Batch size

Batch size measures how much work is bundled up in a change. Swarmia offers tools for evaluating pull request batch size by looking at the total number of changes in a single pull request.

Definition

Batch size is calculated by the lines of code changed (lines added + lines removed) in a given pull request.

Excluding auto-generated files

Repositories often contain generated files, which could be related to e.g. package dependencies. In order to provide an accurate view of the real changes, Swarmia automatically cleans up the total change count of some commonly used generated files.

Excluded file names:

Filename	Reason / Ecosystem
Cargo.toml	Manifest file for Cargo (Rust)
Cartfile.resolved	Carthage lockfile (iOS)
go.sum	Go dependency checksums
gradlew	Gradle wrapper script (Android)
gradlew.bat	Gradle wrapper script (Windows)
local.properties	Local Android config (machine-specific)
maven-metadata.xml	Maven metadata (Android/Java)
package-lock.json	NPM lockfile (JS/TS)
Package.resolved	SwiftPM lockfile (iOS)
pnpm-lock.yaml	pnpm lockfile (JS/TS)
Podfile.lock	CocoaPods lockfile (iOS)
yarn.lock	Yarn lockfile (JS/TS)

Excluded file extensions:

Extension	Reason / Ecosystem
betterer.results	Betterer test snapshots (JS/TS)
bundle	Java/Maven/OSGi bundle descriptors (generated)
classpath	Eclipse / Gradle classpath metadata
iml	IntelliJ / Android Studio module files
lock	Generic lockfiles (Gradle, NPM, CocoaPods, etc.)
log	Build/runtime/crash logs
mode1v3	Old Xcode user state
mode2v3	Old Xcode user state
lock.hcl	Terraform lockfile
pbxuser	Xcode project user settings
perspectivev3	Xcode UI layout state
snap	Snapshot test files (Jest, AVA, etc.)
suo	Visual Studio solution user options
svg	Scalable Vector Graphics
xcuserstate	Xcode workspace state

Excluded directories:

Directory	Reason / Ecosystem
.gradle	Gradle cache (Android)
.idea	IntelliJ/Android Studio project settings
.vscode	VS Code project settings
.xcuserdata	Xcode user-specific project data
.xcworkspace	Xcode workspace metadata (iOS/macOS)
app/build/generated	Android generated sources
app/build/intermediates	Android intermediate build outputs
node_modules	JavaScript dependencies (auto-generated)

Excluded top-level directories:

Directory	Reason / Ecosystem
build	Build output (Android)
DerivedData	Xcode build output (iOS/macOS)

Example

A pull request with 541 lines added and 215 lines removed (+541 -215) has a batch size of 756.

Why it matters

Splitting work into small increments is a great way to improve delivery.

Small pull requests are easier to plan, review, and deploy.

We suggest keeping the pull request size under 500 lines of code and paying attention to work that ends up spanning over 1,000+ lines.

Read more in Analyzing pull request batch size

How to use it

In Swarmia, the chart that shows the pull request size vs cycle time shows a set of pull requests in the selected time frame and charts them based on their individual cycle time and the total number of lines of code changed in the pull request. This chart allows you to see correlations between the size of a pull request and its cycle time.

Pull request size vs. cycle time plot in Swarmia

Seeing the distribution of larger batch sizes and higher cycle times can indicate that your team needs to focus on delivering smaller batch sizes. This change can improve not only your cycle time but also your quality.

See also Analyzing pull request batch size

Where to find it

You can find batch size metrics under Insights → Code → Batch size.