Problem with compaction in SQLite

[kevin-dp]

Consider the following test:

test('should handle compaction with incomparable versions', () => {
  const version1 = v([1, 0])
  const version2 = v([1, 1])
  const version3 = v([2, 0])

  index.addValue('key1', version1, [10, 1])
  index.addValue('key1', version2, [10, 2])
  index.addValue('key1', version3, [10, -1])

  const frontier = new Antichain([v([1, 2]), v([2, 1])])
  index.compact(frontier) // should compact into [1, 1] -> [10, 3] and [2, 1] -> [10, -1]

  const result1 = index.reconstructAt('key1', v([1, 2]))
  expect(result1).toEqual([[10, 3]]) // fails with SQLite

  const result2 = index.reconstructAt('key1', v([2, 1]))
  expect(result2).toEqual([
    [10, 3],
    [10, -1],
  ])
})

The frontier indicates that we will only get updates >= [1, 2] or >= [2, 1].

• Since both [1, 0] and [1, 1] are < [1, 2] we can compact them into timestamp [1, 1] and take the sum of their multiplicities: [10, 3]
• We're not collapsing version [1, 1] with [2, 0] because they are incomparable and we could still receive updates at version [1, 2] for instance

According to the compaction algorithm, the compacted index should be:

'key1' -> [1, 1] -> [10, 3]
       -> [2, 1] -> [10, -1]

The test from above works in-memory but when executed against SQLite it fails because result1 is [] and thus expect(result1).toEqual([[10, 3]]) fails. Seems to indicate that there is a bug in SQLIndex.