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The dispatcher processes support shared server configuration by allowing userprocesses to share a limited number of server processes. With the shared server, fewershared server processes are required for the same number of users, Therefore, theshared server can support a greater number of users, particularly in client/serverenvironments where the client application and server operate on different computers.You can create multiple dispatcher processes for a single database instance. At leastone d

A request from a user is a single program interface call that is part of the user’s SQLstatement. When a user makes a call, its dispatcher places the request on the requestqueue, where it is picked up by the next available shared server process.The request queue is in the SGA and is common to all dispatcher processes of aninstance. The shared server processes check the common request queue for newrequests, picking up new requests on a first-in-first-out basis. One shared serverprocess picks up

Shared server architecture eliminates the need for a dedicated server process for eachconnection. A dispatcher directs multiple incoming network session requests to a poolof shared server processes. An idle shared server process from a shared pool of serverprocesses picks up a request from a common queue, which means a small number ofshared servers can perform the same amount of processing as many dedicated servers.Also, because the amount of memory required for each user is relatively small, le

Each server and background process can write to an associated trace file. When aprocess detects an internal error, it dumps information about the error to its trace file.If an internal error occurs and information is written to a trace file, the administratorshould contact Oracle Support Services.All filenames of trace files associated with a background process contain the name ofthe process that generated the trace file. The one exception to this is trace filesgenerated by job queue processes (

There are several other background processes that might be running. These caninclude the following:MMON performs various manageability-related background tasks, for example:■ Issuing alerts whenever a given metrics violates its threshold value■ Taking snapshots by spawning additional process (MMON slaves)■ Capturing statistics value for SQL objects which have been recently modifiedMMNL performs frequent and light-weight manageability-related tasks, such assession history capture and metrics c

The queue monitor process is an optional background process for Oracle StreamsAdvanced Queuing, which monitors the message queues. You can configure up to 10queue monitor processes. These processes, like the job queue processes, are differentfrom other Oracle background processes in that process failure does not cause theinstance to fail.队列监视进程是个可选的进程for Oracle Streams Advanced Queuing, 用来监视信息队列[@more@]

The archiver process (ARCn) copies redo log files to a designated storage device aftera log switch has occurred. ARCn processes are present only when the database is inARCHIVELOG mode, and automatic archiving is enabled.An Oracle instance can have up to 10 ARCn processes (ARC0 to ARC9). The LGWRprocess starts a new ARCn process whenever the current number of ARCn processes isinsufficient to handle the workload. The alert log keeps a record of when LGWR startsa new ARCn process.If you anticipate

Job queue processes are used for batch processing. They run user jobs. They can beviewed as a scheduler service that can be used to schedule jobs as PL/SQL statementsor procedures on an Oracle instance. Given a start date and an interval, the job queueprocesses try to run the job at the next occurrence of the interval.Job queue processes are managed dynamically. This allows job queue clients to usemore job queue processes when required. The resources used by the new processes arereleased when th

The recoverer process (RECO) is a background process used with the distributeddatabase configuration that automatically resolves failures involving distributedtransactions. The RECO process of a node automatically connects to other databasesinvolved in an in-doubt distributed transaction. When the RECO process reestablishesa connection between involved database servers, it automatically resolves all in-doubttransactions, removing from each database’s pending transaction table any rows thatcorre

The process monitor (PMON) performs process recovery when a user process fails.PMON is responsible for cleaning up the database buffer cache and freeing resourcesthat the user process was using. For example, it resets the status of the activetransaction table, releases locks, and removes the process ID from the list of activeprocesses.PMON periodically checks the status of dispatcher and server processes, and restartsany that have stopped running (but not any that Oracle has terminated intention

The system monitor process (SMON) performs recovery, if necessary, at instancestartup. SMON is also responsible for cleaning up temporary segments that are nolonger in use and for coalescing contiguous free extents within dictionary managedtablespaces. If any terminated transactions were skipped during instance recoverybecause of file-read or offline errors, SMON recovers them when the tablespace or fileis brought back online. SMON checks regularly to see whether it is needed. Otherprocesses can

When a checkpoint occurs, Oracle must update the headers of all datafiles to recordthe details of the checkpoint. This is done by the CKPT process. The CKPT processdoes not write blocks to disk; DBWn always performs that work.The statistic DBWR checkpoints displayed by the System_Statistics monitor inEnterprise Manager indicates the number of checkpoint requests completed.检查点进程当检查点发生时 , Oracle将更新所有数据文件的头来记录检查点 .后面这句话什么意思 ? 哪位大侠告诉我一下 , 谢谢.[@more@]

When a user commits a transaction, the transaction is assigned a system changenumber (SCN), which Oracle records along with the transaction’s redo entries in theredo log. SCNs are recorded in the redo log so that recovery operations can besynchronized in Real Application Clusters and distributed databases.In times of high activity, LGWR can write to the redo log file using group commits. Forexample, assume that a user commits a transaction. LGWR must write thetransaction’s redo entries to disk

LGWR writes synchronously to the active mirrored group of redo log files. If one ofthe files in the group is damaged or unavailable, LGWR continues writing to otherfiles in the group and logs an error in the LGWR trace file and in the system alert log.If all files in a group are damaged, or the group is unavailable because it has not beenarchived, LGWR cannot continue to function.When a user issues a COMMIT statement, LGWR puts a commit record in the redo logbuffer and writes it to disk immediat

Before DBWn can write a modified buffer, all redo recordsassociated with the changes to the buffer must be written to disk (thewrite-ahead protocol). If DBWn finds that some redo records have notbeen written, it signals LGWR to write the redo records to disk andwaits for LGWR to complete writing the redo log buffer before it canwrite out the data buffers.写优先协议当DBWn写出modified buffer之前 , 日志记录中与buffer中相关的需要先写入磁盘 ,如果DBWn发现有日志记录还没有写出 , 它将通知LGWR将这些日志写

The log writer process (LGWR) is responsible for redo log buffermanagement—writing the redo log buffer to a redo log file on disk. LGWR writes allredo entries that have been copied into the buffer since the last time it wrote.The redo log buffer is a circular buffer. When LGWR writes redo entries from the redolog buffer to a redo log file, server processes can then copy new entries over the entriesin the redo log buffer that have been written to disk. LGWR normally writes fastenough to ensure t

什么是链接流行度链接流行度系统是基于网页获得的链接的数量及质量而定的。也就是说，指向你的网页的链接数量越多，你的网页将被搜索引擎认为越重要。数量并不是决定网站重要度的唯一因素，重要度还取决于其他因素，包括被链接到本站点的站点的质量、他们的内容的质量及与本站点的行业相关性等。链接到本站点的网页会把PageRank的部分分值分配到本站点。所以链接页面的PageRank分值越高，分配给本站点的分值也就越高。PageRank也会被链接页面商店所有导出链接所瓜分。譬如，同样PR为5的链接网页，导出链接只有15个的网页会比导出链接为100

1. 在Firefox的书签 - 管理书签 - 文件菜单 - 导出 -导出Firefox收藏夹文件，是个Html文件；2. 用记事本打开导出的书签文件 - 另存为 - 编码选ANSI（其它不变）。注意，仍要保存为HTML格式！3. 打开IE，文件 菜单 - 导入和导出 - 选择导入收藏夹 - 从文件导入-选择刚才你修改编码为ANSI的HTMl文件 - 导入成功。[@more@]

zhidao.baiduweb共享的意思就是可以通过internet的ip地址来访问你所共享的文件夹是以网页的形式来访问，你可以象普通共享一样来设置该共享的访问权限共享就是我们平时通过网上邻居来访问某台机器，来实现文件的共享使用以及该文件夹的读写操作等不同的用法就是，一个是需要通过iis或者是其他的web技术来支持，一个则不需要，一个是必须通过ip或者是网址来访问，一个是一般都在局域网中使用在局域网中的传输文件一般最好用普通共享，而要是离的很远的话，需要远程访问一般用web共享比较好，不过web共享漏洞较多，建议最好不要用.[@more@]

The database writer process (DBWn) writes the contents of buffers to datafiles. TheDBWn processes are responsible for writing modified (dirty) buffers in the databasebuffer cache to disk. Although one database writer process (DBW0) is adequate formost systems, you can configure additional processes (DBW1 through DBW9 andDBWa through DBWj) to improve write performance if your system modifies dataheavily. These additional DBWn processes are not useful on uniprocessor systems.When a buffer in the d