Function TestDB_MaxSizeNotExceeded

db_test.go:1546–1596

Ensure that a database cannot exceed its maximum size https://github.com/etcd-io/bbolt/issues/928

(t *testing.T)

// Ensure that a database cannot exceed its maximum size
// https://github.com/etcd-io/bbolt/issues/928
func TestDB_MaxSizeNotExceeded(t *testing.T) {
	testCases := []struct {
		name    string
		options bolt.Options
	}{
		{
			name: "Standard case",
			options: bolt.Options{
				MaxSize:  5 * 1024 * 1024, // 5 MiB
				PageSize: 4096,
			},
		},
		{
			name: "NoGrowSync",
			options: bolt.Options{
				MaxSize:    5 * 1024 * 1024, // 5 MiB
				PageSize:   4096,
				NoGrowSync: true,
			},
		},
	}

	for _, testCase := range testCases {
		t.Run(testCase.name, func(t *testing.T) {
			db := createFilledDB(t,
				&testCase.options,
				4*1024*1024, // adjust allocation jumps to 4 MiB
				2000,
			)

			path := db.Path()

			// The data file should be 4 MiB now (expanded once from zero).
			// It should have space for roughly one more entry with value size 100kB before trying to grow
			// This next insert should be too big
			err := fillDBWithKeys(db, 2, 100000)
			assert.ErrorIs(t, err, berrors.ErrMaxSizeReached)

			newSz := fileSize(path)
			require.Greater(t, newSz, int64(0), "unexpected new file size: %d", newSz)
			assert.LessOrEqual(t, newSz, int64(db.MaxSize), "The size of the data file should not exceed db.MaxSize")

			// Now try another write that shouldn't increase the max size
			err = fillDBWithKeys(db, 1, 1)
			assert.NoError(t, err, "Adding an entry after a failed, oversized write should not error")

			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
// The maximum size should only apply to growing the data file