乐趣区

关于mysql:OceanBase-特殊的-INT-与时间类型隐式转换问题

本文作者分享了 Oceanbase 工夫与数值类型隐式转换导致查问后果不合乎预期或“不正确”问题的排查思路。

作者:任仲禹

爱可生 DBA 团队成员,善于故障剖析和性能优化,文章相干技术问题,欢送大家一起探讨。

本文起源:原创投稿

  • 爱可生开源社区出品,原创内容未经受权不得随便应用,转载请分割小编并注明起源。

之前在 OceanBase 应用中碰到了一个“令人费解”的数据类型隐式转换问题。论断比较简单,特跟大家分享下排查思路。

问题形容

某客户项目组执行更新 SQL 语句时会偶发失败,报错如下:

脱敏解决后

ERROR bad SQL grammar [update renzy set at=current_timestamp,expire_at=(cast(unix_timestamp(current_timestamp(3) as unsigned) +?)), order_id= ? where id = ? and (expire_at < current_timestamp or order_id = ?)] java.sql.SQLSyntaxErrorException: (conn=1277168) Incorrect value.

查问 OceanBase 版本。

./observer -V

observer (OceanBase 3.2.3.2)
REVISION: 105000092022092216-445151f0edb502e00ae5839dfd92627816b2b822

查看表构造和数据。

MySQL [test]> show create table renzy\G
*************************** 1. row ***************************
       Table: renzy
Create Table: CREATE TABLE `renzy` (`id` varchar(64) NOT NULL,
  `at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `order_id` varchar(64) NOT NULL,
  `expire_at` bigint(20) NOT NULL,
  `vt` timestamp NOT NULL,
  PRIMARY KEY (`id`)
) DEFAULT CHARSET = utf8mb4 ROW_FORMAT = DYNAMIC COMPRESSION = 'zstd_1.3.8' REPLICA_NUM = 3 BLOCK_SIZE = 16384 USE_BLOOM_FILTER = FALSE TABLET_SIZE = 134217728 PCTFREE = 0

MySQL [test]> select * from renzy;
+----+---------------------------+---------------+------------+---------------------------------+
| id | at                  | order_id      | expire_at  | vt                  |
+----+---------------------------+---------------+------------+---------------------------------+
| 1  | 2023-07-07 14:57:13 | 0:16632@172.1 | 1716040750 | 2023-07-07 14:57:13 |
+----+---------------------------+---------------+------------+---------------------------------+
1 row in set (0.02 sec)

问题排查

问题 1:报错语句

间接执行报错的 SQL 语句。

update renzy  set at=CURRENT_TIMESTAMP, expire_at=(cast(unix_timestamp(current_timestamp(3)) as unsigned) + 30000000), order_id= '0:16632@172.24.64.1'  where id = '1'  and (expire_at < CURRENT_TIMESTAMP  or order_id = '0:16632@172.24.64.1')

ERROR 1292 (22007): Incorrect values.

问题 2

然而,当主键 ID 匹配不到任何数据,UPDATE 语句将不会报错。

为啥?先记录下问题接着看日志。

# 表不存在 id=2 的数据
update renzy  set acquired_at=CURRENT_TIMESTAMP, expire_at=(cast(unix_timestamp(current_timestamp(3)) as unsigned) + 30000000), order_id= '0:16632@172.24.64.1'  where id = '2'  and (expire_at < CURRENT_TIMESTAMP  or order_id = '0:16632@172.24.64.1')

Query OK.

报错 SQL 的 sql_auit 输入和日志

带着问题剖析下 sql$gv_audit 输入,得出如下信息:

  • 该语句打算是本地打算,散发到了 0.71 节点。
  • 错误码是 4219(有效的 datetime 值)。
MySQL [oceanbase]> select trace_id,svr_ip,ret_code,retry_cnt,usec_to_time(request_time),elapsed_time,execute_time,plan_type,query_sql from gv$sql_audit where query_sql like 'update id%' and ret_code != 0 order by request_time desc  limit 5;

+-----------------------------------+-------------+----------+-----------+----------------------------+--------------+--------------+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| trace_id                          | svr_ip      | ret_code | retry_cnt | usec_to_time(request_time) | elapsed_time | execute_time | plan_type | query_sql                                                                                                                                                                                                                                                                               |
+-----------------------------------+-------------+----------+-----------+----------------------------+--------------+--------------+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| YB420CF10047-0005FBCCEF6E3635-0-0 | 12.241.0.71 |    -4219 |         0 | 2023-06-06 15:32:08.375051 |          689 |          611 |         1 | update id  set acquired_at=CURRENT_TIMESTAMP, expire_at=(cast(unix_timestamp(current_timestamp(3)) as unsigned) + 30000000), order_id= '0:16632@172.24.64.1'  where id = '2'  and (expire_at < CURRENT_TIMESTAMP  or order_id = '0:16632@172.24.64.1') |
·····
5 rows in set (5.21 sec)

要害报错日志

0.72 的 obs.log

#grep YB420CF10047-0005FBCCEF6E3635-0-0 observer.log.20230606153309

[2023-06-06 15:32:08.375202] WARN  [LIB.TIME] int_to_ob_time_with_date (ob_time_convert.cpp:1618) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=5] [dc=0] datetime is invalid or out of range(ret=-4219, int64=0)

[2023-06-06 15:32:08.375211] WARN  [LIB.TIME] int_to_datetime (ob_time_convert.cpp:329) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=8] [dc=0] failed to convert integer to datetime(ret=-4219)

[2023-06-06 15:32:08.375214] WARN  [SQL] common_int_datetime (ob_datum_cast.cpp:709) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=3] [dc=0] int_datetime failed(ret=-4219)

[2023-06-06 15:32:08.375219] WARN  [SQL] int_datetime (ob_datum_cast.cpp:2076) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=4] [dc=0] fail to exec common_int_datetime(expr, in_val, ctx, res_datum)(ret=-4219, in_val=1716036728)

[2023-06-06 15:32:08.375223] WARN  [SQL] get_comparator_operands (ob_expr_operator.h:1131) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=4] [dc=0] left eval failed(ret=-4219)

[2023-06-06 15:32:08.375227] WARN  [SQL.ENG] def_relational_eval_func (ob_expr_cmp_func.cpp:54) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=4] [dc=0] failed to eval args(ret=-4219)

[2023-06-06 15:32:08.375232] WARN  [SQL.ENG] calc_or_exprN (ob_expr_or.cpp:221) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=5] [dc=0] eval arg 0 failed(ret=-4219)

[2023-06-06 15:32:08.375240] WARN  [SQL.ENG] filter_row (ob_operator.cpp:915) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=7] [dc=0] expr evaluate failed(ret=-4219, expr=0x7f37808ec058)

[2023-06-06 15:32:08.375247] WARN  [STORAGE] check_filtered (ob_multiple_merge.cpp:1249) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=7] [dc=0] filter row failed(ret=-4219)

[2023-06-06 15:32:08.375251] WARN  [STORAGE] process_fuse_row (ob_multiple_merge.cpp:787) [38763][0][YB420CF10047-0005FBCCEF6E3635-0-0] [lt=3] [dc=0] fail to check row filtered(ret=-4219)

察看到最开始抛出谬误的是 int_to_ob_time_with_date 办法,报的错是 “datetime is invalid or out of range(ret=-4219, int64=0)”,即值有效或超过范畴。

这里 UPDATE 的调用链路是:

common_int_datetime -> int_to_datetime -> int_to_ob_time_with_date

问题 3:尝试应用 SELECT 查问后果

表中 EXPIRE_AT 存储的是将来工夫(1716040750),与以后工夫(1686042749)做比拟,查问后果理当不输入后果才对?(先记录为问题 3:查问后果不合乎预期)

# 表中只有 1 行记录,且 EXPIRE_AT 的值为 1716040750
MySQL [mock_db]> select * from renzy where EXPIRE_AT < CURRENT_TIMESTAMP;

+-------+---------------------+---------------------+------------+------------------------------------+
| id | ACQUIRED_AT         | order_id            | EXPIRE_AT  | LST_UP_TM          |
+-------+---------------------+---------------------+------------+------------------------------------+
| 1 | 2023-06-06 16:39:10 | 0:16632@172.24.64.1 | 1716040750 | 2023-06-06 16:39:10 |
+-------+---------------------+---------------------+------------+------------------------------------+

1 row in set (0.05 sec)

# 以后工夫戳
MySQL [mock_db]> select unix_timestamp(CURRENT_TIMESTAMP);

+--------------------------------------------+
| unix_timestamp(CURRENT_TIMESTAMP) |
+--------------------------------------------+
|                        1686042749 |
+--------------------------------------------+

1 row in set (0.03 sec)

SELECT 查问的报错日志。

[2023-06-06 17:08:54.307371] WARN  [LIB.TIME] int_to_ob_time_with_date (ob_time_convert.cpp:1618) [38763][0][YB420CF10047-0005FBCCEF6F9E6D-0-0] [lt=10] [dc=0] datetime is invalid or out of range(ret=-4219, int64=0)

[2023-06-06 17:08:54.307382] WARN  [LIB.TIME] int_to_datetime (ob_time_convert.cpp:329) [38763][0][YB420CF10047-0005FBCCEF6F9E6D-0-0] [lt=10] [dc=0] failed to convert integer to datetime(ret=-4219)

这里 SELECT 的调用链路:int_to_datetime -> int_to_ob_time_with_date

以上就是存疑的几个问题,那在具体分析前,先理解一下前置知识点:OceanBase 的隐式转换。

OceanBase 的隐式转换

数据类型 bigintdatetime 的值是没法间接比拟,须要先将 int 转换为工夫类型,这就是所谓的隐式转换,所以这里 OceanBase 是如何转很重要。

  • int 类型转换成 OceanBase 认可的工夫类型(即 OBTime)并不是用的 from_unixtime 这个函数,而是用的 OceanBase 本人外部的逻辑。
  • 源码中波及 intdoublestring 类型隐式转换的逻辑如下:
int_to_datetime
////////////////////////////////
// int / double / string -> datetime / date / time / year.
int ObTimeConverter::int_to_datetime(int64_t int_part, int64_t dec_part,
                                     const ObTimeConvertCtx &cvrt_ctx, int64_t &value,
                                     const ObDateSqlMode date_sql_mode)
{
  int ret = OB_SUCCESS;
  dec_part = (dec_part + 500) / 1000;
  if (0 == int_part) {value = ZERO_DATETIME;} else {ObTime ob_time(DT_TYPE_DATETIME);
    ObDateSqlMode local_date_sql_mode = date_sql_mode;
    if (cvrt_ctx.is_timestamp_) {local_date_sql_mode.allow_invalid_dates_ = false;}
    if (OB_FAIL(int_to_ob_time_with_date(int_part, ob_time, false, local_date_sql_mode))) {LOG_WARN("failed to convert integer to datetime", K(ret));
    } else if (OB_FAIL(ob_time_to_datetime(ob_time, cvrt_ctx, value))) {LOG_WARN("failed to convert datetime to seconds", K(ret));
    }
  }
  value += dec_part;
  if (OB_SUCC(ret) && !is_valid_datetime(value)) {
    ret = OB_DATETIME_FUNCTION_OVERFLOW;
    LOG_WARN("datetime filed overflow", K(ret), K(value));
  }
  return ret;
}

最终调用的 int_to_ob_time_with_date

////////////////////////////////
// int / uint / string -> ObTime / ObInterval <- datetime / date / time.

int ObTimeConverter::int_to_ob_time_with_date(int64_t int64, ObTime &ob_time, bool is_dayofmonth,
                                              const ObDateSqlMode date_sql_mode)
{
  int ret = OB_SUCCESS;
  int32_t *parts = ob_time.parts_;
  if (is_dayofmonth && 0 == int64) {parts[DT_SEC]  = 0;
    parts[DT_MIN]  = 0;
    parts[DT_HOUR] = 0;
    parts[DT_MDAY] = 0;
    parts[DT_MON]  = 0;
    parts[DT_YEAR] = 0;
  } else if (int64 < power_of_10[2]) {
    ret = OB_INVALID_DATE_VALUE;
    LOG_WARN("datetime integer is out of range", K(ret), K(int64));
  } else if (int64 < power_of_10[8]) {
    // YYYYMMDD.
    parts[DT_MDAY]  = static_cast<int32_t>(int64 % power_of_10[2]); int64 /= power_of_10[2];
    parts[DT_MON]  = static_cast<int32_t>(int64 % power_of_10[2]); int64 /= power_of_10[2];
    parts[DT_YEAR] = static_cast<int32_t>(int64 % power_of_10[4]);
  } else if (int64 / power_of_10[6] < power_of_10[8]) {
    // YYYYMMDDHHMMSS.
    parts[DT_SEC]  = static_cast<int32_t>(int64 % power_of_10[2]); int64 /= power_of_10[2];
    parts[DT_MIN]  = static_cast<int32_t>(int64 % power_of_10[2]); int64 /= power_of_10[2];
    parts[DT_HOUR] = static_cast<int32_t>(int64 % power_of_10[2]); int64 /= power_of_10[2];
    parts[DT_MDAY] = static_cast<int32_t>(int64 % power_of_10[2]); int64 /= power_of_10[2];
    parts[DT_MON]  = static_cast<int32_t>(int64 % power_of_10[2]); int64 /= power_of_10[2];
    parts[DT_YEAR] = static_cast<int32_t>(int64 % power_of_10[4]);
  } else {
    ret = OB_INVALID_DATE_VALUE;
    LOG_WARN("datetime integer is out of range", K(ret), K(int64));
  }
  if (OB_SUCC(ret)) {apply_date_year2_rule(parts[0]);
    if (OB_FAIL(validate_datetime(ob_time, is_dayofmonth, date_sql_mode))) {LOG_WARN("datetime is invalid or out of range", K(ret), K(int64));
    } else if (ZERO_DATE != parts[DT_DATE]) {parts[DT_DATE] = ob_time_to_date(ob_time);
    }
  }
  return ret;
}

下面代码示意 OceanBase 仅能辨认的格局:

  • YYYYMMDD
  • YYYYMMDDHHMMSS

一旦不是上述格局就会抛出报错。下图能够看到只有 2023081620230819111111 两种符合条件。

问题起因

问题 3:SELECT 查出的后果不合乎预期

bigintdatetime 类型 ” 比拟 ” 波及隐式转换导致后果不可预知。

  • select * from renzy where EXPIRE_AT < CURRENT_TIMESTAMP; EXPIRE_AT 的值是 bigint 类型,且值为 1716040750
  • 1716040750 无奈匹配 int_to_ob_time_with_date 规定的格局,将抛出告警“datetime integer is out of range”,日志中也能印证这一点。
  • 这里按理应该在 SQL 执行时抛出报错,不应该输入后果的,然而为了 OB 兼容 MySQL 而抉择输入了“谬误”的值。

    • 为啥 MySQL 不会报错? MySQL 中转换失败之后,其实会有默认值 0,上述 OB 行为转换失败用的默认值,应该和 MySQL 兼容,所以满足了 WHERE 条件 0 < 1686042749SELECT 就输入了后果。

问题 1:UPDATE 语句为何能吐出报错

  • 因为 OB 默认开启了 SQL_MODE 严格模式,如果产生隐式转换且转换失败(用了默认值)的场景,OB 的严格模式比 MySQL 做了一层防备,将禁止 SQL 执行。
  • MySQL 开启 SQL_MODE 严格模式下能执行“胜利”。

问题 2:UPDATE 语句 WHERE 条件中主键匹配到不存在的值不报错

  • UPDATE 走的是 table get 算子,等值查问不到后果后,不须要再 filter 前面的条件。这解释了项目组偶发失败的问题。

最初一个问题:为啥 UPDATE 间接报错,SELECT 确能查出“谬误的值”

此报错仅抛出报错到 obs.log

我这边猜想是因为只在 UPDATE 的时候会遵循严格模式,而 SELECT 则不须要遵循,根据前文提到的调用链路:

  • UPDATE: common_int_datetime -> int_to_datetime -> int_to_ob_time_with_date
  • SELECT: int_to_datetime -> int_to_ob_time_with_date

UPDATE 多了下层的 common_int_datetime,调用入口不一样,而依据这个办法,大抵猜想是因为 SQL_MODE 的严格模式导致。

验证下猜测,看起来清空 SQL_MODE 后,UPDATE 果然能插入胜利。

MySQL [test]> select @@sql_mode;
+--------------------------------------------+
| @@sql_mode                        |
+--------------------------------------------+
| STRICT_ALL_TABLES,NO_ZERO_IN_DATE |
+--------------------------------------------+
1 row in set (0.01 sec)

MySQL [test]> update renzy  set at=CURRENT_TIMESTAMP, expire_at=(cast(unix_timestamp(current_timestamp(3)) as unsigned) + 30000000), order_id= '0:16632@172.24.64.1'  where id = '1'  and (expire_at < CURRENT_TIMESTAMP  or order_id = '0:16632@172.24.64.1');
ERROR 1292 (22007): Incorrect value

MySQL [test]> set sql_mode='';
Query OK, 0 rows affected (0.01 sec)

MySQL [test]> update renzy  set at=CURRENT_TIMESTAMP, expire_at=(cast(unix_timestamp(current_timestamp(3)) as unsigned) + 30000000), order_id= '0:16632@172.24.64.1'  where id = '1'  and (expire_at < CURRENT_TIMESTAMP  or order_id = '0:16632@172.24.64.1');
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

可能我的猜想有问题,但集体能力无限,欢送大家一起斧正和探讨。

论断

  1. 让客户项目组改写 SQL 逻辑。

    • EXPIRE_AT < CURRENT_TIMESTAMP 改成
    • EXPIRE_AT < unix_timestamp(CURRENT_TIMESTAMP)
  2. 强调 SQL 标准,防止隐式转换。

    对于 SQLE

    爱可生开源社区的 SQLE 是一款面向数据库使用者和管理者,反对多场景审核,反对标准化上线流程,原生反对 MySQL 审核且数据库类型可扩大的 SQL 审核工具。

SQLE 获取

类型 地址
版本库 https://github.com/actiontech/sqle
文档 https://actiontech.github.io/sqle-docs/
公布信息 https://github.com/actiontech/sqle/releases
数据审核插件开发文档 https://actiontech.github.io/sqle-docs-cn/3.modules/3.7_audit…
退出移动版