[#MDEV-17451] Query with Window Functions which could use minmax const optimization does not work

The following query reads the full t1 table, although it should only need to fill the tmp table with 1 value, that of min(a) and a random value from a.

The problem seems to be that we consider 'a' from bit_and(a) to be a separate column, yet we could get the value of a when computing min(a).

create table t1 (a int primary key);

insert into t1 values (2), (1), (0);

analyze format=json select bit_and(a) over(order by 1), min(a) from t1;

ANALYZE

  "query_block": {

    "select_id": 1,

    "r_loops": 1,

    "r_total_time_ms": 14744,

    "window_functions_computation": {

      "sorts": {

        "filesort": {

          "sort_key": "1",

          "r_loops": 1,

          "r_total_time_ms": 0.0835,

          "r_used_priority_queue": false,

          "r_output_rows": 1,

          "r_buffer_size": "264"

},

      "temporary_table": {

        "table": {

          "table_name": "t1",

          "access_type": "index",

          "key": "PRIMARY",

          "key_length": "4",

          "used_key_parts": ["a"],

          "r_loops": 1,

          "rows": 3,

          "r_rows": 3,

          "r_total_time_ms": 0.0285,

          "filtered": 100,

          "r_filtered": 100,

          "using_index": true

[MDEV-17451] Query with Window Functions which could use minmax const optimization does not work Created: 2018-10-14 Updated: 2021-03-19
Status:	Open
Project:	MariaDB Server
Component/s:	None
Affects Version/s:	None
Fix Version/s:	10.2

[MDEV-17451] Query with Window Functions which could use minmax const optimization does not work Created: 2018-10-14 Updated: 2021-03-19