Hello, Carlos!

On 06/23/2014 03:19 PM, Carlos H. Cantu wrote:
> NS> Yes, for READ_ONLY + READ COMMITTED transactions you will now
> NS> inhibit GC if you keep a cursor open
> NS> for a long time.
>
> This is serious change, and I'm probably against it being the default
> behavior. So far, it is well advertised that transactions using RC+RO
> does NOT block GC, and several applications out there assumes this
> being true, and uses it in "lookup" datasets without worring about the
> time they will be kept open. A change in this behavior can produce bad
> side-effects for those apps. If this change becomes the default, a new
> way of keeping the previous (non blocking) behavior must be introduced
> and very well advertised.

If this is what people want, it is possible to add new TPB parameter - 
isc_tpb_inconsistency, and 
permit it for READ_ONLY + READ COMMITTED transactions only. For as long you 
don't use returned data 
for anything important it is somewhat safe.

With this change, I shall probably set up snapshots for NO_REC_VERSION mode as 
well. This will make 
this mode completely useless, but it will be safe at least.

Dmitry, agreed?

Nikolay Samofatov


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