23.02.2019 21:14, Adriano dos Santos Fernandes wrote:
Hi!
After changes to use commit number instead of base transaction number, I
offer to make that interfaces for the feature:
I offer to not introduce additional confusing with different usages of commit
numbers.
Commit Number (CN) itself is an unique value assigned to the every committed
transaction. The source of that value is per-database counter. When some
database
snapshot is created it uses current value of database counter of commit numbers
as own identifier. Lets name it Snapshot Number (SN) to distinguish from Commit
Number assigned to transaction. The sourse of CN and SN is the same, but usage
and meaning is very different !
Therefore
SQL command: SET TRANSACTION SNAPSHOT COMMIT NUMBER <cn>
(some variant as SNAPSHOT FROM COMMIT NUMBER or SNAPSHOT BASE COMMIT
NUMBER may be acceptable)
maybe:
SET TRANSACTION SNAPSHOT [USING SNAPSHOT <N>]
or
SET TRANSACTION SNAPSHOT [USING SNAPSHOT NUMBER <N>]
TPB: isc_tpb_snapshot_commit_number, <commit number length> <commit number>
isc_tpb_snapshot_number <len> <value>
Regards,
Vlad
PS we also must add isc_info_tra_snapshot_number and, probably, context
variable.
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