2007-11-23
关于Oracle的一些基础知识
这两天有同事抱怨公司的开发环境Oracle Server总是报告达到最大用户数限制登录，解决问题过程中，知道了一些早就应该掌握的oracle基本概念：
1. What's the difference between connections, sessions and processes?
-- A connection is a physical circuit between you and the database. A connection
might be one of many types -- most popular begin DEDICATED server and SHARED
server. Zero, one or more sessions may be established over a given connection
to the database as show above with sqlplus. A process will be used by a session
to execute statements. Sometimes there is a one to one relationship between
CONNECTION->SESSION->PROCESS (eg: a normal dedicated server connection).
Sometimes there is a one to many from connection to sessions (eg: like
autotrace, one connection, two sessions, one process). A process does not have
to be dedicated to a specific connection or session however, for example when
using shared server (MTS), your SESSION will grab a process from a pool of
processes in order to execute a statement. When the call is over, that process
is released back to the pool of processes.
2. 以后补充..
1. What's the difference between connections, sessions and processes?
-- A connection is a physical circuit between you and the database. A connection
might be one of many types -- most popular begin DEDICATED server and SHARED
server. Zero, one or more sessions may be established over a given connection
to the database as show above with sqlplus. A process will be used by a session
to execute statements. Sometimes there is a one to one relationship between
CONNECTION->SESSION->PROCESS (eg: a normal dedicated server connection).
Sometimes there is a one to many from connection to sessions (eg: like
autotrace, one connection, two sessions, one process). A process does not have
to be dedicated to a specific connection or session however, for example when
using shared server (MTS), your SESSION will grab a process from a pool of
processes in order to execute a statement. When the call is over, that process
is released back to the pool of processes.
2. 以后补充..
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