记一次sql优化Using temporary； Using filesort

 原始sql，由于smdm_item表20多万数据，线上查询近10秒

SELECT
	ccc.*
, spl2.entered_tax_included_price AS last_purchase_price,
	sp.year_pc_num
FROM
	(
		SELECT
			si.item_id,
			si.item_id AS partner_item_id,
			si.item_code,
			hit.item_name,
			si.item_number,
			si.chart_code,
			si.drawing_version,
			si.common_name,
			si.specifications,
			si.model,
			si.brand,
			si.primary_uom_id,
			hu.uom_code,
			hu.uom_name,
			sic.category_id,
			sic.category_code,
			sic.category_name,
			hu.uom_name AS primary_uom_name,
			hu.uom_code AS primary_uom_code,
			si.order_uom_id,
			hup.uom_name AS order_uom_name,
			hup.uom_code AS order_uom_code,
			si.source_code,
			si.enabled_flag,
			si.query_item_code,
			st.tax_id,
			st.description AS tax_description,
			st.tax_code,
			st.tax_rate,
			si.item_abc AS item_abc_class,
			si.planned_price,
			ss.processed_date AS processed_date,
			ss.po_header_id,
			ss.po_line_id
		FROM
			smdm_item si
		LEFT JOIN smdm_item_tl hit ON hit.item_id = si.item_id
		AND hit.lang = 'zh_CN'
		JOIN smdm_uom hu ON si.primary_uom_id = hu.uom_id
		LEFT JOIN smdm_uom hup ON si.order_uom_id = hup.uom_id
		LEFT JOIN smdm_item_category_assign sica ON si.item_id = sica.item_id
		AND (
			sica.default_flag = 1
			OR (
				1 = (
					SELECT
						count(1)
					FROM
						smdm_item_category_assign ssss
					WHERE
						ssss.item_id = si.item_id
				)
			)
		)
		LEFT JOIN smdm_item_category sic ON sica.category_id = sic.category_id
		LEFT JOIN smdm_tax st ON si.tax_id = st.tax_id
		LEFT JOIN (
SELECT
				max(sppa.processed_date) AS processed_date,
				MAX(sppa.po_header_id) AS po_header_id,
				MIN(spl.po_line_id) AS po_line_id,
				spl.item_id
			FROM
				sodr_po_line spl,
				sodr_po_process_action sppa,
				sodr_po_header sph
			WHERE
				spl.tenant_id = 2
			AND spl.po_header_id = sppa.po_header_id
			AND spl.po_header_id = sph.po_header_id
			AND sph.confirmed_flag = 1
			AND sph.company_id = 5
			AND sppa.process_type_code = 'CONFIRM'
			GROUP BY
				spl.item_id
		) ss ON si.item_id = ss.item_id
		WHERE
			si.tenant_id = 2
		AND si.enabled_flag = 1
	) ccc
LEFT JOIN sodr_po_line spl2 ON ccc.po_line_id = spl2.po_line_id
LEFT JOIN (
	SELECT
		sph.attribute_varchar5 AS year_pc_num,
		sps.item_code
	FROM
		spcm_pc_header sph
	JOIN spcm_pc_subject sps ON sps.pc_header_id = sph.pc_header_id
	JOIN spcm_pc_type spt ON spt.pc_type_id = sph.pc_type_id
	WHERE

		sph.tenant_id = 2
	AND sph.company_id = 5
	AND sph.supplier_company_id = 35
	and	sph.pc_status_code = 'CONFIRMED'
	AND sph.attribute_varchar5 LIKE 'NY%'

	AND spt.pc_type_code = 'KJXY-A'
	GROUP BY
		sps.item_code
) sp ON sp.item_code = ccc.item_code
ORDER BY
	ccc.partner_item_id DESC
LIMIT 10

主要看这个子查询，先注释掉两个条件发现查询是毫秒级：

查看执行过程：

 调试过程中发现只要加上这两个条件其中之一，无论怎么改sql以及索引都无法优化

后发现将company_id改成其他的值

 

 大数据表smdm_item si使用的索引发生了改变

推测原因：left join后的子查询的数据量会影响主表的索引使用

将主表强制使用主键索引解决问题smdm_item si FORCE INDEX(PRIMARY)

 修改后sql：

SELECT
	ccc.*
, spl2.entered_tax_included_price AS last_purchase_price,
	sp.year_pc_num
FROM
	(
		SELECT
			si.item_id,
			si.item_id AS partner_item_id,
			si.item_code,
			hit.item_name,
			si.item_number,
			si.chart_code,
			si.drawing_version,
			si.common_name,
			si.specifications,
			si.model,
			si.brand,
			si.primary_uom_id,
			hu.uom_code,
			hu.uom_name,
			sic.category_id,
			sic.category_code,
			sic.category_name,
			hu.uom_name AS primary_uom_name,
			hu.uom_code AS primary_uom_code,
			si.order_uom_id,
			hup.uom_name AS order_uom_name,
			hup.uom_code AS order_uom_code,
			si.source_code,
			si.enabled_flag,
			si.query_item_code,
			st.tax_id,
			st.description AS tax_description,
			st.tax_code,
			st.tax_rate,
			si.item_abc AS item_abc_class,
			si.planned_price,
			ss.processed_date AS processed_date,
			ss.po_header_id,
			ss.po_line_id
		FROM
			smdm_item si FORCE INDEX(PRIMARY)
		LEFT JOIN smdm_item_tl hit ON hit.item_id = si.item_id
		AND hit.lang = 'zh_CN'
		JOIN smdm_uom hu ON si.primary_uom_id = hu.uom_id
		LEFT JOIN smdm_uom hup ON si.order_uom_id = hup.uom_id
		LEFT JOIN smdm_item_category_assign sica ON si.item_id = sica.item_id
		AND (
			sica.default_flag = 1
			OR (
				1 = (
					SELECT
						count(1)
					FROM
						smdm_item_category_assign ssss
					WHERE
						ssss.item_id = si.item_id
				)
			)
		)
		LEFT JOIN smdm_item_category sic ON sica.category_id = sic.category_id
		LEFT JOIN smdm_tax st ON si.tax_id = st.tax_id
		LEFT JOIN (
SELECT
				max(sppa.processed_date) AS processed_date,
				MAX(sppa.po_header_id) AS po_header_id,
				MIN(spl.po_line_id) AS po_line_id,
				spl.item_id
			FROM
				sodr_po_line spl,
				sodr_po_process_action sppa,
				sodr_po_header sph
			WHERE
				spl.tenant_id = 2
			AND spl.po_header_id = sppa.po_header_id
			AND spl.po_header_id = sph.po_header_id
			AND sph.confirmed_flag = 1
			AND sph.company_id = 5
			AND sppa.process_type_code = 'CONFIRM'
			GROUP BY
				spl.item_id
		) ss ON si.item_id = ss.item_id
		WHERE
			si.tenant_id = 2
		AND si.enabled_flag = 1
	) ccc
LEFT JOIN sodr_po_line spl2 ON ccc.po_line_id = spl2.po_line_id
LEFT JOIN (
	SELECT
		sph.attribute_varchar5 AS year_pc_num,
		sps.item_code
	FROM
		spcm_pc_header sph
	JOIN spcm_pc_subject sps ON sps.pc_header_id = sph.pc_header_id
	JOIN spcm_pc_type spt ON spt.pc_type_id = sph.pc_type_id
	WHERE

		sph.tenant_id = 2
	AND sph.company_id = 5
	AND sph.supplier_company_id = 35
	and	sph.pc_status_code = 'CONFIRMED'
	AND sph.attribute_varchar5 LIKE 'NY%'

	AND spt.pc_type_code = 'KJXY-A'
	GROUP BY
		sps.item_code
) sp ON sp.item_code = ccc.item_code
ORDER BY
	ccc.partner_item_id DESC
LIMIT 10