TDengine 3.4.2.5 Release Notes

Release Date: 2026-08-17

Features

1. Add stream observability metrics via information_schema system views for realtime lag, throughput, history fill, and recalculation progress.
2. Optimize wiki MCP search tool and add ask-teddy skill.
3. Support federated stream queries over external sources including InfluxDB, with trigger modes, stream options, and SHOW observability fields.
4. Support start, stop, and recalculate stream actions on the taosExplorer stream page without writing SQL manually.

Enhancements

1. Add configuration parameters numOfStreamRunnerDeploys and numOfStreamRunnerReplicas to tune stream runner deployments and replicas.
2. Add user_app parameter to the Python WebSocket connector for application name identification.
3. Add zstd-compressed message parsing support to taosX Kafka ingestion.
4. Allow stream queries with outer derived-table filters to keep using external window and reduce INTERVAL resource usage.
5. Explorer support for configuring allowedOrigins so cross-origin HTTP/WebSocket clients (such as IDMP data-in) can connect with session authentication.
6. Improve data consumption capability of taosX Kafka Connector.
7. Improve last() query performance over large time ranges by skipping all-NULL data blocks via internal non-null prefiltering.
8. Improve step bar scroll tracking and step navigation on the taosExplorer data subscription sample-code page.
9. Improve taosX incremental backup/restore to support restoring from any backup point via schema snapshots, and add schema restore for virtual tables and stream tasks.
10. Raise XNODE TASK parser and JOB config size limits to 960 KiB and 1 MiB so taosX can create large import tasks with 400+ fields.
11. taosdump adds -M/--content (basic/ext-meta/all) so backup and restore can select content; default is basic only, with phased ext-meta restore to avoid cross-database virtual-table dependency failures.
12. taosdump now writes backup.log / restore.log during backup and restore to record version, parameters, and full SQL details.
13. taosgen supports TIMESTAMP as a regular measurement column and converting time strings to timestamps.
14. WebSocket STMT2 frees the associated query result set on close, aligning with native STMT2 behavior.

Fixes

1. Backup/ETL tasks could still be assigned to a dropped xnode and fail after DROP XNODE.
2. Client abort when a server response arrives while the connection is closing.
3. Downgrade false IDX ERROR logs to debug when a filter is not suitable for the tag index path.
4. Explorer OPC CSV upload failing after /upload response format change, which left the config file path empty and caused validation errors.
5. Explorer PI/OPC configuration page spelling and label-style issues that could make path filter settings display incorrectly.
6. Explorer Slow SQL pagination errors causing memory spikes, empty data after changing page size, and permanently disabled buttons after query failures.
7. Explorer backup task creation allowing duplicate tasks when users repeatedly click save during UI timeouts.
8. Explorer data ingestion task activity panel missing failure reasons and error/warn messages, and missing activity records for some transform errors.
9. Explorer license page incorrectly displaying IDMP-related grants and status.
10. External-window stream result-block reuse could omit capacity growth for larger batches, causing out-of-bounds writes and taosd crashes.
11. First-time taosX TMQ backup task creation timing out due to circular wait when validation created topics.
12. INTERVAL queries failing with Executor internal error when logical Scan clone omitted timezone day-boundary fields.
13. Incomplete default metadata (e.g. root/cluster/mnode) after an interrupted single-node first deploy causing Invalid user on connect; auto-heal missing objects on startup.
14. Inconsistent TIMETRUNCATE day/week truncation between implicit session timezone and explicit fixed offsets (e.g. +0800) on scalar paths used by joins and subqueries.
15. Inconsistent last/last_row results for overlapping INTERVAL+SLIDING windows between direct and subquery paths, and unstable multi-week sliding-window phase alignment.
16. Inconsistent machine codes from taosd -k under root between 3.4.1.0 and 3.4.2.3 compared with earlier versions.
17. Incorrect imputation results caused by not resetting the result write start position after writing timestamps.
18. Incorrect timezone conversion on Windows for TIMETRUNCATE and related functions caused by ISO vs POSIX UTC-offset sign mismatch.
19. InfluxDB 1.x high-cardinality sync that could miss source data and leave TDengine inconsistent, with improved import options and reliability checks.
20. InfluxDB sync task spending excessive startup time by loading full bucket metadata even when only a few measurements are selected.
21. Kafka sync tasks stopping with table-not-exist after a cached child table was deleted when SQL tag cache was enabled.
22. Memory leak from unreleased nested arrays in SStatusReq during status heartbeat handling.
23. Multi-replica mnode upgrades from 3.3 to 3.4.2.0–3.4.2.4 could skip role upgrade and lose default system roles and user privileges.
24. Non-root users got Permission denied on auto-create inserts right after CREATE DATABASE because the client auth cache was not refreshed until the next heartbeat.
25. Notification-only streams with MAX_DELAY crashing on null calc request when WAL returns no data.
26. OPC collection task panicking and failing to start normally when the connection drops while problematic nodes are present.
27. PI Connector task restart loop and silent data loss caused by over-long column names.
28. Python native connector process crash caused by not retaining asynchronous query callbacks.
29. Queries failing when multiple MAVG, STATECOUNT, or STATEDURATION functions are used with ts or ordinary columns in the same SQL.
30. Query performance regression after RPC CRC was introduced in 3.4.2 by enabling hardware CRC on x86 clients and adding the rpcCrcEnable configuration option.
31. Reject taosdump resume (-C) when -F differs from the previous backup format, which previously mixed formats in one directory and broke restore.
32. SHOW CREATE TABLE failing with Unexpected generic error on existing child tables after DROP TAG and ADD TAG on a stable.
33. SHOW SUBSCRIPTIONS process crash caused by underestimating result-block capacity during vnode restore.
34. STMT2 crashing on close due to double-free of shared tableCols in interlace mode.
35. STMT2 multi-table bind/submit failures and taosdump restore data loss when alternating large and small tables.
36. STMT2 query binding lost session timezone context, causing incorrect timezone results from time functions such as to_char.
37. STMT2/WebSocket auto-create inserts failing with table-not-exist when a child table is dropped between bind and exec, without rebuilding from bound tags.
38. Snapshot rate limiting dropping to zero and delivering below the configured speed after hitting the limit.
39. Stmt2 auto-create-table writes were much slower than pre-created tables due to repeated tag parsing.
40. Stream FILL_HISTORY with PARTITION BY failing with Internal error when some child tables have no data after the history start point, preventing historical results from being generated.
41. Stream WebSocket notification frames over 1 MiB causing remote receivers to reject them.
42. Stream computation crashing nodes due to out-of-bounds writes when filling WAL metadata beyond the indexed row capacity.
43. Stream create-only requests for nodelay_create_subtable with no real windows no longer enter the executor with placeholder windows, preventing Invalid parameters on virtual table scans and empty output subtables.
44. Stream processing auto-created table data with invalid timestamps expanding the compute range and driving high CPU.
45. TIMETRUNCATE fixed-offset parsing so scalar and join paths accept supported offset forms and apply POSIX sign semantics consistently.
46. taosAdapter crashing due to incorrect normal-table metadata handling when TMQ syncs stream-created tables.
47. taosBenchmark mixed_query mode did not apply per-SQL result paths, so query results were not written to the configured files.
48. taosExplorer S3 backup tasks failing when canceling the S3 dumper incorrectly canceled the whole task.
49. taosX TMQ WebSocket transfers disconnecting about every two minutes under sustained large-data fetch because heartbeats failed to refresh the taosAdapter read timeout.
50. taosX backup failing to handle table names that contain special characters.
51. taosX backup to Aliyun OSS failing under path-style access; add configurable S3 URI style (path/virtualhost).
52. taosX periodic backup not stopping on schedule because interval parameters were not applied, causing continuous backup growth.
53. taosX sync treating recoverable target-side failures (such as taosd downtime) as fatal, causing the process to exit and preventing sync from resuming after the target recovers.
54. taosX table-specific backup spending too long on pre-check and aborting the whole job when a single table fails.
55. taosX taos-to-taos sync failing to migrate virtual child tables.
56. taosX task-level backup cross-cluster restore succeeding without restoring data due to unrecognized -1 job subdirectory.
57. taosd crash on DROP DATABASE when shared storage is enabled without a default access string.
58. taosdump failing with Invalid column name when backing up tables whose primary time column is not named ts.
59. taosdump treating server unavailability during backup as end-of-data, causing incomplete backups, and improve retries for transient outages.
60. taoskeeper failing to start after Windows All-in-One installation.
61. Temporarily reject aggregate DISTINCT in windows other than INTERVAL at parse time.
62. to_timestamp randomly reported format mismatch for valid dates when a stale thread-local errno ERANGE remained from prior conversions.
63. VGroup incorrectly marked offline before a valid heartbeat last-seen time is available.
64. Virtual child SELECT TAGS incorrectly expanding results by source data rows, and EXPLAIN SELECT TAGS crashing due to null scan-column list dereference.
65. Virtual-table SELECT TAGS failed with Planner slot key not found after ALTER TAG because positional matching used a stale tagRef array.
66. Windows taos client intermittent hang on connection close caused by a libuv race.
67. Windows taosdump crashing on older CPUs without BMI2 because Snappy was built with those instructions; also name crash dump files after the crashing module instead of always using the taosd prefix.
68. XNODE CSV data ingest task creation failing with the default quote character.
69. XNODE showing offline when created with 127.0.0.1 because taosX default listen accepted only IPv6 on some platforms.

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