# Postmortem: Inability to Access SSL Certificate Attributes in Dart http ## During a routine API call using Dart’s `http` package, an engineer attempted to read the SSL certificate attributes (subject, issuer, serial number) of the server after a successful HTTPS request. The operation failed because the `http` package does not expose this information through … Read more
# Production Postmortem: Unreleased WebSocket Connections Preventing Garbage ## A JavaScript WebSocket implementation was leaking connections because new connections were created without closing existing ones. Overwriting the reference to the old connection did not automatically trigger garbage collection or socket cleanup, leading to resource exhaustion. ## Root – The `ws` variable was reassigned to a … Read more
Unexpected MySQL Boolean Full-Text Search behavior where tilde ~ operator boosts relevance scores instead of demoting Observed in MySQL 8.0.40 when using MATCH() AGAINST(… IN BOOLEAN MODE) with ~term Contradicts official MySQL documentation stating ~ should decrease relevance Root Term demotion via ~ doesn’t function as pure subtraction in relevance Relevance scores are composites of: … Read more
## Python scripts failing with `ModuleNotFoundError: No module named ‘requests’` despite successful installation via `pip`. The core issue is **environment mismatch**: the Python interpreter used at runtime differs from the one associated with the `pip` that installed the package. Common triggers include multiple Python installations and IDE misconfiguration. ## Root – **Interpreter-`pip` misalignment**: Commands run … Read more
# Preventing Overheating When Using Pathway Library in ## Experiencing laptop shutdowns during Pathway library execution in VS Code due to overheating caused by uncontrolled resource consumption during data processing pipelines. ## Root – Pathway’s default execution settings aggressively utilize all available CPU – Memory-intensive operations exceed local machine – Lack of resource constraints leads … Read more
# Postmortem: Broken Product Model Search Functionality in ## When users clicked a product’s model number on the OpenCart product page, it failed to perform a search or display results. The existing code (“{{ text_model }} {{ model }}“) only displayed plain text without interactive functionality. ## Root – The template rendered static text instead … Read more
# Postmortem: Serial Data Corruption in Windows API Read ## A C++ application using Windows API for serial communication experienced intermittent data corruption when reading from an Arduino device. Data was clean only when Arduino’s transmission delay was excessively high (1000ms), making real-time control impractical. ## Root Mismatched serial configuration between Arduino and C++ application: … Read more
# Postmortem: Biased Model Training with EEG Signals ## Persistent model bias observed during training on EEG dataset for wheelchair navigation commands: – Models consistently best identified `stop/neutral` → moderately performed on `forward/left` → consistently failed on `right` – Observed across MATLAB Classification Learner models and custom – Best outcomes: ~50% accuracy for problematic classes … Read more
# The Cache Miss Illusion: When Out-of-Order Execution Masks Real ## We investigated the misconception that cache misses consistently cause severe pipeline stalls in out-of-order (OOO) CPUs. While cache misses do incur latency, OOO execution often hides this cost by continuing unrelated work—misleading profiling tools and engineers into misidentifying optimization targets. ## Root – **Misinterpretation … Read more
# Postmortem: Performance Bottleneck in Repeated Python Function Calls from ## A performance-critical data processing pipeline experienced significant slowdowns when integrating Python-calculated variables into an R dataframe using reticulate and dplyr. The implementation repeatedly called the same Python function 7 times per group to extract individual output elements, leading to unnecessary computation. ## Root – … Read more