Environment

• TDengine Version: 3.4.0.0.community
• Client: Native taos CLI
• OS: Linux (Docker container)
• Deployment: Single node
• Database charset: default
• Table type: Super table with multiple sub tables

Problem Description

When executing a query using:

• PARTITION BY tbname
• INTERVAL(4d)
• FILL(NULL)

TDengine crashes with Segmentation fault (signal 11) and the client receives:

DB error: Unable to establish connection [0x8000000B]

The crash is reproducible and only happens when the interval is 4d or larger.
Intervals like 1d, 2d, 3d work correctly and return valid results.

Reproduce Steps

1. Connect

taos
use jet_tsdb_tdengine_dev;

2. Query works fine (INTERVAL 1d)

SELECT _wstart, _wend, meter_id, AVG(pa) AS pa
FROM power_meter_raw
WHERE ts >= '2026-01-05 00:00:00'
  AND ts <  '2026-01-17 00:00:00'
  AND tenant_id = 'JET'
  AND project_id = 'HHDJ'
  AND meter_id IN ('ConnectionCabinet2','ConnectionCabinet112')
PARTITION BY tbname
INTERVAL(1d)
FILL(NULL);

✅ Returns correct results.

3. Query works fine (INTERVAL 2d)

INTERVAL(2d)

✅ Returns correct results.

4. Query works fine (INTERVAL 3d)

INTERVAL(3d)

✅ Returns correct results.

5. Query crashes server (INTERVAL 4d)

SELECT _wstart, _wend, meter_id, AVG(pa) AS pa
FROM power_meter_raw
WHERE ts >= '2026-01-05 00:00:00'
  AND ts <  '2026-01-17 00:00:00'
  AND tenant_id = 'JET'
  AND project_id = 'HHDJ'
  AND meter_id IN ('ConnectionCabinet2','ConnectionCabinet112')
PARTITION BY tbname
INTERVAL(4d)
FILL(NULL);

❌ Result:

Client:

DB error: Unable to establish connection [0x8000000B]

Server log:

FATAL crash signal is 11
Segmentation fault (core dumped) taosd

After crash, all adapters report connection failures until taosd restarts.

Expected Behavior

The query should either:

• Return correct aggregated results, or
• Return a proper error message

It should not crash the taosd process.