pessimistic-transaction: clarify Point Get lock behavior for non-existing keys under different isolation levels (#21740)#21742
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ti-chi-bot[bot] merged 1 commit intoJun 25, 2026
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…ting keys under different isolation levels (pingcap#21740)
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This is an automated cherry-pick of #21740
This PR is translated from: pingcap/docs#23111
What is changed, added or deleted? (Required)
Added a Note in the
Behaviorssection ofpessimistic-transaction.mdto clarify that the Point Get and Batch Point Get lock behavior for non-existing keys applies only to theREPEATABLE READisolation level.Under the
READ COMMITTEDisolation level,Point GetandBatch Point Getoperators do not lock non-existent keys. This is a behavioral difference that can affect applications usingSELECT FOR UPDATEfor existence checks followed byINSERT.Which TiDB version(s) do your changes apply to? (Required)
What is the related PR or file link(s)?
Do your changes match any of the following descriptions?
Verification
This behavior was verified on TiDB v8.5.3:
id = 999id = 888id IN (777, 888)id BETWEEN 100 AND 200A test script was provided in the PR comments for reviewers to verify the behavior locally.