Improve BRIN minmax-multi opclass test coverage

Per the code coverage report, the existing regression tests did not
exercice some a couple important BRIN minmax-multi code paths.

- The tests focused on testing planning with a range of scan key
  strategies, but not the execution. Fixed by adding queries that
  actually test query execution for both equality and inequality.

- All tests created indexes after inserting data, but this only
  exercises the CREATE INDEX strategy that sees all values at once, not
  incremental summary updates. The new tests flip the order and create
  the index before adding data.

- The assert check(s) validating correctness of expanded ranges were
  present only in the "union" code path, which is not covered by
  regression tests at all (as it requires concurrency etc.). Fixed by
  adding the asserts to a couple more places.

Reviewed-by: Heikki Linnakangas
Discussion: https://postgr.es/m/57020b2e-d9c9-9bc7-4892-b36d9bb07563%40enterprisedb.com

3 files changed, 531 insertions, 0 deletions

diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c
index e9ce0f2a1be..f8b2a3f9bc6 100644
--- a/src/backend/access/brin/brin_minmax_multi.c
+++ b/src/backend/access/brin/brin_minmax_multi.c
@@ -1660,6 +1660,9 @@ ensure_free_space_in_buffer(BrinDesc *bdesc, Oid colloid,
 	/* build the expanded ranges */
 	eranges = build_expanded_ranges(cmpFn, colloid, range, &neranges);
 
+	/* Is the expanded representation of ranges correct? */
+	AssertCheckExpandedRanges(bdesc, colloid, attno, attr, eranges, neranges);
+
 	/* and we'll also need the 'distance' procedure */
 	distanceFn = minmax_multi_get_procinfo(bdesc, attno, PROCNUM_DISTANCE);
 
@@ -1675,6 +1678,9 @@ ensure_free_space_in_buffer(BrinDesc *bdesc, Oid colloid,
 									  range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR,
 									  cmpFn, colloid);
 
+	/* Is the result of reducing expanded ranges correct? */
+	AssertCheckExpandedRanges(bdesc, colloid, attno, attr, eranges, neranges);
+
 	/* Make sure we've sufficiently reduced the number of ranges. */
 	Assert(count_values(eranges, neranges) <= range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR);
 
@@ -2859,6 +2865,9 @@ brin_minmax_multi_union(PG_FUNCTION_ARGS)
 									  ranges_a->maxvalues,
 									  cmpFn, colloid);
 
+	/* Is the result of reducing expanded ranges correct? */
+	AssertCheckExpandedRanges(bdesc, colloid, attno, attr, eranges, neranges);
+
 	/* update the first range summary */
 	store_expanded_ranges(ranges_a, eranges, neranges);
 
diff --git a/src/test/regress/expected/brin_multi.out b/src/test/regress/expected/brin_multi.out
index 861a06ef8ca..9f46934c9be 100644
--- a/src/test/regress/expected/brin_multi.out
+++ b/src/test/regress/expected/brin_multi.out
@@ -466,3 +466,360 @@ EXPLAIN (COSTS OFF) SELECT * FROM brin_test_multi WHERE b = 1;
    Filter: (b = 1)
 (2 rows)
 
+-- do some inequality tests
+CREATE TABLE brin_test_multi_1 (a INT, b BIGINT) WITH (fillfactor=10);
+INSERT INTO brin_test_multi_1
+SELECT i/5 + mod(911 * i + 483, 25),
+       i/10 + mod(751 * i + 221, 41)
+  FROM generate_series(1,1000) s(i);
+CREATE INDEX brin_test_multi_1_idx_1 ON brin_test_multi_1 USING brin (a int4_minmax_multi_ops) WITH (pages_per_range=5);
+CREATE INDEX brin_test_multi_1_idx_2 ON brin_test_multi_1 USING brin (b int8_minmax_multi_ops) WITH (pages_per_range=5);
+SET enable_seqscan=off;
+-- int: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 37;
+ count 
+-------
+   124
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 113;
+ count 
+-------
+   504
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 177;
+ count 
+-------
+   829
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 25;
+ count 
+-------
+    69
+(1 row)
+
+-- int: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 120;
+ count 
+-------
+   456
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 180;
+ count 
+-------
+   161
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 71;
+ count 
+-------
+   701
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 63;
+ count 
+-------
+   746
+(1 row)
+
+-- int: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 207;
+ count 
+-------
+     3
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 177;
+ count 
+-------
+     5
+(1 row)
+
+-- bigint: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 73;
+ count 
+-------
+   529
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 47;
+ count 
+-------
+   279
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 199;
+ count 
+-------
+  1000
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 150;
+ count 
+-------
+  1000
+(1 row)
+
+-- bigint: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 93;
+ count 
+-------
+   261
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 37;
+ count 
+-------
+   821
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b >= 215;
+ count 
+-------
+     0
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 201;
+ count 
+-------
+     0
+(1 row)
+
+-- bigint: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 88;
+ count 
+-------
+    10
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 103;
+ count 
+-------
+     9
+(1 row)
+
+-- now do the same, but insert the rows with the indexes already created
+-- so that we don't use the "build callback" and instead use the regular
+-- approach of adding rows into existing ranges
+TRUNCATE brin_test_multi_1;
+INSERT INTO brin_test_multi_1
+SELECT i/5 + mod(911 * i + 483, 25),
+       i/10 + mod(751 * i + 221, 41)
+  FROM generate_series(1,1000) s(i);
+-- int: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 37;
+ count 
+-------
+   124
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 113;
+ count 
+-------
+   504
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 177;
+ count 
+-------
+   829
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 25;
+ count 
+-------
+    69
+(1 row)
+
+-- int: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 120;
+ count 
+-------
+   456
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 180;
+ count 
+-------
+   161
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 71;
+ count 
+-------
+   701
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 63;
+ count 
+-------
+   746
+(1 row)
+
+-- int: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 207;
+ count 
+-------
+     3
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 177;
+ count 
+-------
+     5
+(1 row)
+
+-- bigint: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 73;
+ count 
+-------
+   529
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 47;
+ count 
+-------
+   279
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 199;
+ count 
+-------
+  1000
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 150;
+ count 
+-------
+  1000
+(1 row)
+
+-- bigint: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 93;
+ count 
+-------
+   261
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 37;
+ count 
+-------
+   821
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b >= 215;
+ count 
+-------
+     0
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 201;
+ count 
+-------
+     0
+(1 row)
+
+-- bigint: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 88;
+ count 
+-------
+    10
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 103;
+ count 
+-------
+     9
+(1 row)
+
+DROP TABLE brin_test_multi_1;
+RESET enable_seqscan;
+-- do some inequality tests for varlena data types
+CREATE TABLE brin_test_multi_2 (a UUID) WITH (fillfactor=10);
+INSERT INTO brin_test_multi_2
+SELECT v::uuid FROM (SELECT row_number() OVER (ORDER BY v) c, v FROM (SELECT md5((i/13)::text) AS v FROM generate_series(1,1000) s(i)) foo) bar ORDER BY c + 25 * random();
+CREATE INDEX brin_test_multi_2_idx ON brin_test_multi_2 USING brin (a uuid_minmax_multi_ops) WITH (pages_per_range=5);
+SET enable_seqscan=off;
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a < '33e75ff0-9dd6-01bb-e69f-351039152189';
+ count 
+-------
+   195
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a > '33e75ff0-9dd6-01bb-e69f-351039152189';
+ count 
+-------
+   792
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a <= 'f457c545-a9de-d88f-18ec-ee47145a72c0';
+ count 
+-------
+   961
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a >= 'c51ce410-c124-a10e-0db5-e4b97fc2af39';
+ count 
+-------
+   272
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'cfcd2084-95d5-65ef-66e7-dff9f98764da';
+ count 
+-------
+    12
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'aab32389-22bc-c25a-6f60-6eb525ffdc56';
+ count 
+-------
+    13
+(1 row)
+
+-- now do the same, but insert the rows with the indexes already created
+-- so that we don't use the "build callback" and instead use the regular
+-- approach of adding rows into existing ranges
+TRUNCATE brin_test_multi_2;
+INSERT INTO brin_test_multi_2
+SELECT v::uuid FROM (SELECT row_number() OVER (ORDER BY v) c, v FROM (SELECT md5((i/13)::text) AS v FROM generate_series(1,1000) s(i)) foo) bar ORDER BY c + 25 * random();
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a < '33e75ff0-9dd6-01bb-e69f-351039152189';
+ count 
+-------
+   195
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a > '33e75ff0-9dd6-01bb-e69f-351039152189';
+ count 
+-------
+   792
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a <= 'f457c545-a9de-d88f-18ec-ee47145a72c0';
+ count 
+-------
+   961
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a >= 'c51ce410-c124-a10e-0db5-e4b97fc2af39';
+ count 
+-------
+   272
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'cfcd2084-95d5-65ef-66e7-dff9f98764da';
+ count 
+-------
+    12
+(1 row)
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'aab32389-22bc-c25a-6f60-6eb525ffdc56';
+ count 
+-------
+    13
+(1 row)
+
+DROP TABLE brin_test_multi_2;
+RESET enable_seqscan;
diff --git a/src/test/regress/sql/brin_multi.sql b/src/test/regress/sql/brin_multi.sql
index 070455257c0..d50dbdee682 100644
--- a/src/test/regress/sql/brin_multi.sql
+++ b/src/test/regress/sql/brin_multi.sql
@@ -421,3 +421,168 @@ VACUUM ANALYZE brin_test_multi;
 EXPLAIN (COSTS OFF) SELECT * FROM brin_test_multi WHERE a = 1;
 -- Ensure brin index is not used when values are not correlated
 EXPLAIN (COSTS OFF) SELECT * FROM brin_test_multi WHERE b = 1;
+
+
+-- do some inequality tests
+CREATE TABLE brin_test_multi_1 (a INT, b BIGINT) WITH (fillfactor=10);
+INSERT INTO brin_test_multi_1
+SELECT i/5 + mod(911 * i + 483, 25),
+       i/10 + mod(751 * i + 221, 41)
+  FROM generate_series(1,1000) s(i);
+
+CREATE INDEX brin_test_multi_1_idx_1 ON brin_test_multi_1 USING brin (a int4_minmax_multi_ops) WITH (pages_per_range=5);
+CREATE INDEX brin_test_multi_1_idx_2 ON brin_test_multi_1 USING brin (b int8_minmax_multi_ops) WITH (pages_per_range=5);
+
+SET enable_seqscan=off;
+
+-- int: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 37;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 113;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 177;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 25;
+
+-- int: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 120;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 180;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 71;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 63;
+
+-- int: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 207;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 177;
+
+-- bigint: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 73;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 47;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 199;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 150;
+
+-- bigint: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 93;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 37;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b >= 215;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 201;
+
+-- bigint: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 88;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 103;
+
+-- now do the same, but insert the rows with the indexes already created
+-- so that we don't use the "build callback" and instead use the regular
+-- approach of adding rows into existing ranges
+TRUNCATE brin_test_multi_1;
+
+INSERT INTO brin_test_multi_1
+SELECT i/5 + mod(911 * i + 483, 25),
+       i/10 + mod(751 * i + 221, 41)
+  FROM generate_series(1,1000) s(i);
+
+-- int: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 37;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a < 113;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 177;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a <= 25;
+
+-- int: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 120;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 180;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a > 71;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a >= 63;
+
+-- int: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 207;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE a = 177;
+
+-- bigint: less than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 73;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 47;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b < 199;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b <= 150;
+
+-- bigint: greater than
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 93;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 37;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b >= 215;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b > 201;
+
+-- bigint: equals
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 88;
+
+SELECT COUNT(*) FROM brin_test_multi_1 WHERE b = 103;
+
+
+DROP TABLE brin_test_multi_1;
+RESET enable_seqscan;
+
+
+-- do some inequality tests for varlena data types
+CREATE TABLE brin_test_multi_2 (a UUID) WITH (fillfactor=10);
+INSERT INTO brin_test_multi_2
+SELECT v::uuid FROM (SELECT row_number() OVER (ORDER BY v) c, v FROM (SELECT md5((i/13)::text) AS v FROM generate_series(1,1000) s(i)) foo) bar ORDER BY c + 25 * random();
+
+CREATE INDEX brin_test_multi_2_idx ON brin_test_multi_2 USING brin (a uuid_minmax_multi_ops) WITH (pages_per_range=5);
+
+SET enable_seqscan=off;
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a < '33e75ff0-9dd6-01bb-e69f-351039152189';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a > '33e75ff0-9dd6-01bb-e69f-351039152189';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a <= 'f457c545-a9de-d88f-18ec-ee47145a72c0';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a >= 'c51ce410-c124-a10e-0db5-e4b97fc2af39';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'cfcd2084-95d5-65ef-66e7-dff9f98764da';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'aab32389-22bc-c25a-6f60-6eb525ffdc56';
+
+
+-- now do the same, but insert the rows with the indexes already created
+-- so that we don't use the "build callback" and instead use the regular
+-- approach of adding rows into existing ranges
+
+TRUNCATE brin_test_multi_2;
+INSERT INTO brin_test_multi_2
+SELECT v::uuid FROM (SELECT row_number() OVER (ORDER BY v) c, v FROM (SELECT md5((i/13)::text) AS v FROM generate_series(1,1000) s(i)) foo) bar ORDER BY c + 25 * random();
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a < '33e75ff0-9dd6-01bb-e69f-351039152189';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a > '33e75ff0-9dd6-01bb-e69f-351039152189';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a <= 'f457c545-a9de-d88f-18ec-ee47145a72c0';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a >= 'c51ce410-c124-a10e-0db5-e4b97fc2af39';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'cfcd2084-95d5-65ef-66e7-dff9f98764da';
+
+SELECT COUNT(*) FROM brin_test_multi_2 WHERE a = 'aab32389-22bc-c25a-6f60-6eb525ffdc56';
+
+DROP TABLE brin_test_multi_2;
+RESET enable_seqscan;