>>>>> "Peter" == Peter Zaitsev <pz@stripped> writes:
Peter> I'm wondering how mysql does it's inserts/updates - more certan - what it
Peter> does after it writes this information into data file ? Does it uses fsync()
Peter> or fflush() òî sync data to the disk or it just flushes it into
Peter> system cache (so if MYSQLD crashes data will be writen anyway). I'm just
Peter> asking this because of thinking how to tune my operation system cache
Peter> delayed write to make it work faster - I have a table which has many
Peter> frequent updates which does not touch keys.
During execution of one SQL statement, MySQL may cache rows + keys,
but before returning an ok / error to the client, it will write all
changed data to disk with write(); It will not normally fflush() the
data (you have to start mysqld with --flush for this). In other
words, everything should be in the system cache so things should be
updated ok even if mysqld crashes (as long as the system doesn't
Peter> Could anyone explain this (there is nothing about this in the manual).