Christian Beikov ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HHH-15517 ( https://hibernate.atlassian.net/browse/HHH-15517?atlOrigin=eyJpIjoiMjZjY2... ) Re: "insert from select" With hibernate.default_schema Configured Doesn't Work With Hibernate 6 ( https://hibernate.atlassian.net/browse/HHH-15517?atlOrigin=eyJpIjoiMjZjY2... ) To answer your first question, I would need to see the entity model used for tab_data. I suspect that the entity is using a sequence generator with an allocation size bigger than 1 though, as that will make some intermediate steps necessary, because the sequence gives a value e.g. 1, but we have to generate the next N-1 values manually, as the next sequence call will give use N+1. Between the insert into the HTE table and the insert to the target table you should see some update statements happening against the HTE table, which assign proper id values based on the sequence generator. I don’t know what Hibernate 5 did before, but I suspect you are using {{@GeneratedValue(AUTO)}}which might have defaulted to using identity generation or SEQUENCE with an allocation size of 1 before. In Hibernate 6 the default for AUTO is SEQUENCE with an allocation size of 50 though. I’ll look into the schema prefixing issue as part of this Jira issue. I also created https://hibernate.atlassian.net/browse/HHH-15525 ( https://hibernate.atlassian.net/browse/HHH-15525 ) as an improvement, which will allow to control whether global temporary tables should be created/dropped as part of hbm2ddl or as part of the running transaction. ( https://hibernate.atlassian.net/browse/HHH-15517#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-15517#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100207- sha1:7afd384 )