The flush is a maximum period of time, not a constant. Most O/S will flush in milliseconds depending on system load. Unless the transaction load is huge, this is not normally something that needs to be altered. I believe it really is more of a safety net thing that never really comes into play.
What is responsible for flushing is either the process updating the logset or optionally a separate process running jlogsync. Dan Ell Dan Ell Technical Support Engineer jBASE 9245 Research Drive, Irvine, CA 92618 949-383-2429 [email protected]<mailto:[email protected]> www.jbase.com<http://www.jbase.com> From: [email protected] [mailto:[email protected]] On Behalf Of My_jBase Sent: Wednesday, January 28, 2015 8:03 AM To: [email protected] Subject: TIME BETWEEN LOG FILE SYNCS Hello, Would You like to explain me how jbase journal works ? The jbase manual says : When journaling is running the basic order of operations for updates is as follows: • The database item is updated in memory • The transaction log is updated in memory. • The transaction log is flushed every 10 seconds by default. However this time period can be configured via an option on the administration command, jlogadmin. It is also possible to configure an independent process to execute the jlogsync command, to ensure the transaction log is continuously flushed from memory at the specified interval, thus alleviating the flush procedure from all of the update processes. • The database updates are flushed to disk by the operating system. • The database update to disk and the log update to disk can be forced to be an atomic operation. There is a feature which specifies the number of seconds between each synchronization of the log set with the disk - jlogadmin -s nnn ; All memory used by the log set is force flushed to disk. Should the system crash, the maximum amount of possible data loss is limited to the updates which occurred since the last log set synchronization. By default it is 10 seconds. What will be if I change this to f.e. 10.000 seconds ? - does that mean that I can lose informations from 10.000 seconds if my system will crash ? In my opinion it's not true because I can observe modify time of logset files during a test and they are constantly updated - not in every 10 or 10.000 seconds So what is responsible for logsets synchronization ? Piotr -- -- IMPORTANT: T24/Globus posts are no longer accepted on this forum. To post, send email to [email protected]<mailto:[email protected]> To unsubscribe, send email to [email protected]<mailto:[email protected]> For more options, visit this group at http://groups.google.com/group/jBASE?hl=en --- You received this message because you are subscribed to the Google Groups "jBASE" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. For more options, visit https://groups.google.com/d/optout. -- -- IMPORTANT: T24/Globus posts are no longer accepted on this forum. To post, send email to [email protected] To unsubscribe, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jBASE?hl=en --- You received this message because you are subscribed to the Google Groups "jBASE" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
