[ZODB-Dev] [ zodb-Bugs-550246 ] ClientStorage Deadlock problem

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Bugs item #550246, was opened at 2002-04-29 16:26
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Chris Withers (fresh)
Assigned to: Jeremy Hylton (jhylton)
Summary: ClientStorage Deadlock problem

Initial Comment:
Shane helped me get to the cause of this on #zope...

<hathawsh> The real problem is that if you have multiple ClientStorages that point to the same 
storage on the server, and two or more are involved in the same transaction, a deadlock happens.

This is a pattern that would be very useful to me, it currently causes the storage servers and any 
clients connection to them to hang on get_transaction().commit() until they've _all_ been 
restarted...

cheers,

Chris

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>Comment By: Chris Withers (fresh)
Date: 2002-04-29 19:55

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Well, is there any way to make it so that it doesn't matter whether or not ZEO knows that multiple clients 
are participating in the transaction? I mean, it strikes me that this deadlock should probably not occur, 
regardless of whether ZEO knows they're part of the same transaction or not...

...but of course, I know very little. Shane would be the man to discuss this with :-)

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Comment By: Jeremy Hylton (jhylton)
Date: 2002-04-29 19:15

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This could be really hard to fix...  I don't see a
principled way for a ZEO to know that multiple clients are
part of the same transaction.  Maybe the transaction object
can grow some metadata.


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