Skip to content

br: introduce global variable tidb_advancer_check_point_lag_limit to control log backup checkpoint lag limitation #21481

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 3 commits into
base: master
Choose a base branch
from
Open

br: introduce global variable tidb_advancer_check_point_lag_limit to control log backup checkpoint lag limitation #21481

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
764e61c
draft
Leavrth Jul 31, 2025
882c002
Update system-variables.md
Leavrth Aug 5, 2025
d57201b
Update system-variables.md
hfxsd Aug 5, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 10 additions & 0 deletions system-variables.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1043,6 +1043,16 @@ mysql> SHOW GLOBAL VARIABLES LIKE 'max_prepared_stmt_count';
- Unit: Bytes
- This variable is used to control the threshold at which the TiDB server prefers to send read requests to a replica in the same availability zone as the TiDB server when [`tidb_replica_read`](#tidb_replica_read-new-in-v40) is set to `closest-adaptive`. If the estimated result is higher than or equal to this threshold, TiDB prefers to send read requests to a replica in the same availability zone. Otherwise, TiDB sends read requests to the leader replica.

### tidb_advancer_check_point_lag_limit <span class="version-mark">New in v9.0.0</span>

- Scope: GLOBAL
- Persists to cluster: Yes
- Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No
- Type: Duration
- Default value: `48h0m0s`
- Range: `[1s, 8760h0m0s]`
- This variable is used to control the maximum allowed checkpoint lag for a log backup task. If a task's checkpoint lag exceeds this limit, TiDB Advancer pauses the task.

### tidb_allow_tiflash_cop <span class="version-mark">New in v7.3.0</span>

- Scope: SESSION | GLOBAL
Expand Down