[ZODB-Dev] ZODB blob support.
Toby Dickenson
tdickenson at devmail.geminidataloggers.co.uk
Mon Mar 21 13:08:35 EST 2005
On Monday 21 March 2005 17:50, Chris McDonough wrote:
> - People are are unwilling to accept any weakening of data integrity
> guarantee and who want the ZEO server itself to be responsible
> for writing data (the ZEO clients must send the server the data
> over RPC). OTOH, if configured properly, the data may be read
> from a shared filesystem.
I suspect some weakening is inevitable, unless you severely restrict the
choice of shared filesystem. Every network filesystem has its own ideas about
when client caches should be flushed.
> I think we want to use something like what I'm told Toby does for
> DirectoryStorage (using os.rename in the 2nd phase, keeping a journal to
> be able to back out a failed 2nd-phase commit).
That works great on a local filesystem, but dont expect any strong atomicity
or durability guarantees across networked filesystems.
--
Toby Dickenson
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