✔ PASS
Temporal & Time-Series
task_012_Q12_microsecond_latency_jitter
Scaled: 1M+ Records
Ordered: Yes
Inter-Packet Network Arrival Jitter at Nanosecond Resolution
Candidate Latency (1M Rows)
152.44 ms
(1.0x slower than golden)
Golden Latency (1M Rows)
145.25 ms
DuckDB in-memory engine
Underlying Data Volume
1,000,000 rows
11.4 MiB across 1 table
Evaluated Model
gemini-3.8-flash-low
Gen Latency: 11.3s
✔ Correctness Verified on 1M+ Records
Candidate SQL output matches ground truth golden query across all multiset rows and numeric tolerances (tol=1e-3). Zero data skew or anti-patterns detected on full dataset scale.
1. Analytical Significance & What It Means
Scenario & Frontier TrapBusiness Scenario & Problem
High-speed network telemetry measures packet arrival jitter (variance in inter-packet delay). Jitter spikes indicate network congestion or buffer bloat.
⚡ The Frontier Trap (Why LLMs Fail)
Standard SQL datetime arithmetic truncates to milliseconds or seconds, losing high-frequency microsecond microbursts.
Prompt / User Request Given to Model
High-speed network telemetry measures packet arrival jitter (variance in inter-packet delay). Jitter spikes indicate network congestion or buffer bloat. Execute the required analytical SQL calculation in DuckDB. Expected output columns: packet_id, captured_at, delta_microseconds, rolling_jitter_stddev. Results should be ordered as specified.
2. Underlying Tables, Row Counts & Data Volume
1 Tables (1,000,000 rows • 11.4 MiB)Production-scale fixtures loaded into the isolated DuckDB sandbox with at least 1,000,000 records per table:
📊 packet_stream
1,000,000 rows
11.4 MiB Data Volume
packet_id (INTEGER) captured_at (TIMESTAMP)Data Preview (showing sample rows from 1,000,000 total rows):
| # | packet_id | captured_at |
|---|---|---|
| 1 | 1 | 2026-03-01 12:00:00.000100 |
| 2 | 2 | 2026-03-01 12:00:00.000150 |
| 3 | 3 | 2026-03-01 12:00:00.000300 |
| 4 | 4 | 2026-03-01 12:00:00.000350 |
| 5 | 4 | 2026-03-01 09:30:00.000011 |
| 6 | 5 | 2026-03-01 09:30:00.000034 |
| 7 | 6 | 2026-03-01 09:30:00.000048 |
| 8 | 7 | 2026-03-01 09:30:00.000072 |
| 9 | 8 | 2026-03-01 09:30:00.000085 |
| 10 | 9 | 2026-03-01 09:30:00.000110 |
| 11 | 10 | 2026-03-01 09:30:00.000121 |
| 12 | 11 | 2026-03-01 09:30:00.000149 |
| 13 | 12 | 2026-03-01 09:30:00.000168 |
| 14 | 13 | 2026-03-01 09:30:00.000187 |
| 15 | 14 | 2026-03-01 09:30:00.000208 |
3. Graphical Query Execution Plan & Cost Bottlenecks
Physical Operator Tree (DuckDB 2.0 Profiler)Visual flowchart of the physical execution pipeline. Operators with high relative costs (≥ 20% of query runtime or heavy latency) are visually highlighted:
🔥 17.6% Cost
Latency: 62.45 ms
Rows In/Out: 1,000,000
Data Vol: 26.70 MB
7.9%
Latency: 28.07 ms
Rows In/Out: 1,000,000
Data Vol: 26.70 MB
📁 Projections: ['packet_id', 'capt...
0.0%
Latency: 0.14 ms
Rows In/Out: 1,000,000
Data Vol: 26.70 MB
📁 Projections: ['#0', '#1', '#2', ...
🔥 49.9% Cost
Latency: 177.12 ms
Rows In/Out: 1,000,000
Data Vol: 26.70 MB
📁 Projections: stddev(CAST(delta_m...
1.2%
Latency: 4.24 ms
Rows In/Out: 1,000,000
Data Vol: 19.07 MB
📁 Projections: ['packet_id', 'capt...
0.0%
Latency: 0.10 ms
Rows In/Out: 1,000,000
Data Vol: 19.07 MB
📁 Projections: ['#0', '#1', '#2']
🔥 23.1% Cost
Latency: 81.87 ms
Rows In/Out: 1,000,000
Data Vol: 19.07 MB
📁 Projections: lag(captured_at, 1,...
0.3%
Latency: 1.15 ms
Rows In/Out: 1,000,000
Data Vol: 11.44 MB
📁 memory.main.packet_stream
| Operator | Cost % | Latency | Processed Rows | Data Volume | Details / Table | Status |
|---|---|---|---|---|---|---|
| WINDOW | 49.9% | 177.12 ms | 1,000,000 | 26.70 MB | Projections: stddev(CAST(delta_microseconds AS D | 🔥 BOTTLENECK |
| WINDOW | 23.1% | 81.87 ms | 1,000,000 | 19.07 MB | Projections: lag(captured_at, 1, NULL::TIMESTAMP | 🔥 BOTTLENECK |
| ORDER_BY | 17.6% | 62.45 ms | 1,000,000 | 26.70 MB | - | 🔥 BOTTLENECK |
| PROJECTION | 7.9% | 28.07 ms | 1,000,000 | 26.70 MB | Projections: ['packet_id', 'captured_at', 'delta | Normal |
| PROJECTION | 1.2% | 4.24 ms | 1,000,000 | 19.07 MB | Projections: ['packet_id', 'captured_at', 'delta | Normal |
| TABLE_SCAN | 0.3% | 1.15 ms | 1,000,000 | 11.44 MB | memory.main.packet_stream | Normal |
| PROJECTION | 0.0% | 0.14 ms | 1,000,000 | 26.70 MB | Projections: ['#0', '#1', '#2', '#3'] | Normal |
| PROJECTION | 0.0% | 0.10 ms | 1,000,000 | 19.07 MB | Projections: ['#0', '#1', '#2'] | Normal |
4. Queries Executed (Candidate vs Golden Ground Truth)
Beautified & Syntax HighlightedWITH deltas AS
(SELECT packet_id,
captured_at,
date_diff('microsecond', lag(captured_at) OVER (
ORDER BY captured_at), captured_at) AS delta_microseconds
FROM packet_stream)
SELECT packet_id,
captured_at,
delta_microseconds,
round(stddev(delta_microseconds) OVER (
ORDER BY captured_at ROWS BETWEEN 2 PRECEDING AND CURRENT ROW), 2) AS rolling_jitter_stddev
FROM deltas
ORDER BY captured_at;
-- Compute inter-packet arrival delta in microseconds and identify variance
WITH deltas AS
(SELECT packet_id,
captured_at,
date_diff('microsecond', lag(captured_at) OVER (
ORDER BY captured_at), captured_at) AS delta_microseconds
FROM packet_stream)
SELECT packet_id,
captured_at,
delta_microseconds, -- Measure moving jitter variance over last 3 packets
round(stddev(delta_microseconds) OVER (
ORDER BY captured_at ROWS BETWEEN 2 PRECEDING AND CURRENT ROW), 2) AS rolling_jitter_stddev
FROM deltas
ORDER BY captured_at;
CREATE TABLE packet_stream (packet_id INT, captured_at TIMESTAMP);
INSERT INTO packet_stream
VALUES (1, '2026-03-01 12:00:00.000100'),
(2, '2026-03-01 12:00:00.000150'),
-- +50us
(3, '2026-03-01 12:00:00.000300'),
-- +150us (jitter spike)
(4, '2026-03-01 12:00:00.000350');
5. Query Results & Expected Ground Truth
Tabular Comparison
Actual Candidate Output
(1,000,000 rows × 4 cols)
| # | packet_id | captured_at | delta_microseconds | rolling_jitter_stddev |
|---|---|---|---|---|
| 1 | 4 | 2026-03-01 09:30:00.000011 | NULL | NULL |
| 2 | 5 | 2026-03-01 09:30:00.000034 | 23 | NULL |
| 3 | 6 | 2026-03-01 09:30:00.000048 | 14 | 6.36 |
| 4 | 7 | 2026-03-01 09:30:00.000072 | 24 | 5.51 |
| 5 | 8 | 2026-03-01 09:30:00.000085 | 13 | 6.08 |
| 6 | 9 | 2026-03-01 09:30:00.000110 | 25 | 6.66 |
| 7 | 10 | 2026-03-01 09:30:00.000121 | 11 | 7.57 |
| 8 | 11 | 2026-03-01 09:30:00.000149 | 28 | 9.07 |
| 9 | 12 | 2026-03-01 09:30:00.000168 | 19 | 8.5 |
| 10 | 13 | 2026-03-01 09:30:00.000187 | 19 | 5.2 |
| 11 | 14 | 2026-03-01 09:30:00.000208 | 21 | 1.15 |
| 12 | 15 | 2026-03-01 09:30:00.000235 | 27 | 4.16 |
| 13 | 16 | 2026-03-01 09:30:00.000253 | 18 | 4.58 |
| 14 | 17 | 2026-03-01 09:30:00.000261 | 8 | 9.5 |
| 15 | 18 | 2026-03-01 09:30:00.000288 | 27 | 9.5 |
| 16 | 19 | 2026-03-01 09:30:00.000305 | 17 | 9.5 |
| 17 | 20 | 2026-03-01 09:30:00.000322 | 17 | 5.77 |
| 18 | 21 | 2026-03-01 09:30:00.000345 | 23 | 3.46 |
| 19 | 22 | 2026-03-01 09:30:00.000375 | 30 | 6.51 |
| 20 | 23 | 2026-03-01 09:30:00.000380 | 5 | 12.9 |
| 21 | 24 | 2026-03-01 09:30:00.000414 | 34 | 15.72 |
| 22 | 25 | 2026-03-01 09:30:00.000425 | 11 | 15.31 |
| 23 | 26 | 2026-03-01 09:30:00.000442 | 17 | 11.93 |
| 24 | 27 | 2026-03-01 09:30:00.000462 | 20 | 4.58 |
| 25 | 28 | 2026-03-01 09:30:00.000497 | 35 | 9.64 |
Showing first 25 of 1,000,000 total rows.
Expected Golden Output
(1,000,000 rows × 4 cols)
| # | packet_id | captured_at | delta_microseconds | rolling_jitter_stddev |
|---|---|---|---|---|
| 1 | 4 | 2026-03-01 09:30:00.000011 | NULL | NULL |
| 2 | 5 | 2026-03-01 09:30:00.000034 | 23 | NULL |
| 3 | 6 | 2026-03-01 09:30:00.000048 | 14 | 6.36 |
| 4 | 7 | 2026-03-01 09:30:00.000072 | 24 | 5.51 |
| 5 | 8 | 2026-03-01 09:30:00.000085 | 13 | 6.08 |
| 6 | 9 | 2026-03-01 09:30:00.000110 | 25 | 6.66 |
| 7 | 10 | 2026-03-01 09:30:00.000121 | 11 | 7.57 |
| 8 | 11 | 2026-03-01 09:30:00.000149 | 28 | 9.07 |
| 9 | 12 | 2026-03-01 09:30:00.000168 | 19 | 8.5 |
| 10 | 13 | 2026-03-01 09:30:00.000187 | 19 | 5.2 |
| 11 | 14 | 2026-03-01 09:30:00.000208 | 21 | 1.15 |
| 12 | 15 | 2026-03-01 09:30:00.000235 | 27 | 4.16 |
| 13 | 16 | 2026-03-01 09:30:00.000253 | 18 | 4.58 |
| 14 | 17 | 2026-03-01 09:30:00.000261 | 8 | 9.5 |
| 15 | 18 | 2026-03-01 09:30:00.000288 | 27 | 9.5 |
| 16 | 19 | 2026-03-01 09:30:00.000305 | 17 | 9.5 |
| 17 | 20 | 2026-03-01 09:30:00.000322 | 17 | 5.77 |
| 18 | 21 | 2026-03-01 09:30:00.000345 | 23 | 3.46 |
| 19 | 22 | 2026-03-01 09:30:00.000375 | 30 | 6.51 |
| 20 | 23 | 2026-03-01 09:30:00.000380 | 5 | 12.9 |
| 21 | 24 | 2026-03-01 09:30:00.000414 | 34 | 15.72 |
| 22 | 25 | 2026-03-01 09:30:00.000425 | 11 | 15.31 |
| 23 | 26 | 2026-03-01 09:30:00.000442 | 17 | 11.93 |
| 24 | 27 | 2026-03-01 09:30:00.000462 | 20 | 4.58 |
| 25 | 28 | 2026-03-01 09:30:00.000497 | 35 | 9.64 |
Showing first 25 of 1,000,000 total rows.