@Interleaved(lazy=false) is still lazy for SqlSpannerQuery

[s13o]

There is one more place where @Interleaved(lazy=false) still not supported even after the merge of #2110. The method SqlSpannerQuery#executeReadSql will execute a raw SQL without injection of ARRAY (SELECT AS STRUCT ...) for Interleaved lists. But we can do it more or less safely in a method SpannerStatementQueryExecutor.applySortingPagingQueryOptions line 151 by replacing the

 new StringBuilder("SELECT * FROM (").append(sql).append(")"), (o) -> {

with something like

 new StringBuilder("SELECT *").append(<inject Interleaved here>).appenr(" FROM (").append(sql).append(")"), (o) -> {

I'm afraid that it caused a bug with @Query annotation now - @Interleaved(lazy=false) fields are not "proxied" anymore so they will be not loaded from the database, never, am I right?

[dmitry-s]

@Query annotation is intended to be used with custom projection queries. I don't think we want to modify a user provided query, because users might want to retrieve a limited set of fields for performance reasons.

@s13o could you clarify your use case? Is it possible to use name-based query method instead of @Query annotated one?

Thanks

[s13o]

1. We do modify the SQL provided by the @Query. Please, take a look on SqlSpannerQuery#executeReadSql line 245.
2. We can at least add a "fetchEagerInterleaved" option into the @Query. But, as for me, more natural will be to have skipInterleaved with default value true to skip fetching any Interleaved at all. But if skipnterleaved=false we should fetch them as expected from the definition of @Interleaved annotation.
3. Let's have a look on an entity like this

@Table(name = "Entity")
public class Entity {
    final UUID id;
    
    @Interleaved(lazy = true)
    private List<ApocProviderHist> lazyInterleaved;
    
    @Interleaved(lazy = false)
    private List<ApocProviderHist> eagerInterleaved;
}

I'm afraid today with @Query("select * from Entity") we will have a list of Entities with a correctly proxied lazyInterleaved fields but eagerInterleaved will always be empty. If it is true - It is not expected behavior and it could affect already implemented logics (it seems we should always "lazy" load any type of interleaved lists for backward compatibility even when skipnterleaved=true. In this case - why not to implement skipnterleaved=false ?)

[dmitry-s]

eagerInterleaved will be retrieved lazily in that case. You can see that here https://github.com/spring-cloud/spring-cloud-gcp/blob/9ce0a8094825c4cccc7433ab9aed4d942d594058/spring-cloud-gcp-data-spanner/src/main/java/org/springframework/cloud/gcp/data/spanner/core/SpannerTemplate.java#L588

If you want to give it a try, feel free to propose a PR. By default we would prefer to have the eager fetch disabled for @Query methods, because it is not obvious for users.

[s13o]

I'm not sure that I understood right why propertyValue == null means that the property was not loaded - what if the field of the bean has default value with an empty list? But I'll try.