On 03.12.2010 13:49, flyusa2010 fly wrote:
When writing log, dbms should synchronously flush log to disk. I'm wondering, if it is possible that the logs are in disk cache, while the control is returned to dbms again, so dbms thinks logs are persistent on disk. In this case, if the disk fails, then there's incorrectness for dbms log writing, because the log is not persistent, but dbms considers it is persistent!
I have no idea what you mean. The method we use to flush the WAL to disk should not be fallible to such failures, we wait for fsync() or fdatasync() to return before we assume the logs are safely on disk. If you can elaborate what you mean by "control is returned to dbms", maybe someone can explain why in more detail.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
