make sure the snapshot read TS greater than the TXN TS when create snapshot or clone. #22252
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qingxinhome
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Jul 24, 2025
gouhongshen
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What type of PR is this?
Which issue(s) this PR fixes:
issue ##21978
What this PR does / why we need it:
consider the following example:
(within a session)
...
insert into t1 values (1) ---> commit ts (P2-L3)
insert into t1 values (2) ---> commit ts (P2-L4)
create table t2 clone t1 ---> the read snapshot ts is P2.
limited by the format for the snapshot read TS, the logic TS is truncated,
so in this example, the clone cannot read the newly inserted data.
so we try to increase the txn physical ts here to make sure the snapshot TS
the clone will get is greater than P2.
the same issue exists when create snapshot.