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TDengine 3.4.2.8 Release Notes

Release Date: 2026-08-30

Features​

  1. taosExplorer supports viewing stream runtime metrics (latency, input/output rates, history progress, failure reasons) and recalculation records on the stream page.
  2. TDinsightV3 adds stream computing observability panels with predefined stream-failure and recalculation-failure alerts routable via notification policies such as DingTalk (requires TDengine 3.4.2.7+).
  3. Stream computing supports nested window triggers, allowing multi-layer WINDOW combinations with outer-layer context variables for inner-window computation.
  4. Support batch DROP VTABLE for multiple virtual normal/child tables, including cross-database.
  5. Support creating multiple virtual child tables in a single CREATE VTABLE statement.
  6. Support owned tag columns on virtual normal tables and normal tables via CREATE/ALTER, with SHOW CREATE, SHOW TAGS, and ins_tags.

Enhancements​

  1. taosX TMQ sync tasks retry subscribe with a bounded budget during consumer rebuild, reducing whole-task failures after short source-side restarts.
  2. taosX improves CSV import configurability and throughput for directories with hundreds of thousands of files, avoiding parse/create timeouts and file-count-driven slowdowns.
  3. taosX-Agent reliable write ACK introduces protocol and UUID v7 identity foundation (legacy write path unchanged; Kafka offset behavior unchanged).
  4. Improve stream computing manual recalculation reliability so failures no longer stop the whole stream, unfinished requests persist across restarts, and system views expose error details.
  5. Report stream failure metrics to taosKeeper when a stream first stops on error.
  6. Data subscription TMQ sends a supplemental heartbeat from the poll thread when the timer path is silent for more than two heartbeat intervals, reducing false consumer offline detections.
  7. Improve query PARTITION BY group buffering and spill to reduce frequent disk I/O when many small groups exceed memory pages.
  8. ALTER DATABASE supports changing MAXROWS dynamically; COMPACT FORCE can rewrite existing filesets with the new block sizing.
  9. Support round-robin placement of new WAL segments across level-0 mount points to eliminate single-disk WAL IO bottlenecks.
  10. Add FLUSH MNODE and taosd -fMnode, and enhance sdb JSON export/import for offline edits of global parameters and other metadata in failure scenarios.

Fixes​

  1. taosExplorer normal-table edit page not displaying fields because the column list was not loaded correctly.
  2. taosExplorer normal-table details misplacing composite primary key fields as tags and incorrectly showing stable and tag sections.
  3. taosExplorer data ingestion mapping preview showing wrong subtable name when a template column casts to NULL, dropping literal prefix/suffix.
  4. taosExplorer restore from a selected backup point failing due to a missing task name or incorrectly encoded DSN parameters.
  5. taosExplorer CORS policy being too strict, causing HTTP preflight failures and WebSocket handshake rejections when accessed from different origins such as IDMP.
  6. taosX MySQL datasource tasks not resuming from breakpoints after stop/start and restarting from the configured start time.
  7. taosX OPC UA point-selection mode incorrectly truncating node ids that contain :: or ,, causing some points to collect no data.
  8. taosX MySQL live sync subtracting delay from both window start and end, causing overlapping query windows and duplicate writes.
  9. taosX MySQL source no longer issues oversized queries beyond the configured interval during sample preview and historical sync.
  10. taosX backup tasks hanging indefinitely during completion checks when querying offset positions for non-owned vgroups.
  11. taosX hardens Kafka consumption and downstream write reliability (timeout/IPC) and adds connection-pool/connector observability to help diagnose consumption interruptions.
  12. taosdump ext-meta-only restore did not create all databases before applying stream/topic DDL, causing intermittent failures when cross-database dependencies were involved.
  13. Rust WebSocket connector did not clean up pending channel requests when closing a connection, leaving resources unreleased.
  14. XNode task parser stored length using the pre-unescape SQL token size, leaving trailing NUL bytes that caused JSON parse failures and task load errors after upgrade.
  15. XNode tasks could not be deleted or updated by root or authorized users after the creator user was deleted, failing with invalid user.
  16. STMT2/WebSocket queries with tbname = ? or tbname IN (?) reading the placeholder instead of the bound table name, routing to the wrong vgroup and returning empty results.
  17. STMT2 inserts failing with table-not-exist after a stable is dropped and recreated under the same name, because the cached suid was not refreshed.
  18. STMT2 DECIMAL parameter binding wrongly applying another column's precision/scale when some columns are skipped or column IDs are non-contiguous, causing Decimal value overflow.
  19. Stream computing with nodelay_create_subtable creating group result subtables that appear in information_schema / SHOW TABLES but fail SELECT with table does not exist.
  20. Stream computing external-window result-block reuse could omit capacity growth for larger batches, causing out-of-bounds writes and taosd crashes.
  21. Stream computing manual recalculation (RECALCULATE STREAM) shrinking the user-specified FROM/TO range by runtime boundaries, causing some data to be skipped.
  22. Stream computing reader tasks transiently missing during cluster balance, triggering task failure and leaving stream computing abnormal.
  23. Data subscription WebSocket TMQ client deserialization failures on error responses that could hang or fail requests.
  24. Virtual super table queries intermittently returning Invalid parameters (0x118) when references change after query planning.
  25. Virtual super table queries could intermittently fail with No valid epSet when retry did not refresh stale source-database metadata after VGroup route changes.
  26. Query regexp_in_set producing incorrect results when using an NCHAR column as the delimiter or when an empty NCHAR string is passed.
  27. Query INTERP statements via views or prepared statements incorrectly reporting a function conflict error (0x80002680).
  28. Query RESTful TO_CHAR and other timezone-sensitive functions incorrectly parsing ISO8601 offsets such as +0800 as POSIX, causing incorrect timezone results.
  29. Query LEASTSQUARES across multiple vgroups producing unstable slope and intercept due to non-deterministic data consumption order.
  30. Timezone errors showing the literal Invalid timezone: '%s', and system failures such as too many open files being misreported as an invalid timezone.
  31. Timezone settings no longer reject unsigned POSIX offsets such as UTC0 and UTC8.
  32. Offline replicas not applying leader KEEP configuration after snapshot recovery, causing retention policy mismatch and failure to trim expired data.
  33. SHOW TRANSACTIONS with in-flight transactions could overflow the oper column buffer and crash taosd.
  34. SHOW DISK_INFO or SHOW TABLE DISTRIBUTED could crash taosd when database minRows equals maxRows.

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