session: fix linearizability for non-autocommit async-commit txn #22879
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Signed-off-by: Yilin Chen <[email protected]>
Signed-off-by: Yilin Chen <[email protected]>
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/lgtm |
Signed-off-by: Yilin Chen <[email protected]>
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The way to fix may depend on #22875 |
executor/simple.go
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| @@ -586,7 +586,8 @@ func (e *SimpleExec) executeBegin(ctx context.Context, s *ast.BeginStmt) error { | |||
| // With START TRANSACTION, autocommit remains disabled until you end | |||
| // the transaction with COMMIT or ROLLBACK. The autocommit mode then | |||
| // reverts to its previous state. | |||
| e.ctx.GetSessionVars().SetStatusFlag(mysql.ServerStatusInTrans, true) | |||
| e.ctx.GetSessionVars().SetInTxn(true) | |||
| txnCtx.IsExplicit = true | |||
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why do the assignment again?
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Sorry, I forgot to remove it during refactoring
Signed-off-by: Yilin Chen <[email protected]>
Signed-off-by: Yilin Chen <[email protected]>
Signed-off-by: Yilin Chen <[email protected]>
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@AilinKid: Please use If you have approved this PR, please ignore this reply. This reply is being used as a temporary reply during the migration of the new bot and will be removed on April 1. Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository. |
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/run-all-tests |
sessionctx/variable/session.go
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| Isolation string | ||
| LockExpire uint32 | ||
| ForUpdate uint32 | ||
| // IsExplicit indicates whether the txn is an interactive txn started with a BEGIN statement |
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It's not accurate. A transaction can start with autocommit = 0.
| func (s *SessionVars) SetInTxn(val bool) { | ||
| s.SetStatusFlag(mysql.ServerStatusInTrans, val) | ||
| if val { | ||
| s.TxnCtx.IsExplicit = true |
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Is it reset when startinging a new transaction?
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I think it is always reset by PrepareTxnCtx or NewTxn. I am not sure if there is anything missing.
However, at least the unit test in this PR passes, which I think covers the important cases.
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/LGTM |
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Signed-off-by: Yilin Chen <[email protected]>
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/merge |
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This pull request has been accepted and is ready to merge. Commit hash: e7cb5b4
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/run-tics-test |
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/run-tics-test |
What problem does this PR solve?
#22746 made a mistake.
s.GetSessionVars().IsAutocommit()cannot be used to decide whether the current transaction is an auto-commit transaction.Elsewhere we tend to use
s.GetSessionVars().IsAutocommit() && s.GetSessionVars().IsAutocommit().InTxn()to check, but at the beginning of theCOMMITstatement, we clear theServerStatusInTransflag, soInTxn()always returns false during theCOMMITstatement.What is changed and how it works?
This PR adds
IsExplicitflag totxnCtx. We set the flag totruewhen we start a transaction explicitly. We use this flag to check if this transaction is auto-commit.Check List
Tests
Release note