收到运维同学电话,MySQL服务器连接数满了,登录服务器查看,确实满了,好吧,首先增加连接数到2500,暂时提供对外服务。连接继续升高,又快达到2500。发现有大量的查询时间将近到了1200秒,大量的长连接堆积,导致连接数攀升,看来还是sql的问题。在这些长连接中,发现这样的sql SELECT product_id,gif
目录HTML部分CSS部分JS部分 demo HTML部分 slideshow: 整个轮播图的框架 prev: 上一页按钮 next: 下一页按钮 promo: 轮播图促销图片 circle: 促销图片对应的按钮 promo_now: 当前促销图片对应的按钮 <body> <div class="slideshow"> <a src="" alt=""
目录 定位实例 网页布局总结 标准流 浮动 定位 定位实例 <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <link rel="stylesheet" href="style.c
位图连接索引,就是将事实表和维度表的ROWID提前进行映射,省去了连接时的开销。 下面将位图连接索引和一般的位图索引进行比较。 看以下SQL语句: 点击(此处)折叠或打开select s.prod_id,s.promo_id,s.channel_idfrom sales_A s, products_A pd, promotions_A pm, channels_A ch
一等函数设计模式 1. 案例分析:重构“策略”模式1.1 经典的“策略”模式1.2 使用函数实现“策略”模式1.3 选择最佳策略:简单的方式1.4 找出模块中的全部策略 2. “命令”模式小结 1. 案例分析:重构“策略”模式 如果合理利用作为一等对象的函数,某些设计模式可以简化,“策
Python设计模式: 最佳的"策略"模式实践代码 今天抽空看了下流畅的python,发现里面介绍了不少python自带的库的使用实例,用起来非常的优雅。 平时用Python来写爬虫比较多,所以最近一直在看设计模式的内容。刚好这本书里面有一章单独讲设计模式的,讲的还不错,特意摘录出来。 这段代码的需
choose two In the PROMOTIONS table, the PROMO_BEGTN_DATE columm is of datatype DATE and the default date format is DD-MON-RR. Which two statements are true about expressions using PROMO_BEGIN_DATE contained in a queny? A) TONUMBER(PROMO BEGIN_DATE) - 5 wi
38.choose the best answer View the Exhibit and examine the data in the PROMOTIONS table. PROMO_BEGIN_DATE is stored in the default date format, dd-mon-rr. You need to produce a report that provides the name,cost,and start date of all promos in the POST ca
19.choose the best answer View the Exhibit and examine the structure of the PROMOTIONS table. Evaluate the following SQL statement: SQL>SELECT promo_name,CASE WHEN promo_cost>=(SELECT AVG(promo_cost) FROM promotions WHERE promo_category= 'TV
28.choose the best answer Evaluate the following SQL statement: SQL> SELECT promo_id, promo_category FROM promotions WHERE promo_category = 'Internet' ORDER BY 2 DESC UNION SELECT promo_id, promo_category FROM promotions WHERE promo_category
3.choose three View the Exhibit and examine the description of SALES and PROMOTIONS tables. You want to delete rows from the SALES table, where the PROMO_NAME column in the PROMOTIONS table has either blowout sale or everyday low price as values. Which th