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Fix heap blocks bug add test coverage #59

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080407d
Parallel Bitmap Heap Scan: Fix EXPLAIN reporting of "Heap Blocks"
lfittl Apr 5, 2026
7f39a58
Add regression test coverage for EXPLAIN of Parallel Index Only Scans
lfittl Apr 5, 2026
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33 changes: 26 additions & 7 deletions src/backend/commands/explain.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3924,26 +3924,45 @@ show_indexsearches_info(PlanState *planstate, ExplainState *es)
static void
show_tidbitmap_info(BitmapHeapScanState *planstate, ExplainState *es)
{
uint64 exact_pages;
uint64 lossy_pages;

if (!es->analyze)
return;

/* Start with leader's stats */
exact_pages = planstate->stats.exact_pages;
lossy_pages = planstate->stats.lossy_pages;

/* Accumulate worker stats into node-level totals */
if (planstate->sinstrument != NULL)
{
for (int n = 0; n < planstate->sinstrument->num_workers; n++)
{
BitmapHeapScanInstrumentation *si = &planstate->sinstrument->sinstrument[n];

exact_pages += si->exact_pages;
lossy_pages += si->lossy_pages;
}
}

if (es->format != EXPLAIN_FORMAT_TEXT)
{
ExplainPropertyUInteger("Exact Heap Blocks", NULL,
planstate->stats.exact_pages, es);
exact_pages, es);
ExplainPropertyUInteger("Lossy Heap Blocks", NULL,
planstate->stats.lossy_pages, es);
lossy_pages, es);
}
else
{
if (planstate->stats.exact_pages > 0 || planstate->stats.lossy_pages > 0)
if (exact_pages > 0 || lossy_pages > 0)
{
ExplainIndentText(es);
appendStringInfoString(es->str, "Heap Blocks:");
if (planstate->stats.exact_pages > 0)
appendStringInfo(es->str, " exact=" UINT64_FORMAT, planstate->stats.exact_pages);
if (planstate->stats.lossy_pages > 0)
appendStringInfo(es->str, " lossy=" UINT64_FORMAT, planstate->stats.lossy_pages);
if (exact_pages > 0)
appendStringInfo(es->str, " exact=" UINT64_FORMAT, exact_pages);
if (lossy_pages > 0)
appendStringInfo(es->str, " lossy=" UINT64_FORMAT, lossy_pages);
appendStringInfoChar(es->str, '\n');
}
}
Expand Down
67 changes: 67 additions & 0 deletions src/test/regress/expected/explain.out
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Expand Up @@ -822,3 +822,70 @@ select explain_filter('explain (analyze,buffers off,costs off) select sum(n) ove
(9 rows)

reset work_mem;
-- Test parallel bitmap heap scan reports per-worker heap block stats.
CREATE FUNCTION check_parallel_bitmap_heap_scan() RETURNS boolean AS $$
DECLARE
plan_json json;
node json;
BEGIN
SET LOCAL enable_seqscan = off;
SET LOCAL enable_indexscan = off;
SET LOCAL parallel_setup_cost = 0;
SET LOCAL parallel_tuple_cost = 0;
SET LOCAL min_parallel_table_scan_size = 0;
SET LOCAL min_parallel_index_scan_size = 0;
SET LOCAL max_parallel_workers_per_gather = 2;
SET LOCAL parallel_leader_participation = off;

EXECUTE 'EXPLAIN (ANALYZE, BUFFERS, COSTS OFF, FORMAT JSON)
SELECT count(*) FROM tenk1 WHERE hundred > 1' INTO plan_json;

node := plan_json->0->'Plan';
WHILE node->'Plans' IS NOT NULL AND node->>'Node Type' != 'Bitmap Heap Scan' LOOP
node := node->'Plans'->0;
END LOOP;

RETURN COALESCE((node->>'Exact Heap Blocks')::int, 0) > 0;
END;
$$ LANGUAGE plpgsql;
SELECT check_parallel_bitmap_heap_scan() AS parallel_bitmap_instrumentation;
parallel_bitmap_instrumentation
---------------------------------
t
(1 row)

DROP FUNCTION check_parallel_bitmap_heap_scan;
-- Test parallel index-only scan reports per-worker index search stats.
CREATE FUNCTION check_parallel_indexonly_scan() RETURNS boolean AS $$
DECLARE
plan_json json;
node json;
BEGIN
SET LOCAL enable_seqscan = off;
SET LOCAL enable_bitmapscan = off;
SET LOCAL parallel_setup_cost = 0;
SET LOCAL parallel_tuple_cost = 0;
SET LOCAL min_parallel_index_scan_size = 0;
SET LOCAL min_parallel_table_scan_size = 0;
SET LOCAL max_parallel_workers_per_gather = 2;
SET LOCAL parallel_leader_participation = off;

EXECUTE 'EXPLAIN (ANALYZE, BUFFERS, COSTS OFF, FORMAT JSON)
SELECT count(*) FROM tenk1 WHERE thousand > 95' INTO plan_json;

-- Drill down to the Index Only Scan node
node := plan_json->0->'Plan';
WHILE node->'Plans' IS NOT NULL AND node->>'Node Type' != 'Index Only Scan' LOOP
node := node->'Plans'->0;
END LOOP;

RETURN COALESCE((node->>'Index Searches')::int, 0) > 0;
END;
$$ LANGUAGE plpgsql;
SELECT check_parallel_indexonly_scan() AS parallel_indexonly_instrumentation;
parallel_indexonly_instrumentation
------------------------------------
t
(1 row)

DROP FUNCTION check_parallel_indexonly_scan;
63 changes: 63 additions & 0 deletions src/test/regress/sql/explain.sql
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Expand Up @@ -188,3 +188,66 @@ select explain_filter('explain (analyze,buffers off,costs off) select sum(n) ove
-- Test tuplestore storage usage in Window aggregate (memory and disk case, final result is disk)
select explain_filter('explain (analyze,buffers off,costs off) select sum(n) over(partition by m) from (SELECT n < 3 as m, n from generate_series(1,2500) a(n))');
reset work_mem;

-- Test parallel bitmap heap scan reports per-worker heap block stats.
CREATE FUNCTION check_parallel_bitmap_heap_scan() RETURNS boolean AS $$
DECLARE
plan_json json;
node json;
BEGIN
SET LOCAL enable_seqscan = off;
SET LOCAL enable_indexscan = off;
SET LOCAL parallel_setup_cost = 0;
SET LOCAL parallel_tuple_cost = 0;
SET LOCAL min_parallel_table_scan_size = 0;
SET LOCAL min_parallel_index_scan_size = 0;
SET LOCAL max_parallel_workers_per_gather = 2;
SET LOCAL parallel_leader_participation = off;

EXECUTE 'EXPLAIN (ANALYZE, BUFFERS, COSTS OFF, FORMAT JSON)
SELECT count(*) FROM tenk1 WHERE hundred > 1' INTO plan_json;

node := plan_json->0->'Plan';
WHILE node->'Plans' IS NOT NULL AND node->>'Node Type' != 'Bitmap Heap Scan' LOOP
node := node->'Plans'->0;
END LOOP;

RETURN COALESCE((node->>'Exact Heap Blocks')::int, 0) > 0;
END;
$$ LANGUAGE plpgsql;

SELECT check_parallel_bitmap_heap_scan() AS parallel_bitmap_instrumentation;

DROP FUNCTION check_parallel_bitmap_heap_scan;

-- Test parallel index-only scan reports per-worker index search stats.
CREATE FUNCTION check_parallel_indexonly_scan() RETURNS boolean AS $$
DECLARE
plan_json json;
node json;
BEGIN
SET LOCAL enable_seqscan = off;
SET LOCAL enable_bitmapscan = off;
SET LOCAL parallel_setup_cost = 0;
SET LOCAL parallel_tuple_cost = 0;
SET LOCAL min_parallel_index_scan_size = 0;
SET LOCAL min_parallel_table_scan_size = 0;
SET LOCAL max_parallel_workers_per_gather = 2;
SET LOCAL parallel_leader_participation = off;

EXECUTE 'EXPLAIN (ANALYZE, BUFFERS, COSTS OFF, FORMAT JSON)
SELECT count(*) FROM tenk1 WHERE thousand > 95' INTO plan_json;

-- Drill down to the Index Only Scan node
node := plan_json->0->'Plan';
WHILE node->'Plans' IS NOT NULL AND node->>'Node Type' != 'Index Only Scan' LOOP
node := node->'Plans'->0;
END LOOP;

RETURN COALESCE((node->>'Index Searches')::int, 0) > 0;
END;
$$ LANGUAGE plpgsql;

SELECT check_parallel_indexonly_scan() AS parallel_indexonly_instrumentation;

DROP FUNCTION check_parallel_indexonly_scan;