CREATE TABLE t (
  k INT PRIMARY KEY,
  a INT, 
  INDEX (a)
);

INSERT INTO t
SELECT i, i FROM generate_series(1, 1000) AS g(i);

CREATE STATISTICS __auto__ FROM t;

SHOW STATISTICS FOR TABLE t;
--   statistics_name | column_names |            created            | row_count | distinct_count | null_count | avg_size | partial_predicate |    histogram_id     | full_histogram_id
-- ------------------+--------------+-------------------------------+-----------+----------------+------------+----------+-------------------+---------------------+--------------------
--   __auto__        | {k}          | 2024-11-06 20:52:20.858821+00 |      1000 |           1000 |          0 |        3 | NULL              | 1018612747011162113 |                 0
--   __auto__        | {a}          | 2024-11-06 20:52:20.858821+00 |      1000 |           1000 |          0 |        3 | NULL              | 1018612747014635521 |                 0
-- (2 rows)

SELECT pg_sleep(5);

INSERT INTO t
SELECT i, i FROM generate_series(1001, 2000) AS g(i);

CREATE STATISTICS s FROM t USING EXTREMES;

SELECT pg_sleep(5);

SHOW STATISTICS FOR TABLE t;
--   statistics_name | column_names |            created            | row_count | distinct_count | null_count | avg_size |                  partial_predicate                   |    histogram_id     |  full_histogram_id
-- ------------------+--------------+-------------------------------+-----------+----------------+------------+----------+------------------------------------------------------+---------------------+----------------------
--   __auto__        | {k}          | 2024-11-06 20:52:20.858821+00 |      1000 |           1000 |          0 |        3 | NULL                                                 | 1018612747011162113 |                   0
--   __auto__        | {a}          | 2024-11-06 20:52:20.858821+00 |      1000 |           1000 |          0 |        3 | NULL                                                 | 1018612747014635521 |                   0
--   s               | {k}          | 2024-11-06 20:52:25.921077+00 |      1000 |           1000 |          0 |        3 | (k IS NULL) OR ((k < 1:::INT8) OR (k > 1000:::INT8)) | 1018612763596947457 | 1018612747011162113
--   s               | {a}          | 2024-11-06 20:52:25.932229+00 |      1000 |           1000 |          0 |        3 | (a IS NULL) OR ((a < 1:::INT8) OR (a > 1000:::INT8)) | 1018612763632566273 | 1018612747014635521
-- (4 rows)

EXPLAIN ANALYZE
SELECT * FROM t WHERE a > 1002;
--                                                            info
-- ---------------------------------------------------------------------------------------------------------------------------
--   planning time: 518µs
--   execution time: 3ms
--   distribution: local
--   vectorized: true
--   plan type: custom
--   rows decoded from KV: 998 (31 KiB, 1 gRPC calls)
--   cumulative time spent in KV: 1ms
--   maximum memory usage: 50 KiB
--   network usage: 0 B (0 messages)
--   regions: us-east1
--   sql cpu time: 542µs
--   isolation level: serializable
--   priority: normal
--   quality of service: regular
-- 
--   • scan
--     sql nodes: n1
--     kv nodes: n1
--     regions: us-east1
--     actual row count: 998
--     KV time: 1ms
--     KV contention time: 0µs
--     KV rows decoded: 998
--     KV bytes read: 31 KiB
--     KV gRPC calls: 1
--     estimated max memory allocated: 50 KiB
--     sql cpu time: 542µs
--     estimated row count: 0 (<0.01% of the table; stats collected 5 seconds ago)
--     table: t@t_a_idx  ----------------------  WARNING: the row count estimate is inaccurate, consider running 'ANALYZE t'
--     spans: [/1003 - ]
-- 
--   WARNING: the row count estimate on table "t" is inaccurate, consider running 'ANALYZE t'
-- (32 rows)