lock example

Before doing a test, repeatedly executed several times, found the result is the same:1. Single-threaded synchronized is the most efficient (at the time it felt its efficiency should be the worst);2. Atomicinteger efficiency is the most unstable,

Comparison of concurrency control (LOCK) between DB2 and Oracle Comparison of concurrency control (LOCK) between DB2 and Oracle 1 Introduction The minimal recovery and transaction units in relational databases (DB2, Oracle, Sybase, Informix, and

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1 Introduction The minimal recovery and transaction units in relational databases (DB2, Oracle, Sybase, Informix, and SQL Server) are a transaction (Transactions). Transactions are ACID (atomicity, consistency, isolation, and durability) feature. In

1 Introduction In relational databases (Db2,oracle,sybase,informix and SQL Server) the smallest recovery and transaction units are one transaction (transactions), and transactions have acid (atomicity, consistency, isolation, and permanence)

A lock is a mechanism by which a computer coordinates multiple processes or a purely thread concurrently accessing a resource. in a database, data is a resource that is shared by many users in addition to the contention of traditional computing

Article from http://weiba.weibo.com/10015/t/zkOgtyY0V SAP Lock MechanismI. Why should I set a lock for sap:1. Maintain Data ConsistencyIf several users want to access the same resource, they need to find a synchronous access method to maintain data

In order to better optimize MySQL in high concurrency, it is necessary to understand the locking table mechanism when MySQL query is updated.I. OverviewMySQL has three levels of Lock: page level, table level, row level.MyISAM and MemoryStorageThe

#一. OverviewThe > database locking mechanism simply means that the database is designed to ensure the consistency of the data and to make the various shared resources be ordered by concurrent access. For any kind of database need to have a

SQL Server lock type (SQL) favorites1. holdlock: Keep the shared lock on the table until the entire transaction ends, instead of releasing the added lock immediately after the statement is executed.2. nolock: no shared or exclusive locks are added.