一. SQL Interface1. Select ... Where vs. Select + Check用Select … Where语句效率比Select + Check语句要高,例 如:SELECT * FROM SBOOK INTO SBOOK_WA WHERE CARRID = 'LH' AND CONNID = '0400'.ENDSELECT. SELECT * FROM SBOOK INTO SBOOK_WA. CHECK:…
*modifying a set of lines directly(批量修改内表数据) *使用"LOOP ... ASSIGNING ..."可以直接修改内表中的数据,而不需要先将内表数据复制到相应工作区,然后再更新回去. ***METHOD ONE: LOOP AT itab INTO wa. i = sy-tabix . . wa-flag = 'X'. MODIFY itab FROM wa. ENDIF. ENDLOOP. ***METHOD TWO: field-symbo…
http://www.actel.com/kb/article.aspx?id=TT1002 Logic Replication vs. Preserve Attributes in Synplicity In general, Synplicity's synthesis tool, Synplify, will try to replicate logic rather than add buffers to stay within the stated synthesis constrai…
Table 1-1 Commonly used directories of an iOS app Directory Description AppName.app This is the app’s bundle. This directory contains the app and all of its resources. You cannot write to this directory. To prevent tampering, the bundle directory i…
http://www.onjava.com/pub/a/onjava/2001/05/30/optimization.htmlComparing the performance of LinkedLists and ArrayLists (and Vectors) (Page last updated May 2001, Added 2001-06-18, Author Jack Shirazi, Publisher OnJava). Tips: ArrayList is faster than…
The C10K problem [Help save the best Linux news source on the web -- subscribe to Linux Weekly News! ] It's time for web servers to handle ten thousand clients simultaneously, don't you think? After all, the web is a big place now. And computers are …
原文链接:http://www.kegel.com/c10k.html It's time for web servers to handle ten thousand clients simultaneously,don't you think? After all, the web is a big place now. And computers are big, too. You can buy a 1000MHz machinewith 2 gigabytes of RAM and a…
Writes log messages to one or more files. Since NLog 4.3 the ${basedir} isn't needed anymore for relative paths. Supported in .NET, Silverlight, Compact Framework and Mono. Configuration Syntax <targets> <target xsi:type="File" name=&qu…
The C10K problem 如今的web服务器需要同时处理一万个以上的客户端了,难道不是吗?毕竟如今的网络是个big place了. 现在的计算机也很强大了,你只需要花大概$1200就可以买一个1000MHz的处理器,2G的内存, 1000Mbit/sec的网卡的机器.让我们来看看--20000个客户,每个为50KHz,100Kbyes和 50Kbit/sec,那么没有什么比为这两万个客户端的每个每秒从硬盘读取4千字节然后发送到网络上 去更消耗资源的了.可以看出硬件不再是瓶颈了. (Tha…
4.1. Using Spring for Apache Kafka This section offers detailed explanations of the various concerns that impact using Spring for Apache Kafka. For a quick but less detailed introduction, see Quick Tour for the Impatient. 4.1.1. Configuring Topics If…
InfluxDB HTTP API reference API地址:https://docs.influxdata.com/influxdb/v1.6/tools/api/ The InfluxDB HTTP API provides a simple way interact with the database. It uses HTTP response codes, HTTP authentication, JWT Tokens, and basic authentication, and…
http://www.kegel.com/c10k.html#topIt's time for web servers to handle ten thousand clients simultaneously, don't you think? After all, the web is a big place now. And computers are big, too. You can buy a 1000MHz machine with 2 gigabytes of RAM and a…
两个维度: 1)是否给用户使用: 2)是否持久存储. During installation of a new app, the installer creates a number of container directories for the app inside the sandbox directory. Each container directory has a specific role. The bundle container directory holds the app’…
A. Ropewalkers 题目链接:http://codeforces.com/contest/1185/problem/A 题目: Polycarp decided to relax on his weekend and visited to the performance of famous ropewalkers: Agafon, Boniface and Konrad. The rope is straight and infinite in both directions. At…
We often come across 'ablation study' in machine learning papers, for example, in this paper with the original R-CNN, it has a section of ablation studies. But what does this means? Well, we know that when we build a model, we usually have different…
有点菜,只写出了三道.活不多说,上题开干. A. Ropewalkers Polycarp decided to relax on his weekend and visited to the performance of famous ropewalkers: Agafon, Boniface and Konrad. The rope is straight and infinite in both directions. At the beginning of the performance…
2019-07-17 08:42:11 这是总结昨天的做题情况 总体来说,好久的没做题了,实力下降了许多,这一个月假又学习吧!!!! A - Ropewalkers Polycarp decided to relax on his weekend and visited to the performance of famous ropewalkers: Agafon, Boniface and Konrad. The rope is straight and infinite in both d…
Refer to: http://harriyott.com/2006/01/sql-server-performance-tips A colleague of mine has been looking at SQL Server performance, and come up with a great set of tips (mostly gleaned from this website): Does your SQL statement have a WHERE clause? I…
COMPUTER ORGANIZATION AND ARCHITECTURE DESIGNING FOR PERFORMANCE NINTH EDITION In this section, we look at some of the general characteristics of and the motivation for a reduced instruction set architecture. Specific examples will be seen later in t…
1.使用where语句不推荐Select * from zflight.Check : zflight-airln = ‘LF’ and zflight-fligh = ‘BW222’.Endselect.推荐Select * from zflight where airln = ‘LF’ and fligh = ‘222’.Endselect. 2.使用聚合函数不推荐Maxnu = 0.Select * from zflight where airln = ‘LF’ and cntry = ‘…
Computer Systems A Programmer's Perspective Second Edition In this chapter, we take a brief look at the design of processor hardware. We study the way a hardware system can execute the instructions of a particular ISA. This view will give you a bette…
