Various approaches for processing a B+ tree data structure are described. In one approach, a first data record is deleted from the database as part of processing a first transaction. After removing the first data record, it is determined whether a first data page from which the record was removed should be merged. If the first data page is to be merged, merging of the data page is delayed until after the first transaction has been committed. After committing the first transaction, a nested transaction is initiated to merge of the first data page, and the nested transaction is committed after the data page has been merged.