[...]
(i.e. on NetWare, Oracle uses the DirectFS interface which by-passed the
cache completely). Oracle also provided it's own caching above the OS
for remote SQL users. When they called DirectFS, it was always with an
"O_SYNC" semantic, which I think is the spirit here.
Linux right now how no way to bypass the buffer-cache when writing to
a filesystem.
O_SYNC is as good as you can get, you want to be sure you most
recently issued write(...) has hit the platters (polluting the
page-cache whilst undesirable, is unavoidable at present).
I think this is probably OK.
>From profiling Oracle under Slowaris, I would say Oracle _always_
writes expecting the data to hit the platters immediately (I could be
wrong).
Because linux does not yet support this I assume they use O_SYNC,
hence it must be as fast as possible or things like Oracle will
really suck.
--cw
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This archive was generated by hypermail 2b29 : Mon May 15 2000 - 21:00:26 EST