From e90c866319bbbb23cbf83cc768d0cdd42eeb511c Mon Sep 17 00:00:00 2001 From: Ti Chi Robot Date: Mon, 16 Dec 2024 11:52:39 +0800 Subject: [PATCH] flashback: add limitation with stale read/snapshot (#19347) (#19697) --- sql-statements/sql-statement-flashback-cluster.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sql-statements/sql-statement-flashback-cluster.md b/sql-statements/sql-statement-flashback-cluster.md index 14d3fd38780cc..20ba4d7708651 100644 --- a/sql-statements/sql-statement-flashback-cluster.md +++ b/sql-statements/sql-statement-flashback-cluster.md @@ -15,7 +15,8 @@ Starting from v6.5.6, v7.1.3, v7.5.1, and v7.6.0, TiDB introduces the `FLASHBACK > **Warning:** > -> When specifying a recovery point in time, make sure to check the validity of your target timestamp or TSO and avoid specifying a future time that exceeds the maximum TSO currently allocated by PD (see `Current TSO` on the Grafana PD panel). Otherwise, concurrent processing linear consistency and transaction isolation levels might be violated, leading to serious data correctness issues. +> - When specifying a recovery point in time, make sure to check the validity of your target timestamp or TSO and avoid specifying a future time that exceeds the maximum TSO currently allocated by PD (see `Current TSO` on the Grafana PD panel). Otherwise, concurrent processing linear consistency and transaction isolation levels might be violated, leading to serious data correctness issues. +> - During `FLASHBACK CLUSTER` execution, the data cleanup process does not guarantee transaction consistency. After `FLASHBACK CLUSTER` completes, if you intend to use any historical version reading features in TiDB (such as [Stale Read](/stale-read.md) or [`tidb_snapshot`](/read-historical-data.md)), make sure that the specified historical timestamp falls outside the `FLASHBACK CLUSTER` execution period. Reading a historical version that includes data not fully restored by FLASHBACK might violate concurrent processing linear consistency and transaction isolation levels, leading to serious data correctness issues.