24.07.2018 11:13, liviuslivius wrote:
Hi,
question about this patch
https://github.com/FirebirdSQL/firebird/pull/105
Is this possible that this CN(commit number) of transactions (pair transaction
id + CN) can be stored into some table?
Currently - no. Probably we could find a way for it.
Is it possible to retrive most recent CN from transaction start point (call
this SCN).
Not sure what is it and how it can be used. Probably, you asking for
something like
current snapshot (if any) ? If yes, it can be make available via system context
and\or
new system function (CURRENT_CN). Also, we can make available value of database
CN in
the same way.
It can provide simple way to retrive new records/changes in tables (new
feature).
E.g. whe can then do
SELECT * FROM TABLEX WHERE CN>:SCN;
I know this do not show us deleted records but in many scenarios it is not so
important.
Of course deleted records can also be tracked, if we block record versions to be removed by garbage collector and make way to
retrive this record with some flag(?).
But this then require something what init this blocking mechanism (i suppose this will be then simmilar feature to so called in
Interbase Change Views).
What do you think about?
I don't know if IB's "Change View" really useful feature. Do you have some
expirience\opinon?
We can think about our implementation in FB, if it is really good.
Regards,
Vlad
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
Firebird-Devel mailing list, web interface at
https://lists.sourceforge.net/lists/listinfo/firebird-devel
