one of tiflash oom when run ch workload

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

2 * tiflash-16C-110GB

1、br restore ch data
/br restore db --db tpcc --pd tc-pd.endless-ha-test-htap-tps-7896564-1-962:2379 --storage "s3://qe-testing/nfs/tiflash/ch-2k-flash2-collation?access-key=xxxxxx&secret-access-key=xxxxxx&endpoint=http%3a%2f%2fks3-cn-beijing-internal.ksyuncs.com&force-path-style=false&region=Beijing&provider=ks" --send-credentials-to-tikv=true --check-requirements=false --checksum=true
2、wait tiflash replica ready
3、run ch
go-tpc ch run -D tpcc --host tc-tidb.endless-ha-test-htap-tps-7896564-1-962 -P4000 --warehouses 2000 -T 32 --acThreads 1 --queries q5 --ignore-error '2013,1213,1205,8022,8028,9004,9007,1062,1105' --time 36000m --user root --password '' --interval '10s'

2. What did you expect to see? (Required)

no oom

3. What did you see instead (Required)

one of tiflash oom when run ch workload
tc-tiflash-0 oom at 2025-08-02 10:44:57

4. What is your TiFlash version? (Required)

/tiflash/tiflash version
TiFlash
Release Version: v7.5.7
Edition: Community
Git Commit Hash: d187d42d81ac35238a41cde42fbfdab8433c9dec
Git Branch: HEAD
UTC Build Time: 2025-07-24 10:30:13
Enable Features: jemalloc sm4(GmSSL) avx2 avx512 unwind thinlto
Profile: RELWITHDEBINFO

Raft Proxy
Git Commit Hash: 47ebe57272ab76cc9206d2bed49712871cb479bb
Git Commit Branch: HEAD
UTC Build Time: 2025-07-24 10:45:11
Rust Version: rustc 1.67.0-nightly (96ddd32c4 2022-11-14)
Storage Engine: tiflash
Prometheus Prefix: tiflash_proxy_
Profile: release