Skip to content

sessionctx: restore tidb_paging_size_bytes default to 0 #70052

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

Merged
ti-chi-bot merged 1 commit into from
Jul 27, 2026
+11 −9
Merged

sessionctx: restore tidb_paging_size_bytes default to 0 #70052

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
14 changes: 8 additions & 6 deletions pkg/sessionctx/vardef/tidb_vars.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1519,13 +1519,15 @@ const (
DefInitChunkSize = 32
DefMinPagingSize = int(paging.MinPagingSize)
DefMaxPagingSize = int(paging.MinAllowedMaxPagingSize)
// DefPagingSizeBytes defaults byte-budget paging to 4 MiB. It takes effect only when Resource Control
// is enabled and the active Resource Group is non-burstable (has limited burst).
// DefPagingSizeBytes defaults to 0 (byte-budget paging disabled).
// A non-zero value takes effect only when Resource Control is enabled and the active Resource Group
// is non-burstable (has limited burst).
// Regression tests across cap-bound and under-cap TPC-C, FullScan, and Join workloads found no
// material performance regression. Among the tested 1, 2, 4, 8, and 16 MiB candidates, 4 MiB
// provided the best overall balance of throughput, tail latency, RU stability, RPC overhead, CPU,
// and RU efficiency.
DefPagingSizeBytes = 4 * 1024 * 1024
// material performance regression with byte-budget paging. Among the tested 1, 2, 4, 8, and 16 MiB
// candidates, 4 MiB provided the best overall balance of throughput, tail latency, RU stability,
// RPC overhead, CPU, and RU efficiency. Consider setting this to 4 MiB (4194304) when enabling
// byte-budget paging for resource groups with limited burst.
DefPagingSizeBytes = 0
DefMaxChunkSize = 1024
DefDMLBatchSize = 0
DefMaxPreparedStmtCount = -1
Expand Down
6 changes: 3 additions & 3 deletions tests/integrationtest/r/sessionctx/setvar.result
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1102,11 +1102,11 @@ select /*+ set_var(tidb_paging_size_bytes=1048576) */ @@tidb_paging_size_bytes;
1048576
select @@tidb_paging_size_bytes;
@@tidb_paging_size_bytes
4194304
0
set @@tidb_paging_size_bytes=default;
select @@tidb_paging_size_bytes;
@@tidb_paging_size_bytes
4194304
0
set @@tidb_paging_size_bytes=0;
select @@tidb_paging_size_bytes;
@@tidb_paging_size_bytes
Expand All @@ -1118,7 +1118,7 @@ select @@tidb_paging_size_bytes;
set @@tidb_paging_size_bytes=default;
select @@tidb_paging_size_bytes;
@@tidb_paging_size_bytes
4194304
0
select /*+ set_var(tidb_enable_cascades_planner=0) */ @@tidb_enable_cascades_planner;
@@tidb_enable_cascades_planner
0
Expand Down
Loading