Reset lower bounds if they're too different (#655)

src/main/kotlin/io/emeraldpay/dshackle/upstream/lowerbound/LowerBounds.kt

@@ -22,14 +22,19 @@ class LowerBounds(
     fun updateBound(newBound: LowerBoundData) {
         if (lowerBounds.containsKey(newBound.type)) {
             val lowerBoundCoeffs = lowerBounds[newBound.type]!!
+            val lastBound = lowerBoundCoeffs.getLastBound()
 
             // we add only bounds with different timestamps
-            if (newBound.timestamp != lowerBoundCoeffs.getLastBound().timestamp) {
+            if (newBound.timestamp != lastBound.timestamp) {
                 if (newBound.lowerBound == 1L) {
                     // this is the fully archival node, so there is no need to accumulate bounds and calculate the coeffs
                     lowerBoundCoeffs.updateCoeffs(0.0, 1.0)
                     lowerBoundCoeffs.clearBounds()
                     lowerBoundCoeffs.addBound(newBound)
+                } else if (newBound.lowerBound < lastBound.lowerBound || (newBound.lowerBound - lastBound.lowerBound) >= 100000) {
+                    lowerBoundCoeffs.updateCoeffs(averageSpeed, calculateB(newBound))
+                    lowerBoundCoeffs.clearBounds()
+                    lowerBoundCoeffs.addBound(newBound)
                 } else {
                     // accumulate up to MAX_BOUNDS and preserve this size
                     if (lowerBoundCoeffs.boundsSize() == MAX_BOUNDS) {

src/test/kotlin/io/emeraldpay/dshackle/upstream/lowerbound/LowerBoundsPredictionTest.kt

@@ -194,13 +194,78 @@ class LowerBoundsPredictionTest {
         lowerBounds.updateBound(lowerBound1)
 
         val predicted = lowerBounds.predictNextBound(LowerBoundType.STATE)
-        println(predicted)
 
         assertThat(predicted)
             .isLessThan(37996030)
             .isGreaterThan(37996020)
     }
 
+    @Test
+    fun `reset all bound if the next bound is less than the current one`() {
+        val lowerBounds = LowerBounds(Chain.ETHEREUM__MAINNET)
+        val lowerBoundState1 = LowerBoundData(15060L, 1010, LowerBoundType.STATE)
+        val lowerBoundState2 = LowerBoundData(100L, 1020, LowerBoundType.STATE)
+        val lowerBoundState3 = LowerBoundData(105L, 1030, LowerBoundType.STATE)
+        val lowerBoundState4 = LowerBoundData(108L, 1040, LowerBoundType.STATE)
+        val lowerBoundState5 = LowerBoundData(5L, 1050, LowerBoundType.STATE)
+
+        lowerBounds.updateBound(lowerBoundState1)
+        lowerBounds.updateBound(lowerBoundState2)
+
+        assertThat(lowerBounds.getAllBounds(LowerBoundType.STATE))
+            .hasSize(1)
+        assertThat(lowerBounds.getLastBound(LowerBoundType.STATE))
+            .isEqualTo(lowerBoundState2)
+
+        lowerBounds.updateBound(lowerBoundState3)
+        lowerBounds.updateBound(lowerBoundState4)
+
+        assertThat(lowerBounds.getAllBounds(LowerBoundType.STATE))
+            .hasSize(3)
+        assertThat(lowerBounds.getLastBound(LowerBoundType.STATE))
+            .isEqualTo(lowerBoundState4)
+
+        lowerBounds.updateBound(lowerBoundState5)
+
+        assertThat(lowerBounds.getAllBounds(LowerBoundType.STATE))
+            .hasSize(1)
+        assertThat(lowerBounds.getLastBound(LowerBoundType.STATE))
+            .isEqualTo(lowerBoundState5)
+    }
+
+    @Test
+    fun `reset all bound if the next bound is much bigger than the current one`() {
+        val lowerBounds = LowerBounds(Chain.ETHEREUM__MAINNET)
+        val lowerBoundState1 = LowerBoundData(15060L, 1010, LowerBoundType.STATE)
+        val lowerBoundState2 = LowerBoundData(130000L, 1020, LowerBoundType.STATE)
+        val lowerBoundState3 = LowerBoundData(131000L, 1030, LowerBoundType.STATE)
+        val lowerBoundState4 = LowerBoundData(132000L, 1040, LowerBoundType.STATE)
+        val lowerBoundState5 = LowerBoundData(232000L, 1050, LowerBoundType.STATE)
+
+        lowerBounds.updateBound(lowerBoundState1)
+        lowerBounds.updateBound(lowerBoundState2)
+
+        assertThat(lowerBounds.getAllBounds(LowerBoundType.STATE))
+            .hasSize(1)
+        assertThat(lowerBounds.getLastBound(LowerBoundType.STATE))
+            .isEqualTo(lowerBoundState2)
+
+        lowerBounds.updateBound(lowerBoundState3)
+        lowerBounds.updateBound(lowerBoundState4)
+
+        assertThat(lowerBounds.getAllBounds(LowerBoundType.STATE))
+            .hasSize(3)
+        assertThat(lowerBounds.getLastBound(LowerBoundType.STATE))
+            .isEqualTo(lowerBoundState4)
+
+        lowerBounds.updateBound(lowerBoundState5)
+
+        assertThat(lowerBounds.getAllBounds(LowerBoundType.STATE))
+            .hasSize(1)
+        assertThat(lowerBounds.getLastBound(LowerBoundType.STATE))
+            .isEqualTo(lowerBoundState5)
+    }
+
     @Test
     fun `update different bounds`() {
         val lowerBounds = LowerBounds(Chain.ETHEREUM__MAINNET)