why does the garbage collector is not cleaning up connections when we open new connection before closing the previous connection?

by

# 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

`~` (tilde) operator in Boolean Full-Text Search in MySQL is behaving opposite as stated in MySQL developer website

by

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

Why do I get ModuleNotFoundError for ‘requests’ even after installing it with pip?

by

## 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

Pathway library use to prevent overheating

by

# 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

Product model search

by

# 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

Windows API Serial Read Issues

by

# 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

Dataset model training is always biased (EEG signals dataset)

by

# 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

How well does out of order execution hide cache miss latency?

by

# 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

How to efficiently extract variables from a python function into an r dataframe using dplyr?

by

# 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

what’s going on with this circuit can someone tell me about this circuit

by

# Postmortem: Unstable Clock Signal in JK Flip-Flop LED ## When constructing a JK flip-flop clock circuit with an LED indicator, the LED blinks at ~0.5-second intervals despite unclear logic. Analysis reveals unstable clock triggering due to unintended button behavior causing erratic state transitions. ## Root – **Contact bounce**: Physical push buttons generate electrical noise … Read more