Function TestDB_MaxSizeExceededCanOpen

db_test.go:1601–1627

Ensure that opening a database that is beyond the maximum size succeeds The maximum size should only apply to growing the data file https://github.com/etcd-io/bbolt/issues/928

(t *testing.T)

// The maximum size should only apply to growing the data file
// https://github.com/etcd-io/bbolt/issues/928
func TestDB_MaxSizeExceededCanOpen(t *testing.T) {
	// Open a data file.
	db := createFilledDB(t, nil, 4*1024*1024, 2000) // adjust allocation jumps to 4 MiB, fill with 2000, 1KB keys
	path := db.Path()

	// Insert a reasonable amount of data below the max size.
	err := fillDBWithKeys(db, 2000, 1000)
	require.NoError(t, err, "fillDbWithKeys should succeed")

	err = db.Close()
	require.NoError(t, err, "Close should succeed")

	// The data file should be 4 MiB now (expanded once from zero).
	minimumSizeForTest := int64(1024 * 1024)
	newSz := fileSize(path)
	require.GreaterOrEqual(t, newSz, minimumSizeForTest, "unexpected new file size: %d. Expected at least %d", newSz, minimumSizeForTest)

	// Now try to re-open the database with an extremely small max size
	t.Logf("Reopening bbolt DB at: %s", path)
	db, err = btesting.OpenDBWithOption(t, path, &bolt.Options{
		MaxSize: 1,
	})
	assert.NoError(t, err, "Should be able to open database bigger than MaxSize")

	err = db.Close()
	require.NoError(t, err, "Closing the re-opened database should succeed")
}

// Ensure that opening a database that is beyond the maximum size succeeds,
// even when InitialMmapSize is above the limit (mmaps should not affect file size)