@ -34,4 +45,24 @@ explain select f.id from co_nestloop_idxscan.bar b, co_nestloop_idxscan.foo f wh
 select f.id from co_nestloop_idxscan.foo f, co_nestloop_idxscan.bar b where f.id = b.id;
 set optimizer_enable_hashjoin = on;
 
+-- test with Nested Loop Semi Join for AO/AOCS freed bitmap state get re-init.
+-- Make sure each bitmap index scan contains more than 1 matched tuples,
+-- to make sure rescan frees bitmap state in BitmapHeapScanState. Since if only
+-- 1 tuple matched, the bitmap state in BitmapHeapScanState always get re-init
+-- when read all matched tuples.
+insert into co_nestloop_idxscan.foo select i%10, repeat('xxxxxxxxxx', 100000) from generate_series(1,20) i;
+
+-- Fill enouth tuples on same segment for the outer relation in next loop join
+-- to make sure rescan get called for inner plan.
+insert into co_nestloop_idxscan.bar values (1);
+
+-- turn off the optimizer since we can not make the orca generate the same plan with planner.
+set optimizer = off;
+-- The outher plan of the Nested Loop Semi Join should be Seq Scan on bar b.
+-- The inner plain should be a Bitmap Heap Scan on foo f.
+-- So the Bitmap Heap Scan will call ExecReScanBitmapHeapScan for new outer slot.
+explain select b.id from co_nestloop_idxscan.bar b where b.id in (select f.id from co_nestloop_idxscan.foo f where f.id in (1, 2, 3, 4, 5, 6));
+select b.id from co_nestloop_idxscan.bar b where b.id in (select f.id from co_nestloop_idxscan.foo f where f.id in (1, 2, 3, 4, 5, 6));
+
+reset optimizer;
 drop schema co_nestloop_idxscan cascade;