Function TestCompactionFilePicking

db2_test.go:457–518

This test is for compaction file picking testing. We are creating db with two levels. We have 10 tables on level 3 and 3 tables on level 2. Tables on level 2 have overlap with 2, 4, 3 tables on level 3.

(t *testing.T)

// tables on level 3 and 3 tables on level 2. Tables on level 2 have overlap with 2, 4, 3 tables on
// level 3.
func TestCompactionFilePicking(t *testing.T) {
	dir, err := ioutil.TempDir("", "badger-test")
	require.NoError(t, err)
	defer removeDir(dir)

	db, err := Open(DefaultOptions(dir).WithTableLoadingMode(options.LoadToRAM))
	require.NoError(t, err, "error while opening db")
	defer func() {
		require.NoError(t, db.Close())
	}()

	l3 := db.lc.levels[3]
	for i := 1; i <= 10; i++ {
		// Each table has difference of 1 between smallest and largest key.
		tab := createTableWithRange(t, db, 2*i-1, 2*i)
		addToManifest(t, db, tab, 3)
		require.NoError(t, l3.replaceTables([]*table.Table{}, []*table.Table{tab}))
	}

	l2 := db.lc.levels[2]
	// First table has keys 1 and 4.
	tab := createTableWithRange(t, db, 1, 4)
	addToManifest(t, db, tab, 2)
	require.NoError(t, l2.replaceTables([]*table.Table{}, []*table.Table{tab}))

	// Second table has keys 5 and 12.
	tab = createTableWithRange(t, db, 5, 12)
	addToManifest(t, db, tab, 2)
	require.NoError(t, l2.replaceTables([]*table.Table{}, []*table.Table{tab}))

	// Third table has keys 13 and 18.
	tab = createTableWithRange(t, db, 13, 18)
	addToManifest(t, db, tab, 2)
	require.NoError(t, l2.replaceTables([]*table.Table{}, []*table.Table{tab}))

	cdef := &compactDef{
		thisLevel: db.lc.levels[2],
		nextLevel: db.lc.levels[3],
	}

	tables := db.lc.levels[2].tables
	db.lc.sortByOverlap(tables, cdef)

	var expKey [8]byte
	// First table should be with smallest and biggest keys as 1 and 4.
	binary.BigEndian.PutUint64(expKey[:], uint64(1))
	require.Equal(t, expKey[:], y.ParseKey(tables[0].Smallest()))
	binary.BigEndian.PutUint64(expKey[:], uint64(4))
	require.Equal(t, expKey[:], y.ParseKey(tables[0].Biggest()))

	// Second table should be with smallest and biggest keys as 13 and 18.
	binary.BigEndian.PutUint64(expKey[:], uint64(13))
	require.Equal(t, expKey[:], y.ParseKey(tables[1].Smallest()))
	binary.BigEndian.PutUint64(expKey[:], uint64(18))
	require.Equal(t, expKey[:], y.ParseKey(tables[1].Biggest()))

	// Third table should be with smallest and biggest keys as 5 and 12.
	binary.BigEndian.PutUint64(expKey[:], uint64(5))