【DataBase】SQL优化问题
在DAO层的动态SQL：
//订单新增，查询配件主数据
@SuppressWarnings("rawtypes")
public PageInfoDto getPartsForPartOrder(ElemBean condition) {
// String oldDate="2015-01-01";//过滤老数据
UserInfoDto logonUser = UserUtil.getSessionUser();
List<Map> userList =queryAscInfoById(logonUser.getOrgId());
Long factoryCompanyId=0L;
Long ascId =0L;
String priceUseType = Constant.PRICE_DEALER_TYPE_NODE;
if(userList !=null && userList.size()>0){
factoryCompanyId=Long.valueOf(userList.get(0).get("FACTORY_COMPANY_ID")+"");
ascId=Long.valueOf(userList.get(0).get("ASC_ID")+"");
priceUseType =String.valueOf(userList.get(0).get("PRICE_USE_TYPE"));
} if(condition.eq("priceUseType", Constant.PRICE_DEALER_TYPE_DISCOUNT)) {
priceUseType = Constant.PRICE_DEALER_TYPE_DISCOUNT;
} if(condition.eq("priceUseType", Constant.PRICE_DEALER_TYPE_COST)) {
priceUseType = Constant.PRICE_DEALER_TYPE_COST;
} if(condition.eq("priceUseType", Constant.PRICE_DEALER_TYPE_PLAN)) {
priceUseType = Constant.PRICE_DEALER_TYPE_PLAN;
} // Double parmValue =getSafeStockParm();
double securityRadix = 1.5;
BusinessParamDto bpDto = bpu.getFirstParamOfParam(BPConstant.PRM00068, "JMC");
if(bpDto != null) {
securityRadix = new Double(bpDto.getParaValue());
}
List<Object> params = new ArrayList<>();
StringBuffer sql= new StringBuffer();
sql.append("SELECT L.PART_ID,L.PART_NO,L.PART_NAME_CN,L.PART_REMARK,L.UNIT,L.CN_UNIT,L.UNIT_PRICE,\n");
sql.append(" L.IS_ZF,L.MIN_PACKAGE_QUANTITY,L.TOTAL_NUM,L.TOTAL_PRICES,L.STCOK_QTY,0 MAX_BUY_NUMS,\n");
sql.append(" L.MAX_BUY_NUM,L.PART_STATUS,L.ENGLISH_DESC,L.HAS_HIS_PART,L.BUY_STOCK_TYPE,\n");
sql.append(" L.LAST_DATE_S,L.PRICE_USE_TYPE\n");
sql.append("FROM (SELECT TPM.PART_ID, \n");
sql.append(" TPM.PART_NO, \n");
sql.append(" TPM.PART_NAME_CN, \n");
sql.append(" TPM.PART_REMARK, \n");
sql.append(" TPM.UNIT, \n");
sql.append(" IFNULL(TPU.UNIT_NAME,TPM.UNIT) AS CN_UNIT, \n");
sql.append(" IFNULL(TPP.PART_PRICE, 0) AS UNIT_PRICE, \n");
sql.append(" IFNULL(TOP.IS_ZF,"+Constant.IF_TYPE_NO+") IS_ZF, \n");
sql.append(" IFNULL(TOP.MIN_PACKAGE_QUANTITY, 0) MIN_PACKAGE_QUANTITY, \n");
sql.append(" IFNULL(TOP.MIN_PACKAGE_QUANTITY, 0) * 1 TOTAL_NUM, \n");
sql.append(" IFNULL(TPP.PART_PRICE, 0) * IFNULL(TOP.MIN_PACKAGE_QUANTITY, 0) * 1 AS TOTAL_PRICES, \n");
if(!condition.isNull("orderType") && Constant.PART_ORDER_TYPE_13.equals(condition.get("orderType"))){
sql.append(" IFNULL(STOCK.STCOK_QTY,0) - IFNULL(STOCK.LOC_QTY, 0) - CEIL("+securityRadix+"*IFNULL(STOCK.SAFE_STOCK_NUM,0)) AS STCOK_QTY, \n");
}else{
sql.append(" IFNULL(STOCK.STCOK_QTY,0) - IFNULL(STOCK.LOC_QTY, 0) AS STCOK_QTY, \n");
}
sql.append(" TPL.MAX_BUY_NUM, \n");
sql.append(" TPM.PART_STATUS, \n");
sql.append(" TPM.ENGLISH_DESC, \n");
sql.append(" T3.PART_ID AS HAS_HIS_PART, \n");
sql.append(" '"+condition.get("buyStockType")+"' as BUY_STOCK_TYPE, \n");
sql.append(" '"+condition.get("lastDate")+"' as LAST_DATE_S, \n");
sql.append(" '"+priceUseType+"' as PRICE_USE_TYPE\n");
sql.append(" FROM TT_PT_MAINDATA TPM \n"); UserInfoDto userInfo = UserUtil.getSessionUser();
if(!Constant.PRICE_DEALER_TYPE_DISCOUNT.equals(priceUseType)) {
sql.append(" INNER JOIN (SELECT DISTINCT TI1.PARAMETER_CLASS_CODE, TI1.COMPANY_ID FROM TM_PART_PARM_CLASS TI1, TM_PART_PARM_ITEM TI2 \n");
sql.append(" WHERE TI1.PARAMETER_CLASS_ID = TI2.PARAMETER_CLASS_ID \n");
sql.append(" AND TI1.PARAMETER_TYPE = 'PART_CLASS' \n");
sql.append(" AND TI1.COMPANY_ID=").append(factoryCompanyId).append(" \n");
sql.append(" AND TI2.VALID_STATUS=10011001 \n");
sql.append(" AND TI2.LINK_CODE NOT IN (SELECT BRAND_CODE FROM TT_PART_ORDER_ASC_BRAND WHERE ASC_CODE='ALLNOT' AND VALID_STATUS=10011001) \n");
sql.append(" UNION \n");
sql.append(" SELECT DISTINCT TI1.PARAMETER_CLASS_CODE, TI1.COMPANY_ID FROM TM_PART_PARM_CLASS TI1, TM_PART_PARM_ITEM TI2 \n");
sql.append(" WHERE TI1.PARAMETER_CLASS_ID = TI2.PARAMETER_CLASS_ID \n");
sql.append(" AND TI1.PARAMETER_TYPE = 'PART_CLASS' \n");
sql.append(" AND TI1.COMPANY_ID=").append(factoryCompanyId).append(" \n");
sql.append(" AND TI2.VALID_STATUS=10011001 \n");
sql.append(" AND TI2.LINK_CODE IN (SELECT BRAND_CODE FROM TT_PART_ORDER_ASC_BRAND WHERE ASC_CODE=? AND VALID_STATUS=10011001)) TPPC \n");
params.add(userInfo.getOrgCode());
sql.append(" ON TPM.CLASS_CODE=TPPC.PARAMETER_CLASS_CODE AND TPM.COMPANY_ID=TPPC.COMPANY_ID \n");
} sql.append(" LEFT JOIN TM_PART_UNIT TPU ON TPU.UNIT_CODE = TPM.UNIT \n");
sql.append(" LEFT JOIN TM_PT_PART_PRICE TPP ON TPP.PART_ID = TPM.PART_ID \n");
sql.append(" AND TPP.COMPANY_ID =TPM.COMPANY_ID \n");
sql.append(" AND TPP.PRICE_TYPE = "+(StringUtils.isNotEmpty(priceUseType) ? priceUseType : Constant.PRICE_DEALER_TYPE_NODE)+" \n");
sql.append(" LEFT JOIN TM_PT_ORDER_PARA TOP ON TOP.PART_ID = TPM.PART_ID \n");
sql.append(" LEFT JOIN tm_pt_maxbuynum TPL ON TPL.PART_ID = TPM.PART_ID AND TPL.ORDER_TYPE=? AND TPL.VALID_STATUS=10011001 \n");
params.add(condition.get("orderType"));
sql.append(" LEFT JOIN (SELECT PART_ID, SUM(STCOK_QTY) STCOK_QTY, SUM(LOC_QTY) LOC_QTY, \n");
sql.append(" SUM(SAFE_STOCK_NUM) SAFE_STOCK_NUM \n");
sql.append(" FROM TT_PT_FACTORY_STOCK \n");
sql.append(" GROUP BY PART_ID) STOCK ON STOCK.PART_ID = TPM.PART_ID \n");
sql.append(" LEFT JOIN (SELECT TZ.PART_ID, \n");
sql.append(" IFNULL(IFNULL(SUM(TZ.SHIP_NUM), 0) + \n");
sql.append(" IFNULL(SUM(TZ.MATCH_NUM), 0), \n");
sql.append(" 0) EXSITS_NUM \n");
sql.append(" FROM TT_PT_ORDITEM TZ, TT_PT_ORDER TS \n");
sql.append(" WHERE TZ.ORDER_ID = TS.ORDER_ID \n");
sql.append(" AND TS.ASC_ID = "+ascId+" \n");
sql.append(" AND DATE_FORMAT(TS.LAST_DATE, '%y/%c/%d') >= \n");
sql.append(" DATE_FORMAT(NOW(), '%y/%c/%d') GROUP BY TZ.PART_ID) T2 ON T2.PART_ID =TPM.PART_ID \n");
sql.append(" left join (SELECT DISTINCT T.PART_ID \n");
sql.append(" FROM TT_PT_ORDITEM T, TT_PT_ORDER T1 \n");
sql.append(" WHERE T.ORDER_ID = T1.ORDER_ID \n");
sql.append(" AND T1.ASC_ID = "+ascId+" \n");
sql.append(" AND IFNULL(T.MATCH_NUM, 0) < T.TOTAL_NUM \n");
sql.append(" AND STATUS NOT IN ('"+Constant.PART_ORDITEM_STATUS_COMPLETE+"', '"+Constant.PART_ORDITEM_STATUS_CANCEL+"', '"+Constant.PART_ORDITEM_STATUS_CLEAN+"','"+Constant.PART_ORDITEM_STATUS_OTHER_CANCEL+"') \n");
sql.append(" GROUP BY T.PART_ID) T3 ON T3.PART_ID = TPM.PART_ID \n");
sql.append(" WHERE TPM.COMPANY_ID = "+factoryCompanyId+" \n");
sql.append(" AND TOP.BUY_STOCK_TYPE IN ("+condition.get("buyStockType")+") \n"); if(Constant.PRICE_DEALER_TYPE_DISCOUNT.equals(priceUseType)) {
sql.append(" AND TPP.STATUS=57171002 AND TPP.PART_PRICE>0 \n");
} //维修站类型
if(!condition.isNull("category") && (Constant.CATEGORY_FCO.toString()).equals(condition.get("category"))){
sql.append(" AND (EXISTS (SELECT 1 FROM TT_FCO_PARTS_AUTHORITY TFPA \n");
sql.append(" WHERE TFPA.PART_CLASS_CODE = TPM.CLASS_CODE AND TFPA.ASC_CODE = "+logonUser.getOrgCode()+" )) \n");
} sql.append(" AND (EXISTS (SELECT 1 \n");
sql.append(" FROM TM_ASC_INFO TZ1 \n");
sql.append(" WHERE IFNULL(TZ1.CATEGORY, '1') <> "+Constant.CATEGORY_FCO+" \n");
sql.append(" AND TZ1.ORG_ID = ? AND TZ1.ORG_TYPE IN (15061010, 15061012)) OR \n");
params.add(userInfo.getOrgId());
sql.append(" (EXISTS (SELECT 1 \n");
sql.append(" FROM TM_ASC_INFO TZ1 \n");
sql.append(" WHERE IFNULL(TZ1.CATEGORY, '1') = "+Constant.CATEGORY_FCO+" \n");
sql.append(" AND TZ1.ORG_ID = ? AND TZ1.ORG_TYPE IN (15061010, 15061012)) AND EXISTS \n");
params.add(userInfo.getOrgId());
// sql.append(" (SELECT 1 \n");
// sql.append(" FROM TM_PART_PARM_CLASS TY1, TM_PART_PARM_ITEM TY2 \n");
// sql.append(" WHERE TY1.PARAMETER_CLASS_ID = TY2.PARAMETER_CLASS_ID \n");
// sql.append(" AND TY1.PARAMETER_CLASS_CODE = TPM.CLASS_CODE \n");
// sql.append(" AND TY2.LINK_CODE = 'U' \n");
// sql.append(" AND TY1.PARAMETER_TYPE = 'PART_CLASS' \n");
// sql.append(" )))");
sql.append(" (SELECT 1 \n");
sql.append(" FROM TT_FCO_PARTS_AUTHORITY TFPA \n");
sql.append(" WHERE TFPA.PART_CLASS_CODE = TPM.CLASS_CODE \n");
sql.append(" AND TFPA.ASC_CODE= \n");
sql.append(" (SELECT ASC_CODE FROM tm_asc_info WHERE ORG_ID= ").append(userInfo.getOrgId()).append(" AND CATEGORY<>"+Constant.CATEGORY_JMC+") \n");
sql.append(" )))"); if(!condition.isNull("partNo")){
sql.append(" AND TPM.PART_NO LIKE ?\n");
params.add("%"+condition.get("partNo")+"%");
}
if(!condition.isNull("partName")){
sql.append(" AND TPM.PART_NAME_CN LIKE ?\n");
params.add("%"+condition.get("partName")+"%");
}
if(!condition.isNull("partIds")){
sql.append(" AND TPM.PART_ID=?\n");
params.add(condition.get("partIds"));
}
if(!condition.isNull("partNos")){
sql.append(" AND TPM.PART_NO IN ("+condition.get("partNos")+") \n");
}
if(!condition.isNull("orderType") && Constant.PART_ORDER_TYPE_09.equals(condition.get("orderType"))){
//直发订单
sql.append(" AND TOP.IS_ZF="+Constant.IF_TYPE_YES+"\n");
// sql.append(" AND EXISTS (select 1 from tt_pt_amount_detail a,tt_pt_amount b \n");
// sql.append(" where a.amount_id=b.amount_id and b.asc_id="+ascId+" and a.part_id=TPM.part_id) \n");
sql.append("AND TPM.PART_ID IN (SELECT a.part_id FROM tt_pt_amount_detail a, tt_pt_amount b WHERE a.amount_id = b.amount_id AND b.asc_id = " + ascId + ")\n");
}else if(!condition.isNull("orderType") && Constant.PART_ORDER_TYPE_11.equals(condition.get("orderType"))){
//特殊加工件
sql.append(" AND TOP.IS_SPECIAL_MACH="+Constant.IF_TYPE_YES+"\n");
}
sql.append(" ) L\n");
PageInfoDto pageInfoDto = DcsDaoUtil.pageQuery(sql.toString(),params); return pageInfoDto;
}
在经过DEBUG之后抽出的SQL和参数合并：
这个SQL会无法查询出结果，原因的语句我用标红显示
最下面联表 MainData TPM
SELECT
L.PART_ID,
L.PART_NO,
L.PART_NAME_CN,
L.PART_REMARK,
L.UNIT,
L.CN_UNIT,
L.UNIT_PRICE,
L.IS_ZF,
L.MIN_PACKAGE_QUANTITY,
L.TOTAL_NUM,
L.TOTAL_PRICES,
L.STCOK_QTY,
0 MAX_BUY_NUMS,
L.MAX_BUY_NUM,
L.PART_STATUS,
L.ENGLISH_DESC,
L.HAS_HIS_PART,
L.BUY_STOCK_TYPE,
L.LAST_DATE_S,
L.PRICE_USE_TYPE
FROM
(
SELECT
TPM.PART_ID,
TPM.PART_NO,
TPM.PART_NAME_CN,
TPM.PART_REMARK,
TPM.UNIT,
IFNULL( TPU.UNIT_NAME, TPM.UNIT ) AS CN_UNIT,
IFNULL( TPP.PART_PRICE, 0 ) AS UNIT_PRICE,
IFNULL( TOP.IS_ZF, 10041002 ) IS_ZF,
IFNULL( TOP.MIN_PACKAGE_QUANTITY, 0 ) MIN_PACKAGE_QUANTITY,
IFNULL( TOP.MIN_PACKAGE_QUANTITY, 0 ) * 1 TOTAL_NUM,
IFNULL( TPP.PART_PRICE, 0 ) * IFNULL( TOP.MIN_PACKAGE_QUANTITY, 0 ) * 1 AS TOTAL_PRICES,
IFNULL( STOCK.STCOK_QTY, 0 ) - IFNULL( STOCK.LOC_QTY, 0 ) AS STCOK_QTY,
TPL.MAX_BUY_NUM,
TPM.PART_STATUS,
TPM.ENGLISH_DESC,
T3.PART_ID AS HAS_HIS_PART,
'57071002,57071003' AS BUY_STOCK_TYPE,
'null' AS LAST_DATE_S,
'57111003' AS PRICE_USE_TYPE
FROM
TT_PT_MAINDATA TPM
INNER JOIN (
SELECT DISTINCT
TI1.PARAMETER_CLASS_CODE,
TI1.COMPANY_ID
FROM
TM_PART_PARM_CLASS TI1,
TM_PART_PARM_ITEM TI2
WHERE
TI1.PARAMETER_CLASS_ID = TI2.PARAMETER_CLASS_ID
AND TI1.PARAMETER_TYPE = 'PART_CLASS'
AND TI1.COMPANY_ID = 1000000001
AND TI2.VALID_STATUS = 10011001
AND TI2.LINK_CODE NOT IN ( SELECT BRAND_CODE FROM TT_PART_ORDER_ASC_BRAND WHERE ASC_CODE = 'ALLNOT' AND VALID_STATUS = 10011001 ) UNION
SELECT DISTINCT
TI1.PARAMETER_CLASS_CODE,
TI1.COMPANY_ID
FROM
TM_PART_PARM_CLASS TI1,
TM_PART_PARM_ITEM TI2
WHERE
TI1.PARAMETER_CLASS_ID = TI2.PARAMETER_CLASS_ID
AND TI1.PARAMETER_TYPE = 'PART_CLASS'
AND TI1.COMPANY_ID = 1000000001
AND TI2.VALID_STATUS = 10011001
AND TI2.LINK_CODE IN ( SELECT BRAND_CODE FROM TT_PART_ORDER_ASC_BRAND WHERE ASC_CODE = '21101060' AND VALID_STATUS = 10011001 )) TPPC ON TPM.CLASS_CODE = TPPC.PARAMETER_CLASS_CODE
AND TPM.COMPANY_ID = TPPC.COMPANY_ID
LEFT JOIN TM_PART_UNIT TPU ON TPU.UNIT_CODE = TPM.UNIT
LEFT JOIN TM_PT_PART_PRICE TPP ON TPP.PART_ID = TPM.PART_ID
AND TPP.COMPANY_ID = TPM.COMPANY_ID
AND TPP.PRICE_TYPE = 57111003
LEFT JOIN TM_PT_ORDER_PARA TOP ON TOP.PART_ID = TPM.PART_ID
LEFT JOIN tm_pt_maxbuynum TPL ON TPL.PART_ID = TPM.PART_ID
AND TPL.ORDER_TYPE = '57011009'
AND TPL.VALID_STATUS = 10011001
LEFT JOIN ( SELECT PART_ID, SUM( STCOK_QTY ) STCOK_QTY, SUM( LOC_QTY ) LOC_QTY, SUM( SAFE_STOCK_NUM ) SAFE_STOCK_NUM FROM TT_PT_FACTORY_STOCK GROUP BY PART_ID ) STOCK ON STOCK.PART_ID = TPM.PART_ID
LEFT JOIN (
SELECT
TZ.PART_ID,
IFNULL( IFNULL( SUM( TZ.SHIP_NUM ), 0 ) + IFNULL( SUM( TZ.MATCH_NUM ), 0 ), 0 ) EXSITS_NUM
FROM
TT_PT_ORDITEM TZ,
TT_PT_ORDER TS
WHERE
TZ.ORDER_ID = TS.ORDER_ID
AND TS.ASC_ID = 6
AND DATE_FORMAT( TS.LAST_DATE, '%y/%c/%d' ) >= DATE_FORMAT( NOW(), '%y/%c/%d' )
GROUP BY
TZ.PART_ID
) T2 ON T2.PART_ID = TPM.PART_ID
LEFT JOIN (
SELECT DISTINCT
T.PART_ID
FROM
TT_PT_ORDITEM T,
TT_PT_ORDER T1
WHERE
T.ORDER_ID = T1.ORDER_ID
AND T1.ASC_ID = 6
AND IFNULL( T.MATCH_NUM, 0 ) < T.TOTAL_NUM
AND STATUS NOT IN ( '57091004', '57091005', '57091006', '57091007' )
GROUP BY
T.PART_ID
) T3 ON T3.PART_ID = TPM.PART_ID
WHERE
TPM.COMPANY_ID = 1000000001
AND TOP.BUY_STOCK_TYPE IN ( 57071002, 57071003 )
AND (
EXISTS (
SELECT
1
FROM
TM_ASC_INFO TZ1
WHERE
IFNULL( TZ1.CATEGORY, '1' ) <> 60111004
AND TZ1.ORG_ID = 416
AND TZ1.ORG_TYPE IN ( 15061010, 15061012 ))
OR (
EXISTS (
SELECT
1
FROM
TM_ASC_INFO TZ1
WHERE
IFNULL( TZ1.CATEGORY, '1' ) = 60111004
AND TZ1.ORG_ID = 416
AND TZ1.ORG_TYPE IN ( 15061010, 15061012 ))
AND EXISTS (
SELECT
1
FROM
TT_FCO_PARTS_AUTHORITY TFPA
WHERE
TFPA.PART_CLASS_CODE = TPM.CLASS_CODE
AND TFPA.ASC_CODE = ( SELECT ASC_CODE FROM tm_asc_info WHERE ORG_ID = 416 AND CATEGORY <> 60111001 )
)))
AND TOP.IS_ZF = 10041001
AND EXISTS (
SELECT
1
FROM
tt_pt_amount_detail a,
tt_pt_amount b
WHERE
a.amount_id = b.amount_id
AND b.asc_id = 6
AND a.part_id = TPM.part_id
)
) L
一开始花了很多时间才定位这个语句导致
然后我的想法是直接在里面联表查
SELECT
1
FROM
tt_pt_amount_detail a,
tt_pt_amount b,
(上面的那张TPM表放这里) TPM
WHERE
a.amount_id = b.amount_id
AND b.asc_id = 6
AND a.part_id = TPM.part_id
)
然后他用EXISTS去判断，作为一个条件
所以我就在这个语句结尾追加LIMIT 更快速的返回记录来给EXISTS去判断
但是这样的优化不符合业务的逻辑，问了同事之后又改成了：
AND TPM.PART_ID IN (
SELECT
a.part_id
FROM
tt_pt_amount_detail a,
tt_pt_amount b
WHERE
a.amount_id = b.amount_id
AND b.asc_id = 6
)
同事给出的原话是这样：
外大里小用in 外小里大用EXISTS
我的优化结果是 从【无结果】 -> 【4秒】
同事的优化结果是【1.9秒】
今天的收获备忘录
【DataBase】SQL优化问题的更多相关文章
- (转)SQL 优化原则
一.问题的提出 在应用系统开发初期,由于开发数据库数据比较少,对于查询SQL语句,复杂视图的的编写等体会不出SQL语句各种写法的性能优劣,但是如果将应用 系统提交实际应用后,随着数据库中数据的增加,系 ...
- MySQL 数据库性能优化之SQL优化
前言 有人反馈之前几篇文章过于理论缺少实际操作细节,这篇文章就多一些可操作性的内容吧. 注:这篇文章是以 MySQL 为背景,很多内容同时适用于其他关系型数据库,需要有一些索引知识为基础. 优化目标 ...
- SQL优化（zhuan）
转自:http://www.jfox.info/SQL-you-hua 数据库的优化问题 一.问题的提出 在应用系统开发初期,由于开发数据库数据比较少,对于查询SQL语句,复杂视图的的编写等体会不出S ...
- SQL 优化原则
一.问题的提出 在应用系统开发初期,由于开发数据库数据比较少,对于查询SQL语句,复杂视图的的编写等体会不出SQL语句各种写法的性能优劣,但是如果将应用 系统提交实际应用后,随着数据库中数据的增加,系 ...
- 大型系统开发sql优化总结（转）
Problem Description: 1.每个表的结构及主键索引情况 2.每个表的count(*)记录是多少 3.对于创建索引的列,索引的类型是什么?count(distinct indexcol ...
- 浅谈sql优化
问题的发现: 菜鸟D在工作的时候发现项目的sql语句很怪,例如 : select a.L_ZTBH, a.D_RQ, a.VC_BKDM, (select t.vc_name from tb ...
- Oracle SQL优化[转]
Oracle SQL优化 1. 选用适合的ORACLE优化器 ORACLE的优化器共有3种: a. RULE (基于规则) b. COST (基于成本) c. CHOOSE (选择性) 设置缺省的优化 ...
- 聊聊数据库~4.SQL优化篇
1.5.查询的艺术 上期回顾:https://www.cnblogs.com/dotnetcrazy/p/10399838.html 本节脚本:https://github.com/lotapp/Ba ...
- SQL优化工具SQLAdvisor使用
一.简介在数据库运维过程中,优化SQL是业务团队与DBA团队的日常任务.例行SQL优化,不仅可以提升程序性能,还能够降低线上故障的概率. 目前常用的SQL优化方式包括但不限于:业务层优化.SQL逻辑优 ...
- Oracle SQL 优化规则
一.问题的提出 在应用系统开发初期,由于开发数据库数据比较少,对于查询SQL语句,复杂视图的的编写等体会不出SQL语句各种写法的性能优劣,但是如果将应用 系统提交实际应用后,随着数据库中数据的增加,系 ...
随机推荐
- C# asp.net mvc 创建虚拟目录
使用背景: 虚拟目录(virtual directory),计算机术语,每个 Internet服务可以从多个目录中发布.通过以通用命名约定 (UNC) 名.用户名及用于访问权限的密码指定目录,可将每个 ...
- .NET8 Hello World!
使用ASP.NET Core Web Application模板创建的Empty项目如下: 这是一个最简单的Web项目,运行起来会在根路径响应Hello World! 2.1.1 Progra ...
- 国产搜索引擎崛起：Elasticsearch 国产化加速
背景 多年来,Elasticsearch(简称:ES) 在搜索领域一直独占鳌头,其卓越的性能和广泛的应用深受国内众多企业的青睐.从查询搜索到数据分析,再到安全分析,Elasticsearch 均展现出 ...
- json字符串忽略null，忽略字段，首字母大写等gson,jackson,fastJson实现demo,T data JSON.parseObject json转换
json字符串忽略null,忽略字段,首字母大写等gson,jackson,fastJson实现demo package com.example.core.mydemo.json.vo; import ...
- python重拾第十二天-MYSQL数据库
本节内容 数据库介绍 mysql 数据库安装使用 mysql管理 mysql 数据类型 常用mysql命令 创建数据库 外键 增删改查表 权限 事务 索引 python 操作mysql 1. 数据库介 ...
- Linux 内核：设备驱动模型（3）class与device
Linux 内核:设备驱动模型(3)class与device 背景 前面我们知道了设备如何通过总线与驱动匹配,也了解了设备插拔时与用户空间是如何通过uevent基于环境变量进行交互的. 前面看过了设备 ...
- 关于docker-compose up -d 出现超时情况处理
由于要搭建一个ctf平台,用docker一键搭建是出现超时情况 用了很多办法,换源,等之类的一样没办法,似乎它就是只能用官方那个一样很怪. 只能用一种笨办法来处理了,一个个pull. 打个比如: 打开 ...
- mtr和traceroute的区别，以及为什么traceroute不显示路径mtr却可以显示路径
最近工作主要都是网络策略的开通和网络测试,在测试的过程当中发现当网络不通时,用traceroute来看路由路径的时候总是无法显示出来,于是就换了个工具-mtr,发现mtr可以正常显示出路由路径,帮助我 ...
- koa web框架入门
1.在hello-koa这个目录下创建一个package.json,这个文件描述了我们的hello-koa工程会用到哪些包.完整的文件内容如下: { "name": "h ...
- css 手稿
CSS 网页的布局和外观的显示样式 没有一张图解决不了的事:https://www.processon.com/mindmap/5e368a8be4b0d27af184e118 选择器 * 通配符选择 ...