MatrixOne-v4.2.8

Release date: November 4, 2026
MatrixOne version: v4.2.8

MatrixOne 4.2.8 is a patch release on the 4.2 line, adding query-level IVF search tuning and fixing concurrent writes, DELETE planning, transaction-local scan visibility, role grants, and FileService HTTP tracing.

Key Improvements

Vector Search

• Query-Level IVF nprobe: Override the session probe setting for individual IVFFLAT and IVFPQ queries. Defaults are unchanged; increasing nprobe can increase search cost. Invalid or unknown rank options now return errors rather than being ignored.

Key Bug Fixes

SQL and Transaction Correctness

• Concurrent ODKU Writes: Lock the actual row resolved through a secondary UNIQUE key, while retaining incoming-primary-key locking for new rows, to prevent conflicting writes from producing duplicate rows or inconsistent indexes.
• DELETE Target Scope: Validate targets against their original FROM sources and keep joined deletes on row-based execution instead of incorrectly treating them as unrestricted deletes.
• Transaction-Local Reads: Keep uncommitted persisted objects on the initiating CN during distributed scans, and preserve execution constraints when applying execType hints.
• Auto-Increment Inserts: Check actual key conflicts instead of repeatedly retrying solely because more than 64 objects changed within the cached allocation window.

Reliability and Access Control

• Concurrent Role Grants: Serialize role-graph changes and refresh validation visibility so competing grants cannot commit a role-inheritance cycle.
• FileService HTTP Tracing: Give each HTTP request its own trace lifetime and synchronize callback timing state, avoiding pooled-trace reset races.

Upgrade Notes

• The ODKU fix prevents the affected write path from introducing new inconsistencies; already-corrupt tables still require separate assessment and repair. Upgrade all SQL-serving CNs before relying on the corrected behavior.
• IVF search remains approximate. In 4.2 AUTO mode, an empty result triggers PRE fallback, but a nonempty short page does not. Query-level nprobe does not guarantee complete recall or a full result page.

What's Changed

• [4.2] fix(disttae): prevent count-only auto-increment conflict retries by @XuPeng-SH in #31799
• [4.2] fix(plan): preserve DELETE target scope by @XuPeng-SH in #31796
• [4.2] fix(disttae): retain uncommitted objects on the local scan owner by @gouhongshen in #31811
• [4.2] fix: prevent concurrent role grants from forming cycles by @jiangxinmeng1 in #31873
• [4.2] fix(plan): lock the resolved ODKU row by @LeftHandCold in #31957
• Support query-level IVF nprobe on 4.2 by @iamlinjunhong in #31754

Full Changelog: v4.2.7...v4.2.8