Method testReadPage

test/simpledb/systemtest/BTreeScanTest.java:211–285

Test that scanning the BTree for predicates does not read all the pages

()

    
    /** Test that scanning the BTree for predicates does not read all the pages */
    @Test public void testReadPage() throws Exception {
    	// Create the table
        final int LEAF_PAGES = 30;
    	
    	List<List<Integer>> tuples = new ArrayList<>();
        int keyField = 0;
        BTreeFile f = BTreeUtility.createBTreeFile(2, LEAF_PAGES*502, null, tuples, keyField);
        tuples.sort(new TupleComparator(keyField));
        TupleDesc td = Utility.getTupleDesc(2);
        InstrumentedBTreeFile table = new InstrumentedBTreeFile(f.getFile(), keyField, td);
        Database.getCatalog().addTable(table, SystemTestUtil.getUUID());
        
        // EQUALS
        TransactionId tid = new TransactionId();
        List<List<Integer>> tuplesFiltered = new ArrayList<>();
        IndexPredicate ipred = new IndexPredicate(Op.EQUALS, new IntField(r.nextInt(LEAF_PAGES*502)));
        Iterator<List<Integer>> it = tuples.iterator();
        while(it.hasNext()) {
        	List<Integer> tup = it.next();
        	if(tup.get(keyField) == ((IntField) ipred.getField()).getValue()) {
        		tuplesFiltered.add(tup);
        	}
        }
        
        Database.resetBufferPool(BufferPool.DEFAULT_PAGES);
        table.readCount = 0;
        BTreeScan scan = new BTreeScan(tid, f.getId(), "table", ipred);
        SystemTestUtil.matchTuples(scan, tuplesFiltered);
        // root pointer page + root + leaf page (possibly 2 leaf pages)
        assertTrue(table.readCount == 3 || table.readCount == 4);
        
        // LESS_THAN
        tuplesFiltered.clear();
        ipred = new IndexPredicate(Op.LESS_THAN, new IntField(r.nextInt(LEAF_PAGES*502)));
        it = tuples.iterator();
        while(it.hasNext()) {
        	List<Integer> tup = it.next();
        	if(tup.get(keyField) < ((IntField) ipred.getField()).getValue()) {
        		tuplesFiltered.add(tup);
        	}
        }
        
        Database.resetBufferPool(BufferPool.DEFAULT_PAGES);
        table.readCount = 0;
        scan = new BTreeScan(tid, f.getId(), "table", ipred);
        SystemTestUtil.matchTuples(scan, tuplesFiltered);
        // root pointer page + root + leaf pages
        int leafPageCount = tuplesFiltered.size()/502;
        if(leafPageCount < LEAF_PAGES)
        	leafPageCount++; // +1 for next key locking
        assertEquals(leafPageCount + 2, table.readCount);
        
        // GREATER_THAN
        tuplesFiltered.clear();
        ipred = new IndexPredicate(Op.GREATER_THAN_OR_EQ, new IntField(r.nextInt(LEAF_PAGES*502)));
        it = tuples.iterator();
        while(it.hasNext()) {
        	List<Integer> tup = it.next();