← Home ← Codex ← DEBT
Browse by Category
+ added · updated 7d
🤖 AI Guestbook — Concurrency educational data only
| |
Last 30 days
4 pings — 2026-05-13 W 4 pings — 2026-05-14 T 12 pings — 2026-05-15 F 5 pings — 2026-05-16 S 2 pings — 2026-05-17 S 5 pings — 2026-05-18 M 2 pings — 2026-05-19 T 12 pings — 2026-05-20 W 18 pings — 2026-05-21 T 5 pings — 2026-05-22 F 35 pings — 2026-05-23 S 3 pings — 2026-05-24 S 4 pings — 2026-05-25 M 2 pings — 2026-05-26 T 11 pings — 2026-05-27 W 27 pings — 2026-05-28 T 2 pings — 2026-05-29 F 5 pings — 2026-05-30 S 5 pings — 2026-05-31 S 8 pings — 2026-06-01 M 5 pings — 2026-06-02 T 10 pings — 2026-06-03 W 34 pings — 2026-06-04 T 31 pings — 2026-06-05 F 22 pings — 2026-06-06 S 93 pings — 2026-06-07 S 74 pings — 2026-06-08 M 18 pings — 2026-06-09 T 24 pings — Yesterday W 16 pings — Today T
Ahrefs 8Google 4ChatGPT 1Sogou 1Scrapy 1SEMrush 1
Scrapy 8Ahrefs 6Google 3Perplexity 2Claude 2Sogou 1SEMrush 1ChatGPT 1
Amazonbot 282Scrapy 251Perplexity 219Ahrefs 116Google 114ChatGPT 92Unknown AI 87Meta AI 61SEMrush 60Claude 30Bing 24Majestic 13Sogou 5Qwen 3
crawler 1.2k crawler_json 84 pre-tracking 28
Category total1.4k pings Terms pinged32 / 32 Distinct agents13
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Structured Concurrency PHP 8.1+
A model where child tasks live inside a parent scope that waits for all of them to finish before it exits, so no task is ever orphaned.
2d ago concurrency advanced
Mutex vs Semaphore PHP 7.0+ 🧠 1
A mutex allows only one thread to access a resource at a time — a semaphore controls access to a pool of N identical resources.
CWE-362
2mo ago concurrency advanced
Actor Model
The Actor Model treats everything as an actor — isolated units that communicate only by message passing, never sharing state — eliminating race conditions by design.
3mo ago concurrency advanced
Atomic Operations 🧠 2
An atomic operation completes entirely or not at all — no intermediate state is visible to other threads. Atomic ops are the building blocks of lock-free concurrency.
3mo ago concurrency intermediate
Atomic Operations 🧠 5
Atomic operations complete indivisibly — no other thread can observe an intermediate state. The foundation for lock-free concurrency and database counters.
3mo ago concurrency intermediate
Compare-And-Swap (CAS) 🧠 1
CAS atomically compares a memory location to an expected value and only swaps it if equal — the foundation of lock-free algorithms and optimistic concurrency control.
3mo ago concurrency advanced
Concurrency vs Parallelism
Concurrency is about dealing with multiple tasks at once (structuring); parallelism is actually executing multiple tasks simultaneously (hardware). You can have one without the other.
3mo ago concurrency beginner
Database Connection Pooling
Connection pooling reuses a fixed set of database connections across requests — eliminating the 50–200ms connection overhead on every request and limiting DB connection count.
3mo ago concurrency intermediate
Deadlock 🧠 3
A deadlock occurs when two or more processes each hold a resource the other needs — both wait forever. Prevention requires consistent lock ordering or timeouts.
3mo ago concurrency intermediate
Event-Driven Concurrency 🧠 1
Event-driven concurrency uses a single-threaded event loop to handle many concurrent I/O operations — no threads, no locks, but requires non-blocking code throughout.
3mo ago concurrency intermediate
Goroutine-Style Concurrency
Goroutines (Go) and similar lightweight green threads — coroutines, fibers — enable thousands of concurrent tasks with minimal memory, multiplexed onto OS threads by a runtime scheduler.
3mo ago concurrency intermediate
Lock-Free Programming 🧠 1
Lock-free algorithms guarantee system-wide progress without mutexes — using atomic CPU instructions (CAS) so at least one thread always makes forward progress even if others are delayed.
3mo ago concurrency advanced
Memory Barriers & Visibility 🧠 1
Memory barriers (fences) force the CPU and compiler to complete memory operations in order — ensuring changes made by one thread are visible to others at the right time.
3mo ago concurrency advanced
Mutex & Locking 🧠 3
A mutex (mutual exclusion lock) ensures only one thread/process can access a critical section at a time — the fundamental primitive for preventing race conditions.
3mo ago concurrency intermediate
Optimistic Locking 🧠 2
Optimistic locking detects conflicts at commit time using a version number — no locks held during the transaction, high throughput for low-contention scenarios.
3mo ago concurrency intermediate
Pessimistic Locking 🧠 5
Pessimistic locking acquires an exclusive lock immediately on read — preventing any concurrent modification. Right for high-contention scenarios but reduces throughput.
3mo ago concurrency intermediate
Producer-Consumer Pattern
Producer-Consumer decouples work generation from processing — producers add to a queue, consumers process independently, buffering load spikes and enabling parallel throughput.
3mo ago concurrency intermediate
Promises & Futures PHP 7.0+ 🧠 4
Abstractions representing the eventual result of an async operation — a Promise or Future is a placeholder for a value not yet available, enabling non-blocking code composition without nested callbacks.
3mo ago concurrency intermediate
Race Condition 🧠 4
A race condition occurs when the outcome of a program depends on the relative timing of concurrent operations — two threads reading and writing shared state without coordination.
3mo ago concurrency intermediate
Semaphore 🧠 4
A semaphore is a generalised mutex that allows N concurrent accesses — a counting semaphore with value N lets N threads proceed, blocking the (N+1)th.
3mo ago concurrency intermediate
✓ schema.org compliant