Re: [pgsql-hackers-win32] SRA Win32 sync() code

Shridhar Daithankar wrote:

>Does 30% difference above count as significant?
>  
>
No. It's Linux, we can look at the sources: there is no per-fd cache, 
the page cache is global. Thus fsync() syncs the whole cache to disk.
A problem could only occur if the file cache is not global - perhaps a 
per-node file cache on NUMA systems - IRIX on an Origin 2000 cluster or 
something similar.

But as I read the unix spec, fsync is guaranteed to sync all data to disk:
Draft 6 of the posix-200x spec:
SIO If _POSIX_SYNCHRONIZED_IO is defined, the fsync( ) function shall 
force all currently queued I/O operations associated with the file 
indicated by file descriptor fildes to the synchronized I/O completion 
state. All I/O operations shall be completed as defined for synchronized 
I/O file integrity completion.

"All I/O operations associated with the file", not all operations 
associated with the file descriptor.

--
    Manfred