core/filtermaps: fix log index initialization (ethereum#31750)

This PR fixes an initialization bug that in some cases caused the map
renderer to leave the last, partially rendered map as is and resume
rendering from the next map. At initialization we check whether the
existing rendered maps are consistent with the current chain view and
revert them if necessary. Until now this happened through an ugly hacky
solution, a "limited" chain view that was supposed to trigger a rollback
of some maps in the renderer logic if necessary. This whole setup worked
under assumptions that just weren't true any more. As a result it always
tried to revert the last map but also it did not shorten the indexed
range, only set `headIndexed` to false which indicated to the renderer
logic that the last map is fully populated (which it wasn't).
Now an explicit rollback of any unusable (reorged) maps happens at
startup, which also means that no hacky chain view is necessary, as soon
as the new `FilterMaps` is returned, the indexed range and view are
consistent with each other.

In the first commit an extra check is also added to `writeFinishedMaps`
so that if there is ever again a bug that would result in a gapped index
then it will not break the db with writing the incomplete data. Instead
it will return an indexing error which causes the indexer to revert to
unindexed mode and print an error log instantly. Hopefully this will not
ever happen in the future, but in order to test this safeguard check I
manually triggered the bug with only the first commit enabled, which
caused an indexing error as expected. With the second commit added (the
actual fix) the same operation succeeded without any issues.

Note that the database version is also bumped in this PR in order to
enforce a full reindexing as any existing database might be potentially
broken.

Fixes ethereum#31729

Author: zsfelfoldi

core/filtermaps/chain_view.go

@@ -135,14 +135,6 @@ func (cv *ChainView) SharedRange(cv2 *ChainView) common.Range[uint64] {
 	return common.NewRange(0, sharedLen)
 }
 
-// limitedView returns a new chain view that is a truncated version of the parent view.
-func (cv *ChainView) limitedView(newHead uint64) *ChainView {
-	if newHead >= cv.headNumber {
-		return cv
-	}
-	return NewChainView(cv.chain, newHead, cv.BlockHash(newHead))
-}
-
 // equalViews returns true if the two chain views are equivalent.
 func equalViews(cv1, cv2 *ChainView) bool {
 	if cv1 == nil || cv2 == nil {

core/filtermaps/filtermaps.go

@@ -50,7 +50,7 @@ var (
 )
 
 const (
-	databaseVersion       = 1    // reindexed if database version does not match
+	databaseVersion       = 2    // reindexed if database version does not match
 	cachedLastBlocks      = 1000 // last block of map pointers
 	cachedLvPointers      = 1000 // first log value pointer of block pointers
 	cachedBaseRows        = 100  // groups of base layer filter row data
@@ -244,6 +244,8 @@ func NewFilterMaps(db ethdb.KeyValueStore, initView *ChainView, historyCutoff, f
 		disabledCh:        make(chan struct{}),
 		exportFileName:    config.ExportFileName,
 		Params:            params,
+		targetView:        initView,
+		indexedView:       initView,
 		indexedRange: filterMapsRange{
 			initialized:      initialized,
 			headIndexed:      rs.HeadIndexed,
@@ -265,16 +267,8 @@ func NewFilterMaps(db ethdb.KeyValueStore, initView *ChainView, historyCutoff, f
 		baseRowsCache:   lru.NewCache[uint64, [][]uint32](cachedBaseRows),
 		renderSnapshots: lru.NewCache[uint64, *renderedMap](cachedRenderSnapshots),
 	}
+	f.checkRevertRange() // revert maps that are inconsistent with the current chain view
 
-	// Set initial indexer target.
-	f.targetView = initView
-	if f.indexedRange.initialized {
-		f.indexedView = f.initChainView(f.targetView)
-		f.indexedRange.headIndexed = f.indexedRange.blocks.AfterLast() == f.indexedView.HeadNumber()+1
-		if !f.indexedRange.headIndexed {
-			f.indexedRange.headDelimiter = 0
-		}
-	}
 	if f.indexedRange.hasIndexedBlocks() {
 		log.Info("Initialized log indexer",
 			"first block", f.indexedRange.blocks.First(), "last block", f.indexedRange.blocks.Last(),
@@ -303,29 +297,40 @@ func (f *FilterMaps) Stop() {
 	f.closeWg.Wait()
 }
 
-// initChainView returns a chain view consistent with both the current target
-// view and the current state of the log index as found in the database, based
-// on the last block of stored maps.
-// Note that the returned view might be shorter than the existing index if
-// the latest maps are not consistent with targetView.
-func (f *FilterMaps) initChainView(chainView *ChainView) *ChainView {
-	mapIndex := f.indexedRange.maps.AfterLast()
-	for {
-		var ok bool
-		mapIndex, ok = f.lastMapBoundaryBefore(mapIndex)
-		if !ok {
-			break
+// checkRevertRange checks whether the existing index is consistent with the
+// current indexed view and reverts inconsistent maps if necessary.
+func (f *FilterMaps) checkRevertRange() {
+	if f.indexedRange.maps.Count() == 0 {
+		return
+	}
+	lastMap := f.indexedRange.maps.Last()
+	lastBlockNumber, lastBlockId, err := f.getLastBlockOfMap(lastMap)
+	if err != nil {
+		log.Error("Error initializing log index database; resetting log index", "error", err)
+		f.reset()
+		return
+	}
+	for lastBlockNumber > f.indexedView.HeadNumber() || f.indexedView.BlockId(lastBlockNumber) != lastBlockId {
+		// revert last map
+		if f.indexedRange.maps.Count() == 1 {
+			f.reset() // reset database if no rendered maps remained
+			return
 		}
-		lastBlockNumber, lastBlockId, err := f.getLastBlockOfMap(mapIndex)
+		lastMap--
+		newRange := f.indexedRange
+		newRange.maps.SetLast(lastMap)
+		lastBlockNumber, lastBlockId, err = f.getLastBlockOfMap(lastMap)
 		if err != nil {
-			log.Error("Could not initialize indexed chain view", "error", err)
-			break
-		}
-		if lastBlockNumber <= chainView.HeadNumber() && chainView.BlockId(lastBlockNumber) == lastBlockId {
-			return chainView.limitedView(lastBlockNumber)
+			log.Error("Error initializing log index database; resetting log index", "error", err)
+			f.reset()
+			return
 		}
+		newRange.blocks.SetAfterLast(lastBlockNumber) // lastBlockNumber is probably partially indexed
+		newRange.headIndexed = false
+		newRange.headDelimiter = 0
+		// only shorten range and leave map data; next head render will overwrite it
+		f.setRange(f.db, f.indexedView, newRange, false)
 	}
-	return chainView.limitedView(0)
 }
 
 // reset un-initializes the FilterMaps structure and removes all related data from

core/filtermaps/map_renderer.go

@@ -468,15 +468,25 @@ func (r *mapRenderer) writeFinishedMaps(pauseCb func() bool) error {
 			r.f.filterMapCache.Remove(mapIndex)
 		}
 	}
+	var blockNumber uint64
+	if r.finished.First() > 0 {
+		// in order to always ensure continuous block pointers, initialize
+		// blockNumber based on the last block of the previous map, then verify
+		// against the first block associated with each rendered map
+		lastBlock, _, err := r.f.getLastBlockOfMap(r.finished.First() - 1)
+		if err != nil {
+			return fmt.Errorf("failed to get last block of previous map %d: %v", r.finished.First()-1, err)
+		}
+		blockNumber = lastBlock + 1
+	}
 	// add or update block pointers
-	blockNumber := r.finishedMaps[r.finished.First()].firstBlock()
 	for mapIndex := range r.finished.Iter() {
 		renderedMap := r.finishedMaps[mapIndex]
-		r.f.storeLastBlockOfMap(batch, mapIndex, renderedMap.lastBlock, renderedMap.lastBlockId)
-		checkWriteCnt()
 		if blockNumber != renderedMap.firstBlock() {
-			panic("non-continuous block numbers")
+			return fmt.Errorf("non-continuous block numbers in rendered map %d (next expected: %d  first rendered: %d)", mapIndex, blockNumber, renderedMap.firstBlock())
 		}
+		r.f.storeLastBlockOfMap(batch, mapIndex, renderedMap.lastBlock, renderedMap.lastBlockId)
+		checkWriteCnt()
 		for _, lvPtr := range renderedMap.blockLvPtrs {
 			r.f.storeBlockLvPointer(batch, blockNumber, lvPtr)
 			checkWriteCnt()