Bug #119664 Inconsistant result when modifying tables' partition strategy
Submitted: 13 Jan 5:16 Modified: 13 Jan 7:59
Reporter: Jiyuan Li Email Updates:
Status: Not a Bug Impact on me:
None 
Category:MySQL Server: Optimizer Severity:S3 (Non-critical)
Version: 9.3.0-cluster OS:Ubuntu
Assigned to: CPU Architecture:Any

[13 Jan 5:16] Jiyuan Li
Description:
Same query return inconsistent results after modifying tables' partition strategy

How to repeat:

create table if not exists t0(c0 float zerofill unique key comment 'asdf' primary key) ;
create table if not exists t1(c0 float zerofill primary key storage memory comment 'asdf' column_format default not null unique) ;
insert into t0(c0) values(436790095);
insert delayed into t0(c0) values(0.851835924302088);
alter table t1 compression 'none', stats_auto_recalc 1, row_format redundant, checksum 0, pack_keys 1, rename to t4, stats_persistent 0, disable keys, algorithm copy, force;
create table if not exists t0_oracle(c0 float zerofill unique key comment 'asdf' primary key) partition by key(c0) partitions 28;
create table if not exists t1_oracle(c0 float zerofill primary key storage memory comment 'asdf' column_format default not null unique) partition by key() partitions 94;
INSERT HIGH_PRIORITY IGNORE INTO t0_oracle(c0) VALUES('');
INSERT DELAYED INTO t0_oracle(c0) VALUES(0.851835924302088);

alter table t0 partition by key(c0) partitions 49;
alter table t4 partition by key(c0) partitions 34;

SELECT  DISTINCT SUM((+ (t0.c0))) AS ref0 FROM t0 STRAIGHT_JOIN t0_oracle ON -271423304 LEFT JOIN t4 ON t0_oracle.c0;
+-------------------+
| ref0              |
+-------------------+
| 873580161.7036718 |
+-------------------+
1 row in set (0.00 sec)

alter table t0 remove partitioning;
alter table t4 remove partitioning;

SELECT  DISTINCT SUM((+ (t0.c0))) AS ref0 FROM t0 STRAIGHT_JOIN t0_oracle ON -271423304 LEFT JOIN t4 ON t0_oracle.c0;
+-------------------+
| ref0              |
+-------------------+
| 873580161.7036719 |
+-------------------+
1 row in set (0.00 sec)
[13 Jan 7:59] Roy Lyseng
Thank you for the bug report.
However, small variations in results must be expected when using floating point data types.
Closing as Not a bug.