Get the page number of the first empty page in this BTreeFile. Creates a new page if none of the existing pages are empty. @param tid - the transaction id @param dirtypages - the list of dirty pages which should be updated with all new dirty pages @return the page number of the first empty page @t
(TransactionId tid, HashMap<PageId, Page> dirtypages)
source not stored for this graph (policy: none)