Code for retrieving pages in a random order from the database. If the bufferPoolFirst flag is set, buffer pool pages are retrieved first if possible. Includes a new system test ScanTest_Sunoo which tests the RandomizedPagesSeqScan.
RandomizedPagesSeqScan retrieves pages in a random order, and scans tuples within each page in a random order. If the bufferPoolFirst flag is set, then any unseen pages in the buffer pool will be retrieved first (choosing randomly within unseen pages in the buffer pool). This code passes the new system test ScanTest_Sunoo which tests the RandomizedPagesSeqScan.