TiKV

v8.5.7Storage & Data

Jul 9, 2026Copy link

TiKV/TiDB v8.5.7 is a mixed release combining several default/behavior changes operators must review (stricter max_ts and NOT NULL validation, auto IndexMerge, TiDB Lightning web UI removal, resource-control metric relabeling) with a security-relevant dependency upgrade and a broad set of new features, performance work, and bug fixes.

• breakingmax_ts invalid-update handling now errors by default

  TiKV now rejects max_ts updates confirmed invalid instead of only logging them. If you rely on the previous log-only behavior, set storage.max-ts.action-on-invalid-update to log before upgrading.

• breakingFix control 52869 (auto IndexMerge) enabled by default

  TiDB now enables optimizer fix control 52869 by default, letting the optimizer consider IndexMerge automatically when alternative indexes exist. This can change query plans in some cases; review plans for sensitive queries after upgrade.

• breakingStrict NOT NULL validation on INSERT enabled by default

  tidb_enable_strict_not_null_check now defaults to ON, enforcing strict validation when an INSERT explicitly writes NULL into a NOT NULL column. Statements that previously succeeded may now fail; audit INSERT paths that rely on lenient NULL handling.

• breakingResource-control background metrics lose resource_group label

  TiKV background resource-control metrics are now aggregated globally via a single rate limiter, dropping the per resource_group label. Update dashboards and alerting rules that filter or group by resource_group for background metrics.

• breakingTiDB Lightning web interface removed

  TiDB Lightning drops its web interface starting in v8.5.7. Switch to the command-line tools tidb-lightning for import tasks and tidb-lightning-ctl for checkpoint and troubleshooting operations.

• securityVulnerable TiKV third-party dependencies patched

  This release upgrades vulnerable third-party dependencies used by TiKV 8.5 and aligns required compatibility fixes with upstream, improving stability and security. Upgrade to pick up the patched dependencies.