mysql 8优化实战例子

Posted 2021-05-14 大树叶

表：tax_salary_person, 目前为 6,577,256记录

慢SQL：我在mysql执行为 10.16s, 执行多次，平均在10s，扫描 4.38M, 返回1300

SELECT id, natural_person_id, company_id, net_amount_total, payer_id
    , agency_id, tax_assessment_section_type, tax_period, create_time, update_time
    , is_delete, pay_amount_total, taxable_amount
FROM tax_x
WHERE 1 = 1
    AND company_id IN (2057249)
    AND payer_id = 2
    AND tax_assessment_section_type = 1
    AND tax_period = '2021-04'
    AND is_delete = 0
LIMIT 410800, 1300

优化方案一，采用索引。 测试 效果明显，执行一次，费时 1.32s

ALTER TABLE `shebao_tax`.`tax_x` ADD INDEX `idx_comtaxtypepayer83` (`company_id`, `tax_period`, `tax_assessment_section_type`, `payer_id`, `is_delete`),ALGORITHM=INPLACE, LOCK=NONE;

优化方案一，采用:延迟关联技术。但是效果不大:，费时9.13s。

SELECT a.id, a.natural_person_id, a.company_id, a.net_amount_total,a.payer_id,a.agency_id,a.tax_assessment_section_type,a.tax_period, a.create_time, a.update_time,a.is_delete,a.pay_amount_total,a.taxable_amount FROM tax_x a,( select id from tax_x WHERE company_id IN (2057249) AND payer_id = 2 AND tax_assessment_section_type = 1 AND tax_period = '2021-04' AND is_delete = 0 LIMIT 410800, 1300 ) b where a.id=b.id;