[ZODB-Dev] StorageServer's waiting list

[Christian Theune]

Hi,

in ZEORaid recovery we acquire the commit lock of our RAIDStorage from a
thread to be able to finish recovery atomically.

That RAIDStorage is also being served from a StorageServer which causes
some trouble because it assumes that the only way for a transaction on
the served storage to end is via the StorageServer's tpc_abort or
tpc_finish method.

Thus, when a transaction comes in while the recovery has a transaction
going on the StorageServer puts it into the waiting list but never gets
the signal to continue.

Reading the code talking to tpc_transaction I found that this seems to
be merely an optimization (which I can disable by just letting
tpc_transaction return None all the time).

Why is the waiting list necessary? And why does it work alright in a ZEO
fan-out scenario?

Christian

-- 
Christian Theune · ct at gocept.com
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