Race condition

As explained in Think Distributed Systems

A concurrency situation in which at least one possible ordering of actions produces an incorrect result.

A race condition occurs when concurrent actions can be ordered in more than one way and at least one possible ordering produces an incorrect result. Correctness must be defined for the system’s intended outcome. section 1.8 section 2.2

Model each process as a sequence of atomic actions. The concurrent composition of two processes contains every possible interleaving of their actions; a race exists when some interleavings are incorrect. section 1.8

Two proposers and two acceptors

Two proposers broadcast (+2) and (×2) to acceptors initially holding 0. Because these operations are not commutative, applying them in different orders produces different results. The system therefore needs a consistent ordering so both acceptors reach the intended result. section 2.2

Figure 1.19 Reasoning about race conditions

Visualizes how alternative interleavings create correct or incorrect outcomes. section 1.8

The idea applies beyond threads updating one variable: it covers cooperative or preemptive multitasking, single- or multi-core machines, and multiple machines. Database correctness can require every interleaving to match an equivalent sequential order. section 1.8

How Think Distributed Systems covers it

How deep it goes

Defines races with atomic actions and all interleavings, then demonstrates ordering effects with noncommutative operations.

Examples

Uses atomic-action interleavings and proposers applying (+2) and (×2) to replicated acceptor state.

What it assumes

Assumes only processes, atomic actions, concurrency, and an explicitly chosen notion of correctness.

What you can do after

Evaluate concurrent executions by enumerating possible interleavings and checking whether their results meet the intended correctness condition.

How it connects

Connects race conditions to concurrency, parallelism, event ordering, logical time, commutativity, and serializability.

liveBookmanning.com

Read Think Distributed Systems on liveBook Get the book at manning.com

Also explained in

• 

  liveBookmanning.com
  C++ Concurrency in Action, Second EditionA race condition is a program condition in which behavior depends on the timing or ordering of operations performed by concurrent threads.
• 

  liveBookmanning.com
  Learn Concurrent Programming with GoA race condition is a concurrency defect in which program behavior depends on the timing or interleaving of unsynchronized operations.
• 

  liveBookmanning.com
  Learn Go with Pocket-Sized ProjectsA race condition is a correctness fault in which the result depends on the timing or interleaving of concurrent operations.
• 

  liveBookmanning.com
  Python Concurrency with asyncioA race condition is a concurrency bug in which the result or observable behavior depends on the timing or ordering of concurrent operations.
• 

  liveBookmanning.com
  Functional Design and Architecture: Examples in HaskellA race condition is a concurrency defect in which the outcome depends on an unexpected competition between threads for a shared resource.
• 

  liveBookmanning.com
  Java Persistence with Spring Data and Hibernate epubA race condition is a correctness problem in which the outcome depends on the timing or interleaving of concurrent operations.
• 

  liveBookmanning.com
  Grokking ConcurrencyA race condition is a concurrency bug in which the result depends on the timing or ordering of competing accesses to shared state or resources.
• 

  liveBookmanning.com
  Troubleshooting Java, Second EditionA race condition is a concurrency defect whose outcome depends on the timing or interleaving of operations.
• 

  liveBookmanning.com
  Advanced Algorithms and Data StructuresA race condition is a concurrency error in which program behavior depends on the timing or interleaving of operations.
• 

  liveBookmanning.com
  Functional Programming in Scala, Second EditionA race condition is a concurrency defect in which a result depends on the timing or interleaving of operations from multiple threads.
• 

  liveBookmanning.com
  C# Concurrency: Asynchronous and multithreaded programmingA race condition is a concurrent-execution defect in which program results depend on uncontrollable timing or interleaving between execution flows.
• 

  liveBookmanning.com
  Go by ExampleA race condition is a concurrency defect in which program behavior depends on the timing or ordering of operations accessing shared state.
• 

  liveBookmanning.com
  Modern C, Third EditionA race condition is an execution condition in which the result depends on the relative timing or interleaving of accesses by concurrent or asynchronously executing code.
• 

  liveBookmanning.com
  React Hooks in Action: With Suspense and Concurrent ModeA race condition is a correctness problem in which the result depends on the timing or ordering of concurrent operations.
• 

  liveBookmanning.com
  100 Go Mistakes and How to Avoid ThemA race condition is a concurrency defect in which program behavior depends on the timing or ordering of operations on shared state.
• 

  liveBookmanning.com
  Rust Servers, Services, and AppsA race condition is a concurrency defect in which the result depends on the timing or interleaving of operations.
• 

  liveBookmanning.com
  Object-Oriented Software Design in C++A race condition is a concurrency defect in which program behavior depends on the timing or ordering of simultaneous operations.
• 

  liveBookmanning.com
  Go in Practice, Second EditionA race condition is a correctness or timing defect caused by program behavior depending on the uncontrolled ordering of concurrent operations.
• 

  liveBookmanning.com
  F# in Action: A Revised Edition of Get Programming with F#A race condition is a concurrency defect in which a result depends on the timing or interleaving of competing operations.

Compare how 20 books explain race condition →

Related concepts

• lockingaddressed by · Locking is a synchronization technique that restricts concurrent access to shared resources or protected operations.
• data raceincludes · A data race is a concurrent access to shared data in which at least one access is a write and the accesses are not adequately synchronized.
• deadlockcontrasts with · A deadlock is a state in concurrent execution where two or more activities are indefinitely blocked by dependencies on resources, events, or progress that cannot become available.
• go testmeasured by · go test is the Go command that builds and runs tests for specified packages and can also execute benchmarks and report coverage.
• double-checked locking patternproduced by · Double-checked locking is a synchronization pattern that checks a shared pointer before and after acquiring a lock to avoid locking when initialization is complete.
• read-modify-write operationproduced by · An operation that reads a value from a location, computes or selects an update, and writes the resulting value back to that location.

This explainer was generated by Manning's knowledge graph from the text of Think Distributed Systems. The section links point to the parts of the book it draws on.