Fix minmax-multi on infinite date/timestamp values

Make sure that infinite values in date/timestamp columns are treated as
if in infinite distance. Infinite values should not be merged with other
values, leaving them as outliers. The code however returned distance 0
in this case, so that infinite values were merged first. While this does
not break the index (i.e. it still produces correct query results), it
may make it much less efficient.

We don't need explicit handling of infinite date/timestamp values when
calculating distances, because those values are represented as extreme
but regular values (e.g. INT64_MIN/MAX for the timestamp type).

We don't need an exact distance, just a value that is much larger than
distanced between regular values. With the added cast to double values,
we can simply subtract the values.

The regression test queries a value in the "gap" and checks the range
was properly eliminated by the BRIN index.

This only affects minmax-multi indexes on timestamp/date columns with
infinite values, which is not very common in practice. The affected
indexes may need to be rebuilt.

Backpatch to 14, where minmax-multi indexes were introduced.

Reported-by: Ashutosh Bapat
Reviewed-by: Ashutosh Bapat, Dean Rasheed
Backpatch-through: 14
Discussion: https://postgr.es/m/eef0ea8c-4aaa-8d0d-027f-58b1f35dd170@enterprisedb.com

diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c
index 3bac8c98a00f15a4e4b9e410c72e0243afc66929..978acb87e271033ab721315f5bbe522612cf356f 100644 (file)
--- a/src/backend/access/brin/brin_minmax_multi.c
+++ b/src/backend/access/brin/brin_minmax_multi.c
@@ -2079,9 +2079,6 @@ brin_minmax_multi_distance_date(PG_FUNCTION_ARGS)
    DateADT     dateVal1 = PG_GETARG_DATEADT(0);
    DateADT     dateVal2 = PG_GETARG_DATEADT(1);
 
-   if (DATE_NOT_FINITE(dateVal1) || DATE_NOT_FINITE(dateVal2))
-       PG_RETURN_FLOAT8(0);
-
    delta = (float8) dateVal2 - (float8) dateVal1;
 
    Assert(delta >= 0);
@@ -2140,9 +2137,6 @@ brin_minmax_multi_distance_timestamp(PG_FUNCTION_ARGS)
    Timestamp   dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp   dt2 = PG_GETARG_TIMESTAMP(1);
 
-   if (TIMESTAMP_NOT_FINITE(dt1) || TIMESTAMP_NOT_FINITE(dt2))
-       PG_RETURN_FLOAT8(0);
-
    delta = (float8) dt2 - (float8) dt1;
 
    Assert(delta >= 0);

diff --git a/src/test/regress/expected/brin_multi.out b/src/test/regress/expected/brin_multi.out
index ce10147afeeda0417200258be066cb2504a1208f..2155b7bfc38a0d7e8e0c3c15d9a196947305c0d0 100644 (file)
--- a/src/test/regress/expected/brin_multi.out
+++ b/src/test/regress/expected/brin_multi.out
@@ -498,6 +498,63 @@ SELECT * FROM brin_date_test WHERE a = '2023-01-01'::date;
          Index Cond: (a = '2023-01-01'::date)
 (4 rows)
 
+DROP TABLE brin_date_test;
+RESET enable_seqscan;
+-- test handling of infinite timestamp values
+CREATE TABLE brin_timestamp_test(a TIMESTAMP);
+INSERT INTO brin_timestamp_test VALUES ('-infinity'), ('infinity');
+INSERT INTO brin_timestamp_test
+SELECT i FROM generate_series('2000-01-01'::timestamp, '2000-02-09'::timestamp, '1 day'::interval) s(i);
+CREATE INDEX ON brin_timestamp_test USING brin (a timestamp_minmax_multi_ops) WITH (pages_per_range=1);
+SET enable_seqscan = off;
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_timestamp_test WHERE a = '2023-01-01'::timestamp;
+                                  QUERY PLAN                                  
+------------------------------------------------------------------------------
+ Bitmap Heap Scan on brin_timestamp_test (actual rows=0 loops=1)
+   Recheck Cond: (a = '2023-01-01 00:00:00'::timestamp without time zone)
+   ->  Bitmap Index Scan on brin_timestamp_test_a_idx (actual rows=0 loops=1)
+         Index Cond: (a = '2023-01-01 00:00:00'::timestamp without time zone)
+(4 rows)
+
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_timestamp_test WHERE a = '1900-01-01'::timestamp;
+                                  QUERY PLAN                                  
+------------------------------------------------------------------------------
+ Bitmap Heap Scan on brin_timestamp_test (actual rows=0 loops=1)
+   Recheck Cond: (a = '1900-01-01 00:00:00'::timestamp without time zone)
+   ->  Bitmap Index Scan on brin_timestamp_test_a_idx (actual rows=0 loops=1)
+         Index Cond: (a = '1900-01-01 00:00:00'::timestamp without time zone)
+(4 rows)
+
+DROP TABLE brin_timestamp_test;
+RESET enable_seqscan;
+-- test handling of infinite date values
+CREATE TABLE brin_date_test(a DATE);
+INSERT INTO brin_date_test VALUES ('-infinity'), ('infinity');
+INSERT INTO brin_date_test SELECT '2000-01-01'::date + i FROM generate_series(1, 40) s(i);
+CREATE INDEX ON brin_date_test USING brin (a date_minmax_multi_ops) WITH (pages_per_range=1);
+SET enable_seqscan = off;
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_date_test WHERE a = '2023-01-01'::date;
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Bitmap Heap Scan on brin_date_test (actual rows=0 loops=1)
+   Recheck Cond: (a = '2023-01-01'::date)
+   ->  Bitmap Index Scan on brin_date_test_a_idx (actual rows=0 loops=1)
+         Index Cond: (a = '2023-01-01'::date)
+(4 rows)
+
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_date_test WHERE a = '1900-01-01'::date;
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Bitmap Heap Scan on brin_date_test (actual rows=0 loops=1)
+   Recheck Cond: (a = '1900-01-01'::date)
+   ->  Bitmap Index Scan on brin_date_test_a_idx (actual rows=0 loops=1)
+         Index Cond: (a = '1900-01-01'::date)
+(4 rows)
+
 DROP TABLE brin_date_test;
 RESET enable_seqscan;
 RESET datestyle;

diff --git a/src/test/regress/sql/brin_multi.sql b/src/test/regress/sql/brin_multi.sql
index b0dac67f5b045de4d36f143ef4191399a66b150c..feb47ae30599e11beb90e8b39b0a8517bb4600ed 100644 (file)
--- a/src/test/regress/sql/brin_multi.sql
+++ b/src/test/regress/sql/brin_multi.sql
@@ -457,6 +457,45 @@ SET enable_seqscan = off;
 EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
 SELECT * FROM brin_date_test WHERE a = '2023-01-01'::date;
 
+DROP TABLE brin_date_test;
+RESET enable_seqscan;
+
+-- test handling of infinite timestamp values
+CREATE TABLE brin_timestamp_test(a TIMESTAMP);
+
+INSERT INTO brin_timestamp_test VALUES ('-infinity'), ('infinity');
+INSERT INTO brin_timestamp_test
+SELECT i FROM generate_series('2000-01-01'::timestamp, '2000-02-09'::timestamp, '1 day'::interval) s(i);
+
+CREATE INDEX ON brin_timestamp_test USING brin (a timestamp_minmax_multi_ops) WITH (pages_per_range=1);
+
+SET enable_seqscan = off;
+
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_timestamp_test WHERE a = '2023-01-01'::timestamp;
+
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_timestamp_test WHERE a = '1900-01-01'::timestamp;
+
+DROP TABLE brin_timestamp_test;
+RESET enable_seqscan;
+
+-- test handling of infinite date values
+CREATE TABLE brin_date_test(a DATE);
+
+INSERT INTO brin_date_test VALUES ('-infinity'), ('infinity');
+INSERT INTO brin_date_test SELECT '2000-01-01'::date + i FROM generate_series(1, 40) s(i);
+
+CREATE INDEX ON brin_date_test USING brin (a date_minmax_multi_ops) WITH (pages_per_range=1);
+
+SET enable_seqscan = off;
+
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_date_test WHERE a = '2023-01-01'::date;
+
+EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF)
+SELECT * FROM brin_date_test WHERE a = '1900-01-01'::date;
+
 DROP TABLE brin_date_test;
 RESET enable_seqscan;
 RESET datestyle;