Removed generic AOT documentation with a reference to the section in Spring Data Commons.
See spring-projects/spring-data-commons#3384
See #5078
Original pull request #5080
This chapter covers Spring Data's Ahead of Time (AOT) optimizations that build upon {spring-framework-docs}/core/aot.html[Spring's Ahead of Time Optimizations].
For a general explanation of what Ahead of Time (AoT) Optimizations Spring Data offers and how to enable them see
xref:{commons}@data-commons::page$aot.adoc[]
[[aot.hints]]
== Runtime Hints
Running an application as a native image requires additional information compared to a regular JVM runtime.
Spring Data contributes {spring-framework-docs}/core/aot.html#aot.hints[Runtime Hints] during AOT processing for native image usage.
These are in particular hints for:
* Auditing
* `ManagedTypes` to capture the outcome of class-path scans
* Repositories
** Reflection hints for entities, return types, and Spring Data annotations
** Repository fragments
** Querydsl `Q` classes
** Kotlin Coroutine support
* Web support (Jackson Hints for `PagedModel`)
[[aot.repositories]]
== Ahead of Time Repositories
AOT Repositories are an extension to AOT processing by pre-generating eligible query method implementations.
Query methods are opaque to developers regarding their underlying queries being executed in a query method call.
AOT repositories contribute query method implementations based on derived or annotated queries, updates or aggregations that are known at build-time.
This optimization moves query method processing from runtime to build-time, which can lead to a significant bootstrap performance improvement as query methods do not need to be analyzed reflectively upon each application start.
The resulting AOT repository fragment follows the naming scheme of `<Repository FQCN>Impl__Aot` and is placed in the same package as the repository interface.
You can find all queries in their MQL form for generated repository query methods.
[TIP]
====
`spring.aot.repositories.enabled` property needs to be set to `true` for repository fragment code generation.
====
[NOTE]
====
Consider AOT repository classes an internal optimization.
Do not use them directly in your code as generation and implementation details may change in future releases.
====
=== Running with AOT Repositories
AOT is a mandatory step to transform a Spring application to a native executable, so it is automatically enabled when running in this mode.
When AOT is enabled (either for native compilation or by setting `spring.aot.enabled=true`), AOT repositories are automatically enabled by default.
You can disable AOT repository generation entirely or only disable MongoDB AOT repositories:
* Set the `spring.aot.repositories.enabled=false` property to disable generated repositories for all Spring Data modules.
* Set the `spring.aot.mongodb.repositories.enabled=false` property to disable only MongoDB AOT repositories.
AOT repositories contribute configuration changes to the actual repository bean registration to register the generated repository fragment.
[NOTE]
====
When AOT optimizations are included, some decisions that have been taken at build-time are hard-coded in the application setup.
For instance, profiles that have been enabled at build-time are automatically enabled at runtime as well.
Also, the Spring Data module implementing a repository is fixed.
Changing the implementation requires AOT re-processing.
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=== Eligible Methods in Data MongoDB
AOT repositories filter methods that are eligible for AOT processing.
These are typically all query methods that are not backed by an xref:repositories/custom-implementations.adoc[implementation fragment].
Each module offers optimizations for a slightly different set of repository method.
With Spring Data MongoDb we generally support query methods that are not backed by an xref:repositories/custom-implementations.adoc[implementation fragment], and don't require, with a few limitations detailed below.
Jens Schauder
1 month ago