Learn IT with Shikha Blogs

  Camunda Parallel Gateway Explained (Fork, Join, and Deadlock Scenarios) Parallel gateways in Camunda are powerful—but also one of the most misunderstood BPMN elements . Many developers face issues like: Execution stuck at gateway Tokens not synchronizing Unexpected deadlocks In this guide, we’ll clearly explain: Fork (parallel split) Join (synchronization) Deadlock scenarios & fixes 🔹 1. What is a Parallel Gateway? A Parallel Gateway (AND Gateway) is used to: Split execution into multiple paths Synchronize multiple paths back into one 👉 It works with tokens , not conditions 🔹 2. Fork (Parallel Split) When execution reaches a fork: 👉 Camunda: Creates multiple tokens Executes all outgoing paths simultaneously Example: Send email Update database Call external API 👉 All run in parallel 🔹 3. Join (Synchronization) At join gateway: 👉 Camunda waits until: All incoming tokens arrive Then: Merges them into one Key Rule: 👉 Missing token = process stuck 🔹 4. Common Deadlock Sc...

  Introduction Lors de la conception de workflows BPMN avec des moteurs comme Camunda , un problème fréquent est que l'exécution du processus reste bloquée au niveau d'une passerelle parallèle (Parallel Gateway) . Le modèle BPMN peut sembler correct, mais l’instance du processus n’avance plus . La raison principale est la gestion des jetons (tokens) dans les passerelles parallèles. Une passerelle parallèle (AND Gateway) divise le processus en plusieurs chemins exécutés en parallèle et attend ensuite que tous les jetons arrivent avant de continuer. Si un seul jeton manque, l’exécution reste bloquée indéfiniment . Fonctionnement d'une Passerelle Parallèle 4 Une passerelle parallèle fonctionne de deux manières: 1️⃣ Division (Fork) Un jeton entrant est divisé en plusieurs jetons exécutés en parallèle. Exemple : Tâche A | Passerelle Parallèle / \ Tâche B Tâche C Les tâches B et C s'exécutent en même temps. 2️⃣ Synchronisation (Join) La passerelle attend tous...

 Introduction While designing BPMN workflows in engines like Camunda, one of the most common runtime issues developers encounters is process execution getting stuck at a Parallel Gateway . At first glance, everything may look correct in the model, but the process instance never moves forward. Understanding how tokens behave at a parallel gateway is the key to solving this problem. A Parallel Gateway (AND Gateway) splits the workflow into multiple parallel paths and synchronizes them later. The workflow continues only when all incoming sequence flows reach the gateway . If one token never arrives, the process waits indefinitely , causing the execution to appear stuck. BPMN Parallel Gateway Basics A parallel gateway works in two ways: 1️⃣ Split (Fork) One incoming token creates multiple parallel tokens. Example: Task A | Parallel Gateway / \ Task B Task C Both Task B and Task C execute simultaneously. 2️⃣ Join (Synchronization) A joining parallel gateway waits for tok...