Sampling Error，You have an error in your SQL syntax; about soar

[hhyo]

@liipx
另外一个Sampling data的错误

• 准备表结构和数据

create table soar_test(
  id bigint unsigned primary key auto_increment,
  v varchar(10) not null default ''
);
insert into soar_test (v)
values ('');

• 输入语句
  select * from soar_test;

• 错误日志

2018/10/29 16:30:20.994 [D] [mysql.go:76] Execute SQL with DSN(127.0.0.1:3306/optimizer_osGC5MGrm3tl97k4) : CREATE TABLE `soar_test` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `v` varchar(10) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8
2018/10/29 16:30:21.020 [D] [env.go:397] createTable, Start Sampling data from archery.soar_test to optimizer_osGC5MGrm3tl97k4.soar_test ...
2018/10/29 16:30:21.025 [D] [mysql.go:76] Execute SQL with DSN(mysql:3306/archery) : show table status where name = 'soar_test'
2018/10/29 16:30:21.032 [D] [mysql.go:76] Execute SQL with DSN(mysql:3306/archery) : show table status where name = 'soar_test'
2018/10/29 16:30:21.039 [D] [sampling.go:99] SamplingData, tableRows: 1, wantRowsCount: 30000, factor: 30000.000000
2018/10/29 16:30:21.039 [D] [sampling.go:118] Sampling data execute: select DATA_TYPE from information_schema.COLUMNS where TABLE_SCHEMA='optimizer_osGC5MGrm3tl97k4' and TABLE_NAME = 'soar_test'
2018/10/29 16:30:21.046 [E] [sampling.go:227] doSampling Error from optimizer_osGC5MGrm3tl97k4.soar_test: Received #1048 error from MySQL server: "Column 'v' cannot be null"
2018/10/29 16:30:21.046 [D] [sampling.go:215] 1 rows sampling out

[LPX-E5BD8]

贴case的时候时候小心泄露隐私数据。

[hhyo]

贴case的时候时候小心泄露隐私数据。

谢谢提醒，是特意准备的测试数据，库名也是开源的项目测试库。不过问一句wantRowsCount: 30000是可配置还是固定的。

[martianzhang]

wantRowsCount := 300 * common.Config.SamplingStatisticTarget

soar -h | grep -i sampling
  -sampling-statistic-target int
        SamplingStatisticTarget, 数据采样因子，对应postgres的default_statistics_target (default 100)

[lenovore]

Received #1048 error from MySQL server: "Column 'v' cannot be null"

Sampling data会把空字符串转换成null？

[hhyo]

两个case测试都正常，谢谢~