Creating lucene index for oracle db - performance

Question

After exchanging my pc with a pc of identical hardware I reinstalled all software. A spring-boot app uses hibernate-search to create a lucene index on startup. The database (schema, indices,...) and data itself are identical to the old setup. Everything works fine (the app etc.) except now the creation of the index takes a lot longer. Before 75 documents have been created per second but now only 7. I compared the database parameters and they are the same. To make sure there is no hardware problem I used a disk performance tool to compare the pc's (the new one is a little faster).

What could be the cause of that huge decrease in performance and how could I solve it?

Answer 1

Forgot to update this post. The reason was too many eager fetching sets. When creating the index all tables are then left outer joined. A huge query was the result. Now changed all to lazy fetching and it runs just fine .

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