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estados de una BD

Posted in 2003

Topics: General Discussion

in4mix peru — — source: Usenet: comp.databases.informix

Saludos: Cuando creo una nueva BD en mi instancia, por defecto el estado de mi estado de mi sistema es NO LOGGING. Sabemos que IDS tiene tres estados: NO-LOGGING, BUFFER y UNBEFFER. Mi pregunta es: - Cuales es el concepto de estos estados - Cuales son los beneficios de tenerlos asi - Cual es lo recomendable. Saludos _________________________________________________________________ 'Est's buscando un auto nuevo? http://www.yupimsn.com/autos/ sending to informix-list

↪ replying to in4mix peru
Fernando Nunes — — source: Usenet: comp.databases.informix

in4mix peru wrote: > Saludos: > Cuando creo una nueva BD en mi instancia, por defecto el estado de mi > estado de mi sistema es NO LOGGING. Sabemos que IDS tiene tres estados: > NO-LOGGING, BUFFER y UNBEFFER. > Mi pregunta es: > - Cuales es el concepto de estos estados > - Cuales son los beneficios de tenerlos asi > - Cual es lo recomendable. > > Saludos > > _________________________________________________________________ > 'Est's buscando un auto nuevo? http://www.yupimsn.com/autos/ > > sending to informix-list This is an english speaking group... But answering to your questions: - NO LOGGING causes your database to disable logging (ohoh... that's new ;) ). You can't have transactions. If an operation fails in a certain point it will be left as is. No rollback will be done. It's impossible to guarantee database consistency without logging. - BUFFERED LOGGING is a mode of loggin in wich the log buffers (RAM area where a description of transactions are held before saving them to logical logs on disks) will be done only when the buffer is full. The buffer size is a parameter in you onconfig file. It's more efficient then the next one but leaves space for a bit of operation loss in case of a server crash - UNBUFFERED LOGGING is a mode where as soon as a transaction in the logical log buffers ends (commit or rollback) the buffer is immediatly flushed to disk. It's marginally less efficient then the previous one but guarantees absolutly no operation loss. Note that both BUFFERED and UNBUFFERED LOGGING alow for transactions and guarantee database consistency. Regards.

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