key index

Do you have this feeling, when you search for a thing in Baidu or a problem, the return results are often not satisfactory, and some are in the advertising, some irrelevant, but also a jump link. Now the network is really full of too much rubbish.

Recently, there was a project requirement to ensure that multiple machines did not obtain the same data. later, we found that the Mysql Query statement used select .. forupdate often leads to database deadlocks. the following small series will

Recently, there was a project requirement to ensure that multiple machines did not obtain the same data. later, we found that the Mysql Query statement used select .. forupdate often leads to database deadlocks. the following small series will

In MySQL, a row-level lock is not a direct lock record, but a lock index. Indexes are primary key index and non-primary key index Two, if a SQL statement operation primary Key index, MySQL will lock the primary key index, if a statement operation

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Recently there is a business needs, multiple machines need to query data from a MySQL table at the same time and do follow-up business logic, in order to prevent more than one machine to get the same data, each machine needs to be in the acquisition

Background knowledge:MySQL has three levels of Lock: page level, table level, row level.The MyISAM and memory storage engines use table-level locks (table-level locking), BDB storage engines use page locks (page-level locking), but table-level locks

oracle| Design | Optimization Preface The vast majority of Oracle database performance problems are caused by unreasonable database design, only a small number of problems rooted in db Buffer, Share Pool, Redo Log buffer and other memory module

The ORACLE tutorial is: several methods to optimize the design of Oracle database tables. Preface Most Oracle Database performance problems are caused by unreasonable Database design. Only a small number of problems are rooted in the unreasonable

In computer science, a lock is a synchronization mechanism used to forcibly restrict access to resources when executing multiple threads, which is used to guarantee the satisfaction of mutex requirements in concurrency control.As described in the

Indexes can often greatly improve the efficiency of queries, and if there is no index, MongoDB must scan every file in the collection and select those records that meet the query criteria when reading the data. This scan full set of query efficiency

The previous blog says you can use the slow query log to locate time-consuming SQL, use the explain command to view the execution plan for MySQL, and use the profiling tool to see where the statement execution is really time-consuming, and how to

Index: Constraint + Quick FindAn index is a data structure that is used in a database to help users quickly query data. Similar to a directory in a dictionary, you can find the contents of the dictionary based on the directory to locate the data,

It has been nearly a year since I came into contact with mongodb, And I have accumulated a lot of experience in indexing it. On this dark night, I would like to summarize the mongodb index. I. Index description mongodb has two types of indexes:

Database usage-create and classify oracle Indexes Database usage-create and classify oracle Indexes An index is an optional data structure in a database. It is usually related to tables or clusters. You can create an index on a column or series of

This paper introduces the key length, clear text length and ciphertext length that must be taken into account in RSA plus decryption, and for the first time developers of RSA, RSA is a more complicated algorithm, and the complexity of RSA is because

First, IntroductionDefault lock level for MySQL engine:MyISAM and memory Use table-level locks (table-level locking).The BDB uses page locks (page-level locking) or table-level locks, which are page locks by default.InnoDB supports row-level locks

MySQL Plus Lock Processing analysis Original: http://hedengcheng.com/?p=7711 background 11.1 Mvcc:snapshot Read vs current Read 21.2 Cluster Index: Clustered Indexes 31.3 2pl:two-phase Locking 31.4 Isolation Level 42 A simple SQL Lock implementation

Note: This article is reproduced from http://www.hollischuang.com/archives/914In computer science, a lock is a synchronization mechanism used to forcibly restrict access to resources when executing multiple threads, which is used to guarantee the

This article from: Ho Dengcheng's Technical BlogI. BACKGROUNDMysql/innodb's locking analysis has been a difficult topic. In the course of my work, my colleagues have often consulted on this issue. At the same time, the micro-blog also often receive