Sql Dba Queries

You can think of it as a cloud version of SQL Server, but you can't simply think of SQL Azure as a cloud-built SQL Server. 　　SQL Azure is a relational database that can be deployed in the cloud to provide customers with a service based on a relational database at any time. We can think of it as a cloud version of SQL Server, but it's not easy to think of SQL Azure as a cloud-built SQL S ...

With regard to NoSQL and SQL, it is well known that NoSQL only allows data to be accessed in restricted predefined modes. For example, DHT (Distributed Hash Table) is accessed through the Hashtable API. Other NoSQL data service access modes are also restricted. Scalability and performance structures are therefore predictable and reliable. In SQL, access patterns are not known beforehand, SQL is a common language that allows data to be accessed in a variety of ways, and programmers have limited control over the execution capabilities of SQL statements. In other words, in s ...

What is the real difference between NoSQL and SQL? Essentially, because different access patterns lead to differences in NoSQL and SQL scalability and performance. NoSQL only allows data to be accessed in restricted predefined modes. For example, DHT (Distributed Hash Table) is accessed through the Hashtable API. Other NoSQL data service access modes are also restricted. Scalability and performance structures are therefore predictable and reliable. In SQL, access patterns are not known beforehand, and SQL is a ...

MAPR today updated its Hadoop release, adding Apache Drill 0.5 to reduce the heavy data engineering effort. Drill is an open source distributed ANSI query engine, used primarily for self-service data analysis. This is the open source version of Google's Dremel system, which is used primarily for interactive querying of large datasets-which support its bigquery servers. The objective of the Apache Drill project is to enable it to scale to 10,000 servers or more servers, while processing in a few seconds ...

NoSQL systems generally advertise a feature that is good performance and then why? relational database has developed for so many years, various optimization work has been done very deep, nosql system is generally absorbing relational database technology, and then, in the end what is the constraints on the performance of relational database? We look at this problem from the perspective of http://www.aliyun.com/zixun/aggregation/9344.html "> System design." 1, index support. Relational data ...

In the development of friends especially and MySQL have contact friends will encounter sometimes MySQL query is very slow, of course, I refer to the large amount of data millions level, not dozens of, the following we take a look at the resolution of the query slow way. -Often find developers looking up statements that are not indexed or limit n, which can have a significant impact on the database, such as a large table of tens of millions of records to scan all, or do filesort, and the database and server IO impact. This is the case above the mirrored library. And ...

Any web software and applications that need a powerful database to back up, there are countless database management tools online, and developers choose a suitable for their own particularly important.　　This article introduces developers to 10 free database management tools, developers can use them for SQL operations, Multilink, multiple database engine operations, and so on. 1.Open Keyval Open Keyval is an open source free key value database management tool, web-based, and based on PHP development, the goal is to use the simplest way to manage we ...

As a software developer or DBA, one of the essential tasks is to deal with databases, such as MS SQL Server, MySQL, Oracle, PostgreSQL, MongoDB, and so on. As we all know, MySQL is currently the most widely used and the best free open source database, in addition, there are some you do not know or useless but excellent open source database, such as PostgreSQL, MongoDB, HBase, Cassandra, Couchba ...

In the current enterprise IT architecture, system administrators and DBAs will consider using the NoSQL database to solve problems that the RDBMS cannot solve, especially the internet industry. Traditional relational databases store data mainly as tables (table), and cannot meet the challenge of unstructured data. In the process of data standardization, the performance of relational database is encountering bottleneck. NoSQL, as its name suggests, is Not-only SQL, which can be a good complement to relational databases. In the report before the TechTarget database, ...

MySQL optimization is very important. The most common and most needed optimization is limit. 　　The limit of MySQL brings great convenience to paging, but when the amount of data is large, the performance of limit is reduced dramatically. The same is 10 data select * FROM Yanxue8_visit limit 10000,10 and select * from Yanxue8_visit limit 0,10 is not a quantitative level ...