Chapter 250: Pressure and Thresholds

The weightless sensation as the elevator descended was faint, but Lin Chen’s left foot still tensed on instinct. The metal doors opened on the second basement level, and a dry cold wind rushed at him, carrying the smell of ozone and dustproof paint. At the end of the corridor, the machine room indicator lights glowed a dim blue, like some kind of silent breathing.

He walked very slowly. His right leg bore his weight; the toes of his left foot barely touched the floor. Each bend of the knee sent a dull ache through the seams of the bone. Bracing himself against the wall, he edged over to the folding chair in front of the monitoring terminal and sat down. He propped his left foot on a cardboard box beside him, adjusted his posture, and spread the load away from his lumbar spine. The screen lit up. The log window began to scroll.

Ten-thirty sharp. The glass door of the machine room was pushed open. Two men in dark jackets came in, carrying laptops and testing terminals. The older man in front had graying temples and very level eyes. He skipped the pleasantries, set his work badge on the desk, and nodded. Lin Chen nodded back and handed over the portable hard drive.

“The test network segment has been isolated. The scripts are deployed in Docker containers, and logs are synchronized to the intranet monitoring system in real time.” Lin Chen’s voice was low, his pace steady. “You bring your own stress-testing tools. We’re only responsible for watching the metrics.”

The older man took the hard drive and plugged it in. “Understood. We’ll follow Level 3 classified protection standards. Baseline first, then dirty-data injection, and concurrent pressure last. No intervention midway unless the system crashes.”

“Good.”

The sound of typing began. The test started.

The first ten minutes were a routine scan: port probing, protocol handshakes, basic SQL-injection probes. The curves on the monitoring panel rose steadily. CPU usage held at around 35 percent, and memory fluctuated between 1.2 and 1.4 GB. Average response time was 118 ms. Everything was within expectations.

Lin Chen stared at the screen, his fingers tapping unconsciously on his knee. The muscles in his left calf began to tighten, as if a thin wire were being slowly pulled beneath his skin. He picked up his thermos, unscrewed it, and pressed the cup wall against the cramping gastrocnemius. The chill of the metal made the muscle loosen slightly. He did not move. His eyes never left the logs.

Eleven-oh-five. The older man switched test scripts. The request rate on the screen suddenly accelerated. Dirty-data injection began.

Large volumes of malformed strings, truncated ID numbers, and field names mixed with full-width symbols were batch-submitted into the API endpoints. The pre-validation module activated instantly. Regular expressions filtered line by line; exception-capture logs began flooding the screen. Memory usage jumped to 1.7 GB. Response time climbed to 132 ms.

“What’s the collision rate?” the man asked.

“0.0008 percent.” Lin Chen pulled up the hash distribution chart. “The salt is dispersing normally. No duplicate mappings.”

The man stared at the chart for a few seconds without speaking, his fingers moving faster over the keyboard. He bypassed conventional injection and launched fuzz testing directly against the secondary salt logic that concatenated timestamps and random numbers. An extremely long malformed string caught on the regular-expression boundary, and a buffer-overflow warning flashed once in the pre-validation module.

Lin Chen’s pupils tightened slightly. He immediately switched to the terminal, entered a command, restarted the pre-validation subprocess, and temporarily raised the container’s memory ceiling. Thirty seconds. The warning disappeared. The logs returned to stability. Response time: 138 ms.

“The boundary condition wasn’t hardcoded,” the man said, looking up at him.

“It was. But nonstandard control characters were mixed into the raw data, and the regex engine used an extra frame while parsing them.” Lin Chen’s voice remained even. “It’s hot-fixed. The next version will switch to a state-machine parser.”

The man nodded and asked no further questions. The test continued.

Eleven-forty. The concurrency stress test began. It simulated peak outpatient traffic, with requests doubling every second. The memory curve shot upward, and the frequency of GC—garbage collection—increased. Response time pushed toward 145 ms. The hum of the fans grew louder in the machine room. Lin Chen had completely lost feeling in his left foot; all that remained was a hollow, wave-like ache deep inside his knee. He clenched his back teeth, shifted his weight to the right, and typed quickly to adjust the rate-limiting parameters, tuning the token-bucket algorithm on the API gateway.

148 ms.

It stopped there.

The curve rose no further. The system held.

“Stop.” The man pressed the termination key. Only the low, steady operation of the servers remained in the machine room.

He closed his laptop, pulled a paper report from his bag, signed it, and pushed it over. “The logic is clean. The pre-validation layer withstood the dirty-data impact. The hash distribution meets national cryptography standards. You passed.” He paused. “But during peak concurrency, the GC pauses are on the long side. If production traffic doubles again, I recommend adding an asynchronous queue, or moving desensitization logic down to the gateway layer.”

“We’re already doing it.” Lin Chen took the report. “Next week’s iteration.”

The man packed up and left. The glass door closed. The machine room fell quiet again.

Lin Chen leaned back in the chair and closed his eyes. His breathing was slow. Pain in his left foot woke again at the nerve endings, rising like a tide. He sat for two minutes before slowly standing. He put the hard drive back into his backpack and walked out of the machine room.

The sound-activated lights in the corridor lit one by one with his footsteps. The light was stark white. When the elevator doors closed, he leaned against the wall of the car and pressed his thumb to his temple.

When he returned to the office, Su Man was checking logs across two monitors. She glanced up at him. Without asking about the result, she pushed over a printed performance-analysis report. “The memory leak is traced. A third-party library wasn’t releasing handles. The patch is already applied.”

Lin Chen sat down and opened the report. The data was clear and the conclusion precise. He picked up a pen and signed at the end.

His phone vibrated. Two messages.

Director Li from the hospital information department: Pilot qualification retained. Next Monday we sign the formal data-access agreement.

Zhao Qiming: TS sent. Wager terms slightly adjusted. Tomorrow night, eight o’clock, Guomao café. Bring the full financial model.

Lin Chen opened the attachment. The valuation was ten percent lower than expected. The liquidation-preference clause was written hard. He saved the file and opened a new Excel spreadsheet. He began building a cash-flow forecast: R&D costs, server rental, compliance audits, staffing expenses. The numbers jumped in the cells like a silent countdown.

He had reached the third row when the screen of his personal phone lit up.

His mother had sent a photo. Xiaoman sat on the threshold of the main room, an old picture book spread across his knees. It showed stars, but the lines were messy and the colors spilled past the edges. Beneath the photo was a line of text: Xiaoman had a fever last night and said his leg hurt. The village doctor looked at him and said we should go to the county hospital for an X-ray. You’re busy, so I’ll take him first.

Lin Chen’s fingers stopped on the keyboard. The cursor blinked inside the cell. The cold light of the screen reflected on his face, deepening the dark shadows under his eyes. He picked up the phone and dialed.

A long ring tone came through the receiver. Once. Twice. Three times.