MariaDB MAX_JOIN_SIZE错误，无索引提示

问题描述

有MariaDB 10.4.14，max_join_size = 300M，以及带有约150,000条记录的硬币式InnoDB表。

足够简单的查询会产生MAX_JOIN_SIZE错误：

SELECT * FROM coin z -- USE INDEX(PRIMARY)
WHERE z.id IN (5510,5511,5512 /* more item IDs up to 250 */)
  AND z.currency_id IN (8,227)
  AND z.distribution_id IN (1,2);

Error Code: 1104
The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET sql_BIG_SELECTS=1 or SET MAX_JOIN_SIZE=# if the SELECT is okay

但是带有索引提示的相同查询效果很好。命中[“ PRIMARY”，“ currency_id_idx”，“ distribution_id”]甚至是issue_date_idx都无关紧要 即使根本没有索引USE INDEX（），它也可以工作。

这可能是什么问题？为什么查询没有提示就不能工作？

顺便说一句，此查询在MariaDB 10.3.24上运行良好，而在10.5.5上不工作

OPTIMIZE TABLE coin; -- didn't help

Table DDL and query EXPLAIN
CREATE TABLE `coin` (
  `id` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,`name` varchar(90) NOT NULL DEFAULT '',`country_id` smallint(5) unsigned NOT NULL DEFAULT 0,`currency_id` smallint(5) unsigned NOT NULL DEFAULT 0,`distribution_id` tinyint(3) unsigned NOT NULL,`issue_date` date NOT NULL DEFAULT '0000-00-00',-- and other,total 29 fields
  PRIMARY KEY (`id`),KEY `issue_date_idx` (`issue_date`),KEY `currency_id_idx` (`currency_id`),KEY `distribution_id` (`distribution_id`),total 21 indices for other fields which don't use currency_id or distribution_id
  CONSTRAINT `coin_ibfk_4` FOREIGN KEY (`currency_id`) REFERENCES `currency` (`id`),CONSTRAINT `coin_ibfk_11` FOREIGN KEY (`distribution_id`) REFERENCES `distribution` (`id`),total 13 CONSTRAINTs
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

EXPLAIN FORMAT=JSON -- for SELECT above without index hint
{
  "query_block": {
    "select_id": 1,"table": {
      "table_name": "z","access_type": "range","possible_keys": ["PRIMARY","currency_id_idx","distribution_id"],"key": "PRIMARY","key_length": "3","used_key_parts": ["id"],"rows": 50,"filtered": 100,"attached_condition": "z.`id` in (5510,5512,/* ... total 100 */) and z.currency_id in (8,227) and z.distribution_id in (1,2)"
    }
  }
}

上面的SELECT在没有可能具有最大MAX_JOIN_SIZE值且没有最大值-1：的索引提示的情况下工作

SET MAX_JOIN_SIZE=18446744073709551615 -- this works
SET MAX_JOIN_SIZE=18446744073709551614 -- this doesn't work

解决方法

可以通过恢复先前的默认值来修复MAX_JOIN_SIZE错误

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