best database for large data

First, IntroductionUltra-large systems are characterized by:1. The number of users to deal with is generally more than million, and some more than tens of millions of data, the database generally more than 1TB;2. The system must provide real-time response function, the system needs to operate without downtime, requiring a high availability and scalability of the

access files that can only be viewed by the general manager. The random ID automatically generated by the operating system is generally invisible to users. Dual-Primary keys are now widely used in various database systems and are not limited to user management systems. 4. Fixed databases and tables to cope with changing customer needs This is mainly based on the following considerations: 4.1 normal use and maintenance of

Real-time changes (daily) data comes from queries of a large amount of data, resulting in loading of real-time changes (daily) data from queries of a large amount of data, resulting in loading takes a long time, ask how to optimiz

Usually at work, often encounter this kind of thing, from a large table a , extract the field a in a relatively small B table data, for example, from a detailed list, extract tens of thousands of user number of the single out. At such times, in general, To make an association query:create table A1 as select a.* from A , number table B Wherea. number = B. number Of course, this statement ac

Solution to data loss problem when PHP post large amount of data This article mainly introduces the PHP post a lot of data to find the solution to the problem of data loss, because the default configuration of the data volume con

migrate data from one database to another, which is bound to be used in DB link. For example, we need to import data from database A to database B. After the DBA assigns DB link permissions, use the following statement to create DB link on

write records back to the data source, the initial values in the Data row will be compared with the records in the data source. If they match, it indicates that the database records have not been changed after being read. In this case, the changed values in the dataset are successfully written to the

Scene Description:1 million data, data value between 0~65535, please use as little memory and fastest speed from small to large sortVoidsort (int* array, int n){The value of n is around 1 million.Your implementation}We first observed that all the data had been saved in array arrays, and what we need to do now is to sor

, the period of a large number of requests to wear to the database, and then "stale set" is a data consistency problem, If an instance updates the data to refresh the cache while another instance reads Miss attempts to read the database, the two cache write order is not guar

with the above statement.Later consulted Baidu, get the following codeThe complete query statement is: SELECT * from ' table ' WHERE ID>=(SELECT Floor(rand () * (selectmax (id from ' table ' )-( selectmin (id ' table ' ) + (selectmin (idfrom ' table ' NBSP; ORDER by ID LIMIT 1; Copy Code SELECT * From' Table 'as T1 JOIN(SELECT ROUND (rand () * ((selectmax (id from ' table ' )-( selectmin (id ' table ' selectmin (id) fromasid) as t2 WHERE T1.

Code:Import Java.util.arraylist;import java.util.list;/** * Simulate batch processing data * When too much data is too large to cause problems such as timeouts can be processed in batches * @author "" * */public class batchutil {public static void Listbatchutil (ListImplementation results:Implementation of batch processing da