DATABASE
Cache Reheating - Not to be Ignored
An important aspect to keep in mind with databases is the cost of cache reheating after a server restart. Consider the following diagram which shows several cache servers (e.g., memcached) in front of a database server.This sort of setup is common and can work quite well when appropriate; it removes read load from the database and allows more RAM to be utilized for scaling (when the database doesn’t scale horizontally). But what happens if all the cache servers restart at the same time, say, on a power glitch in a data center?We then have a cache reheating scenario. After the bounce the...
3,137 0 DATABASE ADVICE COST CACHE REHEATING
Database Testing – Practical Tips and Insight on How to Test Database
Database is one of the inevitable parts of a software application these days. It does not matter at all whether it is web or desktop, client server or peer to peer, enterprise or individual business, database is working at backend. Similarly, whether it is healthcare of finance, leasing or retail, mailing application or controlling spaceship, behind the scene a database is always in action.Moreover, as the complexity of application increases the need of stronger and secure database emerges. In the same way, for the applications with high frequency of transactions (e.g. banking or finance appli...
SQL Grammar Summary
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An example of SQL outer join
SELECT MEMBER.Name, MEMBER.Address, ORGANIZER.phoneNo, TRAVEL.Tour_Name, TRAVEL.Start_Date, TRAVEL.End_DateFROM TRAVEL RIGHT JOIN ((MEMBER LEFT JOIN ORGANIZER ON MEMBER.Member_ID=ORGANIZER.memberID) LEFT JOIN PARTICIPATION ON MEMBER.Member_ID=PARTICIPATION.MemberID) ON TRAVEL.TravelID=PARTICIPATION.TravelID;...
3,128 0 ACCESS SQL OUTER JOIN