MongoDB schema creation fails in AWS DocumentDB due to overly-long index name

[jpars]

Hello,

When using MongoRepository with AWS DocumentDB, MongoSchemaManager.ensureSchema() fails to create the compound index of commitMetadata.properties.key and commitMetadata.properties.value in jv_snapshots, because the autogenerated index name is too long. Both MongoDB and DocumentDB limit the fully-qualified index name (<db>.<col>.$<index>) to under 128 characters, but DocumentDB places the additional restriction that the unqualified index name (<col>.$<index>) must be under 64 characters. In this case, the complete autogenerated index name, jv_snapshots.$commitMetadata.properties.key_1_commitMetadata.properties.value_1, exceeds that limit. This issue also occurs in MongoDB, if using an unusually long DB name.

Perhaps MongoSchemaManager.ensureSchema() could explicitly set a shorter index name?

Thanks!

[bartoszwalacik]

ok, consider contributing a PR

[jpars]

PR is opened, however i just learned that this index isn't compatible with DocumentDB anyway, as it does not yet support compound indexes with multiple array fields. Amazon's docs seem to imply that this feature is coming, so maybe it's not worth addressing this issue until support is added. I can close the PR and perhaps follow up later if you prefer.

[bartoszwalacik]

PR is merged. The index on commitProperties is quite important but maybe we can start with DocumentDB experimental support, so without this index in the first place.

[bartoszwalacik]

released in 5.2.4 as experimental support
see https://javers.org/documentation/repository-configuration/